JPQL全称Java Persistence Query Language
package com.ytkj.entity;
import javax.persistence.*;
import java.io.Serializable;
/**
* @Entity
* 作用：指定当前类是实体类。
* @Table
* 作用：指定实体类和表之间的对应关系。
* 属性：
* name：指定数据库表的名称
* @Id
* 作用：指定当前字段是主键。
* @GeneratedValue
* 作用：指定主键的生成方式。。
* 属性：
* strategy ：指定主键生成策略。
* @Column
* 作用：指定实体类属性和数据库表之间的对应关系
* 属性：
* name：指定数据库表的列名称。
* unique：是否唯一
* nullable：是否可以为空
* inserttable：是否可以插入
* updateable：是否可以更新
* columnDefinition: 定义建表时创建此列的DDL
* secondaryTable: 从表名。如果此列不建在主表上（默认建在主表），该属性定义该列所在从表的名字搭建开发环境[重点]
*
* 客户实体类
* 配置映射关系
* 实体类和表映射
* 实体类属性和表字段映射
*/
@Entity
@Table(name = "cst_customer")
public class Customer implements Serializable {
/**
* 声明主键配置
*/
@Id
/**
* 配置主键的生成策略
*/
@GeneratedValue(strategy = GenerationType.IDENTITY)
/**
* 指定实体类属性和数据库表之间的对应关系
*/
@Column(name ="cust_id")
private Long custId;//客户主键
@Column(name = "cust_name")
private String custName;//客户名称
@Column(name ="cust_source" )
private String custSource;//客户来源
@Column(name = "cust_industry")
private String custIndustry;//客户行业
@Column(name ="cust_level")
private String custLevel;//客户级别
@Column(name ="cust_address")
private String custAddress;//客户地址
@Column(name = "cust_phone")
private String custPhone;//客户电话
public Long getCustId() {
return custId;
}
public void setCustId(Long custId) {
this.custId = custId;
}
public String getCustName() {
return custName;
}
public void setCustName(String custName) {
this.custName = custName;
}
public String getCustSource() {
return custSource;
}
public void setCustSource(String custSource) {
this.custSource = custSource;
}
public String getCustIndustry() {
return custIndustry;
}
public void setCustIndustry(String custIndustry) {
this.custIndustry = custIndustry;
}
public String getCustLevel() {
return custLevel;
}
public void setCustLevel(String custLevel) {
this.custLevel = custLevel;
}
public String getCustAddress() {
return custAddress;
}
public void setCustAddress(String custAddress) {
this.custAddress = custAddress;
}
public String getCustPhone() {
return custPhone;
}
public void setCustPhone(String custPhone) {
this.custPhone = custPhone;
}
@Override
public String toString() {
return "Customer{" +
"custId=" + custId +
", custName='" + custName + '\'' +
", custSource='" + custSource + '\'' +
", custIndustry='" + custIndustry + '\'' +
", custLevel='" + custLevel + '\'' +
", custAddress='" + custAddress + '\'' +
", custPhone='" + custPhone + '\'' +
'}';
}
}
package com.ytkj.test;
import com.ytk.utils.JpaUtils;
import org.junit.Test;
import javax.persistence.EntityManager;
import javax.persistence.EntityTransaction;
import javax.persistence.Query;
import java.util.List;
/**
* jpql测试
*/
public class JpqlTest {
/**
* 查询全部
*/
@Test
public void findAll(){
EntityManager entityManager = JpaUtils.getEntityManager();
//开启事务
EntityTransaction transaction = entityManager.getTransaction();
transaction.begin();
//创建query对象 操作实体类而不是直接取操作数据库
String jpql="from Customer";
Query query = entityManager.createQuery(jpql);
//查询
List list = query.getResultList();
for (Object o : list) {
System.out.println(o);
}
//5.提交事务
transaction.commit();
//6.释放资源
entityManager.close();
}
/**
* 排序查询
*/
@Test
public void findAllOrderBy(){
EntityManager entityManager = JpaUtils.getEntityManager();
//开启事务
EntityTransaction transaction = entityManager.getTransaction();
transaction.begin();
//创建query对象 操作实体类而不是直接取操作数据库
String jpql="from Customer order by custId desc";
Query query = entityManager.createQuery(jpql);
//查询
List list = query.getResultList();
for (Object o : list) {
System.out.println(o);
}
//5.提交事务
transaction.commit();
//6.释放资源
entityManager.close();
}
/**
* 查询总数
*/
@Test
public void getCount(){
EntityManager entityManager = JpaUtils.getEntityManager();
//开启事务
EntityTransaction transaction = entityManager.getTransaction();
transaction.begin();
//创建query对象 操作实体类而不是直接取操作数据库
String jpql="select count(custId) from Customer ";
Query query = entityManager.createQuery(jpql);
//查询
Object result = query.getSingleResult();
System.out.println(result);
//5.提交事务
transaction.commit();
//6.释放资源
entityManager.close();
}
/**
* 分页查询
*/
@Test
public void getByPage(){
EntityManager entityManager = JpaUtils.getEntityManager();
//开启事务
EntityTransaction transaction = entityManager.getTransaction();
transaction.begin();
//创建query对象 操作实体类而不是直接取操作数据库
int pageNum=0;
int pageSize=2;
String jpql=" from Customer";
Query query = entityManager.createQuery(jpql);
//对分页参数赋值
query.setFirstResult(pageNum);
query.setMaxResults(pageSize);
//查询
List list = query.getResultList();
for (Object o : list) {
System.out.println(o);
}
//5.提交事务
transaction.commit();
//6.释放资源
entityManager.close();
}
/**
* 条件查询
*/
@Test
public void getByCondition(){
EntityManager entityManager = JpaUtils.getEntityManager();
//开启事务
EntityTransaction transaction = entityManager.getTransaction();
transaction.begin();
//创建query对象 操作实体类而不是直接取操作数据库
String jpql=" from Customer where custName like ?";
Query query = entityManager.createQuery(jpql);
//对占位符参数赋值
query.setParameter(1,"zhe%");
//查询
List list = query.getResultList();
for (Object o : list) {
System.out.println(o);
}
//5.提交事务
transaction.commit();
//6.释放资源
entityManager.close();
}
}
