学习笔记--Spring框架

Posted 2020-09-18

//概述

轻量级，一站式，开发框架

IoC，Inversion of Control，控制反转

DI，Dependency Injection，依赖注入

AOP，Aspect-Oriented Programming，面向切面编程：业务逻辑与非业务逻辑分离，如日志、安全...

IoC容器：

对象创建、装配

对象生命周期管理

上下文环境

//IoC容器

IoC = ApplicationContext  (org.springframework.context,  spring-context)

初始化

ApplicationContext context = new ClassPathXmlApplicationContext("application-context.xml");

或

ApplicationContext context = new FileSystemXmlApplicationContext("/home/user/conf/application-context.xml");

或在web.xml中

<context-param>

    <param-name>contextConfigLocation</param-name>

    <param-value>classpath:application-context.xml</param-value>

</context-param>

<listener>

    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>

</listener>

Bean定义

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"

    xmlns:p="http://www.springframework.org/schema/p"

    xsi:schemaLocation="http://www.springframework.org/schema/beans

    http://www.springframework.org/schema/beans/spring-beans.xsd

    http://www.springframework.org/schema/context

    http://www.springframework.org/schema/context/spring-context.xsd">

    <bean id="screwDriver" class="com.netease.course.ScrewDriver"></bean>

</beans>

Bean使用

//初始化容器

ApplicationContext context = new ClassPathXmlApplicationContext("application-context.xml");

//获取对象

ScrewDriver screwDriver = context.getBean("screwDriver", ScrewDriver.class);

//使用对象

screwDriver.use();

Bean作用域

singleton，单例

    <bean id="screwDriver" class="com.netease.course.ScrewDriver" scope="singleton"></bean>

默认为单例

prototype，每次引用创建一个实例

    <bean id="screwDriver" class="com.netease.course.ScrewDriver" scope="prototype"></bean>

request scope, requestBean

session scope, sessionBean

application scope, appBean

global scope

Bean生命周期回调

创建，申请资源

可以通过实现接口

public interface InitializingBean {

    void afterPropertiesSet() throws Exception;

}

或者直接在application-context.xml中配置

    <bean id="screwDriver" class="com.netease.course.ScrewDriver" init-method="init"></bean>

对应代码

public class ScrewDriver {

   public void init() {

        System.out.println("Init screwDriver");

   }

}

销毁

可以通过实现接口

public interface DisposableBean {

    void destroy() throws Exception;

}

或者直接在application-context.xml中配置

    <bean id="screwDriver" class="com.netease.course.ScrewDriver" destroy-method="cleanup"></bean>

对应代码

public class ScrewDriver {

   public void cleanup() {

        System.out.println("Cleanup screwDriver");

   }

}

关闭Bean

((ConfigurableApplicationContext) context).close();

依赖注入

构造函数，强依赖

Setter函数，可选依赖

配置bean的类的构造函数的参数

    <bean id="straightHeader" class="com.netease.course.StraightHeader">

        <constructor-arg value="red"></constructor-arg>

        <constructor-arg value="15"></constructor-arg>

    </bean>

或

    <bean id="straightHeader" class="com.netease.course.StraightHeader">

        <constructor-arg index="0" value="red"></constructor-arg>

        <constructor-arg index="1" value="15"></constructor-arg>

    </bean>

或

    <bean id="straightHeader" class="com.netease.course.StraightHeader">

        <constructor-arg type="java.lang.String" value="red"></constructor-arg>

        <constructor-arg type="int" value="15"></constructor-arg>

    </bean>

或

    <bean id="straightHeader" class="com.netease.course.StraightHeader">

        <constructor-arg name="color" value="red"></constructor-arg>

        <constructor-arg name="size" value="15"></constructor-arg>

    </bean>

需要传递集合类型的构造函数参数（如map）时

    <bean id="straightHeader" class="com.netease.course.StraightHeader">

        <constructor-arg>

            <map>

                <entry key="color" value="red"></entry>

                <entry key="size" value="15"></entry>

            </map>

        </constructor-arg>

        <constructor-arg name="size" value="15"></constructor-arg>

    </bean>

传入list时

    <bean id="straightHeader" class="com.netease.course.StraightHeader">

        <constructor-arg>

            <list>

                <value>red</value>

                <value>15</value>

            </list>

        </constructor-arg>

        <constructor-arg name="size" value="15"></constructor-arg>

    </bean>

传入Properties时

    <bean id="straightHeader" class="com.netease.course.StraightHeader">

        <constructor-arg>

            <props>

                <prop key="color">red</prop>

                <prop key="size">15</prop>

            </props>

        </constructor-arg>

        <constructor-arg name="size" value="15"></constructor-arg>

    </bean>

从外部倒入配置时

    <bean id="straightHeader" class="com.netease.course.StraightHeader">

        <constructor-arg name="color" value="${color}"></constructor-arg>

        <constructor-arg name="size" value="${size}"></constructor-arg>

    </bean>

    <bean id="headerProperties" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">

