MyBatis学习笔记（一）IntelliJ IDEA的第一个MyBatis Demo

2019-11-10 19:55:47

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参考

（1）使用IDEA创建javaweb项目（2）MyBatis学习笔记(一）入门（重点）（3）IntelliJ IDEA手动配置连接MySQL 数据库（4）IntelliJ IDEA单元测试入门

创建Java Web项目

参考：使用IDEA创建javaweb项目这里写图片描述

导入MyBatis所需的jar包

参考：MyBatis学习笔记(一）入门 mybatis需要jar包：mybatis-3.4.2.jar mysql驱动jar包：mysql-connector-java-5.1.39-bin.jar 日志记录jar包：log4j-1.2.17.jar，slf4j-api-1.7.12.jar，slf4j-log4j12-1.7.12.jar 这里写图片描述

创建数据库mybatis和表t_user

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IDEA配置MySQL数据源

参考：IntelliJ IDEA手动配置连接MySQL数据库这里写图片描述点击Test Connection 点击OK后，可以看到

MyBatis入门Demo

参考：MyBatis学习笔记(一）入门

（1）代码结构

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（2）mysql驱动配置文件

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jdbc.driver=com.mysql.jdbc.Driverjdbc.url=jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=UTF-8jdbc.username=rootjdbc.passWord=123456

（3）日志配置文件

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### 设置Logger输出级别和输出目的地 ###log4j.rootLogger=debug,stdout,logfile### 把日志信息输出到控制台 ###log4j.appender.stdout=org.apache.log4j.ConsoleAppender#log4j.appender.stdout.Target=System.errlog4j.appender.stdout.layout=org.apache.log4j.SimpleLayout### 把日志信息输出到文件：jbit.log ###log4j.appender.logfile=org.apache.log4j.FileAppenderlog4j.appender.logfile.File=jbit.loglog4j.appender.logfile.layout=org.apache.log4j.PatternLayoutlog4j.appender.logfile.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %F %p %m%n###显示SQL语句部分log4j.logger.com.ibatis=DEBUGlog4j.logger.com.ibatis.common.jdbc.SimpleDataSource=DEBUGlog4j.logger.com.ibatis.common.jdbc.ScriptRunner=DEBUGlog4j.logger.com.ibatis.sqlmap.engine.impl.SqlMapClientDelegate=DEBUGlog4j.logger.java.sql.Connection=DEBUGlog4j.logger.java.sql.Statement=DEBUGlog4j.logger.java.sql.PReparedStatement=DEBUG

（4）MyBatis配置文件mybatis.cfg.xml

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（5）创建对应的实体对象UserBean

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package com.zz.mybatis.beans;import java.io.Serializable;public class UserBean implements Serializable{ private static final long serialVersionUID = 1L; private Integer id; private String username; private String password; private Double account; public UserBean() { super(); } public UserBean(String username, String password, Double account) { super(); this.username = username; this.password = password; this.account = account; } public UserBean(Integer id, String username, String password, Double account) { super(); this.id = id; this.username = username; this.password = password; this.account = account; } public Integer getId() { return id; } public void setId(Integer 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 Double getAccount() { return account; } public void setAccount(Double account) { this.account = account; } @Override public String toString() { return "UserBean [id=" + id + ", username=" + username + ", password=" + password + ", account=" + account + "]"; }}

（6）创建方法接口UserMapper.java和定义操作t_user表的sql映射文件UserMapper.xml

这里写图片描述 UserMapper.java

package com.zz.mybatis.mapper;import java.util.List;import com.zz.mybatis.beans.UserBean;public interface UserMapper { /** * 新增用戶 * @param user * @return * @throws Exception */ public int insertUser(UserBean user) throws Exception; /** * 修改用戶 * @param user * @param id * @return * @throws Exception */ public int updateUser (UserBean user,int id) throws Exception; /** * 刪除用戶 * @param id * @return * @throws Exception */ public int deleteUser(int id) throws Exception; /** * 根据id查询用户信息 * @param id * @return * @throws Exception */ public UserBean selectUserById(int id) throws Exception; /** * 查询所有的用户信息 * @return * @throws Exception */ public List<UserBean> selectAllUser() throws Exception;}

