005_Spring Data JPA条件查询
1. 创建一个名为spring-data-jpa-specification-executor的Java项目, 同时添加相关jar包, 并添加JUnit能力。
2. 查看JpaSpecificationExecutor接口下的方法
3. 新建User.java
package com.bjbs.pojo;
import java.io.Serializable;
import java.util.Date;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
import org.springframework.format.annotation.DateTimeFormat;
@Entity // 指定该类是实体类
@Table(name = "user") // 指定数据库表名(表名和实体类对应)
public class User implements Serializable {
private static final long serialVersionUID = 1L;
@Id // 指定为主键
@GeneratedValue(strategy = GenerationType.IDENTITY) // 指定主键生成策略
@Column(name = "id") // 指定表中列名(列名和属性名对应)
private Integer id;
@Column(name = "name")
private String name;
@Column(name = "sex")
private String sex;
@Column(name = "birthday")
@DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
private Date birthday;
@Column(name = "address")
private String address;
public User() {
}
public User(String name, String sex, Date birthday, String address) {
this.name = name;
this.sex = sex;
this.birthday = birthday;
this.address = address;
}
public User(Integer id, String name, String sex, Date birthday, String address) {
this.id = id;
this.name = name;
this.sex = sex;
this.birthday = birthday;
this.address = address;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "User [id=" + id + ", name=" + name + ", sex=" + sex + ", birthday=" + birthday + ", address=" + address
+ "]";
}
}4. 新建UserRepository.java, 实现Repository和JpaSpecificationExecutor接口。
package com.bjbs.dao;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
import org.springframework.data.repository.Repository;
import com.bjbs.pojo.User;
/**
* 参数一T: 当前需要映射的实体; 参数二 T: 当前映射的实体中的id的类型
*/
public interface UserRepository extends Repository, JpaSpecificationExecutor {
} 5. 新建UserService.java
package com.bjbs.service;
import java.util.List;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.data.jpa.domain.Specification;
import com.bjbs.pojo.User;
public interface UserService {
public User findOne(Specification spec);
public List findAll(Specification spec);
public Page findAll(Specification spec, Pageable pageable);
public List findAll(Specification spec, Sort sort);
} 6. 新建UserServiceImpl.java
package com.bjbs.service.impl;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.data.jpa.domain.Specification;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import com.bjbs.dao.UserRepository;
import com.bjbs.pojo.User;
import com.bjbs.service.UserService;
@Service
@Transactional
public class UserServiceImpl implements UserService {
@Autowired
private UserRepository userRepository;
@Override
public User findOne(Specification spec) {
return userRepository.findOne(spec);
}
@Override
public List findAll(Specification spec) {
return userRepository.findAll(spec);
}
@Override
public Page findAll(Specification spec, Pageable pageable) {
return userRepository.findAll(spec, pageable);
}
@Override
public List findAll(Specification spec, Sort sort) {
return userRepository.findAll(spec, sort);
}
} 7. 新建TestUserRepository.java
package com.bjbs.test;
import java.util.ArrayList;
import java.util.List;
import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Predicate;
import javax.persistence.criteria.Root;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.data.domain.Sort.Direction;
import org.springframework.data.jpa.domain.Specification;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import com.bjbs.pojo.User;
import com.bjbs.service.UserService;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class TestUserRepository {
@Autowired
private UserService userService;
/**
* 查询名字叫'曹操'的用户
*/
@Test
public void findOne() {
Specification spe = new Specification() {