      <property name="location" value="classpath:header.properties" />

  </bean>

在一个bean中添加所依赖的bean

    <bean id="screwDriver" class="com.netease.course.ScrewDriver">

        <constructor-arg>

            <ref bean="straightHeader" />

        </constructor-arg>

    </bean>

通过Setter方法注入依赖

    <bean id="straightHeader" class="com.netease.course.StraightHeader">

        <property name="color" value="${color}"></property>

        <property name="size" value="${size}"></property>

    </bean>

自动装配

constructor是按byType方式注入

   <bean id="screwDriver" class="com.netease.course.ScrewDriver" autowire="constructor">

    </bean>

或

   <bean id="screwDriver" class="com.netease.course.ScrewDriver" autowire="byName">

    </bean>

或

   <bean id="screwDriver" class="com.netease.course.ScrewDriver" autowire="byType">

    </bean>

或

Annotation

@Component：定义Bean，或@Component("name")

@Value：properties注入

@Autowired & @Resource：自动装配依赖

@PostConstruct & @PreDestroy：生命周期回调

在xml中加入

   <context:component-scan base-package="com.netease.course" />

//AOP技术

AOP术语

Aspect：日志、安全等功能

Join point：函数执行或者属性访问

Advice：在某个函数执行点上要执行的切面功能

Pointcut：匹配横切目标函数的表达式

Advice类型

Before：函数执行之前

After returning：函数正常返回之后

After throwing：函数抛出异常之后

After finally：函数返回之后

Around：函数执行前后

Spring AOP

非完整AOP实现

整合AOP和与IoC

XML schema-based AOP

@AspectJ annotation-based AOP

@AspecsJ annotation-based AOP

aspectjweaver.jar

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xmlns:aop="http://www.springframework.org/schema/aop"

    xsi:schemaLocation="http://www.springframework.org/schema/beans

    http://www.springframework.org/schema/beans/spring-beans-2.0.xsd

    http://www.springframework.org/schema/aop

    http://www.springframework.org/schema/aop/spring-aop-2.0.xsd">

    

    <aop:aspectj-autoproxy />

   

</beans>

定义Aspect

   <bean id="loggingAspect" class="com.netease.course.LoggingAspect">

           <!-- configure properties of aspect here as normal -->

   </bean>

相应代码中类名前加入@Aspect

定义Pointcut

    @Pointcut("execution(* com.netease.course.Calculator.*(..))")

    private void arithmetic() {}

Pointcut表达式

designator(modifiers? return-type declaring-type? name(param) throws?)

designator: execution, within

modifiers: public, private

return-type: 返回类型，*

declaring-type: 包名，类名

name: 函数名，*

param: 参数列表，()无参，(..)任意参数

throws: 异常类型

可以组合

定义Advice

    @Before("com.netease.course.LoggingAspect.arithmetic()")

    public void doLog() {

      //

    }

或

    @Before("execution(* com.netease.course.Calculator.*(..))")

    public void doLog() {

        //

    }

或

    @AfterReturning("com.netease.course.LoggingAspect.arithmetic()")

    public void doLog() {

        //

    }

或

    @AfterThrowing("com.netease.course.LoggingAspect.arithmetic()")

    public void doLog() {

        //

    }

或

    @After("com.netease.course.LoggingAspect.arithmetic()")

    public void doLog() {

        //

    }

Advice参数

函数上下文信息

    @Before("com.netease.course.LoggingAspect.arithmetic()")

    public void doLog(JoinPoint jp) {

        System.out.println(jp.getSignature() + ", " + jp.getArgs());

    }

 或   

    @Around("com.netease.course.LoggingAspect.arithmetic()")

    public void doLog(ProceedingJoinPoint pjp) {

        System.out.println("start method: " + pjp.toString());

        Object retVal = pjp.proceed();

        System.out.println("stop method: " + pjp.toString());

    }

返回值

    @AfterReturning(pointcut="com.netease.course.LoggingAspect.arithmetic()"),

                    returning="retVal")

    public void doLog(Object retVal) {

        //

    }

异常

    @AfterThrowing(pointcut="com.netease.course.LoggingAspect.arithmetic()"),

                   throwing="ex")

    public void doLog(IllegalArgumentException ex) {

        //

    }

目标函数参数

    @Before("com.netease.course.LoggingAspect.arithmetic() && args(a, ..)")

