Java:使用HttpClient进行POST和GET请求以及文件上传和下载

来源：互联网发布：方太云魔方的缺点知乎编辑：程序博客网时间：2024/05/22 05:30

1.HttpClient

大家可以先看一下HttpClient的介绍，这篇博文写的还算不错：http://blog.csdn.net/wangpeng047/article/details/19624529

当然，详细的文档，你可以去官方网站查看和下载：http://hc.apache.org/httpclient-3.x/

2.本博客简单介绍一下POST和GET以及文件下载的应用。

代码如下：

[java] view plain copy
 
package net.mobctrl;  
  
import java.io.ByteArrayOutputStream;  
import java.io.File;  
import java.io.FileOutputStream;  
import java.io.IOException;  
import java.io.InputStream;  
import java.util.ArrayList;  
import java.util.List;  
import java.util.Map;  
import java.util.Set;  
import java.util.concurrent.ExecutorService;  
import java.util.concurrent.Executors;  
  
import org.apache.http.HttpEntity;  
import org.apache.http.NameValuePair;  
import org.apache.http.client.entity.UrlEncodedFormEntity;  
import org.apache.http.client.methods.CloseableHttpResponse;  
import org.apache.http.client.methods.HttpGet;  
import org.apache.http.client.methods.HttpPost;  
import org.apache.http.entity.ContentType;  
import org.apache.http.entity.mime.MultipartEntityBuilder;  
import org.apache.http.entity.mime.content.FileBody;  
import org.apache.http.entity.mime.content.StringBody;  
import org.apache.http.impl.client.CloseableHttpClient;  
import org.apache.http.impl.client.HttpClients;  
import org.apache.http.message.BasicNameValuePair;  
import org.apache.http.util.EntityUtils;  
  
/** 
 * @web http://www.mobctrl.net 
 * @author Zheng Haibo 
 * @Description: 文件下载 POST GET 
 */  
public class HttpClientUtils {  
  
    /** 
     * 最大线程池 
     */  
    public static final int THREAD_POOL_SIZE = 5;  
  
    public interface HttpClientDownLoadProgress {  
        public void onProgress(int progress);  
    }  
  
    private static HttpClientUtils httpClientDownload;  
  
    private ExecutorService downloadExcutorService;  
  
    private HttpClientUtils() {  
        downloadExcutorService = Executors.newFixedThreadPool(THREAD_POOL_SIZE);  
    }  
  
    public static HttpClientUtils getInstance() {  
        if (httpClientDownload == null) {  
            httpClientDownload = new HttpClientUtils();  
        }  
        return httpClientDownload;  
    }  
  
    /** 
     * 下载文件 
     *  
     * @param url 
     * @param filePath 
     */  
    public void download(final String url, final String filePath) {  
        downloadExcutorService.execute(new Runnable() {  
  
            @Override  
            public void run() {  
                httpDownloadFile(url, filePath, null, null);  
            }  
        });  
    }  
  
    /** 
     * 下载文件 
     *  
     * @param url 
     * @param filePath 
     * @param progress 
     *            进度回调 
     */  
    public void download(final String url, final String filePath,  
            final HttpClientDownLoadProgress progress) {  
        downloadExcutorService.execute(new Runnable() {  
  
            @Override  
            public void run() {  
                httpDownloadFile(url, filePath, progress, null);  
            }  
        });  
    }  
  
