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

时间 2019-12-10

标签 java httpclient 3.x asynchttpclient1.9.x asynchttpclient 使用总结栏目 Java 繁體版

原文原文链接

　　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~html

　　下面使用的同步http是HttpClient 3.X的版本，不过早已不在维护，若是刚开始使用http，建议你们都换成4.X版本，别看下面的有关同步http的部分了，4.x效率有质地提升，总结3.X只是由于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.htmlgit

　　但鉴于可能有些旧的系统仍是采用3.X版本的HttpClient，因此本文仍是先记录下使用方法。github

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

　　http使用场景不少，据以往经验，对于客户端来讲，咱们使用http通常会发出如下几种常见的场景：设计模式

以get方式请求服务器
1. 不带任何参数
2. 带上key-value对
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

　　以上的场景通常能够知足通常的需求，而后，咱们能够在这基础上扩展一点点：假如遇到一个相似于报表的子系统，主系统要在关键的逻辑链路中“打点”，经过http调用报表子系统记录一些相关的信息时，那么若是咱们使用同步http来请求报表子系统的话，一旦报表子系统挂了，那么确定会影响到主系统的运行。api

　　为了避免影响到主系统的运行，咱们能够采用“异步” 的方式经过http（AsyncHttpClient ）请求报表子系统，那么即便子系统挂了，对主系统的关键链路的执行也不会产生多大的影响。因此，封装一个http组件，天然而然少不了封装异步http请求。而异步http所可以作的事情，也应该覆盖上面提到的几种场景。数组

　　再者，考虑到效率问题，除非有足够的理由，不然每次调用http接口，都建立立一个新的链接，是至关没效率的，因此MultiThreadedHttpConnectionManager 诞生了，HttpClient在内部维护一个链接池，经过MultiThreadedHttpConnectionManager 咱们能够设置“默认链接数”、“最大链接数”、“链接超时”、“读取数据超时”等等配置，从而来提升效率。服务器

　　废话完了，怎么实现以上需求呢。app

　　包的引用：异步

　　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，其须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>

　　为了实现链接池，咱们经过一个工厂类来生成httpClient，为了上一层方便调用，咱们定义了一个接口，规范了同步、异步http应该实现的方法。包结构以下：

1、同步的HttpClient 3.X

　　从工厂入手，工厂负责初始化httpClient的配置，包括“默认链接数”、“最大链接数”、“链接超时”、“读取数据超时”等等，不一样的服务咱们应该建立不一样的manager，由于不可能咱们调服务A和调服务B使用同一套配置是吧，好比超时时间，应该考虑会有所差别。初始化完配置后，把 manager传到实现类，在实现类中new HttpClient。

工厂代码以下：

    // 专门针对xx服务器的链接管理对象
    // 由于不一样服务可能超时等参数不用，因此针对不一样服务，把链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服务器的链接参数
        xxconnectionManager = new MultiThreadedHttpConnectionManager();
        HttpConnectionManagerParams paramsSearch = new HttpConnectionManagerParams();
        paramsSearch.setDefaultMaxConnectionsPerHost(1000);    // 默认链接数
        paramsSearch.setMaxTotalConnections(1000);            // 最大链接数
        paramsSearch.setConnectionTimeout(30000);             // 链接超时
        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，这些链接数，超时等的配置，要作要调查工做以后再定夺，是根据访问服务的不一样，咱们本身的机器能有多少剩余的可用空间的不一样而不一样的，而不是随随便便就设置一个参数。

实现类的构造方法以下：

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，而后传到实现类？经测试，改为静态的效率并无提升，在文件传输的测试中，甚至降低了，这个有点困惑，你们能够试一试一块儿讨论一下。

而后，在实现类中实现各类方法。

第一种，经过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：经过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：经过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：经过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(),CHARACTER);
                    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;
    }

注意Part stringPart = new StringPart(entry.getKey(),entry.getValue(),CHARACTER);这句代码，必定要加上编码格式，否则服务端会乱码。

2、异步的AsyncHttpClient

一样的，按照这种思路，异步的AsyncHttpClient也有相似的实现，不过写法不一样而已，在工厂中，AsyncHttpClient使用的是AsyncHttpClientConfig.Builder做为管理配置的类，也有相似链接超时，最大链接数等配置。

工厂类：

// 专门针对xx服务器的链接管理对象
    // 由于不一样服务可能超时等参数不用，因此针对不一样服务，把链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);    // 链接超时
        xxbuilder.setReadTimeout(2000);        // 读取数据超时
        xxbuilder.setMaxConnections(1000);    // 最大链接数
    }

    /*
     * 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对象就建立完毕了。接下来是各类场景的实现，感受异步的AsyncHttpClient封装得比HttpClient 3.X更加容易使用，设计得更好。

第一种：经过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;
    }

一样的，咱们写了一个getBytesFromInputStream()方法解析服务端返回的流，咱们发现，两个实现类里面都有一些共同的方法，这里能够考虑写一个父类，把这些方法提取出来。

第二种：经过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：经过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：经过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，更多的用法能够本身去看文档了，请不要局限以上几种经常使用的场景。