利用java怎么实现一个微信公众平台消息接口应用？很多新手对此不是很清楚，为了帮助大家解决这个难题，下面小编将为大家详细讲解，有这方面需求的人可以来学习下，希望你能有所收获。
具体如下：
微信公众平台现在推出自动回复消息接口，但是由于是接口内容用的是PHP语言写的，很多地方操作起来让本人这个对Java比较熟悉的小伙很别扭，所以仿照PHP的接口代码做了一套jsp语言编写的接口。
首先先把整个接口代码贴出来做下比较，然后我们再分析代码：
JAVA:
<%@page import="java.util.Date"%>
<%@page import="org.dom4j.Element"%>
<%@page import="org.dom4j.DocumentHelper"%>
<%@page import="org.dom4j.Document"%>
<%@page import="java.io.IOException"%>
<%@page import="java.io.InputStreamReader"%>
<%@page import="java.io.BufferedReader"%>
<%@page import="java.io.Reader"%>
<%@page import="java.security.MessageDigest"%>
<%@page import="java.util.Arrays"%>
<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%>
<%
//WeiXinHandler为内部类不能使用非final类型的对象
final String TOKEN="weixin";
final HttpServletRequest final_request=request;
final HttpServletResponse final_response=response;
%>
<%
class WeiXinHandler{
public void valid(){
String echostr=final_request.getParameter("echostr");
if(null==echostr||echostr.isEmpty()){
responseMsg();
}else{
if(this.checkSignature()){
this.print(echostr);
}else{
this.print("error");
}
}
}
//自动回复内容
public void responseMsg(){
String postStr=null;
try{
postStr=this.readStreamParameter(final_request.getInputStream());
}catch(Exception e){
e.printStackTrace();
}
//System.out.println(postStr);
if (null!=postStr&&!postStr.isEmpty()){
Document document=null;
try{
document = DocumentHelper.parseText(postStr);
}catch(Exception e){
e.printStackTrace();
}
if(null==document){
this.print("");
return;
}
Element root=document.getRootElement();
String fromUsername = root.elementText("FromUserName");
String toUsername = root.elementText("ToUserName");
String keyword = root.elementTextTrim("Content");
String time = new Date().getTime()+"";
String textTpl = ""+
"%3$s "+
"0 "+
" ";
if(null!=keyword&&!keyword.equals(""))
{
String msgType = "text";
String contentStr = "Welcome to wechat world!";
String resultStr = textTpl.format(textTpl, fromUsername, toUsername, time, msgType, contentStr);
this.print(resultStr);
}else{
this.print("Input something...");
}
}else {
this.print("");
}
}
//微信接口验证
public boolean checkSignature(){
String signature = final_request.getParameter("signature");
String timestamp = final_request.getParameter("timestamp");
String nonce = final_request.getParameter("nonce");
String token=TOKEN;
String[] tmpArr={token,timestamp,nonce};
Arrays.sort(tmpArr);
String tmpStr=this.ArrayToString(tmpArr);
tmpStr=this.SHA1Encode(tmpStr);
if(tmpStr.equalsIgnoreCase(signature)){
return true;
}else{
return false;
}
}
//向请求端发送返回数据
public void print(String content){
try{
final_response.getWriter().print(content);
final_response.getWriter().flush();
final_response.getWriter().close();
}catch(Exception e){
}
}
//数组转字符串
public String ArrayToString(String [] arr){
StringBuffer bf = new StringBuffer();
for(int i = 0; i < arr.length; i++){
bf.append(arr[i]);
}
return bf.toString();
}
//sha1加密
public String SHA1Encode(String sourceString) {
String resultString = null;
try {
resultString = new String(sourceString);
MessageDigest md = MessageDigest.getInstance("SHA-1");
resultString = byte2hexString(md.digest(resultString.getBytes()));
} catch (Exception ex) {
}
return resultString;
}
public final String byte2hexString(byte[] bytes) {
StringBuffer buf = new StringBuffer(bytes.length * 2);
for (int i = 0; i < bytes.length; i++) {
if (((int) bytes[i] & 0xff) < 0x10) {
buf.append("0");
}
buf.append(Long.toString((int) bytes[i] & 0xff, 16));
}
return buf.toString().toUpperCase();
}
//从输入流读取post参数
public String readStreamParameter(ServletInputStream in){
StringBuilder buffer = new StringBuilder();
BufferedReader reader=null;
try{
reader = new BufferedReader(new InputStreamReader(in));
String line=null;
while((line = reader.readLine())!=null){
buffer.append(line);
}
}catch(Exception e){
e.printStackTrace();
}finally{
if(null!=reader){
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return buffer.toString();
}
}
%>
<%
WeiXinHandler handler=new WeiXinHandler();
handler.valid();
%> 
