MyBatis 系列教程2-單表操做

時間 2019-11-09

原文原文鏈接

對單表進行CRUD操做

模型對象Userjava

package com.jege.mybatis.mapper;

/** * @author JE哥 * @email 1272434821@qq.com * @description:單表 */
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.xmlgit

<?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">

    <!-- 刪表 -->
    <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>

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

    <!-- 獲取全部 -->
    <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>

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



</mapper>

測試類SingleTableTestgithub

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:單表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會經過mapper文件配置把保存後的主鍵放到當前對象的id裏面
  @Test
  public void insert() throws Exception {
    sqlSession = sqlSessionFactory.openSession();
    User user = new User("je-ge", 22);
    System.out.println("保存以前：" + user);

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

    System.out.println("保存以後：" + 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("修改後：" + 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("刪除前：" + user);

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

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

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

}