    /** 
     * 下载文件 
     *  
     * @param url 
     * @param filePath 
     */  
    private void httpDownloadFile(String url, String filePath,  
            HttpClientDownLoadProgress progress, Map<String, String> headMap) {  
        CloseableHttpClient httpclient = HttpClients.createDefault();  
        try {  
            HttpGet httpGet = new HttpGet(url);  
            setGetHead(httpGet, headMap);  
            CloseableHttpResponse response1 = httpclient.execute(httpGet);  
            try {  
                System.out.println(response1.getStatusLine());  
                HttpEntity httpEntity = response1.getEntity();  
                long contentLength = httpEntity.getContentLength();  
                InputStream is = httpEntity.getContent();  
                // 根据InputStream 下载文件  
                ByteArrayOutputStream output = new ByteArrayOutputStream();  
                byte[] buffer = new byte[4096];  
                int r = 0;  
                long totalRead = 0;  
                while ((r = is.read(buffer)) > 0) {  
                    output.write(buffer, 0, r);  
                    totalRead += r;  
                    if (progress != null) {// 回调进度  
                        progress.onProgress((int) (totalRead * 100 / contentLength));  
                    }  
                }  
                FileOutputStream fos = new FileOutputStream(filePath);  
                output.writeTo(fos);  
                output.flush();  
                output.close();  
                fos.close();  
                EntityUtils.consume(httpEntity);  
            } finally {  
                response1.close();  
            }  
        } catch (Exception e) {  
            e.printStackTrace();  
        } finally {  
            try {  
                httpclient.close();  
            } catch (IOException e) {  
                e.printStackTrace();  
            }  
        }  
    }  
  
    /** 
     * get请求 
     *  
     * @param url 
     * @return 
     */  
    public String httpGet(String url) {  
        return httpGet(url, null);  
    }  
  
    /** 
     * http get请求 
     *  
     * @param url 
     * @return 
     */  
    public String httpGet(String url, Map<String, String> headMap) {  
        String responseContent = null;  
        CloseableHttpClient httpclient = HttpClients.createDefault();  
        try {  
            HttpGet httpGet = new HttpGet(url);  
            CloseableHttpResponse response1 = httpclient.execute(httpGet);  
            setGetHead(httpGet, headMap);  
            try {  
                System.out.println(response1.getStatusLine());  
                HttpEntity entity = response1.getEntity();  
                responseContent = getRespString(entity);  
                System.out.println("debug:" + responseContent);  
                EntityUtils.consume(entity);  
            } finally {  
                response1.close();  
            }  
        } catch (Exception e) {  
            e.printStackTrace();  
        } finally {  
            try {  
                httpclient.close();  
            } catch (IOException e) {  
                e.printStackTrace();  
            }  
        }  
        return responseContent;  
    }  
  
    public String httpPost(String url, Map<String, String> paramsMap) {  
        return httpPost(url, paramsMap, null);  
    }  
  
    /** 
     * http的post请求 
     *  
     * @param url 
     * @param paramsMap 
     * @return 
     */  
    public String httpPost(String url, Map<String, String> paramsMap,  
            Map<String, String> headMap) {  
        String responseContent = null;  
        CloseableHttpClient httpclient = HttpClients.createDefault();  
        try {  
            HttpPost httpPost = new HttpPost(url);  
            setPostHead(httpPost, headMap);  
            setPostParams(httpPost, paramsMap);  
            CloseableHttpResponse response = httpclient.execute(httpPost);  
            try {  
                System.out.println(response.getStatusLine());  
                HttpEntity entity = response.getEntity();  
                responseContent = getRespString(entity);  
                EntityUtils.consume(entity);  
            } finally {  
                response.close();  
            }  
        } catch (Exception e) {  
            e.printStackTrace();  
        } finally {  
            try {  
                httpclient.close();  
            } catch (IOException e) {  
                e.printStackTrace();  
            }  
        }  
        System.out.println("responseContent = " + responseContent);  
        return responseContent;  
    }  
  
    /** 
     * 设置POST的参数 
     *  
     * @param httpPost 
     * @param paramsMap 
     * @throws Exception 
     */  
    private void setPostParams(HttpPost httpPost, Map<String, String> paramsMap)  
            throws Exception {  
        if (paramsMap != null && paramsMap.size() > 0) {  
            List<NameValuePair> nvps = new ArrayList<NameValuePair>();  
            Set<String> keySet = paramsMap.keySet();  
            for (String key : keySet) {  
                nvps.add(new BasicNameValuePair(key, paramsMap.get(key)));  
            }  
            httpPost.setEntity(new UrlEncodedFormEntity(nvps));  
        }  
    }  
  
