JAVA MyBatis入门学习过程记录

目录一、Mybatis1、mybatis-config.xml2、Mapper.xml3、db.properties4、MybatisUtils工具类5、多对一AND多对一：6、使用注解开发7、自定义缓存：ehcache8、mybatis 其他工具二、MAVEN资源导出错误解决三、常用依赖导入四、LOG4J1、log4j.properties 配置文件2、log4j 在mybatis-config.xml的配置3、使用场景好用的插件：1、lombok总结

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.Driverurl=jdbc:mysql://localhost:3306/mybatisusername=rootpassword=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

collection 集合 一对多

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

    <!--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>

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();

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

总结

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