jpa（springdate-jpa）简单应用

分手后的思念是犯贱 2021-09-17 03:04 351阅读 0赞

原创博客地址：[https://blog.csdn.net/cheidou123/article/details/84428092][https_blog.csdn.net_cheidou123_article_details_84428092]

# JPA 基础(一) #

JPA全称Java Persistence API，是一组用于将数据存入数据库的类和方法的集合。

#### 一、JPA的基本配置 ####

##### 1 jpa配置 #####

<dependency>
    			<groupId>mysql</groupId>
    			<artifactId>mysql-connector-java</artifactId>
    </dependency>
    <dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    
     
      
       2 创建dto对象 package com.example.demo.dto;
    import javax.persistence.Entity;
    import javax.persistence.GeneratedValue;
    import javax.persistence.GenerationType;
    import javax.persistence.Id;
    @Entity
    public class Customer { 
        @Id
        @GeneratedValue(strategy=GenerationType.AUTO)
        private Long id;
        private String firstName;
        private String lastName;
        protected Customer() { }
        public Customer(String firstName, String lastName) { 
            this.firstName = firstName;
            this.lastName = lastName;
        }
        @Override
        public String toString() { 
            return String.format(
                    "Customer[id=%d, firstName='%s', lastName='%s']",
                    id, firstName, lastName);
        }
    }
    
       
         
          3 创建操作数据的Repository对象 package com.example.demo.repositories;
    import com.example.demo.dto.Customer;
    import org.springframework.data.jpa.repository.JpaRepository;
    public interface CustomerRepository extends JpaRepository<Customer, Long>; { 
    }
    
         
            
             二、JpaRepository JpaRepository PagingAndSortingRepository CrudRepository QueryByExampleExecutor 三、自定义的方法 1.一些基本的自定义方法样例 2.举个例子 在CustomerRepository接口中，有如下定义 /** * 根据lastName查询结果 * @param lastName * @return */
    List<Customer> findByLastName(String lastName);

[https_blog.csdn.net_cheidou123_article_details_84428092]: https://blog.csdn.net/cheidou123/article/details/84428092