    public void doLog(JoinPoint jp, int a) {

        //

    }

XML schema-based AOP

定义Aspect和PointCut

   <aop:config>

       <aop:aspect id="loggingAspect" ref="loggingBean">

           <aop:pointcut id="arithmetic" expression="execution(* com.netease.course.Calculator.*(..))" />

       </aop:aspect>

   </aop:config>

定义Advice

   <aop:config>

       <aop:aspect id="loggingAspect" ref="loggingBean">

           <aop:before pointcut-ref="arithmetic" method="doLog" />

       </aop:aspect>

   </aop:config>

或

   <aop:config>

       <aop:aspect id="loggingAspect" ref="loggingBean">

           <aop:before pointcut="execution(* com.netease.course.Calculator.*(..))" method="doLog" />

       </aop:aspect>

   </aop:config>

或

   <aop:config>

       <aop:aspect id="loggingAspect" ref="loggingBean">

           <aop:after-returning pointcut-ref="arithmetic" returning="retVal" method="doLog" />

       </aop:aspect>

   </aop:config>

或

   <aop:config>

       <aop:aspect id="loggingAspect" ref="loggingBean">

           <aop:after-throwing pointcut-ref="arithmetic" throwing="ex" method="doLog" />

       </aop:aspect>

   </aop:config>

或

       <aop:aspect id="loggingAspect" ref="loggingBean">

           <aop:around pointcut-ref="arithmetic" method="doLog" />

       </aop:aspect>

//数据访问

DAO，Data Access Object

数据访问相关接口

ORM，Object Relation Mapping

对象关系映射

DataSource (javax.sql)

DriverManagerDataSource (org.springframework.jdbc.datasource)

BasicDataSource (org.apache.commons.dbcp)

   <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">

       <property name="driverClassName" value="${jdbc.driverClassName}" />

       <property name="url" value="${jdbc.url}" />

       <property name="username" value="${jdbc.username}" />

       <property name="password" value="${jdbc.password}" />

   </bean>

   

   <context:property-placeholder location="db.properties" />

JdbcTemplate (org.springframework.jdbc.core)

设置JdbcTemplate的数据库配置信息

    private JdbcTemplate jdbcTemplate;

    

    @Autowired

    public void setDataSource(DataSource dataSource) {

        this.jdbcTemplate = new JdbcTemplate(dataSource);

    }

查询操作

        int rowCount = this.jdbcTemplate.queryForObject("select count(*) from user", Integer.class);

        int countOfNamedJoe = this.jdbcTemplate.queryForObject("select count(*) from user where first_name = ?", Integer.class, "Joe");

        String lastName = this.jdbcTemplate.queryForObject("select last_name from user where id = ?", new Object[]{1212L}, String.class);

更改操作

this.jdbcTemplate.update("insert into user (first_name, last_name) values (?, ?)", "Meimei", "Han");

或

this.jdbcTemplate.execute("create table user (id integer, first_name varchar(100), last_name varchar(100))");

对象匹配

        User user = this.jdbcTemplate.queryForObject("select last_name from user where id = ?",

                new Object[]{1212L},

                new RowMapper<User>() {

            public User mapRow(ResultSet rs, int rowNum) throws SQLException {

                User user = new User();

                user.setFirstName(rs.getString("first_name"));

                user.setLastName(rs.getString("last_name"));

                return user;

            }

        });

或

        List<User> users = this.jdbcTemplate.query("select last_name from user where id = ?",

                new Object[]{1212L},

                new RowMapper<User>() {

            public User mapRow(ResultSet rs, int rowNum) throws SQLException {

                User user = new User();

                user.setFirstName(rs.getString("first_name"));

                user.setLastName(rs.getString("last_name"));

                return user;

            }

        });

定义JdbcTemplate

public class JdbcExampleDao implements ExampleDao {

    private JdbcTemplate jdbcTemplate;

    public void setDataSource(DataSource dataSource) {

        this.jdbcTemplate = new JdbcTemplate(dataSource);

    }

    //...DAO接口实现

}

可以在xml中配置相应的bean

也可以用annotation的方法，如下：

@Repository

public class JdbcExampleDao implements ExampleDao {

    private JdbcTemplate jdbcTemplate;

    @Autowired

    public void setDataSource(DataSource dataSource) {

        this.jdbcTemplate = new JdbcTemplate(dataSource);

    }

    //...DAO接口实现

}

NamedParameterJdbcTemplate (org.springframework.jdbc.core)

    private NamedParameterJdbcTemplate namedParameterJdbcTemplate;

    

    @Autowired

    public void setDataSource(DataSource dataSource) {

        this.namedParameterJdbcTemplate= new NamedParameterJdbcTemplate (dataSource);

    }

public int countOfUserByFirstName(String firstName) {

    String sql = "select count(*) from usertest where first_name = :first_name";

