一、 项目介绍

1、Mybatis的Dao接口动态代理实现CRUD（增、删、改、查）案例

2、项目开发工具：

   (1) jdk1.8.0_92
   (2) mysql-5.5.45-winx64
   (3) Navicat_for_MySQL_11.0.10
   (4) IDEA-2019.3.4
   (5) apache-maven-3.5.2

3、项目目录结构

4、数据库信息

二、源码

1、pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><groupId>com.hisoft</groupId><artifactId>mybatisdemo1</artifactId><version>1.0-SNAPSHOT</version><dependencies><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.6</version></dependency><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.4.5</version></dependency>
<!-- 日志jar包 --><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.13-beta-1</version><scope>test</scope></dependency>
<!-- 测试jar包--><dependency><groupId>org.slf4j</groupId><artifactId>jcl-over-slf4j</artifactId><version>1.7.29</version></dependency></dependencies></project>

2、resources中的配置文件

   (1) jdbc.properties（mysql数据库的配置信息）

driver=com.mysql.jdbc.Driver
url=jdbc:mysql:/ / /suogu
username=root
password=root

   (2) log4j.properties（日志相关配置信息）

log4j.rootLogger=DEBUG,A1
log4j.logger.org.mybatis=DEBUG
log4j.appender.A1=org.apache.log4j.ConsoleAppender
log4j.appender.A1.layout=org.apache.log4j.PatternLayout
log4j.appender.A1.layout.ConversionPattern=%-d{yyyy-MM-dd HH:mm:ss,SSS} [%t] [%c]-[%p] %m%n

   (3) mybatis-config.xml（mybatis框架相关配置信息）

<?xml version="1.0" encoding="UTF-8" ?>
<!--Mybatis约束信息-->
<!DOCTYPE configurationPUBLIC "-//mybatis.org//DTD Config 3.0//EN""http://mybatis.org/dtd/mybatis-3-config.dtd">
<!--Mybatis的主配置文件-->
<configuration>
<!-- 导入数据源--><properties resource="jdbc.properties"></properties>
<!--配置环境，名字可以任意起--><environments default="development">
<!--配置development环境,id的值与上方default的值一样--><environment id="development">
<!--配置事务类型--><transactionManager type="JDBC"></transactionManager>
<!--            配置数据源（连接池）--><dataSource type="POOLED">
<!--                配置连接数据库的四个基本信息--><property name="driver" value="${driver}"/><property name="url" value="${url}"/><property name="username" value="${username}"/><property name="password" value="${password}"/></dataSource></environment></environments>
<!--    指定映射配置文件的位置，映射配置文件指的是每个Mapper独立的配置文件-->
<mappers><mapper class="com.hisoft.dao.UserMapper"></mapper>
</mappers>
</configuration>
&nbsp;&nbsp;&nbsp;(4) UserMapper.xml（UserMapper接口的映射文件）```java
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!--命名空间-->
<mapper namespace="com.hisoft.dao.UserMapper"><!--    查询所有用户--><select id="selectAll" resultType="com.hisoft.pojo.User">select * from user</select><!--    根据id查询指定用户--><select id="selectUserById" parameterType="INT" resultType="com.hisoft.pojo.User"><!--#{id}中的id可以任意写，只表示占位符的意思-->select * from user where id = #{id}</select><!--    添加用户--><insert id="addUser" parameterType="com.hisoft.pojo.User"><!-- 配置插入操作后，获取插入数据的id--><selectKey keyProperty="id" keyColumn="id" resultType="int" order="AFTER">select last_insert_id ();</selectKey>insert into user values(#{id},#{name},#{salary},#{username},#{password})</insert><!--    根据用户id删除用户--><delete id="deleteUserById" parameterType="INT">delete from user where id = #{id}</delete><!--    修改用户信息--><update id="updateUser" parameterType="com.hisoft.pojo.User">update user set name=#{name},salary=#{salary},username=#{username},password=#{password} where id = #{id}</update><!--    根据名字模糊查询--><select id="findUserByName" parameterType="string" resultType="com.hisoft.pojo.User"><!--     这一种是使用PrepatedStatement的参数占位符的方式，有预处理 -->select * from user where name like #{name}<!--     %${value}是固定写法，此时使用的是Statement对象的拼接SQL的方式--><!--     select * from user where name like '%${value}%' --></select><!--    获取用户的总记录数--><select id="findUserTotal" resultType="int">select count(1) from user</select><!-- 动态SQL  if标签 根据条件查询--><select id="findUserByCondition" parameterType="com.hisoft.pojo.User" resultType="com.hisoft.pojo.User">select * from user where 1=1<if test="name != null">and name = #{name}</if><if test="username != null">and username = #{username}</if></select><!--&lt;!&ndash; 动态SQL  where标签 根据条件查询&ndash;&gt;<select id="findUserByCondition" resultType="pojo.User" parameterType="user">select * from user   //此时就不需要写1=1这个条件了<where><if test="name != null">and username = #{username}</if><if test="salary != null">and salary = #{salary}</if></where></select>-->
</mapper>

