【小白求助】idea右側database連接mysql成功，mysql驅動加載成功，url用戶名密碼正確但getConnection就是進不去
工具：idea、mysql
模式：jsp+servlet+javabean
思路：index為登錄頁面，插入js判斷跳轉到用戶/管理員處理頁面，userLogin_result呼叫userDAO檢驗賬號密碼，userDAO呼叫ConnDB獲取資料庫連接
專案結構：
以下是原始碼
index.jsp
<%@ page pageEncoding="utf-8" %>
<!DOCTYPE HTML>
<html>
<head>
<title>登錄界面</title>
<link rel="stylesheet" type="text/css" href="https://bbs.csdn.net/css/css.css" />
</head>
<body>
<form name="form1" action="./servlet/userLogin_result" method="post">
<h1>圖書管理系統</h1>
<input class=input_1 id=id size=15 name="id" placeholder=賬號><br />
<input class=input_1 id=password type=text size=15 name="password" placeholder=密碼><br />
<span class="radio_box">
<input type="radio" id="radio_1" name="type" value="https://bbs.csdn.net/topics/users" checked>
<label for="radio_1"></label>
普通用戶
</span>
<span class="radio_box">
<input type="radio" id="radio_2" name="type" value="https://bbs.csdn.net/topics/admin">
<label for="radio_2"></label>
管理員
</span><br/>
<input class=input_3 type="button" onclick="login()" value="https://bbs.csdn.net/topics/登錄" />
<input class=input_3 type="button" onclick=document.form1.reset() value="https://bbs.csdn.net/topics/重置" />
</form>
<script type="text/javascript" src="https://bbs.csdn.net/topics/js/script.js"></script>
</body>
</html>
script.js
function login(){
if(form1.id.valuehttps://bbs.csdn.net/topics/===''){
alert('賬號不能為空！');
return false;
}
else if(form1.password.valuehttps://bbs.csdn.net/topics/===''){
alert('密碼不能為空！');
return false;
}
else{
if(form1.type.valuehttps://bbs.csdn.net/topics/==='users')
form1.action="/servlet/userLogin_result";
else
form1.action="/servlet/adminLogin_result";
}
form1.submit();
}
window.onload = function(){
var i3 = document.getElementsByClassName('input_3');
for(var i=0;i<i3.length;i++){
i3[i].onmouseover = function(){
this.style.backgroundColor = "#23271F";
this.style.color = "#fff";
}
i3[i].onmouseout = function(){
this.style.backgroundColor = "#fff";
this.style.color = "#23271F";
}
}
var pass = document.getElementById("password");
pass.onfocus = function(){
pass.type = "password";
}
}userLogin_result.java
package servlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;
import DAO.UserDao;
public class userLogin_result extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {
request.setCharacterEncoding("UTF-8");
response.setCharacterEncoding("UTF-8");
UserDao user = new UserDao();
String Id = request.getParameter("id");
String Password = request.getParameter("password");
int id = Integer.parseInt(Id);
int password = Integer.parseInt(Password);
try {
if (user.checkAccount(id, password)) {
response.sendRedirect("../user.jsp");
}
else {
response.sendRedirect("../index.jsp");
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
UserDao.java
package DAO;
import java.sql.*;
import com.arvin.db.ConnDB;
public class UserDao {
Connection conn = null;
ConnDB db = new ConnDB();
//檢驗賬號密碼是否相匹配
public boolean checkAccount(int id,int password)throws Exception{
ConnDB.getConnection();
String sql = "SELECT U_PASSWORD FROM USER WHERE ID = ?";
PreparedStatement ps = conn.prepareStatement(sql);
ps.setInt(1,id);
ResultSet rs = ps.executeQuery();
ps.close();
ConnDB.closeDb();
return password == rs.getInt("u_password");
}
}
ConnDB.java
package com.arvin.db;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.Properties;
public class ConnDB {
//資料庫的用戶名和密碼
public static String username = "root";
public static String password = "1999";
//獲得連接物件，statement物件和結果集
public static Connection conn = null;
public static Statement state = null;
public static ResultSet rs = null;
//資料庫驅動，在剛開始下載的檔案中
public static String driver_class = "com.mysql.cj.jdbc.Driver";
//oilServer是資料庫名，其他的不變
public static String url = "jdbc:mysql://localhost:3306/booksystem?serverTimezone=GMT";
//獲得資料庫的連接的方法
