//User 用戶的基本信息，也是USERINFO表中的3個列

package 登陸判斷;

public class User {

private String name;

private String loginname;

private String loginpsw;

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public String getLoginname() {

return loginname;

}

public void setLoginname(String loginname) {

this.loginname = loginname;

}

public String getLoginpsw() {

return loginpsw;

}

public void setLoginpsw(String loginpsw) {

this.loginpsw = loginpsw;

}

}//用于注冊和登陸的小小代碼塊

package 登陸判斷;

import java.util.Scanner;

public class In {

public static User getUser(){

User u = new User();

Scanner sc = new Scanner(System.in);

System.out.println("請輸入登陸名");

u.setLoginname(sc.nextLine());

System.out.println("請輸入密碼");

u.setLoginpsw(sc.nextLine());

return u;

}

public static User registerUser(){

User u = new User();

Scanner sc = new Scanner(System.in);

System.out.println("請注冊用戶名名");

u.setName(sc.nextLine());

System.out.println("請注冊登陸名");

u.setLoginname(sc.nextLine());

System.out.println("請注冊密碼");

u.setLoginpsw(sc.nextLine());

return u;

}

}

//登陸時的檢查，判斷登陸名和密碼是否正確，正確則返回 用戶名

package 登陸判斷;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

public class Check {

public static void checkUser(User u)

{

try {

Class.forName("oracle.jdbc.driver.OracleDriver");

} catch (ClassNotFoundException e) {

e.printStackTrace();

}

String url = "jdbc:oracle:thin:@localhost:1521:orcl";

String user = "scott";

String password = "tiger";

Connection conn = null;

ResultSet rs = null;

PreparedStatement pst = null;

String sql = "Select name from USERINFO where loginname = ? and loginpsw = ? ";

try {

conn = DriverManager.getConnection(url, user, password);

pst = conn.prepareStatement(sql);

pst.setString(1, u.getLoginname());

pst.setString(2,u.getLoginpsw());

rs = pst.executeQuery();

while(rs.next()){

u.setName(rs.getString(1));

}

} catch (SQLException e) {

e.printStackTrace();

}finally{

try {

rs.close();

pst.close();

conn.close();

} catch (SQLException e) {

e.printStackTrace();

}

}

if(u.getName() == null || u.getName().isEmpty()){

System.out.println("登陸失敗");

}else{

System.out.println("歡迎"+u.getName()+"登陸");

}

}

}

//注冊界面，要判斷 登陸名是否有重復，有重復則注冊失敗。有點小疑問，已用注釋標出來

package 登陸判斷;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

public class Register {

public static void registUser(User u){

try {

Class.forName("oracle.jdbc.driver.OracleDriver");

} catch (ClassNotFoundException e) {

e.printStackTrace();

}

String url = "jdbc:oracle:thin:@localhost:1521:orcl";

String user = "scott";

String password = "tiger";

Connection conn = null;

String sql = "Insert Into USERINFO values(?,?,?)";

PreparedStatement pst = null;

//判斷登陸名是否已經存在

Statement s = null;

ResultSet rs = null;

String sql_ck = "Select LOGINNAME FROM USERINFO";

try {

conn = DriverManager.getConnection(url, user, password);

pst = conn.prepareStatement(sql);

pst.setString(1, u.getName());

pst.setString(2, u.getLoginname());

pst.setString(3, u.getLoginpsw());

//判斷登陸名是否已經存在

s = conn.createStatement();

rs = s.executeQuery(sql_ck);

while(rs.next()){//為什么用 rs.getString(2)會提示 無效的索引呢

if( rs.getString("LOGINNAME").equals(u.getLoginname()) ){

System.out.println("登陸名已經存在，注冊失敗");

break;

}else{

pst.executeUpdate();

System.out.println("注冊成功");

break;

}

}

} catch (SQLException e) {

e.printStackTrace();

}finally{

try {

rs.close();

pst.close();

s.close();

conn.close();

} catch (SQLException e) {

e.printStackTrace();

}

}

}

}

//main界面//

//數據庫中表的結構式這樣

//name(用戶名，用于顯示),

//loginname(登錄名,即登陸時輸入的ID)

//loginpsw(登陸時輸入的密碼)

package 登陸判斷;

import java.util.Scanner;

public class Test {

public static void main(String[] args) {

int chos = 0;

Scanner sc = new Scanner(System.in);

System.out.println("\t\t登陸請按1\t\t注冊請按2");

chos = sc.nextInt();

switch(chos){

case 1: Check.checkUser(In.getUser());break;

case 2: Register.registUser(In.registerUser());break;

default: System.out.println("請輸入正確的選擇");break;

}

}

}

總結

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