SpringBoot----SpringBoot 整合Spring Data JPA(一)

一.Spring Data JPA介紹

二.SpringBoot 整合Spring Data JPA

1.修改pom文件,添加座標

		<!-- mysql數據庫驅動 -->
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
		</dependency>
		<!-- druid數據庫連接池 -->
		<dependency>
			<groupId>com.alibaba</groupId>
			<artifactId>druid</artifactId>
			<version>1.1.20</version>
		</dependency>

		<!-- spring data jpa的啓動器 -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-data-jpa</artifactId>
		</dependency>

2.在項目中添加application.properties文件

spring.datasource.driverClassName=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/ssm?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
spring.datasource.username=root
spring.datasource.password=root

spring.datasource.type=com.alibaba.druid.pool.DruidDataSource

spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true

3.添加實體類

package com.kennosaur.pojo;

import java.io.Serializable;

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

@Entity
@Table(name = "t_users")
public class Users implements Serializable{
	@Id
	@GeneratedValue(strategy = GenerationType.IDENTITY)
	@Column(name = "id")
	private Integer id;
	@Column(name = "name")
	private String name;
	@Column(name = "age")
	private Integer age;
	@Column(name = "address")
	private String 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 Integer getAge() {
		return age;
	}
	public void setAge(Integer age) {
		this.age = age;
	}
	public String getAddress() {
		return address;
	}
	public void setAddress(String address) {
		this.address = address;
	}
	@Override
	public String toString() {
		return "Users [id=" + id + ", name=" + name + ", age=" + age + ", address=" + address + "]";
	}
	
	
	
}

5.編寫DAO接口

package com.kennosaur.dao;

import org.springframework.data.jpa.repository.JpaRepository;

import com.kennosaur.pojo.Users;

/**
 * 參數一T:當前需要映射的實體
 * 參數二ID:當前映射的實體中的OID的類型
 * @author Administrator
 *
 */
public interface UsersRepository extends JpaRepository<Users, Integer> {

}

6.在pom文件中添加測試啓動器的座標

		<!-- 添加junit環境的jar包 -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
		</dependency>

7.創建啓動類

package com.kennosaur;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class App {
	public static void main(String[] args) {
		SpringApplication.run(App.class, args);
	}
}

8.編寫測試代碼

package com.kennosaur.test;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import com.kennosaur.App;
import com.kennosaur.dao.UsersRepository;
import com.kennosaur.pojo.Users;

/**
 * 測試類
 * @author Administrator
 *
 */

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = App.class)
public class UsersRepositoryTest {
	@Autowired
	private UsersRepository usersRepository;
	
	@Test
	public void testSave() {
		Users users = new Users();
		users.setAddress("北京市海淀");
		users.setAge(20);
		users.setName("張三");
		this.usersRepository.save(users);
	}
}

三.Spring Data JPA提供的核心接口

1.Repository接口

2.CrudRepository接口

3.PagingAndSortingRepository接口

4.JpaRepository接口

5.JPASpecificationExecutor接口

四.Repository接口的使用

1.提供了方法名稱命名查詢方式

1.1編寫接口

//方法的名稱必須要遵循駝峯式命名規則。findBy(關鍵字)+屬性名稱(首字母要大寫)+查詢條件(首字母大寫)

package com.kennosaur.dao;

import java.util.List;

import org.springframework.data.repository.Repository;

import com.kennosaur.pojo.Users;

/**
 * Repository接口的方法名稱命名查詢
 *
 *
 */
public interface UsersRepositoryByName extends Repository<Users, Integer> {

	//方法的名稱必須要遵循駝峯式命名規則。findBy(關鍵字)+屬性名稱(首字母要大寫)+查詢條件(首字母大寫)
	List<Users> findByName(String name);
	
	List<Users> findByNameAndAge(String name,Integer age);
	
	List<Users> findByNameLike(String name);
}

1.2測試代碼

package com.kennosaur.test;

import java.util.List;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import com.kennosaur.App;
import com.kennosaur.dao.UsersRepository;
import com.kennosaur.dao.UsersRepositoryByName;
import com.kennosaur.pojo.Users;

/**
 * 測試類
 * @author Administrator
 *
 */

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = App.class)
public class UsersRepositoryTest {
	
	@Autowired
	private UsersRepositoryByName usersRepositoryByName;
	
