Mybatis学习过程记录
Posted wangweizu99
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一、Mybatis
1、mybatis-config.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<!-- 外部引入db-->
<properties resource="db.properties"/>
<settings>
<!-- 配置日志文件-->
<!-- <setting name="logImpl" value="STDOUT_LOGGING"/>-->
<setting name="logImpl" value="log4j"/>
<!-- 开启A_NAME==>aName-->
<setting name="mapUnderscoreToCamelCase" valie="true"
</settings>
<!-- 减少类型-->
<typeAliases>
<typeAlias type="com.wang.pojo.User" alias="User"/>
</typeAliases>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="$driver"/>
<property name="url" value="$url"/>
<property name="username" value="$username"/>
<property name="password" value="$password"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="com/wang/dao/UserMapper.xml"/>
</mappers>
</configuration>
2、Mapper.xml
<?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">
<mapper namespace="com.wang.dao.UserDao">
<select id="getUserList" resultType="User">
select * from mybatis.user
</select>
</mapper>
3、db.properties
driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/mybatis
username=root
password=123456
4、MybatisUtils工具类
package com.wang.utils;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import java.io.IOException;
import java.io.InputStream;
public class MybatisUtils
private static SqlSessionFactory sqlSessionFactory;
static
InputStream inputStream = null;
try
String resource = "mybatis-config.xml";
inputStream = Resources.getResourceAsStream(resource);
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
catch (IOException e)
e.printStackTrace();
public static SqlSession getsqlsession()
return sqlSessionFactory.openSession();
5、多对一AND多对一：
在Mapper.xml中配置
- association 对象 多对一
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- collection 集合 一对多
- [外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-4d3XQiVc-1623762886966)(C:\\Users\\HP\\AppData\\Roaming\\Typora\\typora-user-images\\image-20210614220615814.png)]
从用参数解释：
- javaType java类型
- ofType 泛型约束类型
6、使用注解开发
-
可在接口中使用注解进行开发，省去Mapper.xml
-
@Select("select * from mybatis.User") List<User> getUserList(); -
在mybatis-config.xml中配置 <mappers> <mapper class="com.wang.Dao.UserMapper" </mappers>
-
7、自定义缓存：ehcache
8、mybatis 其他工具
- mybatis Hepler：https://pagehelper.github.io/
二、MAVEN资源导出错误解决
<build>
<resources>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>true</filtering>
</resource>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>true</filtering>
</resource>
</resources>
</build>
三、常用依赖导入
<!--导入依赖-->
<dependencies>
<!-- mysql-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.49</version>
</dependency>
<!-- mybatis-->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.2</version>
</dependency>
<!-- junit-->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.13</version>
</dependency>
<!-- lombok-->
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.20</version>
</dependency>
<!-- servlet and jsp-->
<dependency>
<groupId>org.mortbay.jetty</groupId>
<artifactId>servlet-api-2.5</artifactId>
<version>6.1.7</version>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>jsp-api</artifactId>
<version>2.1</version>
</dependency>
<!-- standard-->
<dependency>
<groupId>org.apache.karaf.assemblies.features</groupId>
<artifactId>standard</artifactId>
<version>2.4.4</version>
</dependency>
<dependency>
<groupId>taglibs</groupId>
<artifactId>standard</artifactId>
<version>1.1.2</version>
</dependency>
<!-- jstl-->
<dependency>
<groupId>javax.servlet.jsp.jstl</groupId>
<artifactId>jstl-api</artifactId>
<version>1.2</version>
</dependency>
<dependency>
<groupId>org.glassfish.web</groupId>
<artifactId>jstl-impl</artifactId>
<version>1.2</version>
</dependency>
<!-- fastjson-->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.76</version>
</dependency>
<!--Log4j-->
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
</dependencies>
四、LOG4J
1、log4j.properties 配置文件
# priority :debug<info<warn<error
#you cannot specify every priority with different file for log4j
log4j.rootLogger=debug,stdout,info,debug,warn,error
#console
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern= [%dyyyy-MM-dd HH:mm:ss a]:%p %l%m%n
#info log
log4j.logger.info=info
log4j.appender.info=org.apache.log4j.DailyRollingFileAppender
log4j.appender.info.DatePattern='_'yyyy-MM-dd'.log'
log4j.appender.info.File=./src/com/hp/log/info.log
log4j.appender.info.Append=true
log4j.appender.info.Threshold=INFO
log4j.appender.info.layout=org.apache.log4j.PatternLayout
log4j.appender.info.layout.ConversionPattern=%dyyyy-MM-dd HH:mm:ss a [Thread: %t][ Class:%c >> Method: %l ]%n%p:%m%n
#debug log
log4j.logger.debug=debug
log4j.appender.debug=org.apache.log4j.DailyRollingFileAppender
log4j.appender.debug.DatePattern='_'yyyy-MM-dd'.log'
log4j.appender.debug.File=./src/com/hp/log/debug.log
log4j.appender.debug.Append=true
log4j.appender.debug.Threshold=DEBUG
log4j.appender.debug.layout=org.apache.log4j.PatternLayout
log4j.appender.debug.layout.ConversionPattern=%dyyyy-MM-dd HH:mm:ss a [Thread: %t][ Class:%c >> Method: %l ]%n%p:%m%n
#warn log
log4j.logger.warn=warn
log4j.appender.warn=org.apache.log4j.DailyRollingFileAppender
log4j.appender.warn.DatePattern='_'yyyy-MM-dd'.log'
log4j.appender.warn.File=./src/com/hp/log/warn.log
log4j.appender.warn.Append=true
log4j.appender.warn.Threshold=WARN
log4j.appender.warn.layout=org.apache.log4j.PatternLayout
log4j.appender.warn.layout.ConversionPattern=%dyyyy-MM-dd HH:mm:ss a [Thread: %t][ Class:%c >> Method: %l ]%n%p:%m%n
#error
log4j.logger.error=error
log4j.appender.error = org.apache.log4j.DailyRollingFileAppender
log4j.appender.error.DatePattern='_'yyyy-MM-dd'.log'
log4j.appender.error.File = ./src/com/hp/log/error.log
log4j.appender.error.Append = true
log4j.appender.error.Threshold = ERROR
log4j.appender.error.layout = org.apache.log4j.PatternLayout
log4j.appender.error.layout.ConversionPattern = %dyyyy-MM-dd HH:mm:ss a [Thread: %t][ Class:%c >> Method: %l ]%n%p:%m%n
2、log4j 在mybatis-config.xml的配置
<settings>
<setting name="logImpl" value="LOG4J"/>
</settings>
3、使用场景
-
在具体类中引入
Logger logger = Logger.getLogger(UserDaoTest.class); logger.error(); logger.debug();
好用的插件：
1、lombok
常用注解：
- @Data 自动生成geter seter
- @AllArgsConstructor 生成有参构造函数
- @NoArgsConstructor 生成无参构造函数
=“logImpl” value=“LOG4J”/>
## 3、使用场景
- 在具体类中引入
```java
Logger logger = Logger.getLogger(UserDaoTest.class);
logger.error();
logger.debug();
好用的插件：
1、lombok
常用注解：
- @Data 自动生成geter seter
- @AllArgsConstructor 生成有参构造函数
- @NoArgsConstructor 生成无参构造函数
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