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java之httpClient 3.x、AsyncHttpClient1.9.x使用总结

首先请大牛们见谅菜鸟重复造轮子的学习方式,本文适合新手看~

下面使用的同步http是HttpClient 3.X 的版本,不过早已 不在维护 ,如果刚开始使用http,建议大家都换成 4.X 版本,别看下面的有关同步http的部分了,4.x效率有质地提高,总结3.X只是因为无奈旧项目还在使用。后面再更新一篇有关4.x的,最新的HttpClient 4.X官方地址: http://hc.apache.org/httpcomponents-client-4.5.x/index.html

但鉴于可能有些旧的系统还是采用3.X版本的HttpClient,所以本文还是先记录下使用方法。

相反下面的异步http是Async Http Client 的 1.9.8 版本,这个版本还是挺好的。API请见: http://asynchttpclient.github.io/async-http-client/apidocs/com/ning/http/client/AsyncHttpClient.html

http使用场景很多,据以往经验,对于客户端来说,我们使用http一般会发出以下几种常见的场景:

  1. 以get方式请求服务器
    1. 不带任何参数
    2. 带上key-value对
  2. 以post方式请求服务器
    1. 不带任何参数
    2. 带上key-value对
    3. 带上字节数组
    4. 带上文件
    5. 带上文件+key-value对

以上的场景一般可以满足一般的需求,然后,我们可以在这基础上扩展一点点:假如遇到一个类似于报表的子系统,主系统要在关键的逻辑链路中“打点”,通过http调用报表子系统记录一些相关的信息时,那么如果我们使用同步http来请求报表子系统的话,一旦报表子系统挂了,那么肯定会影响到主系统的运行。

为了不影响到主系统的运行,我们可以采用“ 异步 ” 的方式通过http(AsyncHttpClient )请求报表子系统,那么即使子系统挂了,对主系统的关键链路的执行也不会产生多大的影响。所以,封装一个http组件,自然而然少不了封装异步http请求。而异步http所能够做的事情,也应该覆盖上面提到的几种场景。

再者,考虑到效率问题,除非有足够的理由,否则每次调用http接口,都创建立一个新的连接,是相当没效率的,所以MultiThreadedHttpConnectionManager 诞生了,HttpClient在内部维护一个 连接池 ,通过MultiThreadedHttpConnectionManager 我们可以设置“默认连接数”、“最大连接数”、“连接超时”、“读取数据超时”等等配置,从而来提高效率。

废话完了,怎么实现以上需求呢。

包的引用:

同步的http我使用的是org.apache.commons.httpclient的HttpClient的3.1版本。

maven配置为:

<!-- httpClient --> <dependency> <groupId>commons-httpclient</groupId> <artifactId>commons-httpclient</artifactId> <version>3.1</version> </dependency>

异步的http我使用的是com.ning.http.client的AsyncHttpClien的1.9.8版本。 注意 ,其需要依赖几个日志相关的组件、分别为log4j、slf4j、slf4j-log4j

maven配置为:

<!-- slf4j-log4j --> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-log4j12</artifactId> <version>1.7.7</version> </dependency> <!-- slf4j --> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-api</artifactId> <version>1.7.5</version> </dependency> <!-- log4j --> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.16</version> </dependency> <!-- 异步IO --> <dependency> <groupId>com.ning</groupId> <artifactId>async-http-client</artifactId> <version>1.9.8</version> </dependency>

为了实现连接池,我们通过一个工厂类来生成httpClient,为了上一层方便调用,我们定义了一个接口,规范了同步、异步http应该实现的方法。包结构如下:

java之httpClient 3.x、AsyncHttpClient1.9.x使用总结

一、同步的HttpClient 3.X

从工厂入手,工厂负责初始化httpClient的配置,包括“默认连接数”、“最大连接数”、“连接超时”、“读取数据超时”等等,不同的服务我们应该创建不同的manager,因为不可能我们调服务A和调服务B使用同一套配置是吧,比如超时时间,应该考虑会有所差异。初始化完配置后,把 manager传到实现类,在实现类中new HttpClient。

工厂代码如下:

