Mybatis實現資料的增刪改查
阿新 • • 發佈：2018-12-16
首先在pom.xml中加入依賴
<dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.3.0</version> </dependency> <!-- 不寫版本號會識別不出SqlSessionFactory--> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency>
然後在resource中建立一個Configuration.xml檔案用於連線資料庫
<?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> <!-- mybatis別名定義 alias別名名稱，用package的別名就是包下實體類的名稱--> <!--第二種方法更好--> <typeAliases> <!--<typeAlias type="com.lixin.mybatis.User" alias="User"/>--> <package name="com.lixin.mybatis"/> </typeAliases> <environments default="development"> <environment id="development"> <transactionManager type="JDBC"/> <dataSource type="POOLED"> <property name="driver" value="com.mysql.jdbc.Driver"/> <property name="url" value="jdbc:mysql://127.0.0.1:3306/test" /> <property name="username" value="root"/> <property name="password" value="115600LX"/> </dataSource> </environment> </environments> <!-- mybatis的mapper檔案，每個xml配置檔案對應一個介面 --> <mappers> <!-- 註冊自定義的對映檔案 --> <mapper resource="mappers/user.xml"/> </mappers> </configuration>
建立實體類User
package com.lixin.mybatis; public class User { private int id; private String username; private int sex; private int age; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public int getSex() { return sex; } public void setSex(int sex) { this.sex = sex; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } @Override public String toString() { return "User{" + "id=" + id + ", username='" + username + '\'' + ", sex=" + sex + ", age=" + age + '}'; } }
建立resource-mappers-user.xml實現對資料的增刪改查（對映檔案）
在mybatis中，對映檔案中的namespace是用於繫結Dao介面的，即面向介面程式設計。-------Mapper檔案
<?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">
<!-- 使用介面方式 載入名稱空間 使用代理模式 -->
<mapper namespace="com.lixin.mybatis.IUserOperaton">
<select id="findUserById" parameterType="int" resultType="User">
SELECT * FROM user1 WHERE id = #{id}
</select>
<select id="findAllUser" resultType="User">
SELECT * FROM user1;
</select>
<insert id="addUser" parameterType="User" useGeneratedKeys="true" keyProperty="id">
insert into user1(id,username,sex,age) values (#{id},#{username},#{sex},#{age})
</insert>
<delete id="deleteUser" parameterType="int">
delete from user1 where id=#{id}
</delete>
</mapper>建立介面類IUserOperation
IUserOperation為操作介面，函式名和mybatis的xml配置檔案中的操作id名對應。
package com.lixin.mybatis;
import java.util.List;
public interface IUserOperaton {
public User findUserById(int id);
public List<User>findAllUser();
public void addUser(User user);
public void deleteUser(int id);
}
編寫Mybatis工具類Util
用靜態程式碼塊進行建立SqlSessionFactory，只在類載入時建立一次，保證了整個程式執行時只有一個工廠例項。
package com.lixin.mybatis;
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.InputStream;
import java.io.Reader;
import java.util.List;
public class Util {
private static SqlSessionFactory sqlSessionFactory;
private static Reader reader;
private User user;
private static int Ret;
//從xml中獲取sqlSessionFactory
// 建立sqlSessionFactory物件，因為整個應用程式只需要一個例項物件，故用靜態程式碼塊
static {
try {
Reader reader = Resources.getResourceAsReader("Configuration.xml");
sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
SqlSession session = sqlSessionFactory.openSession();
} catch (Exception e) {
e.printStackTrace();
}
}
//返回SessionFactory
public static SqlSessionFactory getSqlSessionFactory() {
return sqlSessionFactory;
}
//返回Session;
public static SqlSession getSession() {
return sqlSessionFactory.openSession();
}
/*
isAutoCommit:
true 表示建立的SqlSession物件在執行完SQL之後會自動提交事務
false 表示建立的SqlSession物件在執行完SQL之後不會自動提交事務，這時就需要我們手動呼叫sqlSession.commit()
*/
public static SqlSession getSqlSession(boolean isAutoCommit) {
return getSqlSessionFactory().openSession(isAutoCommit);
}
}測試類--Test
package com.lixin.mybatis;
import org.apache.ibatis.session.SqlSession;
import java.util.ArrayList;
import java.util.List;
public class Test {
public void findAllUsers(){
SqlSession sqlSession =Util.getSqlSession(true);
IUserOperaton usermapper=sqlSession .getMapper(IUserOperaton.class);
List<User>users=usermapper .findAllUser() ;
for(User u:users ){
System.out .println("ID:"+u.getId() +";Usernamr:"+u.getUsername() +";Sex:"+u.getSex() +";Age:"+u.getAge() );
}
sqlSession .close() ;
}
public void addUser(){
SqlSession sqlSession =Util.getSqlSession(true);
IUserOperaton usermapper=sqlSession .getMapper(IUserOperaton.class);
User newuser =new User() ;
newuser .setUsername("李鑫");
newuser .setAge(18);
newuser.setSex(2);
usermapper.addUser(newuser );
sqlSession .close() ;
}
public void deleteUser(int id){
SqlSession sqlSession =Util.getSqlSession(true);
IUserOperaton usermapper=sqlSession .getMapper(IUserOperaton.class);
usermapper .deleteUser(id);
sqlSession .close() ;
}
public void updateUser(){
SqlSession sqlSession =Util.getSqlSession(true);
IUserOperaton usermapper=sqlSession .getMapper(IUserOperaton.class);
User newuser=new User() ;
newuser.setId(1);
newuser .setSex(1) ;
newuser .setUsername("秦鬆");
newuser .setAge(22);
usermapper .updateUser(newuser );
sqlSession .close() ;
}
}
主函式
package com.lixin.mybatis;
import org.apache.ibatis.session.SqlSession;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
@SpringBootApplication
public class MybatisApplication {
public static void main(String[] args) {
Test test=new Test() ;
test.findAllUsers() ;//查詢所有User
test.addUser() ;//新增User
test.deleteUser(3);//根據id號刪除User
test.updateUser() ;//更新User資訊
}
}