mybatis入门 - 码农教程

一、导入相关pom依赖

pom.xml

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

<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/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.zhuling</groupId>
  <artifactId>mybatis1</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>mybatis1 Maven Webapp</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
  </properties>

  <dependencies>
    <!-- ********************** junit单元测试依赖 ********************** -->
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
      <scope>test</scope>
    </dependency>

    <!-- ********************** Java Servlet API  ********************** -->
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>4.0.0</version>
      <scope>provided</scope>
    </dependency>

    <!-- ********************** Mybatis依赖 ********************** -->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>3.4.5</version>
    </dependency>

    <!-- ********************** Mysql JDBC驱动 ********************** -->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.44</version>
    </dependency>

    <!-- **********************  日志配置  ********************** -->
    <!--记得修改mybatis.cfg.xml添加如下内容-->
    <!--<setting name="logImpl" value="LOG4J2"/>-->
    <!--核心log4j2jar包-->
    <dependency>
      <groupId>org.apache.logging.log4j</groupId>
      <artifactId>log4j-core</artifactId>
      <version>2.9.1</version>
    </dependency>
    <dependency>
      <groupId>org.apache.logging.log4j</groupId>
      <artifactId>log4j-api</artifactId>
      <version>2.9.1</version>
    </dependency>
    <!--web工程需要包含log4j-web，非web工程不需要-->
    <dependency>
      <groupId>org.apache.logging.log4j</groupId>
      <artifactId>log4j-web</artifactId>
      <version>2.9.1</version>
    </dependency>
  </dependencies>



  <build>
    <finalName>mybatis1</finalName>
    <resources>
      <!--解决mybatis-generator-maven-plugin运行时没有将XxxMapper.xml文件放入target文件夹的问题-->
      <resource>
        <directory>src/main/java</directory>
        <includes>
          <include>**/*.xml</include>
        </includes>
      </resource>
      <!--解决mybatis-generator-maven-plugin运行时没有将jdbc.properites文件放入target文件夹的问题-->
      <resource>
        <directory>src/main/resources</directory>
        <includes>
          <include>jdbc.properties</include>
          <include>*.xml</include>
        </includes>
      </resource>
    </resources>

    <plugins>
      <plugin>
        <groupId>org.mybatis.generator</groupId>
        <artifactId>mybatis-generator-maven-plugin</artifactId>
        <version>1.3.2</version>
        <dependencies>
          <!--使用Mybatis-generator插件不能使用太高版本的mysql驱动 -->
          <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.44</version>
          </dependency>
        </dependencies>
        <configuration>
          <overwrite>true</overwrite>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

Jdbc.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/sys?useUnicode=true&characterEncoding=UTF-8
jdbc.username=root
jdbc.password=123

Web.xml

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">

</web-app>

接下来安装以下插件

Free mybatis plugin

Mybatis generater

mybatis tools

maven helper

详细介绍

https://blog.csdn.net/yangshijin1988/article/details/63258960/

generatorConfig.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE generatorConfiguration PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd" >
<generatorConfiguration>
    <!-- 引入配置文件 -->
    <properties resource="jdbc.properties"/>

    <!--指定数据库jdbc驱动jar包的位置-->
    <classPathEntry location="D:\\initpath\\mvn_repository\\mysql\\mysql-connector-java\\5.1.44\\mysql-connector-java-5.1.44.jar"/>

    <!-- 一个数据库一个context -->
    <context id="infoGuardian">
        <!-- 注释 -->
        <commentGenerator>
            <property name="suppressAllComments" value="true"/><!-- 是否取消注释 -->
            <property name="suppressDate" value="true"/> <!-- 是否生成注释代时间戳 -->
        </commentGenerator>

        <!-- jdbc连接 -->
        <jdbcConnection driverClass="${jdbc.driver}"
                        connectionURL="${jdbc.url}" userId="${jdbc.username}" password="${jdbc.password}"/>

        <!-- 类型转换 -->
        <javaTypeResolver>
            <!-- 是否使用bigDecimal， false可自动转化以下类型（Long, Integer, Short, etc.） -->
            <property name="forceBigDecimals" value="false"/>
        </javaTypeResolver>

        <!-- 01 指定javaBean生成的位置 -->
        <!-- targetPackage：指定生成的model生成所在的包名 -->
        <!-- targetProject：指定在该项目下所在的路径  -->
        <javaModelGenerator targetPackage="com.zhuling.model"
                            targetProject="src/main/java">
            <!-- 是否允许子包，即targetPackage.schemaName.tableName -->
            <property name="enableSubPackages" value="false"/>
            <!-- 是否对model添加构造函数 -->
            <property name="constructorBased" value="true"/>
            <!-- 是否针对string类型的字段在set的时候进行trim调用 -->
            <property name="trimStrings" value="false"/>
            <!-- 建立的Model对象是否 不可改变  即生成的Model对象不会有 setter方法，只有构造方法 -->
            <property name="immutable" value="false"/>
        </javaModelGenerator>

        <!-- 02 指定sql映射文件生成的位置 -->
        <sqlMapGenerator targetPackage="com.zhuling.mapper"
                         targetProject="src/main/java">
            <!-- 是否允许子包，即targetPackage.schemaName.tableName -->
            <property name="enableSubPackages" value="false"/>
        </sqlMapGenerator>

        <!-- 03 生成XxxMapper接口 -->
        <!-- type="ANNOTATEDMAPPER",生成Java Model 和基于注解的Mapper对象 -->
        <!-- type="MIXEDMAPPER",生成基于注解的Java Model 和相应的Mapper对象 -->
        <!-- type="XMLMAPPER",生成SQLMap XML文件和独立的Mapper接口 -->
        <javaClientGenerator targetPackage="com.zhuling.mapper"
                             targetProject="src/main/java" type="XMLMAPPER">
            <!-- 是否在当前路径下新加一层schema,false路径com.oop.eksp.user.model， true:com.oop.eksp.user.model.[schemaName] -->
            <property name="enableSubPackages" value="false"/>
        </javaClientGenerator>