// 专门针对xx服务器的连接管理对象  // 因为不同服务可能超时等参数不用,所以针对不同服务,把连接管理对象区分开来,这只是其中一个  private static MultiThreadedHttpConnectionManager xxconnectionManager = new MultiThreadedHttpConnectionManager();  static {   // 专门针对xx服务器的连接参数   xxconnectionManager = new MultiThreadedHttpConnectionManager();   HttpConnectionManagerParams paramsSearch = new HttpConnectionManagerParams();   paramsSearch.setDefaultMaxConnectionsPerHost(1000); // 默认连接数   paramsSearch.setMaxTotalConnections(1000);   // 最大连接数   paramsSearch.setConnectionTimeout(30000);    // 连接超时   paramsSearch.setSoTimeout(20000);      // 读数据超时   xxconnectionManager.setParams(paramsSearch);  }  /*   * 返回针对XX服务的httpClient包装类   */  public static SyncHttpClientWapperImpl getXXSearchHttpClient() {   return new SyncHttpClientWapperImpl(xxconnectionManager);  } 

注意 一点,这些连接数,超时等的配置,要做要调查工作之后再定夺,是根据访问服务的不同,我们自己的机器能有多少剩余的可用空间的不同而不同的,而不是随随便便就设置一个参数。

实现类的构造方法如下:

private HttpClient client;// httpClient  private final static String CHARACTER  = "UTF-8";  // 构造器,由工厂调用  public SyncHttpClientWapperImpl(MultiThreadedHttpConnectionManager connectionManager) {   client = new HttpClient(connectionManager);   // 字符集   client.getParams().setParameter(HttpMethodParams.HTTP_CONTENT_CHARSET, CHARACTER);  } 

这里有一个 挺困惑 的点:HttpClient有必要弄成静态的吗?即直接在工厂里面为每种服务生成一个静态的HttpClient,然后传到实现类?经测试,改成静态的效率并没有提高,在文件传输的测试中,甚至下降了,这个有点困惑,大家可以试一试一起讨论一下。

然后,在实现类中实现各种方法。

第一种,通过URL,以get方式请求服务器,返回字节数组。

public byte[] getWithQueryURL(String queryURL) throws HttpClientException {   if(queryURL == null) {    throw new HttpClientException("queryURL is null.");   }   byte[] newbuf = executeByGet(queryURL);   if ((newbuf == null) || (newbuf.length == 0)) {    throw new HttpClientException("Server response is null: " + queryURL);   }   return newbuf;  } private byte[] executeByGet(String url) throws HttpClientException {   HttpMethod method = new GetMethod(url);   // RequestHeader     method.setRequestHeader("Content-type" , "text/html; charset=UTF-8");   // 提交请求   try {    client.executeMethod(method);   } catch (Exception e) {    method.releaseConnection();    throw new HttpClientException(url, e);   }   // 返回字节流   byte[] responseBody = null;   try {    responseBody = getBytesFromInpuStream(method.getResponseBodyAsStream());   } catch (IOException e) {    throw new HttpClientException(e);   } finally {    method.releaseConnection();   }   return responseBody;  } 

接着,写一个通用的流解析方法,负责把返回的流解析成字节数组。

private byte[] getBytesFromInpuStream(InputStream instream) throws IOException {  ByteArrayOutputStream outstream = new ByteArrayOutputStream();  try {   int length;   byte[] tmp = new byte[8096];   while ((length = instream.read(tmp)) != -1) {    outstream.write(tmp, 0, length);   }   return outstream.toByteArray();  } finally {   instream.close();   outstream.close();  } } 