    Map<String, String> namedParameters = Collections.singletonMap("first_name", firstName);

    return this.namedParameterJdbcTemplate.queryForObject(sql, namedParameters, Integer.class);

}

其他api接口

queryForObject(String sql, Map<String, ?> paramMap, RowMapper<T> rowMapper)

queryForObject(String sql, SqlParameterSource paramSource, Class<T> requiredType)

SqlParameterSource: MapSqlParameterSource, BeanPropertySqlParameterSource (org.springframework.jdbc.core.namedparam)

如：

public int countOfUserByFirstName(User user) {

    String sql = "select count(*) from usertest where first_name = :first_name";

    SqlParameterSource namedParameters = new BeanPropertySqlParameterSource(user);

    return this.namedParameterJdbcTemplate.queryForObject(sql, namedParameters, Integer.class);

}

异常处理

DataAccessException, "unchecked", 是一个基类 （org.springframework.dao）

//事务管理

spring事务管理

统一的事务编程模型，编程式事务及声明式事务（AOP）

public interface PlatformTransactionManager {

    TransactionStatus getTransaction(TransactionDefinition definition) throws TransactionException;

    void commit(TransactionStatus status) throws TransactionException;

    void rollback(TransactionStatus status) throws TransactionException;

}

事务管理器

PlatformTransactionManager (org.springframework.transaction)：

DataSourceTransactionManager (org.springframework.jdbc.datasource), JDBC

HibernateTransactionManager (org.springframework.orm.hibernate), Hibernate

TransactionDefinition

getName：事务名称

getIsolationLevel：隔离级别

getPropagationBehavior：传播行为

getTimeout：超时时间

isReadOnly：是否只读

TransactionStatus

isNewTransaction：是否是新事务

hasSavePoint：是否有savepoint（诊断，NESTED）

isCompleted：是否完成

isRollbackOnly：事务结果是否是rollback-only
setRollbackOnly：设置事务为rollback-only

隔离级别

ISOLATION_READ_UNCOMMITTED：读未提交

ISOLATION_READ_COMMITTED：读提交

ISOLATION_REPEATABLE_READ：重复读

ISOLATION_SERIALIZABLE：串行化

ISOLATION_DEFAULT：默认

传播行为

PROPAGATION_MANDATORY：必须在一个事务中运行，不存在则抛异常

PROPAGATION_NEVER：不应该在事务中运行，存在则抛异常

PROPAGATION_NOT_SUPPORTED：不应该在事务中运行，存在则挂起

PROPAGATION_SUPPORTS：不需要事务，有则在事务中执行

PROPAGATION_REQUIRED：必须在事务中执行，如果不存在，则启动新事务（内部事务会影响外部事务）

PROPAGATION_NESTED：必须在事务中执行，如果不存在，则启动新事务（事务之间互不影响）

PROPAGATION_REQUIRES_NEW：必须在新事务中执行，挂起当前事务（独立physical事务）

声明式事务

添加schema

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"

    xmlns:tx="http://www.springframework.org/schema/tx"

    xsi:schemaLocation="http://www.springframework.org/schema/beans

    http://www.springframework.org/schema/beans/spring-beans-2.0.xsd

    http://www.springframework.org/schema/tx

    http://www.springframework.org/schema/tx/spring-tx.xsd

    http://www.springframework.org/schema/aop

    http://www.springframework.org/schema/aop/spring-aop-2.0.xsd">

定义事务管理器

    <bean id="txManager"

        class="org.springframework.jdbc.datasource.DataSourceTransactionManager">

        <property name="dataSource" ref="dataSource" />

    </bean>

    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"

        destroy-method="close">

        <property name="driverClassName" value="${jdbc.driverClassName}" />

        <property name="url" value="${jdbc.url}" />

        <property name="username" value="${jdbc.username}" />

        <property name="password" value="${jdbc.password}" />

    </bean>

    <context:property-placeholder location="db.properties" />

定义事务Advice

    <tx:advice id="txAdvice" transaction-manager="txManager">

        <tx:attributes>

            <tx:method name="get*" read-only="true" />

            <tx:method name="*" />

        </tx:attributes>

    </tx:advice>

定义Pointcut

    <aop:config>

        <aop:pointcut id="daoOperation"

            expression="execution(* com.netease.course.AccountDao.*(..))" />

        <aop:advisor advice-ref="txAdvice" pointcut-ref="daoOperation" />

    </aop:config>

配置<tx:method />

name: 匹配的函数名称，支持*匹配

propagation：事务传播行为

isolation：事务隔离级别

timeout：超时

read-only：是否只读事务

rollback-for：触发回滚的异常，用逗号分隔

no-rollback-for：不触发回滚的异常

采用annotation方法

@Transactional

xml中添加

<tx:annotation-driven transaction-manager="txManager" />

相应代码

@Transactional(propagation=Propagation.REQUIRED, rollbackFor=Exception.class)