    /** 
     * 设置http的HEAD 
     *  
     * @param httpPost 
     * @param headMap 
     */  
    private void setPostHead(HttpPost httpPost, Map<String, String> headMap) {  
        if (headMap != null && headMap.size() > 0) {  
            Set<String> keySet = headMap.keySet();  
            for (String key : keySet) {  
                httpPost.addHeader(key, headMap.get(key));  
            }  
        }  
    }  
  
    /** 
     * 设置http的HEAD 
     *  
     * @param httpGet 
     * @param headMap 
     */  
    private void setGetHead(HttpGet httpGet, Map<String, String> headMap) {  
        if (headMap != null && headMap.size() > 0) {  
            Set<String> keySet = headMap.keySet();  
            for (String key : keySet) {  
                httpGet.addHeader(key, headMap.get(key));  
            }  
        }  
    }  
  
    /** 
     * 上传文件 
     *  
     * @param serverUrl 
     *            服务器地址 
     * @param localFilePath 
     *            本地文件路径 
     * @param serverFieldName 
     * @param params 
     * @return 
     * @throws Exception 
     */  
    public String uploadFileImpl(String serverUrl, String localFilePath,  
            String serverFieldName, Map<String, String> params)  
            throws Exception {  
        String respStr = null;  
        CloseableHttpClient httpclient = HttpClients.createDefault();  
        try {  
            HttpPost httppost = new HttpPost(serverUrl);  
            FileBody binFileBody = new FileBody(new File(localFilePath));  
  
            MultipartEntityBuilder multipartEntityBuilder = MultipartEntityBuilder  
                    .create();  
            // add the file params  
            multipartEntityBuilder.addPart(serverFieldName, binFileBody);  
            // 设置上传的其他参数  
            setUploadParams(multipartEntityBuilder, params);  
  
            HttpEntity reqEntity = multipartEntityBuilder.build();  
            httppost.setEntity(reqEntity);  
  
            CloseableHttpResponse response = httpclient.execute(httppost);  
            try {  
                System.out.println(response.getStatusLine());  
                HttpEntity resEntity = response.getEntity();  
                respStr = getRespString(resEntity);  
                EntityUtils.consume(resEntity);  
            } finally {  
                response.close();  
            }  
        } finally {  
            httpclient.close();  
        }  
        System.out.println("resp=" + respStr);  
        return respStr;  
    }  
  
    /** 
     * 设置上传文件时所附带的其他参数 
     *  
     * @param multipartEntityBuilder 
     * @param params 
     */  
    private void setUploadParams(MultipartEntityBuilder multipartEntityBuilder,  
            Map<String, String> params) {  
        if (params != null && params.size() > 0) {  
            Set<String> keys = params.keySet();  
            for (String key : keys) {  
                multipartEntityBuilder  
                        .addPart(key, new StringBody(params.get(key),  
                                ContentType.TEXT_PLAIN));  
            }  
        }  
    }  
  
    /** 
     * 将返回结果转化为String 
     *  
     * @param entity 
     * @return 
     * @throws Exception 
     */  
    private String getRespString(HttpEntity entity) throws Exception {  
        if (entity == null) {  
            return null;  
        }  
        InputStream is = entity.getContent();  
        StringBuffer strBuf = new StringBuffer();  
        byte[] buffer = new byte[4096];  
        int r = 0;  
        while ((r = is.read(buffer)) > 0) {  
            strBuf.append(new String(buffer, 0, r, "UTF-8"));  
        }  
        return strBuf.toString();  
    }  
}  

我们可以使用如下代码进行测试：

[java] view plain copy
 
import java.util.HashMap;  
import java.util.LinkedHashMap;  
import java.util.Map;  
  
import net.mobctrl.HttpClientUtils;  
import net.mobctrl.HttpClientUtils.HttpClientDownLoadProgress;  
  
/** 
 * @date 2015年1月14日 下午1:49:50 
 * @author Zheng Haibo 
 * @Description: 测试 
 */  
public class Main {  
  
    public static void main(String[] args) {  
        /** 
         * 测试下载文件 异步下载 
         */  
        HttpClientUtils.getInstance().download(  
                "http://newbbs.qiniudn.com/phone.png", "test.png",  
                new HttpClientDownLoadProgress() {  
  