3、pojo层（实体映射层）

   User.java

package com.hisoft.pojo;public class User {int id;String name;double salary;String username;String password;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 double getSalary() {return salary;}public void setSalary(double salary) {this.salary = salary;}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}@Overridepublic String toString() {return "User{" +"id=" + id +", name='" + name + '\'' +", salary=" + salary +", username='" + username + '\'' +", password='" + password + '\'' +'}';}
}

4、dao层（直接与数据库进行交互的层）

   UserMapper.java

package com.hisoft.dao;import com.hisoft.pojo.User;import java.util.List;public interface UserMapper {//    查询所有用户public List<User> selectAll();//根据id查询指定用户public User selectUserById(int id);//    添加用户public void addUser(User user);//    根据id删除用户public void deleteUserById(int id);//修改用户信息public void updateUser(User user);//模糊查询用户public List<User> findUserByName(String name);//获取用户总记录数public int findUserTotal();//动态sql，根据条件查询用户public List<User> findUserByCondition(User user);
}

5、test文件

   UserTset.java

import com.hisoft.dao.UserMapper;
import com.hisoft.pojo.User;
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.apache.ibatis.io.Resources;
import org.junit.Test;import java.io.IOException;
import java.io.InputStream;
import java.util.List;public class UserTset {//new 一个userDao1对象private UserMapper userMapper;private SqlSession sqlSession;//定义成全局的对象private InputStream in;@Beforepublic void init() throws IOException {//读取配置文件String resource = "mybatis-config.xml";in = Resources.getResourceAsStream(resource);//创建SqlSessionFactorySqlSessionFactoryBuilder ssfb = new SqlSessionFactoryBuilder();SqlSessionFactory sqlSessionFactory = ssfb.build(in);//生产sqlSession对象sqlSession = sqlSessionFactory.openSession();//使用sqlSession创建dao接口的代理对象userMapper = sqlSession.getMapper(UserMapper.class);}@Test//查询所有用户信息public void selectAll() {List<User> users = userMapper.selectAll();for (User user : users) {System.out.println(user);}}@Test
//    根据id查询指定的用户信息public void selectUserById() {User user = userMapper.selectUserById(1001);System.out.println(user);}@Test
//    添加用户public void addUser() {User user = new User();user.setName("小可爱");user.setSalary(10000);user.setUsername("xka");user.setPassword("1234XKA");System.out.println("提交事务前：" + user);userMapper.addUser(user);System.out.println("******************************");System.out.println("提交事务后：" + user);}@Test
//    根据用户id删除用户public void deleteUserById() {userMapper.deleteUserById(1009);}@Test
//    修改用户信息public void updateUser() {User user = new User();user.setId(1010);user.setName("小提莫");user.setUsername("xtm");user.setSalary(100000);user.setPassword("1234xtm");userMapper.updateUser(user);}@Test
//    根据名字模糊查询用户public void findUserByName() {List<User> users = userMapper.findUserByName("%旭%");//        List<User> users = userDao1.findByName("旭");for (User user : users) {System.out.println(user);}}
@Test
//获取用户的总记录数
public void findUserTotal(){int i = userMapper.findUserTotal();System.out.println("总记录数是："+i);
}
@Test
//根据动态条件查询用户
public void findUserByCoudition(){User u = new User();u.setName("小提莫");u.setUsername("xtm");List<User> users = userMapper.findUserByCondition(u);for(User user: users){System.out.println(user);}
}@Afterpublic void destroy() throws IOException {
//        提交事务sqlSession.commit();//不开启事务是写入不到数据库里去的//释放资源sqlSession.close();in.close();}
}

源码，以及导入项目到自己的idea中，可以地下评论留下QQ号，看到后会及时回复，也可以加群交流，谢谢