請服用logforj java,各類java系統都會用的log套件,也有其他語言的版本…
https://blog.xuite.net/chihho32/blog/9121126-%5BJAVA%5D+Log4J
小弟補充log4j 目前最新版是這個:
<dependency>
    <groupId>log4j</groupId>
    <artifactId>log4j</artifactId>
    <version>1.2.17</version>
</dependency>
                    大大好:
我java寫上去就一直錯誤....
我也有import jar,也有加入xml和property了.
不知錯在哪....
Servlet.java
public class Servlet {
    	private static Logger logger = Logger.getLogger(Servlet.class);
   public static void main(String[] args) {
     BasicConfigurator.configure();
     logger.info("This is an info message.");
 }
謝謝
大大好:
我已經可以產生log檔了
但我試著紀錄帳號密碼
我的log或是txt都空白耶
<%@page import="java.util.logging.FileHandler"%>
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@ include file = "db.jsp"%> 
<%@ page import="org.apache.log4j.*" %>
<!DOCTYPE html>
<html>
   
    <body>
    <center>登入系統</br> </br> 
    
<div class="container">
<form class="form-horizontal" action="login.jsp" method = "post">
    <div class="form-group">
     帳號:
    <input type="account" id="acc"  name="acc">
    </div>
    <div class="form-group">
     密碼:          
<input type="password" id="pwd"  name="pwd">
    </div>
    
    <div class="form-group">        
<button type="submit"  name = "login">登入</button> 
    </div>
  </form>
<%       String acc = request.getParameter("acc");
       String pwd = request.getParameter("pwd");
    PropertyConfigurator.configure("../WEB-INF/log4j.properties");
Logger log = Logger.getLogger(this.getClass());
   FileHandler fileHandler = new FileHandler("C:/Log/test.log");
	    
log.info(acc+ "  "+pwd);
    int i;
    String sql;
         if(request.getParameter("login") != null )
           {  sql = "select* from login where acc= '" + acc + "' and pwd=  '" + pwd + "'"; 
                ResultSet rs = stmt.executeQuery(sql); 
       while(rs.next()){ 
         response.sendRedirect("index.jsp");
           }
              out.println("帳密錯誤!!"); 
	  } 
	%> 
        </div>
    </body>
</html>
</html>
                    1.可行
2.沒有套件,自己寫
選我正解