public boolean deleteClusterByClusterId(Sring clusterId) {

    // do work

}

@transactional

value：使用的TransactionManager

propagation：事务传播行为

isolation：事务隔离级别

timeout：超时

readOnly：是否只读

rollbackFor：触发回滚的异常类对象数组

rollbackForClassName：触发回滚的异常类名称数组

noRollbackFor：不触发回滚的异常类对象数组

noRollbackForClassName：不触发回滚的异常类名称数组

编程式事务

定义TransactionTemplate

public class SimpleService implements Service {

    private final TransactionTemplate transactionTemplate;

    public SimpleService(PlatformTransactionManager transactionManager) {

        this.transactionTemplate = new TransactionTemplate(transactionManager);

        this.transactionTemplate.setIsolationLevel(TransactionDefinition.ISOLATION_READ_UNCOMMITTED);

        this.transactionTemplate.setTimeout(30);

    }

}

使用TransactionTemplate

    public Object someMethod() {

        return transactionTemplate.execute(new TransactionCallback() {

            public Object doInTransaction(TransactionStatus status) {

                updateOperation1();

                return resultOfUpdateOperation2();

            }

        });

    }

或（不返回结果）

    public Object someMethodWithoutResult() {

        return transactionTemplate.execute(new TransactionCallbackWithoutResult() {

            protected void doInTransactionWithoutResult(TransactionStatus status) {

                updateOperation1();

                updateOperation2();

            }

        });

    }

或（设置为遇到异常时只能回滚）

    public Object someMethodWithoutResult() {

        return transactionTemplate

                .execute(new TransactionCallbackWithoutResult() {

                    protected void doInTransactionWithoutResult(

                            TransactionStatus status) {

                        try {

                            updateOperation1();

                            updateOperation2();

                        } catch (SomeBusinessException e) {

                            status.setRollbackOnly();

                        }

                    }

                });

    }

PlatformTransactionManager的实现

    DefaultTransactionDefinition def = new DefaultTransactionDefinition();

    def.setName("TxName");

    def.setPropagationBehavior(TransactionDefinition.PROPAGATION_REQUIRED);

    

    TransactionStatus status = txManager.getTransaction(def);

    try {

        //do something

    } catch (MyException ex) {

        txManager.rollback(status);

        throw ex;

    }

    txManager.commit(status);

整合MyBatis

SqlSessionFactory

添加mybatis-spring依赖

        <dependency>

            <groupId>org.mybatis</groupId>

            <artifactId>mybatis-spring</artifactId>

            <version>1.2.3</version>

        </dependency>

        <dependency>

            <groupId>org.mybatis</groupId>

            <artifactId>mybatis</artifactId>

            <version>3.3.0</version>

        </dependency>

定义SqlSessionFactoryBean

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">

        <property name="dataSource" ref="dataSource" />

        <property name="configLocation" value="classpath:sqlMapConfig.xml" />

        <property name="mapperLocations" value="classpath*:sample/config/mappers/**/*.xml" />

    </bean>

定义Mapper

public interface UserMapper {

    @Select("SELECT * FROM users WHERE id = #{userId}")

    User getUser(@Param("userId") String userId);

}

配置结果映射

    @Results({

        @Result(property="id", column="id"),

        @Result(property="firstName", column="first_name"),

        @Result(property="lastName", column="last_name")

    })

或者采用xml的方法，见Mybatis部分

定义Mapper Bean

    <bean id="userMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">

        <property name="mapperInterface" value="com.netease.course.UserMapper" />

        <property name="sqlSessionFactory" ref="sqlSessionFactory" />

    </bean>

或采用自动发现的机制

<beans xmlns="http://www.springframework.org/schema/beans"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xmlns:mybatis="http://mybatis.org/schema/mybatis-spring"

    xsi:schemaLocation="http://www.springframework.org/schema/beans

    http://www.springframework.org/schema/beans/spring-beans.xsd

    http://mybatis.org/schema/mybatis-spring

    http://mybatis.org/schema/mybatis-spring.xsd">

    

    <mybatis:scan base-package="com.netease.course" />

</beans>

当需要指定SqlSessionFactory时

    <mybatis:scan base-package="com.netease.course" factory-ref="sqlSessionFactory" />

或者

    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">

        <property name="basePackage" value="com.netease.course" />

        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory" />

    </bean>

使用Mapper

public class SomeService {

    @Autowired

    private UserMapper userMapper;

    public User getUser(String userId) {

        return userMapper.getUser(userId);

