王孝东的个人空间

JPA

Spring JPA

• JPA的完整配置示例：

  spring:
    jpa:
      show-sql: true
      database: mysql
      hibernate:
        ddl-auto: create
        naming:
          physical-strategy: org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl
      properties:
        hibernate:
          dialect: org.hibernate.dialect.MySQL5Dialect
    datasource:
      url: jdbc:mysql://localhost:3306/mydatabase?useUnicode=true&characterEncoding=utf8
      username: admin
      password: ******
      driver-class-name: com.mysql.jdbc.Driver
      testWhileIdle: true
      validationQuery: SELECT 1
  

• JPA配置自动创建表时，按指定的表名及列名创建(指定大小写)，需要用如下策略：spring.jpa.hibernate.naming.physical-strategy=org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl
• spring.jpa.hibernate.ddl-auto: none, vlidate, update, create, create-drop
  • validate: validate the schema, makes no changes to the database.
  • update: update the schema.
  • create: creates the schema, destroying previous data.
  • create-drop: drop the schema at the end of the session
  • none: 生产环境应该用none
  • 对于hsqldb, h2, derby默认值为create-drop, 其他数据库的默认值为none

• 对于CreateDate或UpdateDate这样的字段，如果想直接使用数据库的时间可以用如下方法：

      @CreationTimestamp
      @Temporal(TemporalType.TIMESTAMP)
      @Column(name="CREATE_DATE", insertable = false, updatable = false)
      private Date createDate;
    
      @UpdateTimestamp
      @Temporal(TemporalType.TIMESTAMP)
      @Column(name="UPDATE_DATE", insertable = false, updatable = false)
      private Date updateDate;
  

  Date需要使用java.util.Date