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<listener>
<listener-class>packname.classname</listener-class>
</listener>
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OnLineDemo.java
package demo;

import java.util.ArrayList;
import java.util.List;

import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.http.HttpSessionAttributeListener;
import javax.servlet.http.HttpSessionBindingEvent;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;

/*
* <listener> <listener-class>demo.OnLineDemo</listener-class>
* </listener>
*/

public class OnlineDemo implements ServletContextListener, HttpSessionListener,
HttpSessionAttributeListener {
// ÉùÃ÷Ò»¸öServletContext¶ÔÏó
private ServletContext application = null;

public void contextInitialized(ServletContextEvent sce) {
// ÈÝÆ÷³õʼ»¯Ê±£¬ÏòapplicationÖдæ·ÅÒ»¸ö¿ÕµÄÈÝÆ÷
this.application = sce.getServletContext();
this.application.setAttribute


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¡¡¡¡public class MyClass {
¡¡¡¡public static void main(String[] args) {
¡¡¡¡String str1 = "str1";
¡¡¡¡String str2 = "str2";
¡¡¡¡String str3 = "str3";
¡¡¡¡str1.concat(str2);
¡¡¡¡System.out.println(str3.concat(str1));
¡¡¡¡}
¡¡¡¡}
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 PATH = .;%JAVA_HOME%/bin
 CLASSPTAH = .;%JAVA_HOME%/lib
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import java.io.*;
public class TestConsole{
public static void main(String[] args){
Console console;
char[] pwd;
if((console = System.console()) != null && (pwd = console.readPassword("[%s]", "Please Enter Password:")) != null){
System.out.println(String.valueOf(pwd));
}
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