    }

}

定义SqlSessionTemplate使用

    <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">

        <constructor-arg index="0" ref="sqlSessionFactory" />

    </bean>

SqlSessionTemplate使用

public class UserDao {

    @Autowired

    private SqlSession sqlSession;

    public User getUser(String userId) {

        return (User) sqlSession.selectOne("com.netease.course.UserMapper.getUser", userId);

    }

}

//Web框架

DispatcherServlet

[servlet-name]-servlet.xml

HandlerMapping

Controllers

View解析相关

WebApplicationContext

ContextLoaderListener

<listener>

    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>

</listener>

<context-param>

    <param-name>contextConfigLocation</param-name>

    <param-value>/WEB-INF/applicationContext*.xml</param-value>

</context-param>

Servlet WebApplicationContext (containing controllers, view resolvers, and other web-related beans)

Root WebAppliacationContext (containing middler-tier services, datasources, etc.)

实现Controller

@Controller

@RequestMapping(value = "/hello")

public class HelloController {

    @RequestMapping(value = "/spring")

    public void spring(HttpServletResponse response) throws IOException {

        response.getWriter().write("Hello, Spring Web!!");

    }

}

定义Controller

自动发现

   <context:component-scan base-package="com.netease.course" />

@RequestMapping

name: 名称

value & path: 路径，如"/hello"

method: 请求方法，如"GET"

params: 请求参数

headers: 请求头

consumes: 请求的媒体类型，"Content-Type"

produces: 响应的媒体类型，"ACCEPT"

注入路径中的变量

    @RequestMapping(value="/users/{userId}")

    public String webMethod(@PathVariable String userId) {

        //do work

    }

或

    @RequestMapping(value="/users/{userId:[a-z]+}")

    public String webMethod(@PathVariable String userId) {

        //do work

    }

函数参数

HttpServletRequest / HttpServletResponse, HttpSession (Servlet API)

Reader / Writer

@PathVariable

@RequestParam

@RequestHeader

HttpEntity

@RequestBody

Map / Model / ModelMap

函数返回值

void

String: view名称，@ResponseBody

HttpEntity

View

Map

Model

ModelAndView

函数实现

    @RequestMapping(value="/spring/{user}")

    public void helloSpring(

            @PathVariable("user") String user,

            @RequestParam("msg") String msg,

            @RequestHeader("host") String host,

            HttpServletRequest request,

            Writer writer) throws IOException {

        writer.write("URI: " + request.getRequestURI());

        writer.write("Hello, " + user + ": " + msg + ", host=" + host);

    }

或

    @RequestMapping(value="/spring/login")

    public void login(@ModelAttribute User user, Writer writer) {

        //do work

    }

或

    @RequestMapping(value="/users/login")

    public String login(@RequestParam("name") String name, @RequestParam("password") String password, ModelMap map) {

        map.addAttribute("name", name);

        map.addAttribute("password", "******");

        return "user";

    }

ModelMap 
ModelMap的实例是由bboss mvc框架自动创建并作为控制器方法参数传入，用户无需自己创建。

Java代码  

1. public String xxxxmethod(String someparam,ModelMap model)   
2. {   
3.      //省略方法处理逻辑若干   
4.       //将数据放置到ModelMap对象model中,第二个参数可以是任何java类型   
5.       model.addAttribute("key",someparam);   
6.      ......   
7.      //返回跳转地址   
8.       return "path:handleok";   
9. }  

ModelAndView 
ModelAndView的实例是由用户手动创建的，这也是和ModelMap的一个区别。

Java代码  

1. public ModelAndView xxxxmethod(String someparam)   
2. {   
3.      //省略方法处理逻辑若干   
4.       //构建ModelAndView实例，并设置跳转地址   
5.       ModelAndView view = new ModelAndView("path:handleok");   
6.       //将数据放置到ModelAndView对象view中,第二个参数可以是任何java类型   
7.       view.addObject("key",someparam);   
8.      ......   
9.      //返回ModelAndView对象view   
10.       return view;   
11. }  

上传文件

定义bean

    <bean id="multipartResolver"

        class="org.springframework.web.multipart.commons.CommonsMultipartResolver">

        <property name="maxUploadSize" value="100000" />

    </bean>

相应代码

    @RequestMapping(value="/form", method=RequestMethod.POST)

    public String handleFormUpload(@RequestParam("file") MultipartFile file) {

        // save the file

    }

相应依赖

<dependency>
  <groupId>commons-fileupload</groupId>
  <artifactId>commons-fileupload</artifactId>
  <version>1.3.1</version>
</dependency>

