MyBatis基础-CRUD

一、mybatis  环境搭建步骤

第一步：创建 maven 工程
第二步：导入坐标
第三步：编写必要代码（实体类和持久层接口）
第四步：编写 SqlMapConfig.xml
第五步：编写映射配置文件
第六步：编写测试类

二、编写sqlMapConfig.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configurationPUBLIC "-//mybatis.org//DTD Config 3.0//EN""http://mybatis.org/dtd/mybatis-3-config.dtd">
<!-- 主配置文件 -->
<configuration><!-- 配置环境 --><environments default="mysql"><environment id="mysql"><transactionManager type="JDBC"></transactionManager><dataSource type="POOLED"><property name="driver" value="com.mysql.jdbc.Driver"/><property name="url" value="jdbc:mysql://localhost:3306/eesy_mybatis"/><property name="username" value="root"/><property name="password" value="123456"/></dataSource></environment></environments><!-- 指定映射配置文件的位置 --><mappers><mapper resource="com/jzq/dao/UserDao.xml"/></mappers>
</configuration>

三、 在持久层（DAO）接口中添加CRUD方法

package com.jzq.dao;import com.jzq.domain.User;import java.util.List;/*** @author jzq* @create 2019-08-24 下午 1:39*/
public interface UserDao {List<User> findAll();/*** 保存方法* @param user*/void saveUser(User user);/*** 修改方法* @param user*/void updateUser(User user);/*** 删除方法* @param userId*/void deleteUser(Integer userId);/*** 寻找指定id用户* @param id* @return*/User findUser(Integer id);/*** 模糊查询*/List<User> findByLikeName(String username);/*** 查询总用户数*/int findTotal();
}

四、 在用户的映射配置文件（Mapper）中配置

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.jzq.dao.UserDao"><select id="findAll" resultType="com.jzq.domain.User">SELECT * from user</select><!-- 保存用户 --><insert id="saveUser" parameterType="com.jzq.domain.User"><!-- 配置插入操作后，获取插入数据id --><selectKey keyProperty="id" keyColumn="id" resultType="int" order="AFTER">SELECT last_insert_id();</selectKey>INSERT INTO user(username,birthday,sex,address)VALUE (#{username},#{birthday},#{sex},#{address})</insert><!-- 更新用户 --><update id="updateUser" parameterType="com.jzq.domain.User">UPDATE user set username=#{username},sex=#{sex} WHERE id=#{id};</update><!-- 删除用户 --><delete id="deleteUser" parameterType="Integer">DELETE FROM user WHERE id = #{uId}</delete><!-- 查询指定id用户 --><select id="findUser" parameterType="Integer" resultType="com.jzq.domain.User">SELECT * from user WHERE id = #{uid}</select><!-- 根据名称模糊查询 --><select id="findByLikeName" parameterType="String" resultType="com.jzq.domain.User">SELECT * from user WHERE username like #{name}</select><!-- 查询用户的总记录数 --><select id="findTotal" resultType="int">SELECT COUNT(id) from user;</select>
</mapper>

五、测试类测试CRUD方法

package com.jzq.test;import com.jzq.dao.UserDao;
import com.jzq.domain.User;
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 org.junit.After;
import org.junit.Before;
import org.junit.Test;import java.io.InputStream;
import java.util.Date;
import java.util.List;/*** @author jzq* @create 2019-08-24 下午 2:44* CRUD操作*/
public class MyBatisTest {private InputStream in;private SqlSession sqlSession;private SqlSessionFactory factory;private UserDao userDao;@Before//在测试方法执行前执行public void init() throws Exception {//读取配置文件，生成字节输入流in = Resources.getResourceAsStream("SqlMapConfig.xml");//获取sqlSessionFactoryfactory = new SqlSessionFactoryBuilder().build(in);//获取SQLSession对象sqlSession = factory.openSession();//获取dao的代理对象userDao = sqlSession.getMapper(UserDao.class);}@After//在测试方法执行后执行public void destroy() throws Exception {//释放资源
        sqlSession.commit();sqlSession.close();in.close();}/*** 测试查询方法** @throws Exception*/@Testpublic void testFindAll() throws Exception {//执行查询所有方法List<User> users = userDao.findAll();for (User user : users) {System.out.println(user);}//释放资源
sqlSession.close();in.close();}/*** 测试保存操作*/@Testpublic void testSave() throws Exception {User user = new User();user.setUsername("mybaitis_save");user.setBirthday(new Date());user.setSex("男");user.setAddress("北京市非台区");//执行保存方法
        userDao.saveUser(user);sqlSession.commit();}/*** 测试保存操作*/@Testpublic void testFindInsertId() throws Exception {User user = new User();user.setUsername("mybaitis_last insert");user.setBirthday(new Date());user.setSex("女");user.setAddress("北京市台区");System.out.println("执行保存操作之前" + user);//执行保存方法
        userDao.saveUser(user);System.out.println("执行保存操作之后" + user);}/*** 测试更新操作*/@Testpublic void testUpdate() throws Exception {User user = new User();user.setId(50);user.setUsername("mybaitis_update");user.setSex("女");//执行查询所有方法
        userDao.updateUser(user);}/*** 测试删除操作*/@Testpublic void testDelete() throws Exception {userDao.deleteUser(48);}/*** 测试查找指定操作*/@Testpublic void testFindOne() throws Exception {User user = userDao.findUser(50);System.out.println(user);}/*** 测试模糊查找操作*/@Testpublic void testFindLikeName() throws Exception {List<User> users = userDao.findByLikeName("%小%");for (User user : users) {System.out.println(user);}}/*** 测试查询总用户数*/@Testpublic void testFindTotal(){int count = userDao.findTotal();System.out.println(count);}
}