JDBC11-18

JDBC11-18

2024 年 11 月 18 日

310 次浏览

4155字数

### StuDAO

```
package com.svse.dao;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

import com.svse.entity.StuEntity;

public class StuDAO {
	// 全查询
	public List<StuEntity> getAll() {
		List<StuEntity> ar = new ArrayList<StuEntity>();
		try {
			String driver = "com.mysql.jdbc.Driver";
			String url = "jdbc:mysql://localhost:3306/test";
			String user = "root";
			String password = "root";
			Connection  conn=null;
			Class.forName(driver);
			conn=DriverManager.getConnection(url, user, password);
			
			String sql="select *  from stuinfo";
			PreparedStatement pre=conn.prepareStatement(sql);
			ResultSet rs=pre.executeQuery();
			while(rs.next())
			{
				int sid=rs.getInt("sid");
				String sname=rs.getString("sname");
				String spsw=rs.getString("spsw");
				
				StuEntity s=new StuEntity();
				s.setSid(sid);
				s.setSname(sname);
				s.setSpsw(spsw);
				
				ar.add(s);
			}

} catch (Exception e) {
			e.printStackTrace();
		}
		return ar;
	}

// 查询一个对象
	public StuEntity getOne(int sid) {
		StuEntity stu = new StuEntity();
		try {
			String driver = "com.mysql.jdbc.Driver";
			String url = "jdbc:mysql://localhost:3306/test";
			String user = "root";
			String password = "root";
			Connection  conn=null;
			Class.forName(driver);
			conn=DriverManager.getConnection(url, user, password);

String sql="select *  from stuinfo where sid=?";
			PreparedStatement pre=conn.prepareStatement(sql);
			pre.setInt(1, sid);
			ResultSet rs=pre.executeQuery();
			while(rs.next())
			{
				String sname=rs.getString("sname");
				String spsw=rs.getString("spsw");
				
				stu.setSid(sid);
				stu.setSname(sname);
				stu.setSpsw(spsw);
			}
			
		} catch (Exception e) {
			e.printStackTrace();
		}
		return stu;
	}

// 修改
	public void updateStu(StuEntity stu) {
		try {
			String driver = "com.mysql.jdbc.Driver";
			String url = "jdbc:mysql://localhost:3306/test";
			String user = "root";
			String password = "root";
			Connection  conn=null;
			Class.forName(driver);
			conn=DriverManager.getConnection(url, user, password);

String sql="update stuinfo set sname=?,spsw=? where sid=?";
			PreparedStatement pre=conn.prepareStatement(sql);
			pre.setString(1,stu.getSname());
			pre.setString(2,stu.getSpsw());
			pre.setInt(3,stu.getSid());
			pre.executeUpdate();
			
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

}

```

### StuEntity
```
package com.svse.entity;

public class StuEntity {

private int sid;
	private String sname;
	private String spsw;

public int getSid() {
		return sid;
	}

public void setSid(int sid) {
		this.sid = sid;
	}

public String getSname() {
		return sname;
	}

public void setSname(String sname) {
		this.sname = sname;
	}

public String getSpsw() {
		return spsw;
	}

public void setSpsw(String spsw) {
		this.spsw = spsw;
	}

}

```

### Test
```
package com.svse.test;

import java.util.List;
import java.util.Scanner;

import com.svse.dao.StuDAO;
import com.svse.entity.StuEntity;

public class Test {
	
	public static void main(String[] args) {
		StuDAO dao=new StuDAO();
		System.out.println("\t\t\t武汉光谷职业学院学生信息");
		System.out.println("以下是全查询学生信息:");
		List<StuEntity> ar=dao.getAll();
		for (StuEntity stuEntity : ar) {
			System.out.println(stuEntity.getSid()+"\t"+stuEntity.getSname()+"\t"+stuEntity.getSpsw());
		}
		System.out.println("请输入你要修改的学生的编号：");
		Scanner sa=new Scanner(System.in);
		int sid=sa.nextInt();
		//一个指定的学生的信息
		StuEntity s=dao.getOne(sid);
		System.out.println("以下是你要修改的学生的信息：");
		System.out.println(s.getSid()+"\t"+s.getSname()+"\t"+s.getSpsw());
		//下面是填写要修改的信息
		System.out.println("请输入要修改的姓名：");
		String sname=sa.next();
		System.out.println("请输入要修改的密码：");
		String spsw=sa.next();
		//封装
		StuEntity ss=new StuEntity();
		ss.setSid(sid);
		ss.setSname(sname);
		ss.setSpsw(spsw);
		//调用 修改
		dao.updateStu(ss);
		System.out.println("修改成功！");
	}

}

```

JDBC11-18