JDBC_ORM原理_使用javabean对象封装一条和多条记录

Demo类

package com.lzy.obj;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class Demo13 {

	public static void main(String[] args) {
		test02();
		
	}
	public static void test01() {//封装一条记录
		Connection conn=JDBCUtil.getMysqlConn();
		PreparedStatement ps=null;
		ResultSet rs=null;
		Emp emp=null;
		
		
		
		try {
			ps=conn.prepareStatement("select empname,salary,age from emp where id=?");
			ps.setObject(1, 1);
			rs=ps.executeQuery();
			
			while(rs.next()) {
				
				emp = new Emp(rs.getString(1),rs.getDouble(2),rs.getInt(3));
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally {
			JDBCUtil.close(rs,ps,conn);
		}
		System.out.println(emp.getEmpname()+"-"+emp.getSalary()+"-"+emp.getAge());
	}
	
	public static void test02() {//封装多条记录
		Connection conn=JDBCUtil.getMysqlConn();
		PreparedStatement ps=null;
		ResultSet rs=null;
		
		List<Emp>list=new ArrayList<>();
		try {
			ps=conn.prepareStatement("select empname,salary,age from emp where id>?");
			ps.setObject(1, 1);
			rs=ps.executeQuery();
			
			while(rs.next()) {
				
				Emp emp = new Emp(rs.getString(1),rs.getDouble(2),rs.getInt(3));
				list.add(emp);
				
				
				
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally {
			JDBCUtil.close(rs,ps,conn);
		}
		///遍历List，就是遍历这一行的多列的信息
		for(Emp emp:list){
			System.out.println(emp.getEmpname()+"-"+emp.getSalary()+"-"+emp.getAge());
		}
	}
}

封装Emp和Dept类（类名要和数据库表名相同，属性要和数据库表里的属性对应一致）
Emp类

package com.lzy.obj;

import java.sql.Date;

public class Emp {//表结构和类对应

	private Integer id;
	private String empname;
	private Integer age;
	private Double salary;
	private Date birthday;
	private Integer deptId;
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public String getEmpname() {
		return empname;
	}
	public void setEmpname(String empname) {
		this.empname = empname;
	}
	public Integer getAge() {
		return age;
	}
	public void setAge(Integer age) {
		this.age = age;
	}
	public Double getSalary() {
		return salary;
	}
	public void setSalary(Double salary) {
		this.salary = salary;
	}
	public Date getBirthday() {
		return birthday;
	}
	public void setBirthday(Date birthday) {
		this.birthday = birthday;
	}
	public Integer getDeptId() {
		return deptId;
	}
	public void setDeptId(Integer deptId) {
		this.deptId = deptId;
	}
	public Emp(Integer id, String empname, Integer age, Double salary, Date birthday, Integer deptId) {
		super();
		this.id = id;
		this.empname = empname;
		this.age = age;
		this.salary = salary;
		this.birthday = birthday;
		this.deptId = deptId;
	}
	public Emp(String empname, Integer age, Double salary, Date birthday, Integer deptId) {
		super();
		this.empname = empname;
		this.age = age;
		this.salary = salary;
		this.birthday = birthday;
		this.deptId = deptId;
	}
	public Emp(String empname, Double salary, Integer age) {
		
		this.empname = empname;
		
		this.salary = salary;
		this.age = age;
	}
	
	public Emp() {
		
	}
	
}

Dept类

package com.lzy.obj;

public class Dept {
	private Integer id;
	private String dname;
	private String address;
	
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public String getDname() {
		return dname;
	}
	public void setDname(String dname) {
		this.dname = dname;
	}
	public String getAddress() {
		return address;
	}
	public void setAddress(String address) {
		this.address = address;
	}
	public Dept(Integer id, String dname, String address) {
		super();
		this.id = id;
		this.dname = dname;
		this.address = address;
	}
	public Dept(String dname, String address) {
		super();
		this.dname = dname;
		this.address = address;
	}
	
	public Dept() {
	}
	
}

JDBCUtil类和文件db.properties与前面文章的一致