MyBatis 系列教程2-单表操作

对单表进行CRUD操作

模型对象User

package com.jege.mybatis.mapper;

/**
 * @author JE哥
 * @email 1272434821@qq.com
 * @description:单表
 */
public class User {
  private Long id;
  private String name;
  private Integer age;

  public User() {

  }

  public User(String name, Integer age) {
    this.name = name;
    this.age = age;
  }

  public Long getId() {
    return id;
  }

  public void setId(Long id) {
    this.id = id;
  }

  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }

  public Integer getAge() {
    return age;
  }

  public void setAge(Integer age) {
    this.age = age;
  }

  @Override
  public String toString() {
    return "User [id=" + id + ", name=" + name + ", age=" + age + "]";
  }

}

映射文件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">
<mapper namespace="com.jege.mybatis.mapper.UserMapper">

    <!-- 删表 -->
    <update id="dropTable">
        DROP TABLE IF EXISTS `t_user`;
    </update>

    <!-- 建表 -->
    <update id="createTable">
        CREATE TABLE IF NOT EXISTS `t_user` (
        `id` bigint(11) NOT NULL AUTO_INCREMENT,
        `name` varchar(255) DEFAULT NULL,
        `age` int(11) DEFAULT NULL,
        PRIMARY KEY (`id`)
        ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
    </update>

    <!-- 保存 -->
    <insert id="insert" parameterType="User" useGeneratedKeys="true" keyProperty="id">
        insert into t_user(name,age)
        values(#{name},#{age})
    </insert>

    <!-- 查询 -->
    <select id="findByKey" resultType="User" parameterType="long">
        select id,name,age from t_user where id=#{id}
    </select>

    <!-- 获取所有 -->
    <select id="findAll" resultType="User">
        select id,name,age from t_user
    </select>

    <!-- 修改 -->
    <update id="update" parameterType="User">
        update t_user set name=#{name},age=#{age} where id=#{id}
    </update>

    <!-- 删除 -->
    <delete id="delete" parameterType="long">
        delete from t_user where id=#{id}
    </delete>



</mapper>

测试类SingleTableTest

package com.jege.mybatis;

import java.io.Reader;
import java.util.List;

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.BeforeClass;
import org.junit.Test;

import com.jege.mybatis.mapper.User;

/**
 * @author JE哥
 * @email 1272434821@qq.com
 * @description:单表CRUD Test
 */
public class SingleTableTest {

  private static final String NAME_SPACE = "com.jege.mybatis.mapper.UserMapper";
  private static SqlSessionFactory sqlSessionFactory = null;
  private SqlSession sqlSession = null;

  @BeforeClass
  public static void setUpBeforeClass() throws Exception {
    Reader reader = Resources.getResourceAsReader("mybatis-config.xml");
    sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
  }

  @Before
  public void setUp() throws Exception {
    sqlSession = sqlSessionFactory.openSession();
    sqlSession.insert(NAME_SPACE + ".dropTable");
    sqlSession.insert(NAME_SPACE + ".createTable");
    sqlSession.commit();
  }

  // mybatis会通过mapper文件配置把保存后的主键放到当前对象的id里面
  @Test
  public void insert() throws Exception {
    sqlSession = sqlSessionFactory.openSession();
    User user = new User("je-ge", 22);
    System.out.println("保存之前：" + user);

    sqlSession.insert(NAME_SPACE + ".insert", user);
    sqlSession.commit();

    System.out.println("保存之后：" + user);
    System.out.println("+++++++++++++++");
  }

  @Test
  public void update() throws Exception {
    insert();

    User user = sqlSession.selectOne(NAME_SPACE + ".findByKey", 1L);
    System.out.println("修改前：" + user);

    user.setName("JE-GE");
    user.setAge(18);
    sqlSession.update(NAME_SPACE + ".update", user);
    sqlSession.commit();

    user = sqlSession.selectOne(NAME_SPACE + ".findByKey", 1L);
    System.out.println("修改后：" + user);
  }

  @Test
  public void findByKey() throws Exception {
    User user = sqlSession.selectOne(NAME_SPACE + ".findByKey", 1L);
    System.out.println(user);
  }

  @Test
  public void findAll() throws Exception {
    List<User> users = sqlSession.selectList(NAME_SPACE + ".findAll");
    for (User user : users) {
      System.out.println(user);
    }
  }

  @Test
  public void delete() throws Exception {
    User user = sqlSession.selectOne(NAME_SPACE + ".findByKey", 1L);
    System.out.println("删除前：" + user);

    sqlSession.delete(NAME_SPACE + ".delete", 1L);
    sqlSession.commit();

    user = sqlSession.selectOne(NAME_SPACE + ".findByKey", 1L);
    System.out.println("删除后：" + user);
  }

  @After
  public void tearDown() throws Exception {
    if (sqlSession != null)
      sqlSession.close();
  }

}

其他关联项目

• MyBatis 系列教程1-环境配置
  http://blog.csdn.net/je_ge/article/details/53998874

源码地址

https://github.com/je-ge/mybatis

如果觉得我的文章或者代码对您有帮助,可以请我喝杯咖啡。
您的支持将鼓励我继续创作!谢谢！