这里写图片描述 UserMapper.xml

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE mapper PUBLIC "-//mybatis.org/DTD Mapper 3.0" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="com.zz.mybatis.mapper.UserMapper">  <resultMap id="userMap" type="UserBean"> <id property="id" column="id" javaType="java.lang.Integer"></id> <result property="username" column="username" javaType="java.lang.String"></result> <result property="password" column="password" javaType="java.lang.String"></result> <result property="account" column="account" javaType="java.lang.Double"></result> </resultMap>     <insert id="insertUser" useGeneratedKeys="true" keyProperty="id"> insert into t_user (username,password,account) values (#{username},#{password},#{account}) </insert> <update id="updateUser" > update t_user set username=#{username},password=#{password},account=#{account} where id=#{id} </update> <delete id="deleteUser" parameterType="int"> delete from t_user where id=#{id} </delete> <select id="selectUserById" parameterType="int" resultMap="userMap"> select * from t_user where id=#{id} </select> <select id="selectAllUser" resultMap="userMap"> select * from t_user </select></mapper>

mybatis.cfg.xml里注册UserMapper.xml文件

<?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>  <properties resource="mysql.properties"></properties>  <typeAliases >   <package name="com.zz.mybatis.beans"/> </typeAliases>  <environments default="zzbatis"> <environment id="zzbatis">  <transactionManager type="JDBC" />     <dataSource type="POOLED"> <property name="driver" value="${jdbc.driver}" /> <property name="url" value="${jdbc.url}" /> <property name="username" value="${jdbc.username}" /> <property name="password" value="${jdbc.password}" /> </dataSource> </environment> </environments> <mappers>   <package name="com/zz/mybatis/mapper"/> </mappers></configuration>

（7）建立一个工具类DBTools

这里写图片描述 DBTools.java：

package com.zz.mybatis.tools;import java.io.Reader;import org.apache.ibatis.io.Resources;import org.apache.ibatis.session.SqlSession;import org.apache.ibatis.session.SqlSessionFactory;import org.apache.ibatis.session.SqlSessionFactoryBuilder;public class DBTools { public static SqlSessionFactory sessionFactory; static{ try { //使用MyBatis提供的Resources类加载mybatis的配置文件 Reader reader = Resources.getResourceAsReader("mybatis.cfg.xml"); //构建sqlSession的工厂 sessionFactory = new SqlSessionFactoryBuilder().build(reader); } catch (Exception e) { e.printStackTrace(); } } //创建能执行映射文件中sql的sqlSession public static SqlSession getSession(){ return sessionFactory.openSession(); }}

（8）测试

参考：IntelliJ IDEA单元测试入门这里写图片描述 UserServiceTest：

package com.zz.mybatis.service;import com.zz.mybatis.beans.UserBean;import com.zz.mybatis.mapper.UserMapper;import com.zz.mybatis.tools.DBTools;import org.apache.ibatis.session.SqlSession;import org.junit.Test;import java.util.List;import static org.junit.Assert.*;public class UserServiceTest { @Test public void insertUser() throws Exception { SqlSession session = DBTools.getSession(); UserMapper mapper = session.getMapper(UserMapper.class); UserBean user = new UserBean("咖啡", "1314520", 7000.0); try { mapper.insertUser(user); System.out.println(user.toString()); session.commit(); } catch (Exception e) { e.printStackTrace(); session.rollback(); } } @Test public void deleteUser() throws Exception { SqlSession session=DBTools.getSession(); UserMapper mapper=session.getMapper(UserMapper.class); try { mapper.deleteUser(1); session.commit(); } catch (Exception e) { e.printStackTrace(); session.rollback(); } } @Test public void selectUserById() throws Exception { SqlSession session=DBTools.getSession(); UserMapper mapper=session.getMapper(UserMapper.class); try { UserBean user= mapper.selectUserById(2); System.out.println(user.toString()); session.commit(); } catch (Exception e) { e.printStackTrace(); session.rollback(); } } @Test public void selectAllUser() throws Exception { SqlSession session=DBTools.getSession(); UserMapper mapper=session.getMapper(UserMapper.class); try { List<UserBean> user=mapper.selectAllUser(); System.out.println(user.toString()); session.commit(); } catch (Exception e) { e.printStackTrace(); session.rollback(); } }}

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