	
	/**
	 * Repository--方法名稱命名測試
	 */
	@Test
	public void testFindByName(){
		List<Users> list = this.usersRepositoryByName.findByName("張三");
		for (Users users : list) {
			System.out.println(users);
		}
	}
	
	/**
	 * Repository--方法名稱命名測試
	 */
	@Test
	public void testFindByNameAndAge(){
		List<Users> list = this.usersRepositoryByName.findByNameAndAge("張三", 20);
		for (Users users : list) {
			System.out.println(users);
		}
	}
	
	/**
	 * Repository--方法名稱命名測試
	 */
	@Test
	public void testFindByNameLike(){
		List<Users> list = this.usersRepositoryByName.findByNameLike("張%");
		for (Users users : list) {
			System.out.println(users);
		}
	}
}

2.提供了基於@Query註解查詢與更新

2.1編寫接口

@Query("update Users set name=:name where id=:id") --------注意使用?佔位符會報錯
@Modifying //需要執行一個更新操作

package com.kennosaur.dao;

import java.util.List;

import org.springframework.data.jpa.repository.Modifying;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.Repository;

import com.kennosaur.pojo.Users;

public interface UsersRepositoryQueryAnnotation extends Repository<Users, Integer> {
	@Query("from Users where name=:name")
	List<Users> queryByNameUseHQL(String name);
	
	@Query(value="select * from t_users where name = ?",nativeQuery=true)
	List<Users> queryByNameUseSQL(String name);
	
	@Query("update Users set name=:name where id=:id")
	@Modifying //需要執行一個更新操作
	void updateUsersNameById(String name,Integer id);
}

2.2測試代碼

@Transactional //@Transactional與@Test 一起使用時事務是自動回滾的。
@Rollback(false) //取消自動回滾

package com.kennosaur.test;

import java.util.List;

import javax.transaction.Transactional;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.annotation.Rollback;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import com.kennosaur.App;
import com.kennosaur.dao.UsersRepository;
import com.kennosaur.dao.UsersRepositoryByName;
import com.kennosaur.dao.UsersRepositoryQueryAnnotation;
import com.kennosaur.pojo.Users;

/**
 * 測試類
 * @author Administrator
 *
 */

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = App.class)
public class UsersRepositoryTest {
	@Autowired
	private UsersRepositoryQueryAnnotation usersRepositoryQueryAnnotation;
	
	/**
	 * Repository--@Query測試
	 */
	@Test
	public void testQueryByNameUseHQL() {
		List<Users> list = this.usersRepositoryQueryAnnotation.queryByNameUseHQL("張三");
		for (Users users : list) {
			System.out.println(users);
		}
	}

	/**
	 * Repository--@Query測試
	 */
	@Test
	public void testQueryByNameUseSQL() {
		List<Users> list = this.usersRepositoryQueryAnnotation.queryByNameUseSQL("張三");
		for (Users users : list) {
			System.out.println(users);
		}
	}
	
	/**
	 * Repository--@Query測試
	 */
	@Test
	@Transactional //@Transactional與@Test 一起使用時 事務是自動回滾的。
	@Rollback(false) //取消自動回滾
	public void testUpdateUsersNameById() {
		this.usersRepositoryQueryAnnotation.updateUsersNameById("張三三", 1);
	}
	

	
	
}

五.CrudRepository接口-----主要作用是完成一些增刪改查的操作,CrudRepository接口繼承了Repository接口

1.編寫接口

package com.kennosaur.dao;

import org.springframework.data.repository.CrudRepository;

import com.kennosaur.pojo.Users;

/**
 * CrudRepository接口
 *
 *
 */
public interface UsersRepositoryCrudRepository extends CrudRepository<Users, Integer> {

}

2.測試代碼

注意:Optional<Users> users = this.usersRepositoryCrudRepository.findById(4);

	/**
	 * CrudRepository測試
	 */
	@Test
	public void testCrudRepositorySave() {
		Users user = new Users();
		user.setAddress("天津");
		user.setAge(32);
		user.setName("張三丰");
		this.usersRepositoryCrudRepository.save(user);
	}
	
	/**
	 * CrudRepository測試
	 */
	@Test
	public void testCrudRepositoryUpdate() {
		Users user = new Users();
		user.setId(4);
		user.setAddress("南京");
		user.setAge(40);
		user.setName("張三丰");
		this.usersRepositoryCrudRepository.save(user);
	}
	
	/**
	 * CrudRepository測試
	 */
	@Test
	public void testCrudRepositoryFindOne() {
		Optional<Users> users = this.usersRepositoryCrudRepository.findById(4);
		System.out.println(users);
	}
	
