自定义主键生成器

比眉伴天荒 2022-02-23 01:46 465阅读 0赞

*  [目录][Link 1]

--------------------

### 1. 编写MyIdGenerator ###

*  这是我们自己的id生成器，首先要继承org.hibernate.id.IdentifierGenerator接口，并实现generate方法，方法返回值即是生成的id

package com.example.springboot.mysqldemo.util;
    
    import org.hibernate.HibernateException;
    import org.hibernate.engine.spi.SharedSessionContractImplementor;
    import org.hibernate.id.IdentifierGenerator;
    
    import java.io.Serializable;
    import java.util.UUID;
    
    public class MyIdGenerator implements IdentifierGenerator {
    
        public static final String TYPE = "com.example.springboot.mysqldemo.util.MyIdGenerator";
    
        @Override
        public Serializable generate(SharedSessionContractImplementor sharedSessionContractImplementor, Object o) throws HibernateException {
        	// 简单示例
            String uuid= UUID.randomUUID().toString();
            System.out.println("my:"+uuid);
            return "my:"+uuid;
        }
    }

### 2. 实体中添加改id生成器 ###

*  给id添加如下注解，strategy 指向我们的id生成器

> @GenericGenerator(name = “myGenerator”, strategy = “com.example.springboot.mysqldemo.util.MyIdGenerator”)  
> @GeneratedValue(generator = “myGenerator”)

*  例

@Entity
    @Table(name = "User_Info")
    public class UserInfo {
    
        private String id;
    
        private String name;
    
       //....
    
    
        @JsonProperty
        @Id
        @GenericGenerator(name = "myGenerator", strategy = "com.example.springboot.mysqldemo.util.MyIdGenerator")
        @GeneratedValue(generator = "myGenerator")
        @Column(name = "ID", unique = true, nullable = false, length = 36)
        public String getId() {
            return id;
        }
    
        public void setId(String id) {
            this.id = id;
        }
    
        @JsonProperty
        @Column(name = "name",  length = 136)
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
           //....
    
    }

### 3. 测试 ###

@RestController
    @RequestMapping("/index")
    @ImportResource(locations = { "classpath:druid-bean.xml" })
    public class IndexController {
        @Autowired
        private UserInfoDao userInfoDao;
    
        @RequestMapping("/addUserInfo")
        public UserInfo getIndex(String name) {
            UserInfo userInfo=new UserInfo();
            userInfo.setName(name);
            userInfoDao.save(userInfo);
            return userInfo;
        }
    }

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*  success

[Link 1]: https://blog.csdn.net/u014296316/article/details/85485741
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