Java用类实现对Student数据表(Mysql)的操作（增删改查）

Java连接mysql数据库利用了mysql-JDBC的jar包，查询操作用的是executeQuery（）方法，除了查询操作外的增删改都是用executeUpdate（）方法实现。

代码：

Student类

package test;

public class Student {
	private int id;
	private String name;
	private int age;

	public Student(int id, String name, int age) {
		super();
		this.id = id;
		this.name = name;
		this.age = age;
	}

	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}

	@Override
	public String toString() {
		return "Student [id=" + id + ", name=" + name + ", age=" + age + "]";
	}

	
}

Sql类：

package test;

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

public class Sql {
	Connection con;

	public Connection getConn() throws SQLException, ClassNotFoundException {
		Class.forName("com.mysql.jdbc.Driver");
		Connection con = DriverManager.getConnection(
				"jdbc:mysql://localhost:3306/school?useUnicode=true&characterEncoding=utf-8", "root", "helloworld");
		System.out.println(con);
		return con;
	}

	public int addStu(Student st) throws SQLException, ClassNotFoundException {
		con=getConn();
		try {
			con = getConn();
		} catch (ClassNotFoundException | SQLException e) {
			e.printStackTrace();
		}
		String sql_insert = "insert into student(id, name, age) values(?, ?, ?)";
		PreparedStatement pst = con.prepareStatement(sql_insert);
		pst.setInt(1, st.getId());
		pst.setString(2, st.getName());
		pst.setInt(3, st.getAge());
		int rest = pst.executeUpdate();
		pst.close();
		con.close();
		return rest;
	}
	public int deleteStu(int id) throws ClassNotFoundException, SQLException {
	  con=getConn();
	  String sql="delete from student where id=?";
	  PreparedStatement pst = con.prepareStatement(sql);
	  pst = con.prepareStatement(sql);
	  pst.setInt(1,id);
	  
	  int result=pst.executeUpdate();
	  pst.close();
	  con.close();
	  return result;  
	}
	public int updateStu(int id, int flag) throws SQLException, ClassNotFoundException {
		con=getConn();
		Scanner cin = new Scanner(System.in);
		String name;
		int age;
		String sql;
		int rst = 0;
		if(flag == 1) {
			name = cin.next();
			sql = "update student set name = ? where id = ?";
			PreparedStatement pst = con.prepareStatement(sql);
			pst.setString(1, name);
			pst.setInt(2, id);
			rst = pst.executeUpdate();
			pst.close();
		}
		else if(flag == 2) {
			age = cin.nextInt();
			sql = "update student set age = ? where id = ?";
			PreparedStatement pst = con.prepareStatement(sql);
			pst.setInt(1, age);
			pst.setInt(2, id);
			rst = pst.executeUpdate();
			pst.close();
		}
		else if(flag == 3) {
			age = cin.nextInt();
			name = cin.next();
			sql = "update student set name = ?, age = ? where id = ?";
			PreparedStatement pst = con.prepareStatement(sql);
			pst.setString(1, name);
			pst.setInt(2, age);
			pst.setInt(3, id);
			rst = pst.executeUpdate();
			pst.close();
		}
		
		con.close();
		return rst;
	}

	public List<Student> queryAll() throws SQLException, ClassNotFoundException {
		con=getConn();
		List<Student> stu = new ArrayList<Student>();
		String sql = "select * from student";
		PreparedStatement pst = con.prepareStatement(sql);
		ResultSet rst = pst.executeQuery();
		while (rst.next()) {
			int id = rst.getInt(1);
			String name = rst.getString(2);
			int age = rst.getInt(3);
			stu.add(new Student(id, name, age));
			//System.out.println(id + "---" + name + "---" + age);
		}
		pst.close();
		con.close();
		return stu;
	}

	public void queryById(int id) throws SQLException, ClassNotFoundException {
		con=getConn();
		String sql = "select name, age from student where id=?";
		PreparedStatement pst = con.prepareStatement(sql);
		pst.setInt(1, id);
		ResultSet rst = pst.executeQuery();
		if(rst.next()!= false) {
			String name = rst.getString("name");
			int age = rst.getInt("age");
			System.out.println("学号为"+id+"的学生："+"\n"+"姓名： "+name+"\n"+"年龄: "+age+"\n");
		}
		pst.close();
		con.close();
	}
}

Main类;

package test;

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

public class Main {
	public static void main(String[] args) throws ClassNotFoundException, SQLException {
		Scanner cin = new Scanner(System.in);
		Sql mysql_obj = new Sql();
		int order = 0;
		System.out.println("请输入指令来进行操作：");
		System.out.println("输入1添加学生信息");
		System.out.println("输入2删除学生信息");
		System.out.println("输入3修改学生信息");
		System.out.println("输入4根据学号查询");
		System.out.println("输入5查询全部学生信息");
		while(cin.hasNext()) {
			
			order = cin.nextInt();
			if(order == 1) {
				System.out.println("输入学生信息id name age");
				Student stu = new Student(cin.nextInt(), cin.next(), cin.nextInt());
				int rst = mysql_obj.addStu(stu);
				if(rst == 1) {
					System.out.println("success!");
				}
				else {
					System.out.println("failed!");
				}
			}
			else if(order == 2) {
				System.out.println("输入学生id");
				int id = cin.nextInt();
				int rst = mysql_obj.deleteStu(id);
				if(rst == 1) {
					System.out.println("success!");
				}
				else {
					System.out.println("failed!");
				}
			}
			else if(order == 3) {
				System.out.println("输入学生id");
				int id = cin.nextInt();
				System.out.println("更改姓名输入1  更改年龄输入2  两者都更改输入3");
				int flag = cin.nextInt();
				int rst = mysql_obj.updateStu(id, flag);
				if(rst == 1) {
					System.out.println("success!");
				}
				else {
					System.out.println("failed!");
				}
			}
			else if(order == 4) {
				System.out.println("输入学生id");
				int id = cin.nextInt();
				mysql_obj.queryById(id);
			}
			else if(order == 5) {
				List<Student> stu = new ArrayList<Student>();
				stu = mysql_obj.queryAll();
				for(Student st: stu) {
					System.out.println(st.toString());
				}
			}
		}
		
	}
}