        <!-- 配置表信息 -->
        <!-- schema即为数据库名 -->
        <!-- tableName为对应的数据库表 -->
        <!-- domainObjectName是要生成的实体类 -->
        <!-- enable*ByExample是否生成 example类 -->
        <!--<table schema="" tableName="t_book" domainObjectName="Book"-->
        <!--enableCountByExample="false" enableDeleteByExample="false"-->
        <!--enableSelectByExample="false" enableUpdateByExample="false">-->
        <!--&lt;!&ndash; 忽略列，不生成bean 字段 &ndash;&gt;-->
        <!--&lt;!&ndash; <ignoreColumn column="FRED" /> &ndash;&gt;-->
        <!--&lt;!&ndash; 指定列的java数据类型 &ndash;&gt;-->
        <!--&lt;!&ndash; <columnOverride column="LONG_VARCHAR_FIELD" jdbcType="VARCHAR" /> &ndash;&gt;-->
        <!--</table>-->

        <table schema="" tableName="t_mvc_book" domainObjectName="Book"
               enableCountByExample="false" enableDeleteByExample="false"
               enableSelectByExample="false" enableUpdateByExample="false">
            <!-- 忽略列，不生成bean 字段 -->
            <!-- <ignoreColumn column="FRED" /> -->
            <!-- 指定列的java数据类型 -->
            <!-- <columnOverride column="LONG_VARCHAR_FIELD" jdbcType="VARCHAR" /> -->
        </table>

    </context>
</generatorConfiguration>

运行mavengenerator命令

Mybatis增删改查案例

写service把你自动生成的Mapper接口复制过来，然后选中类名BookService，Alt+Enter生成实现类

生成 BookServiceImpl

package com.zhuling.service.impl;

import com.zhuling.mapper.BookMapper;
import com.zhuling.model.Book;
import com.zhuling.service.BookService;

/**
 * @author zhuling
 * @site www.xiaomage.com
 * @company xxx公司
 * @create  2019-10-14 22:58
 */
public class BookServiceImpl implements BookService {

    private BookMapper bookMapper;

    public BookMapper getBookMapper() {
        return bookMapper;
    }

    public void setBookMapper(BookMapper bookMapper) {
        this.bookMapper = bookMapper;
    }

    @Override
    public int deleteByPrimaryKey(Integer bid) {
        return bookMapper.deleteByPrimaryKey(bid);
    }

    @Override
    public int insert(Book record) {
        return bookMapper.insert(record);
    }

    @Override
    public int insertSelective(Book record) {
        return bookMapper.insertSelective(record);
    }

    @Override
    public Book selectByPrimaryKey(Integer bid) {
        return bookMapper.selectByPrimaryKey(bid);
    }

    @Override
    public int updateByPrimaryKeySelective(Book record) {
        return bookMapper.updateByPrimaryKeySelective(record);
    }

    @Override
    public int updateByPrimaryKey(Book record) {
        return bookMapper.updateByPrimaryKey(record);
    }
}

SessionUtil

package com.zhuling.util;

import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

/**
 * @author zhuling
 * @site www.xiaomage.com
 * @company xxx公司
 * @create  2019-10-14 23:07
 */
public class SessionUtil {
    private static SqlSessionFactory sessionFactory;
    private static ThreadLocal<SqlSession> threadLocal = new ThreadLocal<SqlSession>();
    static {
        sessionFactory = new SqlSessionFactoryBuilder().build(SessionUtil.class.getResourceAsStream("/mybatis.cfg.xml"));
    }

    public static SqlSession openSession() {
        SqlSession session = threadLocal.get();
        if (null == session) {
            session = sessionFactory.openSession();
            threadLocal.set(session);
        }
        return session;
    }

    public static void main(String[] args) {
        SqlSession session = openSession();
        System.out.println(session.getConnection());
        session.close();
//        System.out.println(session.getConnection());
    }
}

然后测试一下

BookServiceTest

package com.zhuling.service;

import com.zhuling.mapper.BookMapper;
import com.zhuling.model.Book;
import com.zhuling.service.impl.BookServiceImpl;
import com.zhuling.util.SessionUtil;
import org.apache.ibatis.session.SqlSession;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import static org.junit.Assert.*;

/**
 * @author zhuling
 * @site www.xiaomage.com
 * @company xxx公司
 * @create  2019-10-14 23:13
 */
public class BookServiceTest {

    private BookService bookService;
    private SqlSession sqlSession;

    @Before
    public void setUp(){
        BookServiceImpl bookService=new BookServiceImpl();
        sqlSession= SessionUtil.openSession();
        BookMapper mapper=sqlSession.getMapper(BookMapper.class);
        bookService.setBookMapper(mapper);
        this.bookService=bookService;
    }

    @Test
    public void insert() {
        Book book=new Book();
        book.setBid(1);
        book.setBname("mybatis插入");
        book.setPrice(22f);
        bookService.insert(book);
    }

    @Test
    public void selectByPrimaryKey() {
//        Book book = this.bookService.selectByPrimaryKey(27);
        this.bookService.deleteByPrimaryKey(27);
//        System.out.println(book);

    }
        @After
        public void tearDown() throws  Exception{

       sqlSession.commit();
       sqlSession.close();

    }
}

运行

到数据库查看效果

原文地址：https://www.cnblogs.com/BAYOUA/p/11677004.html