CRUD操作
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程序员日常工作中90%都是在处理CRUD相关的操作,今天我们也从这里开始了解mybatis配置相关知识点。
配置文件中namespace中的名称为对应Mapper接口或者Dao接口的完整包名,必须一致!
代码如下(示例):
<?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">
<!--绑定一个对应的dao/Mapper接口-->
<mapper namespace="com.kuang.dao.UserMapper">
<select id="getUserLike" resultType="com.kuang.pojo.User">
select * from mybatis.user where name like #{value};
</select>
<select id="getUserLike2" resultType="com.kuang.pojo.User">
select * from mybatis.user where name like "%"#{value}"%";
</select>
<select id="getUserList" resultType="com.kuang.pojo.User">
select * from mybatis.user;
</select>
<select id="getUserById" parameterType="int" resultType="com.kuang.pojo.User">
select * from mybatis.user where id=#{id};
</select>
<insert id="insertUser" parameterType="com.kuang.pojo.User">
insert into mybatis.user(id,name,pwd) values(#{id},#{name},#{pwd});
</insert>
<insert id="addUser" parameterType="com.kuang.pojo.User">
insert into mybatis.user(id,name,pwd) values(#{id},#{name},#{pwd});
</insert>
<update id="updateUser" parameterType="com.kuang.pojo.User">
update mybatis.user set name=#{name},pwd=#{pwd} where id=#{id};
</update>
<delete id="deleteUser" parameterType="int">
delete from mybatis.user where id=#{id};
</delete>
<insert id="addUser2" parameterType="map">
insert into mybatis.user(id,name,pwd) values(#{id},#{name},#{pwd});
</insert>
</mapper>
代码如下(示例):
import com.kuang.pojo.User;
import java.util.List;
import java.util.Map;
public interface UserMapper {
// 查询所有的用户
List<User> getUserList();
// 查询所有的用户使用like语句
List<User> getUserLike(String value);
// 查询所有的用户使用like语句
List<User> getUserLike2(String value);
// 根据ID查询用户信息
User getUserById(int id);
// 插入一个用户
int insertUser(User user);
// 插入一个用户
int addUser(User user);
// 修改用户
int updateUser(User user);
// 删除一个用户
int deleteUser(int id);
// 万能的map
int addUser2(Map<String,Object> map);
}
数据库中创建表在此省略
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@NoArgsConstructor
@AllArgsConstructor
public class User {
private int id;
private String name;
private String password;
}
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 java.io.IOException;
import java.io.InputStream;
public class MybatisUtils {
private static SqlSessionFactory sqlSessionFactory;
static {
try {
// 第一步:使用mybatis获取SqlSessionFactory
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
} catch (IOException e) {
e.printStackTrace();
}
}
public static SqlSession getsqlSession(){
return sqlSessionFactory.openSession();
}
}
# 数据库连接
driver=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=utf-8&useSSL=false
username=root
password=wang123456
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<!-- 引入外部配置文件-->
<properties resource="db.properties">
<property name="username" value="root"/>
<property name="pwd" value="123456"/>
</properties>
<settings>
<!-- 标准日志工程-->
<setting name="logImpl" value="STDOUT_LOGGING"/>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="${driver}"/>
<property name="url" value="${url}"/>
<property name="username" value="${username}"/>
<property name="password" value="${pwd}"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper class="com.kuang.dao.UserMapper"></mapper>
</mappers>
</configuration>
import com.kuang.pojo.User;
import com.kuang.utils.MybatisUtils;
import org.apache.ibatis.session.RowBounds;
import org.apache.ibatis.session.SqlSession;
import org.apache.log4j.Logger;
import org.junit.Test;
import java.util.HashMap;
import java.util.List;
public class UserDaoTest {
@Test
public void test_getUserByRowBounds(){
SqlSession sqlSession = MybatisUtils.getsqlSession();