这样就完成了最简单的get请求的调用了。

第二种:通过URL和paramsMap参数,以post方式请求服务器,返回字节数组。

public byte[] postWithParamsMap( String queryURL, Map<String,String> paramsMap) throws HttpClientException{   if(queryURL == null) {    throw new HttpClientException("queryURL is null.");   }   byte[] newbuf = executeByPostWithParamsMap(queryURL,paramsMap);   if ((newbuf == null) || (newbuf.length == 0)) {    throw new HttpClientException("Server response is null: " + queryURL);   }   return newbuf;  } private byte[] executeByPostWithParamsMap(String URL, Map<String,String> paramsMap)  throws HttpClientException {   PostMethod method = new PostMethod(URL);   // 构造参数   if(paramsMap != null) {    Set<Entry<String, String>> entrySet = paramsMap.entrySet();    Iterator<Entry<String, String>> iterator = entrySet.iterator();    NameValuePair[] nvps = new NameValuePair[paramsMap.size()];    int i = 0 ;    while(iterator.hasNext()) {     Entry<String, String> entry = iterator.next();     if(entry.getKey() != null) {      NameValuePair nvp = new NameValuePair(entry.getKey(),entry.getValue());      nvps[i++] = nvp;     }    }    method.setRequestBody(nvps);   }   // RequestHeader,key-value对的话,httpClient自动带上application/x-www-form-urlencoded   method.setRequestHeader("Content-type" , "application/x-www-form-urlencoded; charset=UTF-8");   // 提交请求   try {    client.executeMethod(method);   } catch (Exception e) {    method.releaseConnection();    throw new HttpClientException(URL, e);   }   // 返回字节流   byte[] responseBody = null;   try {    responseBody = getBytesFromInpuStream(method.getResponseBodyAsStream());   } catch (IOException e) {    throw new HttpClientException(e);   } finally {    method.releaseConnection();   }   return responseBody;  } 

第三种:通过URL和bytes参数,以post方式请求服务器,返回字节数组。

public byte[] postWithBytes(String queryURL , byte[] bytes) throws HttpClientException{   if(queryURL == null) {    throw new HttpClientException("queryURL is null.");   }   byte[] newbuf = executeByPostWithBytes(queryURL,bytes);   if ((newbuf == null) || (newbuf.length == 0)) {    throw new HttpClientException("Server response is null: " + queryURL);   }   return newbuf;  } private byte[] executeByPostWithBytes(String queryURL, byte[] bytes) throws HttpClientException {   PostMethod method = new PostMethod(queryURL);   RequestEntity requestEntity = new ByteArrayRequestEntity(bytes);   method.setRequestEntity(requestEntity);   // RequestHeader   method.setRequestHeader("Content-type" , "text/plain; charset=UTF-8");   // 提交请求   try {    client.executeMethod(method);   } catch (Exception e) {    method.releaseConnection();    throw new HttpClientException(queryURL, e);   }   // 返回字节流   byte[] responseBody = null;   try {    responseBody = getBytesFromInpuStream(method.getResponseBodyAsStream());   } catch (IOException e) {    throw new HttpClientException(e);   } finally {    method.releaseConnection();   }   return responseBody;  } 

第四种:通过URL、fileList、paramMap参数,以post方式请求服务器,返回字节数组。

public byte[] postWithFileListAndParamMap(String queryURL,List<File> fileList,Map<String,String> paramMap) throws HttpClientException, HttpException, IOException {   if(queryURL == null) {    throw new HttpClientException("queryURL is null.");   }   if(fileList == null) {    throw new HttpClientException("file is null.");   }   if(paramMap == null){    throw new HttpClientException("paramMap is null.");   }   return executeByPostWithFileListAndParamMap(queryURL, fileList, paramMap);  } private byte[] executeByPostWithFileListAndParamMap (String queryURL,List<File> fileList,Map<String,String> paramMap) throws HttpException, IOException, HttpClientException {   if(queryURL != null && fileList != null && fileList.size() > 0) {    // post方法    PostMethod method = new PostMethod(queryURL);    // Part[]    Part[] parts = null;    if(paramMap != null) {     parts = new Part[fileList.size()+paramMap.size()];    }    else {     parts = new Part[fileList.size()];    }    int i = 0 ;    // FilePart    for(File file : fileList){     Part filePart = new FilePart(file.getName(),file);     parts[i++] = filePart;    }    // StringPart    if(paramMap != null ) {     Set<Entry<String, String>> entrySet = paramMap.entrySet();     Iterator<Entry<String, String>> it = entrySet.iterator();     while(it.hasNext()) {      Entry<String, String> entry = it.next();      Part stringPart = new StringPart(entry.getKey(),entry.getValue());      parts[i++] = stringPart;     }    }    // Entity    RequestEntity requestEntity = new MultipartRequestEntity(parts, method.getParams());    method.setRequestEntity(requestEntity);    // RequestHeader,文件的话,HttpClient自动加上multipart/form-data //   method.setRequestHeader("Content-type" , "multipart/form-data; charset=UTF-8");    // excute    try {     client.executeMethod(method);    } catch (Exception e) {     method.releaseConnection();     throw new HttpClientException(queryURL, e);    }    // return     byte[] responseBody = null;    try {     responseBody = getBytesFromInpuStream(method.getResponseBodyAsStream());    } catch (IOException e) {     throw new HttpClientException(e);    } finally {     method.releaseConnection();    }    return responseBody;   }   return null;  } 

