SpringData系列三 Repository Bean 方法定义规范

　　　　本节主要介绍Repository Bean中方法定义规范。

　　1、方法不是随便声明，需要符合一定的规范。

　　2、按照Spring Data的规范，查询方法以find|read|get开头，涉及条件查询时，条件的属性用条件关键字连接，要注意的是：条件属性需要首字母大写。

　　3、Spring Data支持的关键字如下：

　　　

　　　

　　4、支持属性的级联查询，若当前类有符合条件的属性，则优先使用，而不使用级联属性。若想使用级联属性，则属性之间用"_"连接。

 package com.ntjr.springdata;

 import java.util.Date;

 import javax.persistence.CascadeType;
 import javax.persistence.Column;
 import javax.persistence.Entity;
 import javax.persistence.GeneratedValue;
 import javax.persistence.Id;
 import javax.persistence.JoinColumn;
 import javax.persistence.ManyToOne;
 import javax.persistence.Table;

 @Table(name = "JPA_PERSONS")
 @Entity
 public class Person {

     private Integer id;
     private String lastName;
     private String email;
     private Date birth;
     private Address address;
     private Integer addressId;

     @GeneratedValue
     @Id
     public Integer getId() {
         return id;
     }

     public void setId(Integer id) {
         this.id = id;
     }

     public String getLastName() {
         return lastName;
     }

     @Column(name = "LAST_NAME")
     public void setLastName(String lastName) {
         this.lastName = lastName;
     }

     public String getEmail() {
         return email;
     }

     public void setEmail(String email) {
         this.email = email;
     }

     public Date getBirth() {
         return birth;
     }

     public void setBirth(Date birth) {
         this.birth = birth;
     }

     @JoinColumn(name = "ADDRESS_ID")
     @ManyToOne(cascade = { CascadeType.ALL }, targetEntity = Address.class)
     public Address getAddress() {
         return address;
     }

     public void setAddress(Address address) {
         this.address = address;
     }

     public Integer getAddressId() {
         return addressId;
     }

     public void setAddressId(Integer addressId) {
         this.addressId = addressId;
     }

     @Override
     public String toString() {
         return "Person [id=" + id + ", lastName=" + lastName + ", email=" + email + ", birth=" + birth + "]";
     }

 }

Person.java

 package com.ntjr.springdata;

 import javax.persistence.Entity;
 import javax.persistence.GeneratedValue;
 import javax.persistence.Id;
 import javax.persistence.Table;

 @Table(name="JPA_ADDRESSES")
 @Entity
 public class Address {

     private Integer id;
     private String province;
     private String city;

     @GeneratedValue
     @Id
     public Integer getId() {
         return id;
     }

     public void setId(Integer id) {
         this.id = id;
     }

     public String getProvince() {
         return province;
     }

     public void setProvince(String province) {
         this.province = province;
     }

     public String getCity() {
         return city;
     }

     public void setCity(String city) {
         this.city = city;
     }

 }

Address.java

 package com.ntjr.springdata;

 import java.util.Date;
 import java.util.List;

 import org.springframework.data.repository.RepositoryDefinition;

 /**
  *
  * 1、实现Repository接口 2、通过注解的方式@RepositoryDefinition将一个bean定义为Repository接口
  */
 @RepositoryDefinition(idClass = Integer.class, domainClass = Person.class)
 public interface PersonRepsitory {
     // 根据lastName获取对应的person
     Person getByLastName(String lastName);

     // WHERE lastName like ?% AND id<?
     List<Person> findByLastNameStartingWithAndIdLessThan(String lastName, Integer id);

     // WHERE lastName Like %? And Id <?
     List<Person> findByLastNameEndingWithAndIdLessThan(String lastName, Integer id);

     // WHERE email IN(?,?,?) Or birth <?
     List<Person> findByEmailInOrBirthLessThan(List<String> emails, Date birth);

     // WHERE a.id >?
     /**
      * AddressId 优先查找Person类中的AddressId属性，如果Person类中没有，就查找Address类中的Id属性
      * 这样容易出现问题，建议级联查询中，属性之间使用"_"连接
      *
      */
     List<Person> findByAddressIdGreaterThan(Integer id);

     // 这样就很明确是进行级联查询，Address类中的ID属性
     List<Person> findByAddress_IdGreaterThan(Integer id);
 }

PersonRepository.java