How can I return the id of the inserted data when mybatis performs the insert operation ?, Mybatisinsert

How can I return the id of the inserted data when mybatis performs the insert operation ?, Mybatisinsert

1. useGeneratedKeys = "true" to obtain the auto-growth ID. Only the databases with auto-growth mode are supported (mysql, mssql, etc., but oracle does not support this). Therefore, selectKey can be used to obtain the ID.
Eg:

<insert id="xxx" parameterType="yyy" useGeneratedKeys="true"> 
    insert into table(...) values (...) 
    <selectKey resultType="long" order="AFTER" keyProperty="id"> 
    SELECT LAST_INSERT_ID() AS id 
    </selectKey> 
</insert

2. For Primary keys (such as Oracle) that cannot be automatically generated, you can use the following methods:

<insert id="xxx" parameterType="yyy"> 
          <selectKey keyProperty="id" resultType="long" order="BEFORE"> 
             select my_seq.nextval from dual 
          </selectKey> ... </insert>

For the first better solution:

Method: Specify the keyProperty in mapper, for example:

<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, keyProperty = "userId" is specified in insert, where userId represents the primary key attribute of the inserted User object.

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

     // setter and getter
}
  UserDao.java
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public interface UserDao {

     public int insertAndGetId (User user);

}
  test:
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User user = new User ();
user.setUserName ("chenzhou");
user.setPassword ("xxxx");
user.setComment ("Test insert function to return primary key function");

System.out.println ("The primary key before inserting is:" + user.getUserId ());
userDao.insertAndGetId (user); // Insert operation
System.out.println ("The primary key after inserting is:" + user.getUserId ());
Output:
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The primary key before insertion is: 0
After inserting the primary key: 15
As shown above, the primary key id of the record just inserted is 15 

Reprinted from: http://blog.csdn.net/rapier512/article/details/51198684

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