RowBounds rowBounds = new RowBounds(1,4);
List<User> userList =sqlSession.selectList("com.kuang.dao.UserMapper.getUserByRowBounds",
null,
rowBounds);
for (User user : userList) {
System.out.println(user);
}
// 增删改都需要提交事务
sqlSession.commit();
sqlSession.close();
}
@Test
public void test_getUserLimit(){
SqlSession sqlSession = MybatisUtils.getsqlSession();
UserMapper userDao = sqlSession.getMapper(UserMapper.class);
HashMap<String,Object> map = new HashMap<String,Object>();
map.put("startIndex",0);
map.put("pageSize",20);
List<User> userList =userDao.getUserLimit(map);
for (User user : userList) {
System.out.println(user);
}
// 增删改都需要提交事务
sqlSession.commit();
sqlSession.close();
}
@Test
public void test_getUserLike(){
SqlSession sqlSession = MybatisUtils.getsqlSession();
UserMapper userDao = sqlSession.getMapper(UserMapper.class);
List<User> userList = userDao.getUserLike("%王宸玉%");
for (User user : userList) {
System.out.println(user);
}
sqlSession.close();
}
@Test
public void test_getUserLike2(){
SqlSession sqlSession = MybatisUtils.getsqlSession();
UserMapper userDao = sqlSession.getMapper(UserMapper.class);
List<User> userList = userDao.getUserLike2("王宸玉");
for (User user : userList) {
System.out.println(user);
}
sqlSession.close();
}
@Test
public void test_getUserList(){
SqlSession sqlSession = MybatisUtils.getsqlSession();
UserMapper userDao = sqlSession.getMapper(UserMapper.class);
List<User> userList = userDao.getUserList();
for (User user : userList) {
System.out.println(user);
}
sqlSession.close();
}
@Test
public void test_getUserById(){
SqlSession sqlSession = MybatisUtils.getsqlSession();
UserMapper userDao = sqlSession.getMapper(UserMapper.class);
User user = userDao.getUserById(2);
System.out.println(user);
sqlSession.close();
}
@Test
public void test_insertUser(){
SqlSession sqlSession = MybatisUtils.getsqlSession();
UserMapper userDao = sqlSession.getMapper(UserMapper.class);
int num = userDao.insertUser(new User(9,"王宸熙","wangchenxi"));
if(num>0){
System.out.println("插入新的数据成功");
}
// 增删改都需要提交事务
sqlSession.commit();
sqlSession.close();
}
@Test
public void test_addUser2(){
SqlSession sqlSession = MybatisUtils.getsqlSession();
UserMapper userDao = sqlSession.getMapper(UserMapper.class);
HashMap<String,Object> map = new HashMap<String,Object>();
map.put("id",7);
map.put("name","王宸玉");
map.put("pwd","wangchenyu");
int num = userDao.addUser2(map);
if(num>0){
System.out.println("插入新的数据成功");
}
// 增删改都需要提交事务
sqlSession.commit();
sqlSession.close();
}
@Test
public void test_addtUser(){
SqlSession sqlSession = MybatisUtils.getsqlSession();
UserMapper userDao = sqlSession.getMapper(UserMapper.class);
int num = userDao.addUser(new User(5,"王宸玉","wangchenxi"));
if(num>0){
System.out.println("插入新的数据成功");
}
// 增删改都需要提交事务
sqlSession.commit();
sqlSession.close();
}
@Test
public void test_updateUser(){
SqlSession sqlSession = MybatisUtils.getsqlSession();
UserMapper userDao = sqlSession.getMapper(UserMapper.class);
userDao.updateUser(new User(5,"王宸玉","wangchenyu12"));
// 增删改都需要提交事务
sqlSession.commit();
sqlSession.close();
}
@Test
public void test_deleteUser(){
SqlSession sqlSession = MybatisUtils.getsqlSession();
UserMapper userDao = sqlSession.getMapper(UserMapper.class);
userDao.deleteUser(1);
// 增删改都需要提交事务
sqlSession.commit();
sqlSession.close();
}
}
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.22</version>
</dependency>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.5</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
<dependency>
<groupId>org.testng</groupId>
<artifactId>testng</artifactId>
<version>7.3.0</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.16</version>
</dependency>