二、异步的AsyncHttpClient

同样的,按照这种思路,异步的AsyncHttpClient也有类似的实现,不过写法不同而已,在工厂中,AsyncHttpClient使用的是AsyncHttpClientConfig.Builder作为管理配置的类,也有类似连接超时,最大连接数等配置。

工厂类:

// 专门针对xx服务器的连接管理对象  // 因为不同服务可能超时等参数不用,所以针对不同服务,把连接管理对象区分开来,这只是其中一个  private static AsyncHttpClientConfig.Builder xxbuilder = new AsyncHttpClientConfig.Builder();  static {   xxbuilder.setConnectTimeout(3000); // 连接超时   xxbuilder.setReadTimeout(2000);  // 读取数据超时   xxbuilder.setMaxConnections(1000); // 最大连接数  }  /*   * 返回针对XX服务的httpClient包装类   */  public static AsyncHttpClientWapperImpl getXXSearchHttpClient() {   return new AsyncHttpClientWapperImpl(xxbuilder);  } 

其使用了builder 的设计模式,活生生的一个例子,值得学习。

实现类的构造方法:

private AsyncHttpClient client;          public AsyncHttpClientWapperImpl(Builder xxbuilder) {         client = new AsyncHttpClient(xxbuilder.build());     }

这样,AsyncHttpClient对象就创建完毕了。接下来是各种场景的实现,感觉异步的AsyncHttpClient封装得比HttpClient 3.X更加容易使用,设计得更好。

第一种:通过URL,以get方式请求服务器,返回字节数组。

public byte[] getWithQueryURL(String queryURL)   throws HttpClientException, HttpClientException {  if(queryURL == null) {   throw new HttpClientException("queryURL为空");  }  byte[] newbuf = executeByGet(queryURL);  if ((newbuf == null) || (newbuf.length == 0)) {   throw new HttpClientException("Server response is null: " + queryURL);  }  return newbuf; } private byte[] executeByGet(String queryURL) throws HttpClientException {   byte[] responseBody = null;  try {   Future<Response> f = client.prepareGet(queryURL).execute();     responseBody = getBytesFromInpuStream(f.get().getResponseBodyAsStream());  } catch (Exception e) {   throw new HttpClientException(e);  }  return responseBody; } 

同样的,我们写了一个getBytesFromInputStream()方法解析服务端返回的流,我们发现,两个实现类里面都有一些共同的方法,这里可以考虑写一个父类,把这些方法提取出来。

第二种:通过URL和paramsMap参数,以post方式请求服务器,返回字节数组。

public byte[] postWithParamsMap(String queryURL,    Map<String, String> paramsMap) throws HttpClientException {   if(queryURL == null) {    throw new HttpClientException("queryURL为空");   }   byte[] newbuf = executeByPostByParamMap(queryURL,paramsMap);   if ((newbuf == null) || (newbuf.length == 0)) {    throw new HttpClientException("Server response is null: " + queryURL);   }   return newbuf;  } private byte[] executeByPostByParamMap(String queryURL,Map<String,String> paramsMap) throws HttpClientException {   byte[] responseBody = null;   try {    RequestBuilder requestBuilder = new RequestBuilder();    // 添加 key-value参数    if(paramsMap != null && paramsMap.size() > 0) {     Set<Entry<String, String>> entrySet = paramsMap.entrySet();     Iterator<Entry<String, String>> iterator = entrySet.iterator();     while(iterator.hasNext()) {      Entry<String, String> entry = iterator.next();      if(entry.getKey() != null) {       requestBuilder.addFormParam(entry.getKey(), entry.getValue());      }     }    }    // 添加RequestHeader,key    requestBuilder.addHeader("Content-type", "application/x-www-form-urlencoded; charset=UTF-8");    requestBuilder.setMethod("POST");    // 添加URL    requestBuilder.setUrl(queryURL);    // request    Request request = requestBuilder.build();    // 提交    ListenableFuture<Response> f = client.executeRequest(request);    responseBody = getBytesFromInpuStream(f.get().getResponseBodyAsStream());   } catch (Exception e) {    throw new HttpClientException(e);   }   return responseBody;  } 

