package com.mgj;
import java.sql.Date;
/**
* 实体类,存放Employees表中的数据
* */
public class Employees {
int employees_id ;
String first_name;
String last_name;
String email;
String phone_number;
Date hire_date;
String job_id;
float salary;
public int getEmployees_id() {
return employees_id;
}
public void setEmployees_id(int employees_id) {
this.employees_id = employees_id;
}
public String getFirst_name() {
return first_name;
}
public void setFirst_name(String first_name) {
this.first_name = first_name;
}
public String getLast_name() {
return last_name;
}
public void setLast_name(String last_name) {
this.last_name = last_name;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getPhone_number() {
return phone_number;
}
public void setPhone_number(String phone_number) {
this.phone_number = phone_number;
}
public Date getHire_date() {
return hire_date;
}
public void setHire_date(Date hire_date) {
this.hire_date = hire_date;
}
public String getJob_id() {
return job_id;
}
public void setJob_id(String job_id) {
this.job_id = job_id;
}
public float getSalary() {
return salary;
}
public void setSalary(float salary) {
this.salary = salary;
}
@Override
public String toString() {
return "Employees{" +
"employees_id=" + employees_id +
", first_name='" + first_name + '\'' +
", last_name='" + last_name + '\'' +
", email='" + email + '\'' +
", phone_number='" + phone_number + '\'' +
", hire_date=" + hire_date +
", job_id='" + job_id + '\'' +
", salary=" + salary +
'}';
}
}
----------------------------------------------------
package com.mgj;
import java.net.DatagramPacket;
import java.sql.Connection;
import java.sql.Date;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
/**
* 获取结果集测试类
* */
public class ResultSetTest {
/**
* 查询所有用户
* */
public List<Employees> selectEmployeesAll(){
Connection connection = null;
PreparedStatement preparedStatement = null;
ResultSet resultSet = null;
List<Employees> list = new ArrayList<>();
try {
//获取数据库连接
connection = JdbcUtils.getConnection();
//创建PreparedStatement对象
preparedStatement = connection.prepareStatement("SELECT DISTINCT * FROM employees where salary>2000 ORDER BY SALARY DESC");
//执行SQL语句
resultSet = preparedStatement.executeQuery();
//操作ResultSet对象获取查询的结果集
while (resultSet.next()){
int i = resultSet.getInt("employee_id");
String str = resultSet.getString("first_name");
String str2 = resultSet.getString("last_name");
String str3 = resultSet.getString("email");
String str4 = resultSet.getString("phone_number");
Date date = resultSet.getDate("hire_date");
String str6 = resultSet.getString("job_id");
float fl = resultSet.getFloat("salary");
//System.out.println(str+" "+str2+" "+str3+" "+str4+" "+date+" "+str6+"————"+fl);
//ORM映射处理
Employees employees = new Employees();
employees.setEmployees_id(i);
employees.setFirst_name(str);
employees.setLast_name(str2);
employees.setEmail(str3);
employees.setPhone_number(str4);
employees.setHire_date(date);
employees.setJob_id(str6);
employees.setSalary(fl);
list.add(employees);
}
}catch (Exception e){
e.printStackTrace();
}finally {
JdbcUtils.closeResource(resultSet,preparedStatement,connection);
}
return list;
}
}
-------------------------------------------
package com.mgj;
import java.util.List;
public class Test {
public static void main(String[] args) {
/* StatementTest st = new StatementTest();
st.insertUsers("Mr.Meng_",23);
st.updateUsers(4,"Mr.Meng",18);
st.deleteUsersById(1);*/
/*PreparedStatementTest pst = new PreparedStatementTest();
//pst.insertUsers("Hello",19);
//pst.updateUsersById(9,"World",26);
pst.deleteUsersById(7);*/
ResultSetTest resultSetTest = new ResultSetTest();
//resultSetTest.selectEmployeesAll();
List<Employees> list = resultSetTest.selectEmployeesAll();
for (Employees employees:list){
System.out.println(list);
}
}
}
老师,我用这种方法查询Employees表中的数据,况且我添加了distinct去重
为什么我拿到的数据全是重复的呢?