myBatis03

Posted 2020-06-26

1.添加映射

在映射接口中添加方法如下：

package com.java1234.mappers;

import java.util.List;

import com.java1234.model.Student;

public interface StudentMapper {  

public int add(Student student); 

public int update(Student student); 

public int delete(Integer id);   

public Student findStudentByid(Integer id);  

public List<Student> find();   }  

2.修改映射文件  

<?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.java1234.mappers.StudentMapper">  

<!--定义一个resultmap用来接收所有学生 -->

<resultMap type="Student" id="StudentResult">

  <id property="id" column="id" />

  <result property="name" column="name" />

  <result property="age" column="age" />

</resultMap>

<insert id="add" parameterType="Student">

  insert into t_student   values(null,#{name},#{age})  </insert>  

<update id="update" parameterType="Student">  

update t_student set   name=#{name},age=#{age} where id=#{id}  

</update>

 <delete id="delete" parameterType="Integer">  

   delete from t_student where   id=#{id}

 </delete>

<select id="findStudentByid" parameterType="Integer" resultType="Student">  

   select * from t_student where id=#{id}

 </select>  

<select id="find" resultMap="StudentResult">  

select * from t_student;  </select>

</mapper>  

3.添加测试   添加jar包  

package com.java1234.service;  

import static org.junit.Assert.*;  

import java.util.List;

import org.apache.ibatis.session.SqlSession;  

import org.apache.log4j.Logger;

import org.junit.After; import org.junit.Before;

import org.junit.Test;   import com.java1234.mappers.StudentMapper;

import com.java1234.model.Student;

import com.java1234.util.SqlSessionFactoryUtil;  

public class StudentTest2 {

private static Logger logger = Logger.getLogger(StudentTest.class);

private SqlSession sqlSession = null;  

private StudentMapper studentMapper = null;

  @Before  public void setUp() throws Exception {  

  sqlSession = SqlSessionFactoryUtil.openSession(); 

  studentMapper = sqlSession.getMapper(StudentMapper.class);  }  

  @After  public void tearDown() throws Exception {   // 方法执行完成后调用关闭  

  sqlSession.close();  }  

  @Test  public void testAdd() {   logger.info("wu1添加成功！");   

   Student student = new Student("wu1", 30);

   studentMapper.add(student);     sqlSession.commit();    }  

   @Test  public void testUpdate() {   logger.info("wu1修改！");   

   Student student = new Student(12, "wu2", 88);  

   studentMapper.update(student);

   sqlSession.commit();    }  

   @Test  public void testDelete() {   logger.info("删除信息"); 

   studentMapper.delete(11);    sqlSession.commit();  }  

   @Test  public void testFindStudentByid() {   logger.info("查询byid");  

   Student s = studentMapper.findStudentByid(13);     System.out.println(s);   // sqlSession.commit();select不用提交事务  }  

   @Test  public void testFind() {   logger.info("查询所有");   

   List<Student> l = studentMapper.find(); 

   for (Student s : l) {    System.out.println(s);   }     // sqlSession.commit();select不用提交事务  } }

  注意在pojo中重写tostring方法   @Override  public String toString() {   return "Student [id=" + id + ", name=" + name + ", age=" + age + "]";  }