Spring 三种数据库连接方式、传统连接、JdbcTemplate、Spring Jpa data（下）
我现在经常用到Spring JPA Data
和逆向工程一样方便
GitHub地址：https://github.com/binlian/binglian-Spring-JPA-Data
它有自己的定义规则，可以不用在写那些SQL语句了，
可以根据id name来查询 两个一起查询等
public Employee findByName(String name);
这传代码就是 根据name查询数据
Maven jar引入 放入pom.xml
org.springframework.data
spring-data-jpa
1.8.0.RELEASE
org.hibernate
hibernate-entitymanager
4.3.6.Final
配置文件
bean-new.xml
其实这些配置都是一环扣一环的
org.hibernate.cfg.ImprovedNamingStrategy
org.hibernate.dialect.MySQL5InnoDBDialect
true
true
update
然后看下代码
使用Jpa 需要继承Repository
也可以使用注解方式（添加注解能到达到不用extends Repository的功能）
@RepositoryDefinition(domainClass = Employee.class, idClass = Integer.class)
Repository类的定义：
public interface Repository
}
Repository是一个空接口，标记接口
没有包含方法声明的接口
package com.binglian.repository;
import org.springframework.data.jpa.repository.Modifying;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.Repository;
import org.springframework.data.repository.RepositoryDefinition;
import org.springframework.data.repository.query.Param;
import com.binglian.domain.Employee;
import java.util.List;
@RepositoryDefinition(domainClass = Employee.class, idClass = Integer.class)
public interface EmployeeRepository { //extends Repository{
public Employee findByName(String name);
// where name like ?% and age findByNameStartingWithAndAgeLessThan(String name, Integer age);
// where name like %? and age findByNameEndingWithAndAgeLessThan(String name, Integer age);
// where name in (?,?....) or age findByNameInOrAgeLessThan(List names, Integer age);
// where name in (?,?....) and age findByNameInAndAgeLessThan(List names, Integer age);
@Query("select o from Employee o where id=(select max(id) from Employee t1)")
public Employee getEmployeeByMaxId();
@Query("select o from Employee o where o.name=?1 and o.age=?2")
public List queryParams1(String name, Integer age);
@Query("select o from Employee o where o.name=:name and o.age=:age")
public List queryParams2(@Param("name")String name, @Param("age")Integer age);
@Query("select o from Employee o where o.name like %?1%")
public List queryLike1(String name);
@Query("select o from Employee o where o.name like %:name%")
public List queryLike2(@Param("name")String name);
@Query(nativeQuery = true, value = "select count(1) from employee")
public long getCount();
@Modifying
@Query("update Employee o set o.age = :age where o.id = :id")
public void update(@Param("id")Integer id, @Param("age")Integer age);
}
test类
package com.imooc.repository;
import org.hibernate.action.internal.EntityIncrementVersionProcess;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
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 com.binglian.domain.Employee;
import com.binglian.repository.EmployeeJpaRepository;
import com.binglian.repository.EmployeePagingAndSortingReposity;
import com.binglian.repository.EmployeeRepository;
import com.binglian.service.EmployeeService;
import java.util.ArrayList;
import java.util.List;
public class EmployeeJpaRepositoryTest {
private ApplicationContext ctx = null;
private EmployeeJpaRepository employeeJpaRepository=null;
@Before
public void setup() {
ctx = new ClassPathXmlApplicationContext("beans-new.xml");
employeeJpaRepository= ctx.getBean(EmployeeJpaRepository.class);
System.out.println("setup");
}
@After
public void tearDown() {
ctx = null;
System.out.println("tearDown");
}
@Test
public void testFind(){
Employee employee=employeeJpaRepository.findOne(99);
System.out.println("employee:"+employee);
System.out.println("emloyee(10)"+employeeJpaRepository.exists(10));
System.out.println("emloyee(102)"+employeeJpaRepository.exists(102));
}
}
更新删除 需要@Modifying
也需要service 才可以成功运行
@Modifying
@Query("update Employee o set o.age = :age where o.id = :id")
public void update(@Param("id")Integer id, @Param("age")Integer age);
自动创建数据库 根据实体类自动创建数据库
package com.binglian.domain;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
/**
* 雇员：先开发实体类====>自动生成数据表
*/
@Entity
@Table(name="test_employee")
public class Employee {
private Integer id;
private String name;
private Integer age;
@GeneratedValue
@Id
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
@Column(length = 20)
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;
}
}
CrudReository
package com.binglian.repository;
import org.springframework.data.jpa.repository.JpaRepository;
import com.binglian.domain.Employee;
public interface EmployeeJpaRepository extends JpaRepository{
}
test类
save使用
employeeService.save(employees);
package com.imooc.repository;
import org.hibernate.action.internal.EntityIncrementVersionProcess;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.binglian.domain.Employee;
import com.binglian.repository.EmployeeRepository;
import com.binglian.service.EmployeeService;
import java.util.ArrayList;
import java.util.List;
public class EmployeeCrudRepositoryTest {
private ApplicationContext ctx = null;
private EmployeeService employeeService=null;
@Before
public void setup() {
ctx = new ClassPathXmlApplicationContext("beans-new.xml");
employeeService= ctx.getBean(EmployeeService.class);
System.out.println("setup");
}
@After
