httpclient

1.拳头之Get/Post
拳头是最基本的一重武器，也是最重要的，好比练武之人必须先扎稳马步。

java 代码

HttpClient httpclient=new HttpClient();//创建一个客户端，类似打开一个浏览器
GetMethod getMethod=new GetMethod("http://www.blablabla.com");//创建一个get方法，类似在浏览器地址栏中输入一个地址
int statusCode=httpclient.executeMethod(getMethod);//回车——出拳！
System.out.println("response=" + getMethod.getResponseBodyAsString());//察看拳头命中情况，可以获得的东西还有很多，比如head, cookies等等
getMethod.releaseConnection();//释放，记得收拳哦

2.孔雀翎之支持https

如何支持https?

java 代码

static{
    Protocol easyhttps = new Protocol("https", new EasySSLProtocolSocketFactory(), 443);
    Protocol.registerProtocol("https", easyhttps);
}

在执行具体的http method之前，暗中将https协议注册一把，如孔雀翎暗藏玄机，毙敌于无形。记住，官方的binary发行版本没有ssl的contribute包，方法一是下载源代码版本来打造你的孔雀翎。

3.多情环之cookies
常道人老多情，其实是记忆太多，所以情之所至，正如cookies甜心，无论你走到那，总把你牵挂：

java 代码

HttpClient httpclient=new HttpClient();
httpclient.getParams().setCookiePolicy(CookiePolicy.RFC_2109);//RFC_2109是支持较普遍的一个，还有其他cookie协议
HttpState initialState = new HttpState();
Cookie cookie=new Cookie();
cookie.setDomain("www.balblabla.com");
cookie.setPath("/");
cookie.setName("多情环");
cookie.setValue("多情即无情");
initialState.addCookie(cookie);
httpclient.setState(initialState);
...

4.离别钩之解构cookies
多情环的反面即离别钩，钩出，敌之身体某个部件即要与身体别离，端的是无情：

java 代码

...//执行了某些get/post方法后
Cookie[] cookies = httpclient.getState().getCookies();
System.out.println("Present cookies: ");
for (int i = 0; i < cookies.length; i++) {//循环结构零部件
    System.out.println(" - " + cookies[i].toExternalForm());
    System.out.println(" - domain=" + cookies[i].getDomain());
    System.out.println(" - path=" + cookies[i].getPath());
    ...
}

5.霸王抢之post参数
枪，长兵器之王，诸多名将均使一杆或金或银命名的名枪，比如岳飞。post方法在提交参数对时,犹如灵蛇出洞：

java 代码

PostMethod postMethod = new PostMethod("http://www.saybot.com/postme");
NameValuePair[] postData = new NameValuePair[2];
postData[0] = new NameValuePair("武器", "枪");
postData[1] = new NameValuePair("什么枪", "神枪");
postMethod.addParameters(postData);
...//出枪吧

6.七星碧玉刀之支持代理(proxy)
代理，非常重要，尤其在局域网横行的年头，没有代理，你在公司上不了QQ，没有代理，google不了网页快照，代理之威，可比七星碧玉刀，无刀，在局域网和开发当中，一切白搭：

java 代码

HttpClient httpclient=new HttpClient();
httpClient.getHostConfiguration().setProxy("192.168.0.1", 9527);
httpClient.getParams().setAuthenticationPreemptive(true);//重要！！！告诉httpclient，使用抢先认证，否则你会收到“你没有资格”的恶果
/*
  这一步也至关重要，MyProxyCredentialsProvider实现了org.apache.commons.httpclient.auth.CredentialsProvider接口，
  返回代理的credential(username/password)*/
httpClient.getParams().setParameter(CredentialsProvider.PROVIDER, new MyProxyCredentialsProvider());
httpClient.getState().setProxyCredentials(
    new AuthScope("192.168.0.1",
        AuthScope.ANY_PORT, //任意端口哦，可要小心
        AuthScope.ANY_REALM),//任意域哦，可要小心
new UsernamePasswordCredentials("username",//proxy的用户名
                        "password"));//proxy的密码

...

