gpt4 book ai didi

java - 连接 JDBC SQL 错误

转载 作者:行者123 更新时间:2023-11-30 23:01:44 25 4
gpt4 key购买 nike

这是我的jsp页面:

<%@ page language= "java" %>
<%@ page contentType= "text/html; charset=UTF-8" %>
<%@ page import= "java.sql.*" %>


<!DOCTYPE html>


<html>

<head>
<title>Lettura di un database con JSP</title>
</head>


<body>

<h1>Connessione al database</h1>

<%
Connection conn;
Statement st;
ResultSet rs;
String dat;
try{
Class.forName( "com.mysql.jdbc.Driver" ).newInstance(); // crea un'istanza del driver e la inizializza, affinché il Driver Manager stabilisca una connessione con MySQL
}
catch(ClassNotFoundException e){
out.println("<p>ERROR1</p>");
}
try{
conn= DriverManager.getConnection( "jdbc:mysql://94.94.216.82:8080/dale14/dale14_mobshop", "dale14", "ViEh8Udr" );

st = conn.createStatement();
rs = st.executeQuery( "SELECT Nome FROM clienti" );

while( rs.next() ){ // alla prima "next" andiamo sul primo rigo della tabella
dat = rs.getString( "Nome" ); // ottiene il dato, che è di tipo stringa
out.println( "<tr><td>" + dat + "</td></tr>" ); // stampa a video
}

st.close(); // viene chiuso anche il ResultSet
conn.close();
}
catch(SQLException ex){

out.println ( "<P><PRE>" );
while (ex != null) {
out.println("Message: " + ex.getMessage ());
out.println("SQLState: " + ex.getSQLState ());
out.println("ErrorCode: " + ex.getErrorCode ());
ex = ex.getNextException();
out.println("");
}}

%>

</body>

</html>

这是错误:

Message: Communications link failure The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server. SQLState: 08S01 ErrorCode: 0

我不明白为什么!:(

最佳答案

因为SQLState:08S01错误是网络连接问题。

您需要确保:

  1. 数据库正在运行并监听指定的端口
  2. 您有权连接到数据库
  3. 您没有任何可能干扰您的连接的防火墙问题。

还要考虑数据库的大小。如果它非常大,您可能会遇到问题。

此外,您可能需要更改驱动程序(可能需要更改为 jTDS)或更新到最新版本的 SQL Server。

另请查看 System Requirements for JDBC

关于java - 连接 JDBC SQL 错误,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/23701420/

25 4 0
Copyright 2021 - 2024 cfsdn All Rights Reserved 蜀ICP备2022000587号
广告合作:1813099741@qq.com 6ren.com