第15周作业

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。

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。

DB

 1 import java.sql.*;
 2 
 3 public class DB {
 4     private Connection con;
 5     private PreparedStatement pre;
 6     private ResultSet rs;
 7     private static DB db;
 8 
 9     static {
10         try {
11             Class.forName("com.mysql.jdbc.Driver");
12         } catch (ClassNotFoundException e) {
13             e.printStackTrace();
14         }
15     }
16 
17     private DB(){
18         try {
19             con = DriverManager.getConnection("jdbc:mysql://localhost:3306/test","root","");
20         } catch (SQLException e) {
21             e.printStackTrace();
22         }
23     }
24 
25     public static DB getInstance(){
26         if(db == null){
27             db = new DB();
28         }
29         return  db;
30     }
31     public ResultSet executeSelect(String sql,Object[] args){
32         try {
33             pre = con.prepareStatement(sql);
34             if (args.length!=0){
35                 for (int i = 0; i < args.length; i++) {
36                     pre.setObject(i+1,args[i]);
37                 }
38             }
39             rs = pre.executeQuery();
40         } catch (SQLException e) {
41             e.printStackTrace();
42         }
43         return rs;
44     }
45     public int executeModify (String sql, Object[] args) {
46         int n = 0;
47         try {
48             pre = con.prepareStatement(sql);
49             if(args.length !=0) {
50                 for(int i = 0;i< args.length;i++) {
51                     pre.setObject(i+1, args[i]);
52                 }
53             }
54             n = pre.executeUpdate();
55         } catch (SQLException e) {
56             e.printStackTrace();
57         }
58         return n;
59     }
60     public void close() {
61         try {
62             if (rs != null) {
63                 rs.close();
64             }
65             pre.close();
66             con.close();
67         } catch (SQLException e) {
68             e.printStackTrace();
69         }
70     }
71 }

TestMain

 1 import java.sql.*;
 2 import java.util.Scanner;
 3 
 4 public class TestMain {
 5     public static void main(String[] args) {
 6         Scanner reader = new Scanner(System.in);
 7         System.out.println("请输入用户名和密码");
 8         String  username = reader.next();
 9         String password = reader.next();
10         Connection con = null;
11         Statement st = null;
12         ResultSet rs=null;
13 
14         try {
15             Class.forName("com.mysql.jdbc.Driver");
16             con = DriverManager.getConnection("jdbc:mysql://localhost:3306/test","root","");
17             st = con.createStatement();
18             String sql ="insert into t_login(username,password) values('" +username+ "','" + password + "')";
19 
20             int count =st.executeUpdate(sql);
21             if(count>0) {
22                 System.out.println("登陆成功");
23                 rs= DB.getInstance().executeSelect("select * from t_user", args);
24                 while(rs.next()) {
25                     int id = rs.getInt(1);
26                     String name = rs.getString(2);
27                     int sex = rs.getInt(3);
28                     String birthday = rs.getString(4);
29                     System.out.println("id                name            sex               birthday");
30                     System.out.println(id + "          " + name + "            " + sex + "                 " + birthday);
31 
32                 }
33                 System.out.println("添加信息");
34                 String id=reader.next();
35                 String name=reader.next();
36                 Integer sex = Integer.valueOf(reader.next());
37                 String birthday = reader.next();
38                 String sql1="insert into t_user(id,name,sex,birthday) values('"+id+"','"+name+"','"+sex+"','"+birthday+"')";
39                 int count2=DB.getInstance().executeModify(sql1, args);
40                 if(count2>0)
41                     System.out.println("数据添加成功");
42                 else
43                     System.out.println("数据添加失败");
44             }
45             else
46                 System.out.println("登陆失败");
47 
48 
49         } catch (ClassNotFoundException | SQLException e) {
50             e.printStackTrace();
51         }finally {
52             try {
53                 st.close();
54                 con.close();
55             }catch (SQLException e){
56                 e.printStackTrace();
57             }
58         }
59     }
60 }

运行结果

数据库截图

 

                     

posted @ 2019-12-14 21:51  常恒*&&  阅读(151)  评论(0)  编辑  收藏  举报