共计 5398 个字符，预计需要花费 14 分钟才能阅读完成。
在早期的时候，Android上还没有像Volley、OkHttp、Retrofit这些优秀的开源库，如果想要使用网络请求的话，就只能自己封装HttpClient和HttpURLConnection。现在我们就来看下Apache的这两个类。
1. HttpClient
2.1 导入HttpClient
由于从Android 6.0 开始，谷歌就将HttpClient从Android中删除了，所以若现在想使用他，还得导入依赖：
在项目的build.gradle的Android代码块下加入依赖，示例：
1
2
3
4
|
android {
useLibrary 'org.apache.http.legacy'
...
}
|
2.2 HttpClient的Get
首先通过DefaultHttpClient来实例化一个HttpClient，并配置好参数：
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
|
private HttpClient createHttpClient() {
HttpParams mDefaultHttpParams = new BasicHttpParams();
HttpConnectionParams.setConnectionTimeout(mDefaultHttpParams, 15000);
HttpConnectionParams.setSoTimeout(mDefaultHttpParams, 15000);
HttpConnectionParams.setTcpNoDelay(mDefaultHttpParams, true);
HttpProtocolParams.setVersion(mDefaultHttpParams, HttpVersion.HTTP_1_1);
HttpProtocolParams.setContentCharset(mDefaultHttpParams, HTTP.UTF_8);
HttpProtocolParams.setUseExpectContinue(mDefaultHttpParams, true);
HttpClient mHttpClient = new DefaultHttpClient(mDefaultHttpParams);
return mHttpClient;
}
|
接着创建HttpGet和HttpClient，请求网络并得到HttpResponse，并对HttpResponse进行处理：
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
|
private void useHttpClientGet(String url) {
HttpGet mHttpGet = new HttpGet(url);
mHttpGet.addHeader("Connection", "Keep-Alive");
try {
HttpClient mHttpClient = createHttpClient();
HttpResponse mHttpResponse = mHttpClient.execute(mHttpGet);
HttpEntity mHttpEntity = mHttpResponse.getEntity();
int code = mHttpResponse.getStatusLine().getStatusCode();
if (null != mHttpEntity) {
InputStream mInputStream = mHttpEntity.getContent();
String respose = converStreamToString(mInputStream);
Log.i("wangshu", "请求状态码:" + code + "\n请求结果:\n" + respose);
mInputStream.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
|
converStreamToString()方法将请求结果转换成String类型：
1
2
3
4
5
6
7
8
9
10
|
private String converStreamToString(InputStream is) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuffer sb = new StringBuffer();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
String respose = sb.toString();
return respose;
}
|
最后开启线程访问:
1
2
3
4
5
6
|
new Thread(new Runnable() {
@Override
public void run() {
useHttpClientGet("http://www.baidu.com");
}
}).start();
|
1.3 HttpClient的POST
和GET差不多，只需要修改传递的参数：
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
|
private void useHttpClientPost(String url) {
HttpPost mHttpPost = new HttpPost(url);
mHttpPost.addHeader("Connection", "Keep-Alive");
try {
HttpClient mHttpClient = createHttpClient();
List<NameValuePair> postParams = new ArrayList<>();
postParams.add(new BasicNameValuePair("username", "moon"));
postParams.add(new BasicNameValuePair("password", "123"));
mHttpPost.setEntity(new UrlEncodedFormEntity(postParams));
HttpResponse mHttpResponse = mHttpClient.execute(mHttpPost);
HttpEntity mHttpEntity = mHttpResponse.getEntity();
int code = mHttpResponse.getStatusLine().getStatusCode();
if (null != mHttpEntity) {
InputStream mInputStream = mHttpEntity.getContent();
String respose = converStreamToString(mInputStream);
Log.i("wangshu", "请求状态码:" + code + "\n请求结果:\n" + respose);
mInputStream.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
|
2. HttpURLConnection
HttpURLConnection较HttpClient来说更轻量，而且他API也比HttpClient简单。特别是Android 6.0将HttpClient移除之后，现在只能使用HttpURLConnection。
2.1 HttpURLConnection的POST请求
首先我们创建一个UrlConnManager类，然后里面提供getHttpURLConnection()方法用于配置默认的参数并返回HttpURLConnection：
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
|
public static HttpURLConnection getHttpURLConnection(String url){
HttpURLConnection mHttpURLConnection=null;
try {
URL mUrl=new URL(url);
mHttpURLConnection=(HttpURLConnection)mUrl.openConnection();
mHttpURLConnection.setConnectTimeout(15000);
mHttpURLConnection.setReadTimeout(15000);
mHttpURLConnection.setRequestMethod("POST");
mHttpURLConnection.setRequestProperty("Connection","Keep-Alive");
mHttpURLConnection.setDoInput(true);
mHttpURLConnection.setDoOutput(true);
} catch (IOException e) {
e.printStackTrace();
}
return mHttpURLConnection ;
}
|
因为我们要发送POST请求，所以在UrlConnManager类中再写一个postParams()方法用来组织一下请求参数并将请求参数写入到输出流中：
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
|
public static void postParams(OutputStream output,List<NameValuePair>paramsList) throws IOException{
StringBuilder mStringBuilder=new StringBuilder();
for (NameValuePair pair:paramsList){
if(!TextUtils.isEmpty(mStringBuilder)){
mStringBuilder.append("&");
}
mStringBuilder.append(URLEncoder.encode(pair.getName(),"UTF-8"));
mStringBuilder.append("=");
mStringBuilder.append(URLEncoder.encode(pair.getValue(),"UTF-8"));
}
BufferedWriter writer=new BufferedWriter(new OutputStreamWriter(output,"UTF-8"));
writer.write(mStringBuilder.toString());
writer.flush();
writer.close();
}
|
接下来我们添加请求参数，调用postParams()方法将请求的参数组织好传给HttpURLConnection的输出流，请求连接并处理返回的结果：
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
|
private void useHttpUrlConnectionPost(String url) {
InputStream mInputStream = null;
HttpURLConnection mHttpURLConnection = UrlConnManager.getHttpURLConnection(url);
try {
List<NameValuePair> postParams = new ArrayList<>();
postParams.add(new BasicNameValuePair("username", "moon"));
postParams.add(new BasicNameValuePair("password", "123"));
UrlConnManager.postParams(mHttpURLConnection.getOutputStream(), postParams);
mHttpURLConnection.connect();
mInputStream = mHttpURLConnection.getInputStream();
int code = mHttpURLConnection.getResponseCode();
String respose = converStreamToString(mInputStream);
Log.i("wangshu", "请求状态码:" + code + "\n请求结果:\n" + respose);
mInputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
|
最后开启线程请求网络：
1
2
3
4
5
6
7
8
|
private void useHttpUrlConnectionGetThread() {
new Thread(new Runnable() {
@Override
public void run() {
useHttpUrlConnectionPost("http://www.baidu.com");
}
}).start();
}
|