HttpEntity

    @RequestMapping(value="/something")

    public ResponseEntity<String> handle(HttpEntity<byte[]> requestEntity) {

        String requestHeader = requestEntity.getHeaders().getFirst("MyRequestHeader");

        byte[] requestBody = requestEntity.getBody();

        // do something with requestHeader and requestBody

        HttpHeaders responseHeaders = new HttpHeaders();

        responseHeaders.set("MyResponseHeader", "MyValue");

        return new ResponseEntity<String>("hello spring", responseHeaders, HttpStatus.CREATED);

    }

@RequestBody & @ResponseBody

    @RequestMapping(value="/spring")

    @ResponseBody

    public String spring(@RequestBody String body) throws IOException {

        return "hello" + body;

    }

MessageConverter，返回Java对象的转化

RequestBody ---> Object: 参数

ResponseBody <--- Object: 返回值

xml文件配置

<beans xmlns="http://www.springframework.org/schema/beans"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"

    xmlns:mvc=“http://www.springframework.org/schema/mvc”

    xsi:schemaLocation="http://www.springframework.org/schema/beans

    http://www.springframework.org/schema/beans/spring-beans.xsd

    http://www.springframework.org/schema/mvc

    http://www.springframework.org/schema/mvc/spring-mvc.xsd

    http://www.springframework.org/schema/context

    http://www.springframework.org/schema/context/spring-context.xsd">

    <context:component-scan base-package="com.netease.course" />

    <mvc:annotation-driven />

</beans>

添加相应依赖，如JSON相关依赖

        <dependency>

            <groupId>com.fasterxml.jackson.core</groupId>

            <artifactId>jackson-core</artifactId>

            <version>2.6.4</version>

        </dependency>

        <dependency>

            <groupId>com.fasterxml.jackson.core</groupId>

            <artifactId>jackson-databind</artifactId>

            <version>2.6.4</version>

        </dependency>

View解析

String      名称

View

ModelAndView

Map

Model

ViewResolver (org.springframework.web.servlet)：

InternalResourceViewResolver (org.springframework.web.servlet.view)

FreeMarkerViewResolver (org.springframework.web.servlet.view.freemarker)

ContentNegotiatingViewResolver (org.springframework.web.servlet.view)

InternalResourceViewResovler

Servlet, JSP

bean定义

    <bean id="viewResolver"

        class="org.springframework.web.servlet.view.InternalResourceViewResolver">

        <property name="prefix" value="/WEB-INF/jsp/" />

        <property name="suffix" value=".jsp" />

    </bean>

resultView -------> /WEB-INF/jsp/resultView.jsp

FreeMarkerViewResolver 

FreeMarker

bean定义

    <bean id="freemarkerConfig"

        class="org.springframework.web.servlet.view.freemarker.FreeMarkerConfigurer">

        <property name="templateLoaderPath" value="/WEB-INF/freemarker/" />

    </bean>

    <bean id="viewResolver"

        class="org.springframework.web.servlet.view.freemarker.FreeMarkerViewResolver">

        <property name="cache" value="true" />

        <property name="prefix" value="" />

        <property name="suffix" value=".ftl" />

        <property name="contentType" value="text/html; charset=utf-8" />

    </bean>

ContentNegotiatingViewResolver

ViewResovler的组合

扩展名：user.json, user.xml, user.pdf

Accept头（media types)：application / json, application / xml

bean定义

    <bean

        class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">

        <property name="viewResolvers">

            <list>

                <bean id="viewResolver"

