网络协议 Android HTTP请求方式:HttpClient

1.HttpClient使用流程 基本流程：

2.HttpClient使用示例 1）使用HttpClient发送GET请求 直接贴下简单的发送Get请求的代码：

public class MainActivity extends Activity implements OnClickListener {

private Button btnGet;

private WebView wView;

public static final int SHOW_DATA = 0X123;

private String detail = "";

private Handler handler = new Handler() {

public void handleMessage(Message msg) {

if(msg.what == SHOW_DATA)

{

wView.loadDataWithBaseURL("",detail, "text/html","UTF-8","");

}

};

};

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

initView();

setView();

}

private void initView() {

btnGet = (Button) findViewById(R.id.btnGet);

wView = (WebView) findViewById(R.id.wView);

}

private void setView() {

btnGet.setOnClickListener(this);

wView.getSettings().setDomStorageEnabled(true);

}

@Override

public void onClick(View v) {

if (v.getId() == R.id.btnGet) {

GetByHttpClient();

}

}

private void GetByHttpClient() {

new Thread()

{

public void run()

{

try {

HttpClient httpClient = new DefaultHttpClient();

HttpGet httpGet = new HttpGet("http://www.w3cschool.cc/python/python-tutorial.html");

HttpResponse httpResponse = httpClient.execute(httpGet);

if (httpResponse.getStatusLine().getStatusCode() == 200) {

HttpEntity entity = httpResponse.getEntity();

detail = EntityUtils.toString(entity, "utf-8");

handler.sendEmptyMessage(SHOW_DATA);

}

} catch (Exception e) {

e.printStackTrace();

}

};

}.start();

}

} 运行截图

另外，如果是带有参数的GET请求的话，我们可以将参数放到一个List集合中，再对参数进行URL编码， 最后和URL拼接下就好了：

List params = new LinkedList(); params.add(new BasicNameValuePair(“user”, “猪小弟”)); params.add(new BasicNameValuePair(“pawd”, “123”)); String param = URLEncodedUtils.format(params, “UTF-8”); HttpGet httpGet = new HttpGet(“http://www.baidu.com”+“?”+param); 2）使用HttpClient发送POST请求 POST请求比GET稍微复杂一点，创建完HttpPost对象后，通过NameValuePair集合来存储等待提交 的参数，并将参数传递到UrlEncodedFormEntity中，最后调用setEntity(entity)完成， HttpClient.execute(HttpPost)即可；这里就不写例子了，暂时没找到Post的网站，又不想 自己写个Servlet，So,直接贴核心代码吧~

核心代码:

private void PostByHttpClient(final String url) { new Thread() { public void run() { try{ HttpClient httpClient = new DefaultHttpClient(); HttpPost httpPost = new HttpPost(url); List params = new ArrayList(); params.add(new BasicNameValuePair(“user”, “猪大哥”)); params.add(new BasicNameValuePair(“pawd”, “123”)); UrlEncodedFormEntity entity = new UrlEncodedFormEntity(params,“UTF-8”); httpPost.setEntity(entity); HttpResponse httpResponse = httpClient.execute(httpPost); if (httpResponse.getStatusLine().getStatusCode() == 200) { HttpEntity entity2 = httpResponse.getEntity(); detail = EntityUtils.toString(entity2, “utf-8”); handler.sendEmptyMessage(SHOW_DATA); } }catch(Exception e){e.printStackTrace();} }; }.start(); } 3.HttpClient抓数据示例(教务系统数据抓取) 其实关于HttpClient的例子有很多，比如笔者曾经用它来抓学校教务系统上学生的课程表: 这就涉及到Cookie，模拟登陆的东西，说到抓数据(爬虫)，一般我们是搭配着JSoup来解析 抓到数据的，有兴趣可以自己查阅相关资料，这里贴下笔者毕设app里获取网页部分的关键 代码！大家可以体会下：

HttpClient可以通过下述代码获取与设置Cookie： HttpResponse loginResponse = new DefaultHttpClient().execute(getLogin); 获得Cookie:cookie = loginResponse.getFirstHeader(“Set-Cookie”).getValue(); 请求时带上Cookie:httpPost.setHeader(“Cookie”, cookie);