public void tearDown() {
ctx = null;
System.out.println("tearDown");
}
@Test
public void testSave(){
List employees=new ArrayList();
Employee employee=null;
for(int i=0;i<100;i++){
employee=new Employee();
employee.setAge(100-i);
employee.setName("test"+i);
employees.add(employee);
}
employeeService.save(employees);
}
}
这个分页在工作也比较常用
分页、排序
package com.binglian.repository;
import org.springframework.data.repository.PagingAndSortingRepository;
import com.binglian.domain.Employee;
public interface EmployeePagingAndSortingReposity extends PagingAndSortingRepository{
}
Test类
Sort.Direction.DESC,"id"根据id正序
Sort.Order order=new Sort.Order(Sort.Direction.DESC,"id");
Sort sort=new Sort(order);
//page：index是0开始的,不是从1开始的
Pageable pageable=new PageRequest(0, 5);
Page
Page 封装了页数这些属性
System.out.println("查询的总页数"+page.getTotalPages());
System.out.println("查询的总记录数"+page.getTotalElements());
package com.imooc.repository;
import org.hibernate.action.internal.EntityIncrementVersionProcess;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
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 com.binglian.domain.Employee;
import com.binglian.repository.EmployeePagingAndSortingReposity;
import com.binglian.repository.EmployeeRepository;
import com.binglian.service.EmployeeService;
import java.util.ArrayList;
import java.util.List;
public class EmployeePagingSortingRepositoryTest {
private ApplicationContext ctx = null;
private EmployeePagingAndSortingReposity employeePagingAndSortingReposity=null;
@Before
public void setup() {
ctx = new ClassPathXmlApplicationContext("beans-new.xml");
employeePagingAndSortingReposity= ctx.getBean(EmployeePagingAndSortingReposity.class);
System.out.println("setup");
}
@After
public void tearDown() {
ctx = null;
System.out.println("tearDown");
}
@Test
public void testPage(){
//根据id正序排序
Sort.Order order=new Sort.Order(Sort.Direction.DESC,"id");
Sort sort=new Sort(order);
//page：index是0开始的,不是从1开始的
Pageable pageable=new PageRequest(0, 5);
Page page=employeePagingAndSortingReposity.findAll(pageable);
System.out.println("查询的总页数"+page.getTotalPages());
System.out.println("查询的总记录数"+page.getTotalElements());
System.out.println("查询的当前第几页"+page.getNumber());
System.out.println("查询的当前页面的集合"+page.getContent());
System.out.println("查询的当前页面的记录数"+page.getNumberOfElements());
}
}
JpaRepository
package com.binglian.repository;
import org.springframework.data.jpa.repository.JpaRepository;
import com.binglian.domain.Employee;
public interface EmployeeJpaRepository extends JpaRepository{
}
JpaSpecificationRepository
这个是多继承可以使用两个方法
package com.binglian.repository;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
import com.binglian.domain.Employee;
/**
* 也是可以多继承
* @author binglian
*
*/
public interface EmployeeJpaSpecificationExecutorRepository
extends JpaRepository,JpaSpecificationExecutor{
}
/**
* root:就是我们要查询的类型(Employee)
* query:添加查询天剑
* cb:构建Predicate
*/
Specification specification=new Specification() {
@Override
public Predicate toPredicate(Root root,
CriteriaQuery query,
CriteriaBuilder cb) {
Path path=root.get("age");
return cb.gt(path, 50);//age大于20;
}
};
Page page=employeeJpaSpecificationExecutorRepository.findAll(specification,pageable);
package com.imooc.repository;
import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Path;
import javax.persistence.criteria.Predicate;
import javax.persistence.criteria.Root;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
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.jpa.domain.Specification;
import com.binglian.domain.Employee;
import com.binglian.repository.EmployeeJpaRepository;
import com.binglian.repository.EmployeeJpaSpecificationExecutorRepository;
public class EmployeeJpaSpecificationExecutorRepositoryTest {
private ApplicationContext ctx = null;
private EmployeeJpaSpecificationExecutorRepository employeeJpaSpecificationExecutorRepository=null;
@Before
public void setup() {
ctx = new ClassPathXmlApplicationContext("beans-new.xml");
employeeJpaSpecificationExecutorRepository= ctx.getBean(EmployeeJpaSpecificationExecutorRepository.class);
System.out.println("setup");
}
@After
public void tearDown() {
ctx = null;
System.out.println("tearDown");
}
/**
* 分页
* 排序
* 查询条件
*/
@Test
public void testQuery(){
//根据id正序排序
Sort.Order order=new Sort.Order(Sort.Direction.DESC,"id");
Sort sort=new Sort(order);
//page：index是0开始的,不是从1开始的
Pageable pageable=new PageRequest(0, 5);
/**
* root:就是我们要查询的类型(Employee)
* query:添加查询天剑
* cb:构建Predicate
*/
Specification specification=new Specification() {
@Override
public Predicate toPredicate(Root root,
CriteriaQuery query,
CriteriaBuilder cb) {
Path path=root.get("age");
return cb.gt(path, 50);//age大于20;
}
};
Page page=employeeJpaSpecificationExecutorRepository.findAll(specification,pageable);
// Page page=employeeJpaSpecificationExecutorRepository.findAll(pageable);
System.out.println("查询的总页数"+page.getTotalPages());
System.out.println("查询的总记录数"+page.getTotalElements());
System.out.println("查询的当前第几页"+page.getNumber());
System.out.println("查询的当前页面的集合"+page.getContent());
System.out.println("查询的当前页面的记录数"+page.getNumberOfElements());
}
}