                    class="org.springframework.web.servlet.view.freemarker.FreeMarkerViewResolver">

                    <property name="cache" value="true" />

                    <property name="prefix" value="" />

                    <property name="suffix" value=".ftl" />

                </bean>

            </list>

        </property>

        <property name="defaultViews">

            <list>

                <bean

                    class="org.springframework.web.servlet.view.json.MappingJackson2JsonView" />

            </list>

        </property>

    </bean>

DefaultRequestToViewNameTranslator

example/admin/index.html ---------> admin/index

example/display.html -------> display

ContentNegotiatingViewResolver 根据路径后缀，选择不同视图

方法一：使用扩展名

http://localhost:8080/learn/user.xml 获取xml类型数据

http://localhost:8080/learn/user.json  获取json类型数据

http://localhost:8080/learn/user  使用默认view呈现，如jsp

方法二：使用http 请求头的Accept

GET /user HTTP/1.1

Accept:application/xml

GET /user HTTP/1.1

Accept:application/json

方法三：使用参数

http://localhost:8080/learn/user?format=xml

http://localhost:8080/learn/user?format=json

1.    <!-- 同一资源，多种表述 -->  
2.     <bean id="contentNegotiationManager" class="org.springframework.web.accept.ContentNegotiationManagerFactoryBean">  
3.         <!-- 是否启用扩展名支持，默认为true -->  
4.         <property name="favorPathExtenion" value="true" />  
5.         <!-- 是否启用参数支持，默认为true -->  
6.         <property name="favorParameter" value="false" />  
7.         <!-- 是否忽略掉accept header,默认为false -->  
8.         <property name="ignoreAcceptHeader" value="true" />  
9.           
10.         <!-- 扩展名到mimeType的映射 -->  
11.         <property name="mediaTypes">  
12.             <map>  
13.                 <!-- 例如：/user.json 中的 .json 会映射到 application/json -->  
14.                 <entry key="json" value="application/json" />  
15.                 <entry key="xml" value="application/xml" />          
16.             </map>  
17.         </property>  
18.           
19.         <!-- 如果所有mediaType都没匹配上，就使用defaultContentType -->  
20.         <property name="defaultContentType" value="text/html"/>  
21.     </bean>  
22.       
23.     <bean class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">  
24.         <!-- 解析器的执行顺序 -->  
25.         <property name="order" value="1" />  
26.         <property name="contentNegotiationManager" ref="contentNegotiationManager" />  
27.           
28.         <property name="defaultViews">  
29.             <list>  
30.                 <bean class="org.springframework.web.servlet.view.json.MappingJackson2JsonView"></bean>  
31.                 <bean class="org.springframework.web.servlet.view.xml.MarshallingView">  
32.                     <constructor-arg>  
33.                         <bean class="org.springframework.oxm.jaxb.Jaxb2Marshaller">  
34.                             <property name="classesToBeBound">  
35.                                 <list>  
36.                                     <value>com.learn.model.User</value>  
37.                                 </list>  
38.                             </property>  
39.                         </bean>  
40.                     </constructor-arg>  
41.                 </bean>  
42.             </list>  
43.         </property>  
44.           
45.     </bean>  
46.     <!-- 上面没匹配到则会使用这个视图解析器 ,解析为jsp  -->  
47.     <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">  
48.         <property name="order" value="2" />  
49.         <property name="prefix" value="/" />   
50.         <property name="suffix" value=".jsp"/>  
51.     </bean>  
    
    来源： http://blog.csdn.net/littleskey/article/details/53392283

Controller中可以用RequestMapping匹配多个路径后缀

    @RequestMapping(value = {"/users", "/users.html", "/users.json"})

    public String getUsersInfo(ModelMap map) {

        List<User> users = userServiceImp.getUsers();

        map.addAttribute("users", users);

        return "users";

    }

FreeMarker

模板引擎

数据模型

对象：hashes

基本类型：scalars

注释

<#-- 这是注释 -->

插值：表达式

${animal.name}

直接指定值：

    字符串，如“Zoo”, ‘Zoo‘

    数字，如123.45

    布尔值，如true，false

    序列，如["zoo", "bar", 123]

    值域，如0..9，0..<10

    哈希表，如{"name":"green mouse", "price":150}

检索变量：

    顶层变量：user

    哈希表数据：user.name, user["name"]

    列表数据：products[5]

连接操作：

    users + "guest"

    passwords + "joe":"secret123"

算术操作

逻辑操作

比较操作

FTL标签：指令

开始标签：<#directivename parameters>

结束标签：</#directivename>

if指令

    <#if user=="Big Joe">, our beloved leader</#if>

list指令

    <#list animals as animal>

      <tr><td>${animal.name}<td>${animal.price} Euros

    </#list>

include指令

    <#include "/copyright_footer.html">

使用

创建配置

    Configuration cfg = new Configuration(Configuration.VERSION_2_3_0);

    cfg.setDirectoryForTemplateLoading(new File("/where/you/store/templates"));

    cfg.setDefaultEncoding("UTF-8");

    cfg.setTemplateExceptionHandler(TemplateExceptionHandler.RETHROW_HANDLER);

定义模板

定义数据模型

如

    Map<String, Object> root = new HashMap<>();

    root.put("user", "Big Joe");

    Map<String, Object> latestProduct = new HashMap<>();

    root.put("latestProduct", latestProduct);

    latestProduct.put("url", "products/greenmouse.html");

    latestProduct.put("name", "greenmouse");

添加依赖

      <dependency>

          <groupId>org.freemarker</groupId>

          <artifactId>freemarker</artifactId>

          <version>2.3.23</version>

      </dependency>

输出结果

        Template ftl = cfg.getTemplate("user.ftl");

        Writer outWriter = new OutputStreamWriter(System.out);

        ftl.process(root, outWriter);

工程模板

一般java目录

com.netease.course.dao

com.netease.course.meta

com.netease.course.service

com.netease.course.service.impl

com.netease.course.utils

com.netease.course.web.controller

com.netease.course.web.filter