public static Connection getConnection(){
try {
Class.forName(driver_class);//指定連接型別
System.out.println("load db driver success......");
Properties info = new Properties();
info.setProperty("user",username);//
info.setProperty("password",password);
conn = DriverManager.getConnection(url,info);//獲取連接
System.out.println("get db connection success....");
} catch (Exception e) {
e.printStackTrace();
}
return conn;
}
//執行資料庫的查詢操作，回傳的為結果集
public static ResultSet excuteQuery(String sql){
try {
state = conn.createStatement();
rs = state.executeQuery(sql);
return rs;
} catch (Exception e) {
e.printStackTrace();
}
return rs;
}
//關閉資料庫
public static void closeDb(){
try {
if(rs != null)
rs.close();
if(conn != null)
conn.close();
if(state != null)
state.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
index填寫表單選擇普通用戶登錄后顯示error500
mysql資料庫驅動加載成功：
但tomcat日志沒有顯示get db connection success....，說明應該是卡在了獲取連接階段
已知url用戶名密碼確認無誤
請教各位大神這究竟是哪里出了問題？
uj5u.com熱心網友回復：
不用這樣寫代碼，之間用jdbcTemplate去搞，簡單 多了，你不用管這些鏈接。uj5u.com熱心網友回復：
我是沒看懂
conn = DriverManager.getConnection(url,info);//獲取連接 這句是在干么，你已經有username和password了，為什么不直接用
conn = DriverManager.getConnection(url,username，passowrd)；
uj5u.com熱心網友回復：
而且ConnDB里全是靜態方法，不要需要ConnDB db = new ConnDB();初始化后再呼叫ConnDB.getConnection(); 這樣你初始化寫了有什么意義？
uj5u.com熱心網友回復：
直接這樣注入@Autowired
private JdbcTemplate jdbcTemplate;
然后在查詢方法中
@RequestMapping("list")
public List<Map<String, Object>> queryList() {
List<Map<String, Object>> list = jdbcTemplate.queryForList("SELECT id,name FROM test_db.student ", new Object[]{});
return list;
}
uj5u.com熱心網友回復：
開始是直接用的，網上看到別人的這種用法就試試能不能解決問題…
uj5u.com熱心網友回復：
你UserDao.java有問題，都沒賦值給conn,要么你直接用ConnDB的靜態conn值，程式要規范點，靜態寫了不用，你設定靜態干么還不如不寫。改成下面試試
import java.sql.*;
public class UserDao {
Connection conn = null;
//檢驗賬號密碼是否相匹配
public boolean checkAccount(int id,int password)throws Exception{
conn=ConnDB.getConnection(); //這里可以不用
String sql = "SELECT U_PASSWORD FROM USER WHERE ID = ?";
PreparedStatement ps = conn.prepareStatement(sql); // 或者這里直接用 PreparedStatement ps =ConnDB.conn.prepareStatement(sql);
ps.setInt(1,id);
ResultSet rs = ps.executeQuery();
ps.close();
ConnDB.closeDb();
return password == rs.getInt("u_password");
}
}
uj5u.com熱心網友回復：
是你userdao的問題，conn還是空值，沒有傳遞。改為下面就應該可以了。
conn=ConnDB.getConnection();
uj5u.com熱心網友回復：
試了還是報錯500
uj5u.com熱心網友回復：
會不會跟mysql版本過高以致于沒有兼容部分jar包？uj5u.com熱心網友回復：
你除了驗證user，其他呼叫getConnection可能都有問題，都要改。
uj5u.com熱心網友回復：
我只有userDAO呼叫了getConnection啊orzuj5u.com熱心網友回復：
可我只有userDAO呼叫了getConnection啊，其他還沒寫，在這個地方卡殼了好幾天了Orz
uj5u.com熱心網友回復：
我暈了一看的的userDAO你鏈接先關閉了還怎么比對password？
就沒你這么寫的，難道你資料庫就一個password？
public class UserDao {
Connection conn = null;
//檢驗賬號密碼是否相匹配
public boolean checkAccount(int id,int password)throws Exception{
boolean flag=false;
conn=ConnDB.getConnection();
String sql = "SELECT U_PASSWORD FROM USER WHERE ID = ?";
PreparedStatement ps = conn.prepareStatement(sql);
ps.setInt(1,id);
ResultSet rs = ps.executeQuery();
while(rs.next()) {
if(password == rs.getInt("u_password")) {
flag=true;
}
}
ps.close();
ConnDB.closeDb();
return flag;
}
}
uj5u.com熱心網友回復：
是我沒看清楚確實只要比一次就行了，但是資料庫鏈接需要比完了才能關不然，rs無法獲取。
public class UserDao {
Connection conn = null;
//檢驗賬號密碼是否相匹配
public boolean checkAccount(int id,int password)throws Exception{
boolean flag=false;
conn=ConnDB.getConnection();
String sql = "SELECT U_PASSWORD FROM USER WHERE ID = ?";
PreparedStatement ps = conn.prepareStatement(sql);
ps.setInt(1,id);
ResultSet rs = ps.executeQuery();
if(password == rs.getInt("u_password")) {
flag=true;
}
ps.close();
ConnDB.closeDb();
return flag;
}
}
uj5u.com熱心網友回復：
謝謝大佬提醒！但改了以后getConnection還是進不去。。。
uj5u.com熱心網友回復：
補充一下報錯日志HTTP Status 500 – Internal Server Error
Type Exception Report
Message Servlet execution threw an exception
Description The server encountered an unexpected condition that prevented it from fulfilling the request.
