第15次作业

题目1：编写一个应用程序，输入用户名和密码，访问test数据库中t_login表（字段包括id、username、password），验证登录是否成功。

import java.sql.*;
import java.util.Scanner;
 
 public class text7 {
 
    
     public static void main(String[] args) {
  Connection con=null;
        Statement st=null;
        boolean rs;
        ResultSet rt=null;
        Scanner sc=new Scanner(System.in);
        System.out.println("请输入用户名");
        String username=sc.next();
        System.out.println("请输入密码");
        String password=sc.next();
        String sql="select * from login where username='"+username+"'and password='"+password+"'";
        try {
            Class.forName("com.mysql.jdbc.Driver");
            String url="jdbc:mysql://localhost:3306/dbfjd";
            con=DriverManager.getConnection(url,"root","123456");
            st=con.createStatement();
            rs=st.execute(sql);
            if(username.equalsIgnoreCase(username)&&password.equalsIgnoreCase(password)){
    System.out.println("登陆成功");
                rt=DB.getInstance().executeSelect("select * from user", args);           
                while(rt.next()){
     System.out.println("生日"+rt.getString(2)+"性别"+rt.getString(3)+"姓名"+rt.getString(4));   
                    
                }
            else{
                     System.out.println("登陆失败");

   }
     }
 
 }

题目2：在上一题基础上，当登录成功后，将t_user表（id、name、sex、birthday）的信息进行显示（要求使用DB.java完成登录和获取t_user表中数据的操作），最后再对t_user表进行一条记录的添加操作。

package demo;
 
import java.sql.*;
import java.util.Scanner;
public class test {
 
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner scan=new Scanner(System.in);
        String username=scan.next();
        String password=scan.next();
        Connection con=null;
        Statement st=null;
        ResultSet rs=null;
        ResultSet rs1=null;
        try {
            DriverManager.registerDriver(new com.mysql.jdbc.Driver());
            con=DriverManager.getConnection("jdbc:mysql://localhost:3306/bjpowernode","root","082256");
            st=con.createStatement();
 
             String sql = "select * from t_login where username='" + username+ "' and password = '" + password + "'";
             rs=st.executeQuery(sql);
             boolean bl=rs.next();
             if(bl) {
                 System.out.println("登陆成功");
                rs1= DB.getInstance().executeSelect("select * from t_user", args);
                while(rs1.next()) {
                    int id = rs1.getInt(1);
                    String name = rs1.getString(2);
                    String sex = rs1.getString(3);
                    String birthday = rs1.getString(4);
                    System.out.println("用户     名字     性别      生日");
                    System.out.println(id + "           " + name + "         " + sex + "            " + birthday);
                }
                System.out.println("添加信息");
                int id=scan.nextInt();
                String name=scan.next();
                String sex=scan.next();
                String birthday=scan.next();
                String sql1="insert into t_user(id,name,sex,birthday) values('"+id+"','"+name+"','"+sex+"','"+birthday+"')";
                int count=DB.getInstance().executeModify(sql1, args);
                if(count>0) 
                    System.out.println("数据添加成功");
                else
                    System.out.println("数据添加失败");
             }
             else {
                 System.out.println("登陆失败");
             }
        } catch (SQLException e) {
            e.printStackTrace();
        }finally {
            try {
                st.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
            try {
                con.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
 
}