基于Mybatis实现CRUD操作过程解析(xml方式)

基于Mybatis实现CRUD操作过程解析(xml方式)

1、环境搭建

1.1 表结构

create table user (

id int primary key auto_increment,

username varchar(20) not null,

birthday date,

sex char(1) default '男',

address varchar(50)

);

insert into user values (null, '孙悟空','1980-10-24','男','花果山水帘洞');

insert into user values (null, '白骨精','1992-11-12','女','白虎岭白骨洞');

insert into user values (null, '猪八戒','1983-05-20','男','福临山云栈洞');

insert into user values (null, '蜘蛛精','1995-03-22','女','盤丝洞');

1.2 创建项目

导入如下jar

mybatis框架包

数据库驱动包

log4j日志包

junit单元测试包

1.3 准备配置文件

在src下准备配置文件：sqlMapConfig.xml

PUBLIC "-//mybatis.org//DTD Config 3.0//EN"

"http://mybatis.org/dtd/mybaQMbJMwtis-3-config.dtd">

QMbJMw

在 src 下准备配置文件：log4j.properties

# Global logging configuration

log4j.rootLogger=DEBUG, stdout

# Console output...

log4j.appender.stdout=org.apache.log4j.ConsoleAppender

log4j.appender.stdout.layout=org.apache.log4j.PatternLayout

log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n

2-增删改查源码

1.1 执行结果

1.2 User类代码

import java.sql.Date;

/**

用户实体类对象 */

public class User {

private Integer id;

private String username;

private Date birthday;

private String sex;

private String address;

public User() {

}

public User(Integer id, String username, Date birthday, String sex, String address) {

this.id = id;

this.username = username;

this.birthday = birthday;

this.sex = sex;

this.address = address;

}

public Integer getId() {

return id;

}

public void setId(Integer id) {

this.id = id;

}

public String getUsername() {

return username;

}

public void setUsername(String username) {

this.username = username;

}

public Date getBirthday() {

return birthday;

}

public void setBirthday(Date birthday) {

this.birthday = birthday;

}

public String getSex() {

return sex;

}

public void setSex(String sex) {

this.sex = sex;

}

public String getAddress() {

return address;

}

public void setAddress(String address) {

this.address = address;

}

@Override

public String toString() {

return "User{" +

"id=" + id +

", username='" + username + '\'' +

", birthday=" + birthday +

", sex='" + sex + '\'' +

", address='" + address + '\'' +

'}';

}

}

1.3 UserMapper接口代码

package com.vg.dao;

import com.vg.entity.User;

import org.apache.ibatis.annotations.Param;

import java.util.List;

/**

* 数据访问层接口：对用户进行增删改查操作

*/

public interface UserMapper {

/**

* 添加用户

*/

int addUser(User user);

/**

* 根据id删除用户

*/

void deleteUser(Integer id);

/**

* 通过id修改用户信息

*/

/**

* 修改用户信息

*/

void updateUser(User user);

/**

* 查询所有用户

*/

List findAllUsers();

/**

* 根据id查询用户

*/

User findUserById(int id);

/**

* 根据用户名模糊查询用户

*/

List findUsersByName(String username);

/**

* 根据姓名和性别查询用户数据(姓名使用模糊查询)

*/

/**

* 根据用户名称模糊查询用户

*/

}

}

1.4 UserMapper.xml接口映射文件

PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"

"http://mybatis.org/dtd/mybatis-3-mapper.dtd">

select * from user

select * from user where id = #{id};

select *from user where username like #{username}

insert into user values(null,#{username},#{birthday},#{sex},#{address});

update user set username = #{username},

birthday = #{birthday},sex = #{sex}, address = #{address}

where id = #{id}

delete from user where id = #{id}

1.5 在主配置文件中加载接口映射文件

1.6 测试类代码

package com.vg.test;

import com.vg.dao.UserMapper;

import com.vg.entity.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.BeforeClass;

import org.junit.Test;

import java.io.IOException;

import java.io.InputStream;

import java.sql.Date;

import java.util.List;

/**

* 测试类

*/

public class TestUserMapper {

private static SqlSessionFactory sqlSessionFactory =null;

private SqlSession sqlSession =null;

private UserMapper userMapper =null;

// 该方法在所有测试方法执行之前执行1次

@BeforeClass

public static void init() throws Exception {

// 1. 通过Resources类，加载sqlMapConfig.xml，得到文件输入流对

InputStream in = Resources.getResourceAsStream("sqlMapConfig.xml");

// 2. 实例化会话工厂创建类SqlSessionFactoryBuilder对象

SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();

// 3. 根据字节输入流获取SqlSessionFactory对象

sqlSessionFactory = builder.build(in);

}

// 该方法会在每个测试方法执行之前执行1次

@Before

public void before(){

// 4. 获取SqlSession对象，等价连接对象

// true:事务自动提交，false:不自动提交,默认值

sqlSession = sqlSessionFactory.openSession();

// 5. 创建接口 实现类对象

userMapper = sqlSession.getMapper(UserMapper.class);

}

/**

* 测试方法：通过用户名模糊查询用户

*/

@Test

public void testAddUser() throws Exception{

// 1. 获得接口代理对象

UserMapper userMapper = sqlSession.getMapper(UserMapper.class);

// 2. 创建User对象

User u = new User();

u.setUsername("如来佛祖111");

u.setBirthday(Date.valueOf("1980-01-20"));

u.setAddress("西天灵山");

u.setSex("男");

// 3. 保存用户信息

int row = userMapper.addUser(u);

System.out.println("row = " + row);

// 4. 手动提交事务

sqlSession.commit();

}

/**

* 测试方法：通过用户名模糊查询用户

*/

@Test

public void testFindUserByName() throws Exception{

List userList = userMapper.findUsersByName("%精%");

for (User user : userList) {

System.out.println(user);

}

}

/**

* 测试方法：查询所有用户

*/

@Test

public void testFindAllUsers() throws Exception{

List userList = userMapper.findAllUsers();

for (User user : userList) {

System.out.println(user);

}

}

/**

* 根据id查询用户

* @throws Exception

*/

@Test

public void testFindUserById()throws Exception{

// 6. 调用接口的方法根据id查询用户

User user = userMapper.findUserById(1);

System.out.println("user = " + user);

}

@Test

public void testUpdateUser()throws Exception{

// 创建用户对象

User user = new User(

6,

"牛魔王",

Date.valueOf("1998-02-20"),

"妖",

"牛魔洞");

// 更新用户

userMapper.updateUser(user);

// 提交事务

sqlSession.commit();

}

@Test

public void testDeleteUser()throws Exception{

// 1. 获得接口代理对象

UserMapper userMapper = sqlSession.getMapper(UserMapper.class);

// 2. 根据id删除用户

userMapper.deleteUser(6);

// 3. 提交事务

sqlSession.commit();

}

@After

public void after() {

// 7. 关闭会话，释放资源。

sqlSession.close();

}

}

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