Exception
javax.servlet.ServletException: Servlet execution threw an exception
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
Root Cause
java.lang.NoClassDefFoundError: Could not initialize class sun.security.ssl.SSLKeyExchange$1
java.base/sun.security.ssl.SSLKeyExchange.valueOf(SSLKeyExchange.java:202)
java.base/sun.security.ssl.ServerHello$T12ServerHelloConsumer.consume(ServerHello.java:1135)
java.base/sun.security.ssl.ServerHello$ServerHelloConsumer.onServerHello(ServerHello.java:995)
java.base/sun.security.ssl.ServerHello$ServerHelloConsumer.consume(ServerHello.java:877)
java.base/sun.security.ssl.SSLHandshake.consume(SSLHandshake.java:392)
java.base/sun.security.ssl.HandshakeContext.dispatch(HandshakeContext.java:441)
java.base/sun.security.ssl.HandshakeContext.dispatch(HandshakeContext.java:419)
java.base/sun.security.ssl.TransportContext.dispatch(TransportContext.java:177)
java.base/sun.security.ssl.SSLTransport.decode(SSLTransport.java:164)
java.base/sun.security.ssl.SSLSocketImpl.decode(SSLSocketImpl.java:1180)
java.base/sun.security.ssl.SSLSocketImpl.readHandshakeRecord(SSLSocketImpl.java:1091)
java.base/sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:402)
com.mysql.cj.protocol.ExportControlled.performTlsHandshake(ExportControlled.java:316)
com.mysql.cj.protocol.StandardSocketFactory.performTlsHandshake(StandardSocketFactory.java:188)
com.mysql.cj.protocol.a.NativeSocketConnection.performTlsHandshake(NativeSocketConnection.java:99)
com.mysql.cj.protocol.a.NativeProtocol.negotiateSSLConnection(NativeProtocol.java:352)
com.mysql.cj.protocol.a.NativeAuthenticationProvider.negotiateSSLConnection(NativeAuthenticationProvider.java:777)
com.mysql.cj.protocol.a.NativeAuthenticationProvider.proceedHandshakeWithPluggableAuthentication(NativeAuthenticationProvider.java:486)
com.mysql.cj.protocol.a.NativeAuthenticationProvider.connect(NativeAuthenticationProvider.java:202)
com.mysql.cj.protocol.a.NativeProtocol.connect(NativeProtocol.java:1452)
com.mysql.cj.NativeSession.connect(NativeSession.java:165)
com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:955)
com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:825)
com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:455)
com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:240)
com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:199)
java.sql/java.sql.DriverManager.getConnection(DriverManager.java:677)
java.sql/java.sql.DriverManager.getConnection(DriverManager.java:228)
com.arvin.db.ConnDB.getConnection(ConnDB.java:31)
DAO.UserDao.checkAccount(UserDao.java:13)
servlet.userLogin_result.doPost(userLogin_result.java:19)
javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
Note The full stack trace of the root cause is available in the server logs.
Apache Tomcat/7.0.96
uj5u.com熱心網友回復：
可能是jar包版本太低，和你的jdk不兼容。升級一下jar包試試轉載請註明出處，本文鏈接：https://www.uj5u.com/houduan/8245.html
標籤：Web 開發
上一篇：Ios沙箱環境喚起不了支付寶
下一篇：面試被問到的Redis