	/**
	 * CrudRepository測試
	 */
	@Test
	public void testCrudRepositoryFindAll() {
		List<Users> list  =  (List<Users>)this.usersRepositoryCrudRepository.findAll();
		for (Users users : list) {
			System.out.println(users);
		}
	}
	
	/**
	 * CrudRepository測試
	 */
	@Test
	public void testCrudRepositoryDeleteById() {
		this.usersRepositoryCrudRepository.deleteById(4);
		
	}

六.PagingAndSortingRepository接口-------提供了分頁與排序操作,該接口繼承了CrudRepository接口

1.編寫接口

package com.kennosaur.dao;

import org.springframework.data.repository.PagingAndSortingRepository;

import com.kennosaur.pojo.Users;
/**
 * 
 *PagingAndSortingRepository接口
 *
 */
public interface UsersRepositoryPagingAndSorting extends PagingAndSortingRepository<Users,Integer> {

}

2.測試代碼

注意:Sort sort = new Sort(order);報錯

Pageable pageable = new PageRequest(1, 2);報錯

Pageable pageable = new PageRequest(1, 2, sort);報錯

	/**
	 * PagingAndSortingRepository   排序測試
	 */
	@Test
	public void testPagingAndSortingRepositorySort() {
		//Order 定義排序規則
		Order order = new Order(Direction.DESC,"id");
		//Sort對象封裝了排序規則
//		Sort sort = new Sort(order);
		List<Users> list = (List<Users>)this.usersRepositoryPagingAndSorting.findAll(Sort.by(order));
		for (Users users : list) {
			System.out.println(users);
		}
	}
	
	/**
	 * PagingAndSortingRepository   分頁測試
	 */
	@Test
	public void testPagingAndSortingRepositoryPaging() {
		//Pageable:封裝了分頁的參數，當前頁，每頁顯示的條數。注意：他的當前頁是從0開始。
		//PageRequest(page,size) page:當前頁。size:每頁顯示的條數
//		Pageable pageable = new PageRequest(1, 2);
		Pageable pageable = PageRequest.of(1, 2);
	    Page<Users> page = this.usersRepositoryPagingAndSorting.findAll(pageable);
		System.out.println("總條數："+page.getTotalElements());
		System.out.println("總頁數"+page.getTotalPages());
		List<Users> list = page.getContent();
		for (Users users : list) {
			System.out.println(users);
		}
	}
	
	/**
	 * PagingAndSortingRepository   排序+分頁
	 */
	@Test
	public void testPagingAndSortingRepositorySortAndPaging() {
		
//		Sort sort = new Sort(new Order(Direction.DESC, "id"));		
//		Pageable pageable = new PageRequest(1, 2, sort);
		
		Sort sort = Sort.by(new Order(Direction.DESC, "id"));		
		Pageable pageable = PageRequest.of(1, 2, sort);
				
		Page<Users> page = this.usersRepositoryPagingAndSorting.findAll(pageable);
		System.out.println("總條數："+page.getTotalElements());
		System.out.println("總頁數"+page.getTotalPages());
		List<Users> list = page.getContent();
		for (Users users : list) {
			System.out.println(users);
		}
	}

七.JpaRepository接口----------開發中用的比較多.

繼承了PagingAndSortingRepository接口,對繼承的父接口中的方法的返回值進行適配(不需要做強制類型轉換)

1.編寫接口

package com.kennosaur.dao;

import org.springframework.data.jpa.repository.JpaRepository;

import com.kennosaur.pojo.Users;

/**
 * 參數一T:當前需要映射的實體
 * 參數二ID:當前映射的實體中的OID的類型
 * @author Administrator
 *
 */
public interface UsersRepository extends JpaRepository<Users, Integer> {

}

2.測試代碼

	/**
	 * JapRepository   排序測試
	 */
	@Test
	public void testJpaRepositorySort() {
		//Order 定義排序規則
		Order order = new Order(Direction.DESC,"id");
		//Sort對象封裝了排序規則
//		Sort sort = new Sort(order);
		List<Users> list = this.usersRepository.findAll(Sort.by(order));
		for (Users users : list) {
			System.out.println(users);
		}
	}

八.JPASpecificationExecutor接口----是單獨存在,完全獨立的(與上文中的四個接口不存在繼承關係)

