Tk.MyBatis通用Mapper中获取自增主键ID,与使用uuid 做主键时获取 id

我会带着你远行 2022-12-24 04:55 306阅读 0赞

# 1. XML方案 #

1 . MyBatis在各个实体类对应的 mapper.xml文件中加入 这句 ：useGeneratedKeys="true"  keyProperty="ID"

注意:   keyProperty="数据库中的主键字段名对应的实体类字段名" ；【填实体类字段名】

2. 加  SELECT LAST\_INSERT\_ID()

<insert id="saveUser" parameterType="com.yc.Student">
    	
    		<selectKey keyColumn="id" keyProperty="id" order="AFTER"
    			resultType="int">
    			SELECT LAST_INSERT_ID()
    		</selectKey>
    		INSERT INTO `student`
    		(username) VALUES
    		(#{username})
    </insert>

3. 不适用自增ID ，使用UUID做主键  加 SELECT uuid()

<insert id="saveUser1" parameterType="com.yc.Student">
    		
    		<selectKey keyColumn="uuid" keyProperty="uuid" order="BEFORE"
    			resultType="string">
    			SELECT uuid()
    		</selectKey>
    		INSERT INTO `student`
    		(username) VALUES
    		(#{username})
    	</insert>

# 二. 注解 #

1. 自增主键用法：

@Data      //  lombok 注解，节省getter, setter
    @Table(name = "pic")
    public class Pic {
        @Id  // JPA注解,指定此属性为表中的主键
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        private Integer id;   //注意: 对应的数据表中的字段名叫 book_id
        private String path;
        private String description;
    
    
    }

2. 序列主键用法(适用Oracle)：

@Id
    @GeneratedValue(strategy = GenerationType.IDENTITY,Generator = "select SEQ_ID.nextval from dual"  )
    private Integer id;

以下是输出 的日志:

20:25:34.724 [main] DEBUG org.mybatis.spring.transaction.SpringManagedTransaction - JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@687a762c] will be managed by Spring
    20:25:34.730 [main] DEBUG com.yc.piclib.dao.impl.PicMapper.insert - ==>  Preparing: INSERT INTO pic ( id,path,description ) VALUES( ?,?,? )
    20:25:34.761 [main] DEBUG com.yc.piclib.dao.impl.PicMapper.insert - ==> Parameters: null, new pic4534(String), very very good(String)
    20:25:34.763 [main] DEBUG com.yc.piclib.dao.impl.PicMapper.insert - <==    Updates: 1
    20:25:34.812 [main] DEBUG com.yc.piclib.dao.impl.PicMapper.insert!selectKey - ==>  Executing: SELECT LAST_INSERT_ID()
    20:25:34.840 [main] DEBUG com.yc.piclib.dao.impl.PicMapper.insert!selectKey - <==      Total: 1