Mybatis基础：crud操作，规范操作+map操作
1.接口配置文件相关细节（xxMapper.xml）
namespace：绑定这对应接口
<mapper namespace="com.king.dao.UserMapper">
id：对应接口的方法
resultType：返回值类型
<select id="getUserList" resultType="com.king.pojo.User">
parameterType=""参数类型
2.crud操作
pojo
package com.king.pojo; //实体类 public class User { private int id; private String name; private String pwd; public User() { } public User(int id, String name, String pwd) { this.id = id; this.name = name; this.pwd = pwd; } public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getPwd() { return pwd; } public void setPwd(String pwd) { this.pwd = pwd; } @Override public String toString() { return "User{" + "id=" + id + ", name='" + name + '\'' + ", pwd='" + pwd + '\'' + '}'; } }
工具类
package com.king.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; //工厂模式是为了生产产品的，当前就是sqlSessionFactory生产sqlSession //sqlSessionFactory--->sqlSession public class MybatisUtils { private static SqlSessionFactory sqlSessionFactory; static { try { //使用Mybatis第一步，获取sqlSessionFacter对象 String resource = "mybatis-config.xml"; InputStream inputStream = Resources.getResourceAsStream(resource); sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); } catch (IOException e) { e.printStackTrace(); } } //既然有了 SqlSessionFactory，顾名思义，我们可以从中获得 SqlSession 的实例。 // SqlSession 提供了在数据库执行 SQL 命令所需的所有方法。 //你可以通过 SqlSession 实例来直接执行已映射的 SQL 语句 public static SqlSession getSqlSession(){ return sqlSessionFactory.openSession(); } }
2.1 UserMapper
package com.king.dao; import com.king.pojo.User; import java.util.List; //官方文档中Mapper代替了Dao public interface UserMapper { //查询全部用户 List<User> getUserList(); //根据id查询用户 User getUserById(int Id); //插入用户 int addUser(User user); //修改用户 int updateUser(User user); //删除 int deleteUser(int id); }
2.2 UserMapper.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"> <!--namespace=绑定一个对应的Dao/Mapper接口--> <mapper namespace="com.king.dao.UserMapper"> <!--select查询语句--> <!--绑定方法--><!--给返回值类型resultType，引入对应的实体类中--> <select id="getUserList" resultType="com.king.pojo.User" > select * from mybatis.user </select> <select id="getUserById" parameterType="int" resultType="com.king.pojo.User"> select * from mybatis.user where id = #{id} </select> <!--对象属性可以直接取出来--> <insert id="addUser" parameterType="com.king.pojo.User" > insert into mybatis.user (id,`name`,pwd) VALUES(#{id},#{name},#{pwd}) </insert> <!--对象属性可以直接取出来--> <update id="updateUser" parameterType="com.king.pojo.User" > UPDATE mybatis.user SET `name`=#{name},pwd=#{pwd} WHERE id=#{id} </update> <delete id="deleteUser" parameterType="int" > DELETE from mybatis.user WHERE id=#{id} </delete> </mapper>
2.3 核心注册文件+注册机、
<?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"> <!--核心配置文件--> <configuration> <environments default="development"> <environment id="development"> <transactionManager type="JDBC"/> <dataSource type="POOLED"> <property name="driver" value="com.mysql.cj.jdbc.Driver"/> <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSL=true&serverTimezone=UTC&useUnicode=true&characterEncoding=UTF-8"/> <property name="username" value="root"/> <property name="password" value="123456"/> </dataSource> </environment> </environments> <!--每一个mapper.xml（dao层实现类）都需要在Mybatis核心配置文件中注册--> <mappers> <mapper resource="com/king/dao/UserMapper.xml"/> </mappers> </configuration>
2.4 @test单元测试
package com.king.dao; import com.king.pojo.User; import com.king.utils.MybatisUtils; import org.apache.ibatis.session.SqlSession; import org.junit.Test; import java.util.List; public class UserDaoTest { @Test public void test(){ //第一步：获得SqlSession对象 SqlSession sqlSession = MybatisUtils.getSqlSession(); //方式一：getMapper UserMapper userMapper = sqlSession.getMapper(UserMapper.class); List<User> userList = userMapper.getUserList(); for (User user : userList) { System.out.println(user); } //关闭SqlSession sqlSession.close(); } @Test public void getUserById(){ SqlSession sqlSession = MybatisUtils.getSqlSession(); UserMapper mapper = sqlSession.getMapper(UserMapper.class); User user= mapper.getUserById(1); System.out.println(user); sqlSession.close(); } //注意：增删改需要提交事务 @Test public void addUser(){ SqlSession sqlSession = MybatisUtils.getSqlSession(); UserMapper mapper = sqlSession.getMapper(UserMapper.class); int user = mapper.addUser(new User(5, "姚悠", "00001111")); if (user>0){ System.out.println("插入成功"); //提交事务 sqlSession.commit(); } sqlSession.close(); } @Test public void updateUser(){ SqlSession sqlSession = MybatisUtils.getSqlSession(); UserMapper mapper = sqlSession.getMapper(UserMapper.class); int user = mapper.updateUser(new User(1, "老刘", "111222")); if (user>0){ System.out.println("修改成功"); sqlSession.commit(); } sqlSession.close(); } @Test public void deleteUser(){ SqlSession sqlSession = MybatisUtils.getSqlSession(); UserMapper mapper = sqlSession.getMapper(UserMapper.class); int user = mapper.deleteUser(1); if (user>0){ System.out.println("删除成功"); sqlSession.commit(); } sqlSession.close(); } }
Map操作
接口
//利用map实现插入操作 int addUser2(Map<String,Object> map);
接口配置文件
<!--利用map去传参（传递map的key）-->
<insert id="addUser2" parameterType="map">
insert into mybatis.user (id,pwd) VALUES(#{userId},#{userPwd})
</insert>
单元测试
@Test public void getUserByMap(){ SqlSession sqlSession = MybatisUtils.getSqlSession(); UserMapper mapper = sqlSession.getMapper(UserMapper.class); Map<String, Object> map = new HashMap<String, Object>(); map.put("userId",7); map.put("userPwd","233333"); int i = mapper.addUser2(map); if (i>0){ System.out.println("插入成功"); sqlSession.commit(); } sqlSession.close(); }
