SpringBoot+MyBatis+Mysql 详细示例
Posted 阿叮339
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SpringBoot与MyBatis整合,底层数据库为mysql的使用示例
项目下载链接:https://github.com/DFX339/bootdemo.git
新建maven项目,web项目,项目名为 bootdemo
项目结构目录如下:还有个pom.xml文件没有在截图里面
项目需要编写的文件主要有:
项目启动类: Application.java ServletInitializer.java
前端控制器类:UserController.java
业务层的接口与实现类:UserIservice.java UserService.java
Mybatis的接口: UserMapper.java
接口对应的mapper文件:UserMapper.xml
实体类:User.java
maven项目的配置文件: pom.xml
(1)编写实体类 User.java
package smm.springboot_ftl.bean; /** * User实体类 * @author Administrator * */ public class User { private int id; private String username; private String password; private int age; public User(){} public int getId() { return id; } public void setId(int id) { this.id = id; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } }
(2)登录mysql数据库,新建数据库 springboot_mybatis(数据库名)
新建表 user(表名),表的字段如图所示
(3)编写持久层接口: UserMapper.java (定义操作数据库的方法) 这里切记要用@Mapper注解标识
package smm.springboot_ftl.mapper; import org.apache.ibatis.annotations.Mapper; import smm.springboot_ftl.bean.User; @Mapper public interface UserMapper { public void insert(User user); public void update(User user); public void delete(int id); public User find(int id); }
(4)编写持久层接口对应的mapper.xml文件: UserMapper.xml (编写增删改查对应的sql语句)
存储位置: src/main/resources/mapper
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <!-- 指定工作空间,要与接口名相同,源代码没有去看,猜测应该是通过"这里的namespace.下边方法的id"来定位方法的 --> <mapper namespace="smm.springboot_ftl.mapper.UserMapper"> <!-- insert user --> <insert id = "insert" parameterType="smm.springboot_ftl.bean.User"> INSERT INTO USER(ID,USERNAME,PASSWORD,AGE) VALUES(#{id},#{username},#{password},#{age}); </insert> <!-- update user --> <update id="update" parameterType="smm.springboot_ftl.bean.User"> UPDATE USER SET USERNAME=#{username} , PASSWORD=#{password} , AGE = #{age} WHERE ID=#{id} </update> <!-- find user --> <select id="find" parameterType="int" resultType="smm.springboot_ftl.bean.User"> SELECT ID,USERNAME,PASSWORD,AGE FROM USER WHERE ID=#{0} </select> <!-- delete user --> <delete id="delete" parameterType="int"> DELETE FROM USER WHERE ID=#{0} </delete> </mapper>
(5)编写业务层接口: UserIService.java
package smm.springboot_ftl.service; import org.springframework.stereotype.Component; import smm.springboot_ftl.bean.User; public interface UserIService { public void insert(User user);
public void update(User user) ;
public User find(int id);
public void delete(int id);
}
(6)编写业务层接口的实现类:UserService.java (切记要使用@Service("userService")类标识类,表示这是service)
@ComponentScan({"ssm.springboot_ftl.mapper"}):是为了找到对应的UserMapper对象
package smm.springboot_ftl.service; import javax.annotation.Resource; import org.springframework.context.annotation.ComponentScan; import org.springframework.stereotype.Component; import org.springframework.stereotype.Service; import smm.springboot_ftl.bean.User; import smm.springboot_ftl.mapper.UserMapper; @ComponentScan({"ssm.springboot_ftl.mapper"}) @Service("userService") public class UserService implements UserIService{ @Resource private UserMapper userMapper; @Override public void insert(User user) { userMapper.insert(user); } public void update(User user) { userMapper.update(user); } public User find(int id) { return userMapper.find(id); } public void delete(int id){ userMapper.delete(id); } }
(7)编写前端控制器类: UserController.java
@RestController 标识这个类,返回的结果为Json字符串。
@RestController注解,相当于@Controller+@ResponseBody两个注解的结合,返回json数据不需要在方法前面加@ResponseBody注解了,但使用@RestController这个注解,就不能返回jsp,html页面,视图解析器无法解析jsp,html页面
如果需要返回数据到jsp或者html页面,则使用@Controller注解。这里推荐使用@Controller注解,因为需要直接返回数据的时候可以增加@ResponseBody注解
@ComponentScan({"smm.springboot_ftl.service"}) :标识业务层的类,用来找到业务层对象,smm.springboot_ftl.service是业务类的路径
@MapperScan("smm.springboot_ftl.mapper") :标识持久层mapper接口,用来找到mapper对象, smm.springboot_ftl.mapper是接口的路径
这三个注解都不能少!!! 少了SpringBoot就无法正常启动了!!