/**
* @return Predicate: 定义了查询条件。
* @param Root root: 根对象, 封装了查询条件的对象。
* @param CriteriaQuery query: 定义了一个基本的查询, 一般不使用。
* @param CriteriaBuilder cb: 创建一个查询条件。
*/
@Override
public Predicate toPredicate(Root root, CriteriaQuery query, CriteriaBuilder cb) {
Predicate pre = cb.equal(root.get("name"), "曹操");
return pre;
}
};
User userDb = userService.findOne(spe);
System.out.println(userDb);
}
/**
* 查询名字叫'曹操'和性别为'男'的用户
*/
@Test
public void findOneByNameAndSex() {
Specification spe = new Specification() {
@Override
public Predicate toPredicate(Root root, CriteriaQuery query, CriteriaBuilder cb) {
List list = new ArrayList();
list.add(cb.equal(root.get("name"), "曹操"));
list.add(cb.equal(root.get("sex"), "男"));
Predicate[] arr = new Predicate[list.size()];
return cb.and(list.toArray(arr));
}
};
User userDb = userService.findOne(spe);
System.out.println(userDb);
}
/**
* 查询名字叫'曹操'和住址为'安徽省亳州市'的用户
*/
@Test
public void findOneByNameAndAddress() {
Specification spe = new Specification() {
@Override
public Predicate toPredicate(Root root, CriteriaQuery query, CriteriaBuilder cb) {
return cb.and(cb.equal(root.get("name"), "曹操"), cb.equal(root.get("address"), "安徽省亳州市"));
}
};
User userDb = userService.findOne(spe);
System.out.println(userDb);
}
/**
* 查询名字叫'曹操'或'曹植'的用户
*/
@Test
public void findByNameOr() {
Specification spe = new Specification() {
@Override
public Predicate toPredicate(Root root, CriteriaQuery query, CriteriaBuilder cb) {
return cb.or(cb.equal(root.get("name"), "曹操"), cb.equal(root.get("name"), "曹植"));
}
};
List list = userService.findAll(spe);
for (User user : list) {
System.out.println(user);
}
}
/**
* 查询姓李的用户
*/
@Test
public void findByNameLike() {
Specification spe = new Specification() {
@Override
public Predicate toPredicate(Root root, CriteriaQuery query, CriteriaBuilder cb) {
return cb.like(root.get("name"), "李%");
}
};
List list = userService.findAll(spe);
for (User user : list) {
System.out.println(user);
}
}
/**
* 分页查询id在47和51之间的用户
*/
@Test
public void pageable() {
Specification spe = new Specification() {
@Override
public Predicate toPredicate(Root root, CriteriaQuery query, CriteriaBuilder cb) {
return cb.between(root.get("id"), 47, 51);
}
};
Pageable pageable = new PageRequest(0, 5);
Page list = userService.findAll(spe, pageable);
for (User user : list) {
System.out.println(user);
}
}
/**
* 排序查询id>51
*/
@Test
public void sort() {
Specification spe = new Specification() {
@Override
public Predicate toPredicate(Root root, CriteriaQuery query, CriteriaBuilder cb) {
return cb.greaterThan(root.get("id"), 51);
}
};
Sort sort = new Sort(Direction.DESC, "id");
List list = userService.findAll(spe, sort);
for (User user : list) {
System.out.println(user);
}
}
/**
* 分页排序查询id>=51
*/
@Test
public void pageableAndSort() {
Specification spe = new Specification() {
@Override
public Predicate toPredicate(Root root, CriteriaQuery query, CriteriaBuilder cb) {
return cb.ge(root.get("id"), 51);
}
};
Sort sort = new Sort(Direction.DESC, "id");
Pageable pageable = new PageRequest(0, 3, sort);
Page list = userService.findAll(spe, pageable);
for (User user : list) {
System.out.println(user);
}
}
} 8. 在src下新建application.properties
spring.datasource.driverClassName=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://192.168.25.138:3306/StudyMybatis?useSSL=true&useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai
spring.datasource.username=root
spring.datasource.password=lyw1234569. 在src下新建applicationContext.xml
com.bjbs.pojo
10. 数据库user表
11. 查询名字叫'曹操'的用户
12. 查询名字叫'曹操'和性别为'男'的用户
13. 查询名字叫'曹操'和住址为'安徽省亳州市'的用户
14. 查询名字叫'曹操'或'曹植'的用户
15. 查询姓'李'的用户
16. 分页查询id在47和51之间的用户
17. 排序查询id>51
18. 分页排序查询id>=51
