Java implementation of instance method that returns newly added primary key ID

This article mainly introduces the method of MyBatis+MySQL to return the inserted primary key ID. It has certain reference value. Interested friends can refer to it.

Requirement: After using MyBatis to insert a record into the MySQL database, the auto-incremented primary key value of the record needs to be returned.

Method: Specify the keyProperty attribute in mapper. The example is as follows:

<insert id="insertAndGetId" useGeneratedKeys="true" keyProperty="userId" parameterType="com.chenzhou.mybatis.User"> 
  insert into user(userName,password,comment) 
  values(#{userName},#{password},#{comment}) 
</insert>

As shown above, we specified keyProperty="userId" in insert, where userId represents the inserted User The primary key attribute of object .

User.java

public class User { 
  private int userId; 
  private String userName; 
  private String password; 
  private String comment; 

  //setter and getter 
}

UserDao.java

public interface UserDao {  
  public int insertAndGetId(User user);  
}

Test:

User user = new User(); 
user.setUserName("chenzhou"); 
user.setPassword("xxxx"); 
user.setComment("测试插入数据返回主键功能"); 

System.out.println("插入前主键为："+user.getUserId()); 
userDao.insertAndGetId(user);//插入操作 
System.out.println("插入后主键为："+user.getUserId());

Output:

The primary key before insertion is: 0
The primary key after insertion is: 15

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