File structure
1. Entity class instance Employee
package com.bdqn.entity;
import java.util.Date;
public class Employee {
private Integer empNo; //员工编号
private String empName; //员工姓名
private String job; // 职位
private Double salary; // 薪资
private Integer deptNo; // 部门编号
private Date hireDate; // 入职时间
// public Employee(String empName,String job, Double salary,Integer deptNo,Date hireDate){
// this.empName = empName;
// this.job = job;
// this.salary = salary;
// this.deptNo = deptNo;
// this.hireDate = hireDate;
// }
public Integer getEmpNo() {
return empNo;
}
public String getEmpName() {
return empName;
}
public String getJob() {
return job;
}
public Double getSalary() {
return salary;
}
public Integer getDeptNo() {
return deptNo;
}
public Date getHireDate() {
return hireDate;
}
public void setEmpNo(Integer empNo) {
this.empNo = empNo;
}
public void setEmpName(String empName) {
this.empName = empName;
}
public void setJob(String job) {
this.job = job;
}
public void setSalary(Double salary) {
this.salary = salary;
}
public void setDeptNo(Integer deptNo) {
this.deptNo = deptNo;
}
public void setHireDate(Date hireDate) {
this.hireDate = hireDate;
}
@Override
public String toString() {
return "Employee{" +
"empNo=" + empNo +
", empName='" + empName + '\'' +
", job='" + job + '\'' +
", salary=" + salary +
", deptNo=" + deptNo +
", hireDate=" + hireDate +
'}';
}
}
2. The utils class converts the string into Date format
File name: DateUtil.class
package com.bdqn.utils;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.text.ParseException;
public class DateUtil {
/**
* 将字符创转换成 Date 日期格式
* @param str
* @return
* */
public static Date formatDate(String str){
try{
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
return format.parse(str);
} catch (ParseException e){
e.fillInStackTrace();
}
return null;
}
}
3. Expand entity EmployeeVo
com.xxx.vo.EmployeeVo.class
will automatically generate fields without
package com.bdqn.vo;
import com.bdqn.entity.Employee;
import java.util.Date;
import java.util.zip.DataFormatException;
/**
* 自定义查询类
* 该类制作查询条件的参数（方法参数），不做方法的返回值类型
* */
public class EmployeeVo extends Employee {
// 开始时间
private Date startDate;
// 结束时间
private Date endDate;
public Date getStartDate() {
return startDate;
}
public Date getEndDate() {
return endDate;
}
public void setStartDate(Date startDate) {
this.startDate = startDate;
}
public void setEndDate(Date endDate) {
this.endDate = endDate;
}
}
4. Increase
5. Delete
6. Change
6.1
/**
* 按位置进行参数绑定
* 注意：高版本hibernate下标从1开始
* */
@Test
public void testParamter1(){
// 获取Session
Session session = HibernateUtil.getSession();
// 定义HQL语句
String hql = "from Employee where empName like ?1 and salary >= ?2";
// 创建Query对象
Query query = session.createQuery(hql);
// 赋值
// query.setString(1,"%国%");
// query.setDouble(1,5000);
// 推荐使用 setParameter()
query.setParameter(1,"%国%");
query.setParameter(2,5000.0);
// 执行查询
List<Employee> list = query.list();
for (Employee employee : list) {
System.out.println(employee);
}
}
6.2
/**
*
* */
@Test
public void testParamter2(){
// 获取Session
Session session = HibernateUtil.getSession();
// 定义HQL语句
String hql = "from Employee where empName like :empName and salary >= :salary";
// 创建Query对象
Query query = session.createQuery(hql);
// 赋值
// query.setString(1,"%国%");
// query.setDouble(1,5000);
// 推荐使用 setParameter()
query.setParameter("empName","%国%");
query.setParameter("salary",5000.0);
// 执行查询
List<Employee> list = query.list();
for (Employee employee : list) {
System.out.println(employee);
}
}
7. Check
7.1 list()
/**
* 查询所有员工列表
* */
@Test
public void testList(){
// 获取Session(使用openSession()方式获取)
Session session = HibernateUtil.getSession();
try{
// 定义HQl语句 查询的是实体类类名
String hql = "from Employee";
// 创建Query对象
Query query = session.createQuery(hql);
// 执行查询
List<Employee> list = query.list();
// 循环遍历
for (Employee employee : list) {
// 快捷键: iter
System.out.println(employee);
}
} catch (Exception e){
e.printStackTrace();
} finally {
// 关闭资源
HibernateUtil.closeSession(session);
}
}
7.2 iterate()
/**
* 查询所有员工列表
* */
@Test
public void testIternate(){
// 获取Session(使用openSession()方式获取)
Session session = HibernateUtil.getSession();
try{
// 定义HQl语句 查询的是实体类类名
String hql = "from Employee";
// 创建Query对象
Query query = session.createQuery(hql);
// 执行查询
Iterator<Employee> iterate = query.iterate(); // 会发出1+N田sql语句
//循环遍历
while(iterate.hasNext()) {
// 得到每一个员工对象
Employee employee = iterate.next();
System.out.println(employee);
}
} catch (Exception e){
// 关闭资源
HibernateUtil.closeSession(session);
}
}
7.3 Dynamic condition query
/**
* 动态条件查询
* */
@Test
public void testEmployee(){
// 创建查询条件类对象
EmployeeVo employeeVo = new EmployeeVo();
employeeVo.setJob("python程序员");
employeeVo.setStartDate(DateUtil.formatDate("2018-01-01"));
employeeVo.setEndDate(DateUtil.formatDate("2021-01-01"));
// 获取 Session
Session session = HibernateUtil.getSession();
// 定义 sql 语句
StringBuilder hql = new StringBuilder("from Employee where 1=1 ");
// 判断条件是否为空
if(employeeVo != null){
// 薪资
if(employeeVo.getSalary() != null){
hql.append(" and salary >= :salary"); // 命名参数必须与实体类的属性名相同
}
// 职位
if(employeeVo.getJob() != null && employeeVo.getJob().equals("")){
hql.append(" and job = :job"); // 命名参数必须与实体类的属性名相同
}
// 开始时间
if(employeeVo.getStartDate() != null){
hql.append(" and hireDate >= startDate");
}
// 结束时间
if(employeeVo.getEndDate() != null){
hql.append(" and hireDate <= :endDate");
}
}
// 创建 query 对象
Query query = session.createQuery(hql.toString());
// 赋值
query.setProperties(employeeVo);//要求：必须保证命名擦书名称与实体类的属性名相同
// 执行查询
List<Employee> list = query.list();
for (Employee employee : list) {
System.out.println(employee);
}
}