7.长生剑之天下第一
看httpclient的官方文档：jakarta.apache.org/commons/httpclient/userguide.html
看Hilton网友写的小葵花宝典笔记：www.cnjm.net/tech/article1155.html
通读后，你会有种拔剑四顾心茫然的高手感觉

利用HttpClient来获取JSON数据代码：

 public static String getJsonData(String url, String data) throws Exception{  
     
  Integer statusCode = -1;
  // Create HttpClient Object
  DefaultHttpClient client = new DefaultHttpClient();
  // Send data by post method in HTTP protocol,use HttpPost instead of
  // PostMethod which was occurred in former version
  HttpPost post = new HttpPost(url);
  // Construct a string entity
  StringEntity entity = new StringEntity(data,"UTF-8");
  entity.setContentType("application/json;charset=UTF-8");
  // Set XML entity
  post.setEntity(entity);
  // Set content type of request header
  post.setHeader("accept", "application/json");
  post.setHeader("Content-Type", "application/json;charset=UTF-8");
  // Execute request and get the response
  HttpResponse response = client.execute(post);

  // Response Header - StatusLine - status code
  statusCode = response.getStatusLine().getStatusCode();
  
  if (statusCode != HttpStatus.SC_OK) {
   throw new HttpException("Http Status is error.");
  }
  HttpEntity entityRsp = response.getEntity();
  StringBuffer result = new StringBuffer();
  BufferedReader rd = new BufferedReader(new InputStreamReader(entityRsp
    .getContent(), HTTP.UTF_8));
  String tempLine = rd.readLine();
  while (tempLine != null) {
   result.append(tempLine);
   tempLine = rd.readLine();
  }

  if (entityRsp != null) {
   entityRsp.consumeContent();
  }
  return result.toString();

 }

项目中与对方进行数据交互时，对方提供了一套夸域json方式传递数据，并给出了一个js示例

$.getJSON(
    "http://www.----aspx?callback=?",
    {Name:"123",Pass:"123"},
    function(json){
        if(json.UserId==null){
            alert("NO");
        }else{
            alert(json.UserId);
        }
    }
);

 但是此方法处理数据时，只能在页面中进行，局限性很大。因此在具体实施时，使用了HttpClient来代替。

import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.utils.URLEncodedUtils;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.protocol.HTTP;
import org.json.JSONException;
import org.json.JSONObject;
import org.json.JSONTokener;


/**
 * 使用HttpClient请求页面并返回json格式数据.
 * 对方接收的也是json格式数据。
 * 因此使用HttpGet。
 * */
public class Json {

    public static void main(String[] args) throws JSONException {

        JSONObject json = new JSONObject();
        List<NameValuePair> params = new ArrayList<NameValuePair>();
        params.add(new BasicNameValuePair("Name", "123"));
        params.add(new BasicNameValuePair("Pass", "123"));
        //要传递的参数.
        String url = "http://www.----aspx?" + URLEncodedUtils.format(params, HTTP.UTF_8);
        //拼接路径字符串将参数包含进去
        json = get(url);
        System.out.println(json.get("UserId"));

    }

    public static JSONObject get(String url) {

        HttpClient client = new DefaultHttpClient();
        HttpGet get = new HttpGet(url);
        JSONObject json = null;
        try {
            HttpResponse res = client.execute(get);
            if (res.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
                HttpEntity entity = res.getEntity();
                json = new JSONObject(new JSONTokener(new InputStreamReader(entity.getContent(), HTTP.UTF_8)));
            }
        } catch (Exception e) {
            throw new RuntimeException(e);

        } finally{
            //关闭连接 ,释放资源
            client.getConnectionManager().shutdown();
        }
        return json;
    }
}