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 + "]";
    }

}

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;
    }

}

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);
}