SpringData Repository Bean方法定义规范代码实例

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);
}

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