DWR框架简单搭建及介绍
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DWR（Direct Web Remoting）是一个用于改善web页面与Java类交互的远程服务器端Ajax开源框架，可以帮助开发人员开发包含AJAX技术的网站。它可以允许在浏览器里的代码使用运行在WEB服务器上的JAVA函数，就像它就在浏览器里一样。
DWR不认为浏览器/WEB服务器协议是重要的,而更乐于保证编程界面的简单自然.对此最大的挑战就是把AJAX的异步特性和正常JAVA方法调用的同步特性相结合.在异步模式下,结果数据在开始调用之后的一段时间之后才可以被异步访问获取到.DWR允许WEB开发人员传递一个回调函数,来异步处理Java函数调用过程.
把你后台的代码弄到js里面，当成一个函数来调用，是不是会方便很多。用起来都说好的一个框架，记得当年我去面试的时候居然有面试官不知道这个东西还技术总监，瞬间就觉得自己高大上了。
好了程序猿要用代码说话
是准备jar包啦，
这两个jar，也可以通过maven自动下依赖
这里想了想还是用maven来弄这个吧
第一步新建maven工程 结构图
第二步，自然是添加依赖啊
<dependency>
<groupId>org.directwebremoting</groupId>
<artifactId>dwr</artifactId>
<version>2.0.3</version>
</dependency>
<!-- https://mvnrepository.com/artifact/commons-logging/commons-logging -->
<dependency>
<groupId>commons-logging</groupId>
<artifactId>commons-logging</artifactId>
<version>1.2</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jsp-api</artifactId>
<version>2.0</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.42</version>
</dependency>这四个就好了
新建jsp了
index.jsp
<jsp:forward page="/WEB-INF/jsp/first.jsp"></jsp:forward>first.jsp
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>dwr test</title>
</head>
<%
String path = request.getContextPath();
%>
<script type="text/javascript" src="<%=path%>/dwr/engine.js"></script>
<script type="text/javascript" src="<%=path%>/dwr/util.js"></script>
<script type="text/javascript" src="<%=path%>/dwr/interface/DbdoSomething.js"></script>
<script type="text/javascript">
window.onload = function(){
var btn = document.getElementById("sign");
btn.onclick = function(){
var msgData = document.getElementById("msg").value;
DbdoSomething.Send(msgData,function(data){
alert(data);
});
}
}
</script>
<body>
<ul id="ul" style="color:red;font-size:60px"></ul>
<input type="text" name="msg" id="msg"/>
<input type="button" id="sign" value="查询信息"/>
</body>
</html>然后新建dwr文件夹，里面放置从dwr-XXXX.jar里面找的
这两个js
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
<display-name>dwr</display-name>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>dwr-invoker</servlet-name>
<servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class>
<init-param>
<param-name>debug</param-name>
<param-value>true</param-value>
</init-param>
<init-param>
<param-name>allowGetForSafariButMakeForgeryEasier</param-name>
<param-value>true</param-value>
</init-param>
<init-param>
<param-name>activeReverseAjaxEnabled</param-name>
<param-value>true</param-value>
</init-param>
<init-param>
<param-name>crossDomainSessionSecurity</param-name>
<param-value>false</param-value>
</init-param>
<init-param>
<param-name>allowScriptTagRemoting</param-name>
<param-value>true</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>dwr-invoker</servlet-name>
<url-pattern>/dwr/*</url-pattern>
</servlet-mapping>
</web-app>dwr.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 2.0//EN"
"http://getahead.org/dwr/dwr20.dtd">
<dwr>
<allow>
<create creator="new" javascript="DbdoSomething">
<param name="class">com.zkb.DbdoSomething</param>
</create>
</allow>
</dwr>这里头部<!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 2.0//EN"
"http://getahead.org/dwr/dwr20.dtd">根据你当前依赖的jar声明，不同的话会报错这里
弄完之后webapp里面的截图就是这样
java部分我就不拆出来写数据库配置文件啦，直接写代码里面，需要自己修改，一切从简
DbdoSomething.java
package com.zkb;
import java.sql.ResultSet;
import java.sql.SQLException;
import com.mysql.jdbc.Connection;
import com.mysql.jdbc.Statement;
import com.zkb.db.DbCon;
public class DbdoSomething {
public String Send(String msg) throws SQLException{
String json ="";
DbCon db= new DbCon();
Connection conn = (Connection) db.getConnection();
Statement stmt = null;
ResultSet rs = null;
try {
stmt = (Statement) conn.createStatement();
rs = stmt.executeQuery("select id,username,password from userinfo where username='"+msg+"'");
while(rs.next()){
json ="{\"name\":"+rs.getString("username")+",\"id\":"+rs.getString("id")+",\"pass\":"+rs.getString("password")+"}";
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if (!conn.isClosed()) {
conn.close();
}
if (!stmt.isClosed()) {
stmt.close();
}
if (!rs.isClosed()) {
rs.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
return json;
}
}DbCon.java
package com.zkb.db;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.SQLFeatureNotSupportedException;
import java.util.logging.Logger;
import javax.sql.DataSource;
public class DbCon implements DataSource {
private static String driver = "com.mysql.jdbc.Driver";
private static String dbUrl = "jdbc:mysql://localhost:3306/userdb";
private static String dbUserName ="root";
private static String dbPassWord ="root";
@Override
public PrintWriter getLogWriter() throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public int getLoginTimeout() throws SQLException {
// TODO Auto-generated method stub
return 0;
}
@Override
public void setLogWriter(PrintWriter arg0) throws SQLException {
// TODO Auto-generated method stub
}
@Override
public void setLoginTimeout(int arg0) throws SQLException {
// TODO Auto-generated method stub
}
@Override
public boolean isWrapperFor(Class<?> arg0) throws SQLException {
// TODO Auto-generated method stub
return false;
}
@Override
public <T> T unwrap(Class<T> arg0) throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public Connection getConnection() throws SQLException {
Connection con =null;
try {
Class.forName(driver);
con =DriverManager.getConnection(dbUrl, dbUserName, dbPassWord);
} catch (Exception e) {
e.printStackTrace();
}
return con;
}
@Override
public Connection getConnection(String arg0, String arg1)
throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public Logger getParentLogger() throws SQLFeatureNotSupportedException {
// TODO Auto-generated method stub
return null;
}
}
java部分截图
数据库
CREATE TABLE `userinfo` (
`id` int(8) NOT NULL auto_increment,
`username` varchar(20) NOT NULL,
`password` varchar(20) default NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=latin1;
-- ----------------------------
-- Records of userinfo
-- ----------------------------
INSERT INTO `userinfo` VALUES ('1', 'admin', 'admin');
INSERT INTO `userinfo` VALUES ('2', 'user', 'user');
INSERT INTO `userinfo` VALUES ('3', 'pass', 'pass');运行截图
这就弄好了，不要介意我的命名啊，我一个demo东改西改的名字肯定会不一样，注重结果
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