                    @Override  
                    public void onProgress(int progress) {  
                        System.out.println("download progress = " + progress);  
                    }  
                });  
  
        // POST 同步方法  
        Map<String, String> params = new HashMap<String, String>();  
        params.put("username", "admin");  
        params.put("password", "admin");  
        HttpClientUtils.getInstance().httpPost(  
                "http://192.168.31.183:8080/SSHMySql/register", params);  
  
        // GET 同步方法  
        HttpClientUtils.getInstance().httpGet(  
                "http://wthrcdn.etouch.cn/weather_mini?city=北京");  
  
        // 上传文件 POST 同步方法  
        try {  
            Map<String,String> uploadParams = new LinkedHashMap<String, String>();  
            uploadParams.put("userImageContentType", "image");  
            uploadParams.put("userImageFileName", "testaa.png");  
            HttpClientUtils.getInstance().uploadFileImpl(  
                    "http://192.168.31.183:8080/SSHMySql/upload", "android_bug_1.png",  
                    "userImage", uploadParams);  
        } catch (Exception e) {  
            e.printStackTrace();  
        }  
  
    }  
  
}  

运行结果为：

[plain] view plain copy
 
HTTP/1.1 200 OK  
responseContent = {"id":"-2","msg":"添加失败!用户名已经存在！"}  
HTTP/1.1 200 OK  
download progress = 6  
download progress = 11  
download progress = 13  
download progress = 20  
download progress = 22  
download progress = 26  
download progress = 31  
download progress = 33  
download progress = 35  
download progress = 38  
download progress = 40  
download progress = 42  
download progress = 44  
download progress = 49  
download progress = 53  
download progress = 55  
download progress = 57  
download progress = 60  
download progress = 62  
download progress = 64  
download progress = 66  
download progress = 71  
download progress = 77  
download progress = 77  
download progress = 80  
download progress = 82  
HTTP/1.1 200 OK  
debug:{"desc":"OK","status":1000,"data":{"wendu":"3","ganmao":"昼夜温差很大，易发生感冒，请注意适当增减衣服，加强自我防护避免感冒。","forecast":[{"fengxiang":"无持续风向","fengli":"微风级","high":"高温 6℃","type":"晴","low":"低温 -6℃","date":"22日星期四"},{"fengxiang":"无持续风向","fengli":"微风级","high":"高温 6℃","type":"多云","low":"低温 -3℃","date":"23日星期五"},{"fengxiang":"无持续风向","fengli":"微风级","high":"高温 5℃","type":"多云","low":"低温 -3℃","date":"24日星期六"},{"fengxiang":"无持续风向","fengli":"微风级","high":"高温 5℃","type":"阴","low":"低温 -2℃","date":"25日星期天"},{"fengxiang":"无持续风向","fengli":"微风级","high":"高温 4℃","type":"多云","low":"低温 -2℃","date":"26日星期一"}],"yesterday":{"fl":"3-4级","fx":"北风","high":"高温 5℃","type":"晴","low":"低温 -6℃","date":"21日星期三"},"aqi":"124","city":"北京"}}  
download progress = 84  
download progress = 86  
download progress = 88  
download progress = 91  
download progress = 93  
download progress = 95  
download progress = 99  
download progress = 100  
HTTP/1.1 200 OK  
resp={"error_code":2000,"msg":"OK","filepath":"uploadfiles/192.168.31.72_android_bug_1.png"}  

下载过程有进度回调。

相关的libs包，可以在如下链接中下载：http://download.csdn.net/detail/nuptboyzhb/8362801

上述代码，既可以在J2SE,J2EE中使用，也可以在Android中使用，在android中使用时，需要相关的权限。

另外，测试所使用的Web项目为：https://github.com/nuptboyzhb/SSHMySQLDemo

转自http://blog.csdn.net/nupt123456789/article/details/42721003/

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