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

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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:

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<!-- 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:

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<!-- 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:

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:

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// 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
  privatestatic 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
   */
  publicstatic SyncHttpClientWapperImpl getXXSearchHttpClient() {
    returnnew 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:

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private HttpClient client;// httpClient
  privatefinal static String CHARACTER  = "UTF-8";
  // 构造器,由工厂调用
  publicSyncHttpClientWapperImpl(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。

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public byte[] getWithQueryURL(String queryURL) throwsHttpClientException {
    if(queryURL ==null) {
      thrownew HttpClientException("queryURL is null.");
    }
    byte[] newbuf = executeByGet(queryURL);
    if((newbuf == null) || (newbuf.length ==0)) {
      thrownew HttpClientException("Server response is null: "+ queryURL);
    }
    returnnewbuf;
  }
privatebyte[] 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();
      thrownew HttpClientException(url, e);
    }
    // 返回字节流
    byte[] responseBody =null;
    try{
      responseBody = getBytesFromInpuStream(method.getResponseBodyAsStream());
    }catch (IOException e) {
      thrownew HttpClientException(e);
    }finally {
      method.releaseConnection();
    }
    returnresponseBody;
  }

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。
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private byte[] getBytesFromInpuStream(InputStream instream)throws IOException {
  ByteArrayOutputStream outstream =new ByteArrayOutputStream();
  try{
    intlength;
    byte[] tmp =new byte[8096];
    while((length = instream.read(tmp)) != -1) {
      outstream.write(tmp,0, length);
    }
    returnoutstream.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。

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public byte[] postWithParamsMap( String queryURL, Map<String,String> paramsMap)throws HttpClientException{
    if(queryURL ==null) {
      thrownew HttpClientException("queryURL is null.");
    }
    byte[] newbuf = executeByPostWithParamsMap(queryURL,paramsMap);
    if((newbuf == null) || (newbuf.length ==0)) {
      thrownew HttpClientException("Server response is null: "+ queryURL);
    }
    returnnewbuf;
  }
privatebyte[] 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()];
      inti = 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();
      thrownew HttpClientException(URL, e);
    }
    // 返回字节流
    byte[] responseBody =null;
    try{
      responseBody = getBytesFromInpuStream(method.getResponseBodyAsStream());
    }catch (IOException e) {
      thrownew HttpClientException(e);
    }finally {
      method.releaseConnection();
    }
    returnresponseBody;
  }

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。
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public byte[] postWithBytes(String queryURL , byte[] bytes)throws HttpClientException{
    if(queryURL ==null) {
      thrownew HttpClientException("queryURL is null.");
    }
    byte[] newbuf = executeByPostWithBytes(queryURL,bytes);
    if((newbuf == null) || (newbuf.length ==0)) {
      thrownew HttpClientException("Server response is null: "+ queryURL);
    }
    returnnewbuf;
  }
privatebyte[] 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();
      thrownew HttpClientException(queryURL, e);
    }
    // 返回字节流
    byte[] responseBody =null;
    try{
      responseBody = getBytesFromInpuStream(method.getResponseBodyAsStream());
    }catch (IOException e) {
      thrownew HttpClientException(e);
    }finally {
      method.releaseConnection();
    }
    returnresponseBody;
  }

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。
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public byte[] postWithFileListAndParamMap(String queryURL,List<File> fileList,Map<String,String> paramMap)throws HttpClientException, HttpException, IOException {
    if(queryURL ==null) {
      thrownew HttpClientException("queryURL is null.");
    }
    if(fileList ==null) {
      thrownew HttpClientException("file is null.");
    }
    if(paramMap ==null){
      thrownew HttpClientException("paramMap is null.");
    }
    returnexecuteByPostWithFileListAndParamMap(queryURL, fileList, paramMap);
  }
privatebyte[] 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()];
      }
      inti = 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();
        thrownew HttpClientException(queryURL, e);
      }
      // return 
      byte[] responseBody =null;
      try{
        responseBody = getBytesFromInpuStream(method.getResponseBodyAsStream());
      }catch (IOException e) {
        thrownew HttpClientException(e);
      }finally {
        method.releaseConnection();
      }
      returnresponseBody;
    }
    returnnull;
  }

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:

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// 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
  privatestatic 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
   */
  publicstatic AsyncHttpClientWapperImpl getXXSearchHttpClient() {
    returnnew 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:

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private AsyncHttpClient client;
      
    publicAsyncHttpClientWapperImpl(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。

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

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。

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public byte[] postWithParamsMap(String queryURL,
      Map<String, String> paramsMap)throws HttpClientException {
    if(queryURL ==null) {
      thrownew HttpClientException("queryURL为空");
    }
    byte[] newbuf = executeByPostByParamMap(queryURL,paramsMap);
    if((newbuf == null) || (newbuf.length ==0)) {
      thrownew HttpClientException("Server response is null: "+ queryURL);
    }
    returnnewbuf;
  }
privatebyte[] 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) {
      thrownew HttpClientException(e);
    }
    returnresponseBody;
  }

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。
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public byte[] postWithBytes(String queryURL, byte[] bytes)
  throwsHttpClientException {
        if(queryURL ==null) {
  thrownew HttpClientException("queryURL is null.");
        }
        byte[] newbuf = executeByPostWithBytes(queryURL,bytes);
        if((newbuf == null) || (newbuf.length ==0)) {
  thrownew HttpClientException("Server response is null: "+ queryURL);
        }
        returnnewbuf;
    }
privatebyte[] 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) {
  thrownew HttpClientException(e);
        }
        returnresponseBody;
    }

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。
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public byte[] postWithFileListAndParamMap(String queryURL,
      List<File> fileList, Map<String, String> paramMap)
      throwsHttpClientException, HttpException, IOException {
    if(queryURL ==null) {
      thrownew HttpClientException("queryURL is null.");
    }
    if(fileList ==null || fileList.size() ==0) {
      thrownew HttpClientException("fileList is null.");
    }
    if(paramMap ==null || paramMap.size() ==0) {
      thrownew HttpClientException("paramMap is null.");
    }
    returnexecuteByPostWithFileListAndParamMap(queryURL, fileList, paramMap);
  }
privatebyte[] 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) {
        thrownew HttpClientException(e);
      }
      returnresponseBody;
    }
    returnnull;
  }

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。
原文  http://www.cnblogs.com/xiaoMzjm/p/4564540.html
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