該接口主要提供了多條件查詢的支持,並且可以在查詢中添加分頁和排序.通常與JpaRepository共同作用

1.編寫接口

package com.kennosaur.dao;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;

import com.kennosaur.pojo.Users;
/**
 * 
 *JpaSpecificationExecutor
 *
 */
public interface UsersRepositorySpecification extends JpaRepository<Users, Integer>, JpaSpecificationExecutor<Users> {

}

2.測試代碼

/**
	 * JpaSpecificationExecutor   單條件測試
	 */
	@Test
	public void testJpaSpecificationExecutor1() {
		
		/**
		 * Specification<Users>:用於封裝查詢條件
		 */
		Specification<Users> spec = new Specification<Users>() {
			
			//Predicate:封裝了 單個的查詢條件
			/**
			 * Root<Users> root:查詢對象的屬性的封裝。
			 * CriteriaQuery<?> query：封裝了我們要執行的查詢中的各個部分的信息，select  from order by
			 * CriteriaBuilder cb:查詢條件的構造器。定義不同的查詢條件
			 */
			@Override
			public Predicate toPredicate(Root<Users> root, CriteriaQuery<?> query, CriteriaBuilder cb) {
				// where name = '張三三'
				/**
				 * 參數一：查詢的條件屬性
				 * 參數二：條件的值
				 */
				Predicate pre = cb.equal(root.get("name"), "張三三");
				return pre;
			}
		};
		List<Users> list = this.usersRepositorySpecification.findAll(spec);
		for (Users users : list) {
			System.out.println(users);
		}
	}
	
	/**
	 * JpaSpecificationExecutor   多條件測試
	 */
	@Test
	public void testJpaSpecificationExecutor2() {
		
		/**
		 * Specification<Users>:用於封裝查詢條件
		 */
		Specification<Users> spec = new Specification<Users>() {
			
			//Predicate:封裝了 單個的查詢條件
			/**
			 * Root<Users> root:查詢對象的屬性的封裝。
			 * CriteriaQuery<?> query：封裝了我們要執行的查詢中的各個部分的信息，select  from order by
			 * CriteriaBuilder cb:查詢條件的構造器。定義不同的查詢條件
			 */
			@Override
			public Predicate toPredicate(Root<Users> root, CriteriaQuery<?> query, CriteriaBuilder cb) {
				// where name = '張三三' and age = 20				
			    List<Predicate> list = new ArrayList<>();
			    list.add(cb.equal(root.get("name"),"張三三"));
			    list.add(cb.equal(root.get("age"),20)); Predicate[] arr = new
			    Predicate[list.size()];				
				return cb.and(list.toArray(arr));
			}
		};
		List<Users> list = this.usersRepositorySpecification.findAll(spec);
		for (Users users : list) {
			System.out.println(users);
		}
	}

3.多條件查詢測試第二種寫法

/**
	 * JpaSpecificationExecutor   多條件測試第二種寫法
	 */
	@Test
	public void testJpaSpecificationExecutor3() {
		
		/**
		 * Specification<Users>:用於封裝查詢條件
		 */
		Specification<Users> spec = new Specification<Users>() {
			
			//Predicate:封裝了 單個的查詢條件
			/**
			 * Root<Users> root:查詢對象的屬性的封裝。
			 * CriteriaQuery<?> query：封裝了我們要執行的查詢中的各個部分的信息，select  from order by
			 * CriteriaBuilder cb:查詢條件的構造器。定義不同的查詢條件
			 */
			@Override
			public Predicate toPredicate(Root<Users> root, CriteriaQuery<?> query, CriteriaBuilder cb) {
				// where name = '張三三' and age = 20
				/*List<Predicate> list = new ArrayList<>();
				list.add(cb.equal(root.get("name"),"張三三"));
				list.add(cb.equal(root.get("age"),20));
				Predicate[] arr = new Predicate[list.size()];*/
				//(name = '張三' and age = 20) or id = 2
				return cb.or(cb.and(cb.equal(root.get("name"),"張三三"),cb.equal(root.get("age"),20)),cb.equal(root.get("id"), 2));
			}
		};
		
		Sort sort = Sort.by(new Order(Direction.DESC,"id"));
		List<Users> list = this.usersRepositorySpecification.findAll(spec,sort);
		for (Users users : list) {
			System.out.println(users);
		}
	}

SpringBoot----SpringBoot 整合Spring Data JPA(一)

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SpringBoot----SpringBoot 整合Spring Data JPA(一)

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