package smm.springboot_ftl.action; import java.util.Map; import javax.annotation.Resource; import org.mybatis.spring.annotation.MapperScan; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.EnableAutoConfiguration; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.context.annotation.ComponentScan; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.bind.annotation.RestController; import org.springframework.web.servlet.ModelAndView; import smm.springboot_ftl.bean.User; import smm.springboot_ftl.service.UserService; /** * 在定义一个Rest接口时,我们通常会使用GET,POST,PUT,DELETE几种方式来完成我们所需要进行CRUD的一些操作, * 我们在这里罗列和教大家在实际开发中的使用,一些基本概念我们就不再赘述,例如使用POST的优缺点,可使用参数的大小限制等地: GET:一般用于查询数据,不办函数据的更新以及插入操作。由于明文传输的关系,我们一般用来获取一些无关用户的信息。 POST:一般用于数据的插入操作,也是使用最多的传输方式,但是在H5调用时会有跨域的问题,一般使用JSONP来解决。 PUT:我们使用PUT方式来对数据进行更新操作。 DELETE:用于数据删除,注意在数据库内是逻辑删除(改变数据状态,用户不再查询得到,但还保留在数据库内)还是物理删除(真删了)。 * @author Administrator * */ @RestController @ComponentScan({"smm.springboot_ftl.service"}) @MapperScan("smm.springboot_ftl.mapper") public class UserController { @Resource private UserService userService; @RequestMapping("/say") public String say(){ return "springboot-a"+userService; } @RequestMapping("/find") public String find(){ User user = userService.find(18); ModelAndView mav = new ModelAndView(); mav.addObject("user","sadf"); return "HelloWord"+"fasdf--"+user.getUsername()+"--"+user.getPassword(); } @RequestMapping("/ajax") public String find1(){ return "[\'\'message\':\'123dfx\']"; } // public static void main(String[] args){ // SpringApplication.run(UserController.class,args); // } }
(8)ServletInitializer.java 这个类的主要内容如下:
package smm.springboot_ftl; import org.springframework.boot.builder.SpringApplicationBuilder; import org.springframework.boot.web.support.SpringBootServletInitializer; public class ServletInitializer extends SpringBootServletInitializer { @Override protected SpringApplicationBuilder configure(SpringApplicationBuilder application) { return application.sources(Application.class); } }
(9)SpringBoot的配置文件: application.properties 文件内容如下:
存储位置: src/main/resources
server.context-path : 配置访问该项目的项目路径,不配置时默认为 / ,配置后必须加上项目名才能访问项目
server.context-path=/HelloWorld spring.datasource.driver-class-name =com.mysql.jdbc.Driver spring.datasource.url =jdbc:mysql://localhost:3306/springboot_mybatis spring.datasource.username =root spring.datasource.password =root mybatis.typeAliasesPackage=smm.springboot_ftl.bean mybatis.mapperLocations=classpath:/mapper/UserMapper.xml ## Freemarker \\u914D\\u7F6E ## \\u6587\\u4EF6\\u914D\\u7F6E\\u8DEF\\u5F84 spring.freemarker.template-loader-path=classpath:/templates/ spring.freemarker.cache=false spring.freemarker.charset=UTF-8 spring.freemarker.check-template-location=true spring.freemarker.content-type=text/html spring.freemarker.expose-request-attributes=true spring.freemarker.expose-session-attributes=true spring.freemarker.request-context-attribute=request spring.freemarker.suffix=.ftl
(10)配置maven项目的配置文件,pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>smm</groupId> <artifactId>bootdemo</artifactId> <packaging>war</packaging> <version>0.0.1-SNAPSHOT</version> <name>bootdemo Maven Webapp</name> <url>http://maven.apache.org</url> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.5.6.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <build> <finalName>bootdemo</finalName> <plugins> <plugin> <inherited>true</inherited> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <version>3.5.1</version> <configuration> <source>${compiler.source}</source> <target>${compiler.target}</target> <encoding>${project.build.sourceEncoding}</encoding> <compilerArguments> <extdirs>${project.basedir}/src/main/webapp/WEB-INF/lib</extdirs> </compilerArguments> </configuration> </plugin> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <compiler.source>1.7</compiler.source> <compiler.target>1.7</compiler.target> <!-- servlet/jsp/EL (2.4/2.0/?)(2.5/2.1/2.1),(3.0/2.2/2.2),(3.1/2.3/3.0) --> <servlet.version>3.1.0</servlet.version> <jsp.version>2.3.1</jsp.version> <jstl.version>1.2</jstl.version> <junit.version>4.12</junit.version> </properties> <dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>${junit.version}</version> <scope>test</scope> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>javax.servlet-api</artifactId> <version>${servlet.version}</version> <scope>provided</scope> </dependency> <dependency> <groupId>javax.servlet.jsp</groupId> <artifactId>javax.servlet.jsp-api</artifactId> <version>${jsp.version}</version> <scope>provided</scope> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>jstl</artifactId> <version>${jstl.version}</version> </dependency> <dependency> <groupId>org.objenesis</groupId> <artifactId>objenesis</artifactId> <version>1.2</version> </dependency> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>1.2.0</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-tomcat</artifactId> <scope>provided</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-configuration-processor</artifactId> <optional>true</optional> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.6</version> <scope>runtime</scope> </dependency> <!-- freemarker jar包导入 --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-freemarker</artifactId> </dependency> </dependencies> </project>
(11)启动项目,访问项目。
进入 Application.java
右击 --》 Run As --》 Java Application
启动成功后,在浏览器通过URL访问: http://当前ip:8080/server.context-path指定的值 /RequestMapping对应的值
例如: http://127.0.0.1:8080/HelloWorld/find
访问结果如图所示:(注意,这里自己要往数据库中插入一条数据,id为UserController类中find方法对应的id)
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