第三种:通过URL和bytes参数,以post方式请求服务器,返回字节数组。

public byte[] postWithBytes(String queryURL, byte[] bytes)  throws HttpClientException {         if(queryURL == null) {  throw new HttpClientException("queryURL is null.");         }         byte[] newbuf = executeByPostWithBytes(queryURL,bytes);         if ((newbuf == null) || (newbuf.length == 0)) {  throw new HttpClientException("Server response is null: " + queryURL);         }         return newbuf;     } private byte[] executeByPostWithBytes(String queryURL, byte[] bytes) throws HttpClientException {         byte[] responseBody = null;         try {  RequestBuilder requestBuilder = new RequestBuilder();  // 添加 bytes参数  requestBuilder.setBody(bytes);  // 添加RequestHeader,key  requestBuilder.addHeader("Content-type", "text/plain; charset=UTF-8");  requestBuilder.setMethod("POST");  // 添加URL  requestBuilder.setUrl(queryURL);  // request  Request request = requestBuilder.build();  // 提交  ListenableFuture<Response> f = client.executeRequest(request);  responseBody = getBytesFromInpuStream(f.get().getResponseBodyAsStream());         } catch (Exception e) {  throw new HttpClientException(e);         }         return responseBody;     } 

第四种:通过URL、fileList、paramMap参数,以post方式请求服务器,返回字节数组。

public byte[] postWithFileListAndParamMap(String queryURL,    List<File> fileList, Map<String, String> paramMap)    throws HttpClientException, HttpException, IOException {   if(queryURL == null) {    throw new HttpClientException("queryURL is null.");   }   if(fileList == null || fileList.size() == 0) {    throw new HttpClientException("fileList is null.");   }   if(paramMap == null || paramMap.size() == 0) {    throw new HttpClientException("paramMap is null.");   }   return executeByPostWithFileListAndParamMap(queryURL, fileList, paramMap);  } private byte[] executeByPostWithFileListAndParamMap (String queryURL,List<File> fileList,Map<String,String> paramsMap) throws HttpException, IOException, HttpClientException {   if(queryURL != null && fileList != null && fileList.size() > 0) {    byte[] responseBody = null;    try {     RequestBuilder requestBuilder = new RequestBuilder();     // FilePart     for(File file : fileList){      Part filePart = new FilePart(file.getName(),file);      requestBuilder.addBodyPart(filePart);     }     // StringPart     if(paramsMap != null ) {      Set<Entry<String, String>> entrySet = paramsMap.entrySet();      Iterator<Entry<String, String>> it = entrySet.iterator();      while(it.hasNext()) {       Entry<String, String> entry = it.next();       Part stringPart = new StringPart(entry.getKey(),entry.getValue());       requestBuilder.addBodyPart(stringPart);      }     }     // 添加RequestHeader,key     requestBuilder.addHeader("Content-type", "multipart/form-data; charset=UTF-8");     requestBuilder.setMethod("POST");     // 添加URL     requestBuilder.setUrl(queryURL);     // request     Request request = requestBuilder.build();     // 提交     ListenableFuture<Response> f = client.executeRequest(request);     responseBody = getBytesFromInpuStream(f.get().getResponseBodyAsStream());    } catch (Exception e) {     throw new HttpClientException(e);    }    return responseBody;   }   return null;  } 

OK,入了个门后,更多的用法可以自己去看文档了,请不要局限以上几种常用的场景。

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