//获得链接,模拟登录的实现: public int getConnect(String user, String key) throws Exception { // 先发送get请求 获取cookie值和__ViewState值 HttpGet getLogin = new HttpGet(true_url); // 第一步:主要的HTML: String loginhtml = “”; HttpResponse loginResponse = new DefaultHttpClient().execute(getLogin); if (loginResponse.getStatusLine().getStatusCode() == 200) { HttpEntity entity = loginResponse.getEntity(); loginhtml = EntityUtils.toString(entity); // 获取响应的cookie值 cookie = loginResponse.getFirstHeader(“Set-Cookie”).getValue(); System.out.println("cookie= " + cookie); }

// 第二步:模拟登录

// 发送Post请求,禁止重定向

HttpPost httpPost = new HttpPost(true_url);

httpPost.getParams().setParameter(ClientPNames.HANDLE_REDIRECTS, false);

// 设置Post提交的头信息的参数

httpPost.setHeader("User-Agent",

"Mozilla/5.0 (Windows NT 6.3; WOW64; Trident/7.0; rv:11.0) like Gecko");

httpPost.setHeader("Referer", true_url);

httpPost.setHeader("Cookie", cookie);

// 设置请求数据

List params = new ArrayList();

params.add(new BasicNameValuePair("__VIEWSTATE",

getViewState(loginhtml)));// __VIEWSTATE参数，如果变化可以动态抓取获取

params.add(new BasicNameValuePair("Button1", ""));

params.add(new BasicNameValuePair("hidPdrs", ""));

params.add(new BasicNameValuePair("hidsc", ""));

params.add(new BasicNameValuePair("lbLanguage", ""));

params.add(new BasicNameValuePair("RadioButtonList1", "%D1%A7%C9%FA"));

params.add(new BasicNameValuePair("txtUserName", user));

params.add(new BasicNameValuePair("TextBox2", key));

params.add(new BasicNameValuePair("txtSecretCode", "")); // ( ╯□╰ )逗比正方,竟然不需要验证码

// 设置编码方式,响应请求,获取响应状态码:

httpPost.setEntity(new UrlEncodedFormEntity(params, "gb2312"));

HttpResponse response = new DefaultHttpClient().execute(httpPost);

int Status = response.getStatusLine().getStatusCode();

if(Status == 200)return Status;

System.out.println("Status= " + Status);

// 重定向状态码为302

if (Status == 302 || Status == 301) {

// 获取头部信息中Location的值

location = response.getFirstHeader("Location").getValue();

System.out.println(location);

// 第三步:获取管理信息的主页面

// Get请求

HttpGet httpGet = new HttpGet(ip_url + location);// 带上location地址访问

httpGet.setHeader("Referer", true_url);

httpGet.setHeader("Cookie", cookie);

// 主页的html

mainhtml = "";

HttpResponse httpResponseget = new DefaultHttpClient()

.execute(httpGet);

if (httpResponseget.getStatusLine().getStatusCode() == 200) {

HttpEntity entity = httpResponseget.getEntity();

mainhtml = EntityUtils.toString(entity);

}

}

return Status;

} 4.使用HttpPut发送Put请求 示例代码如下：

public static int PutActCode(String actCode, String licPlate, Context mContext) { int resp = 0; String cookie = (String) SPUtils.get(mContext, “session”, “”); HttpPut httpPut = new HttpPut(PUTACKCODE_URL); httpPut.setHeader(“Cookie”, cookie); try {

List params = new ArrayList();

params.add(new BasicNameValuePair("activation_code", actCode));

params.add(new BasicNameValuePair("license_plate", licPlate));

httpPut.setEntity(new UrlEncodedFormEntity(params, "UTF-8"));

HttpResponse course_response = new DefaultHttpClient().execute(httpPut);

if (course_response.getStatusLine().getStatusCode() == 200) {

HttpEntity entity2 = course_response.getEntity();

JSONObject jObject = new JSONObject(EntityUtils.toString(entity2));

resp = Integer.parseInt(jObject.getString("status_code"));

return resp;

}

} catch (Exception e) {

e.printStackTrace();

}

return resp;

}

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