HttpClient远程请求struts2的文件流并实现下载的方法

本篇内容主要讲解“HttpClient远程请求struts2的文件流并实现下载的方法”，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让小编来带大家学习“HttpClient远程请求struts2的文件流并实现下载的方法”吧!

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HttpClientUtil工具类:

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpDelete;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.methods.HttpPut;
import org.apache.http.client.utils.URLEncodedUtils;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.*;
import java.net.URI;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class HttpClientUtil {
	private static final Logger logger = LoggerFactory.getLogger(HttpClientUtil.class);
	
    /**
     * 封装HTTP POST方法
     *
     * @param
     * @param
     * @return
     * @throws ClientProtocolException
     * @throws IOException
     */
    public static String post(String url, Map paramMap) throws ClientProtocolException, IOException {
        HttpClient httpClient = HttpClients.createDefault();
        HttpPost httpPost = new HttpPost(url);
        //设置请求和传输超时时间
        RequestConfig requestConfig = RequestConfig.custom().setSocketTimeout(60000).setConnectTimeout(60000).build();
        httpPost.setConfig(requestConfig);
        List formparams = setHttpParams(paramMap);
        UrlEncodedFormEntity param = new UrlEncodedFormEntity(formparams, "UTF-8");
        httpPost.setEntity(param);
        HttpResponse response = httpClient.execute(httpPost);
//        logger.info("************{}", response);
        String httpEntityContent = getHttpEntityContent(response);
//        logger.info("************{}", httpEntityContent);
        httpPost.abort();
//        logger.info("************{}", httpEntityContent);
        return httpEntityContent;

    }

    /**
     * 封装HTTP POST方法
     *
     * @param
     * @param
     * @return
     * @throws ClientProtocolException
     * @throws IOException
     */
    public static HttpResponse postForResponse(String url, Map paramMap) throws ClientProtocolException, IOException {
        HttpClient httpClient = HttpClients.createDefault();
        HttpPost httpPost = new HttpPost(url);
        //设置请求和传输超时时间
        RequestConfig requestConfig = RequestConfig.custom().setSocketTimeout(60000).setConnectTimeout(60000).build();
        httpPost.setConfig(requestConfig);
        List formparams = setHttpParams(paramMap);
        UrlEncodedFormEntity param = new UrlEncodedFormEntity(formparams, "UTF-8");
        httpPost.setEntity(param);
        HttpResponse response = httpClient.execute(httpPost);
        return response;
    }
    
    /**
     * 封装HTTP POST方法
     *
     * @param
     * @param （如JSON串）
     * @return
     * @throws ClientProtocolException
     * @throws IOException
     */
    public static String post(String url, String data) throws ClientProtocolException, IOException {
        HttpClient httpClient = HttpClients.createDefault();
        HttpPost httpPost = new HttpPost(url);
        //设置请求和传输超时时间
        RequestConfig requestConfig = RequestConfig.custom().setSocketTimeout(60000).setConnectTimeout(60000).build();
        httpPost.setConfig(requestConfig);
        httpPost.setHeader("Content-Type", "text/json; charset=utf-8");
        httpPost.setEntity(new StringEntity(URLEncoder.encode(data, "UTF-8")));
        HttpResponse response = httpClient.execute(httpPost);
        String httpEntityContent = getHttpEntityContent(response);
        httpPost.abort();
        return httpEntityContent;
    }

    /**
     * 封装HTTP GET方法
     *
     * @param
     * @return
     * @throws ClientProtocolException
     * @throws IOException
     */
    public static String get(String url) throws ClientProtocolException, IOException {
        HttpClient httpClient = HttpClients.createDefault();
        HttpGet httpGet = new HttpGet();
        //设置请求和传输超时时间
        RequestConfig requestConfig = RequestConfig.custom().setSocketTimeout(60000).setConnectTimeout(60000).build();
        httpGet.setConfig(requestConfig);
        httpGet.setURI(URI.create(url));
        HttpResponse response = httpClient.execute(httpGet);
        String httpEntityContent = getHttpEntityContent(response);
        httpGet.abort();
        return httpEntityContent;
    }

    /**
     * 封装HTTP GET方法
     *
     * @param
     * @param
     * @return
     * @throws ClientProtocolException
     * @throws IOException
     */
    public static String get(String url, Map paramMap) throws ClientProtocolException, IOException {
        HttpClient httpClient = HttpClients.createDefault();
        HttpGet httpGet = new HttpGet();
        //设置请求和传输超时时间
        RequestConfig requestConfig = RequestConfig.custom().setSocketTimeout(60000).setConnectTimeout(60000).build();
        httpGet.setConfig(requestConfig);
        List formparams = setHttpParams(paramMap);
        String param = URLEncodedUtils.format(formparams, "UTF-8");
        httpGet.setURI(URI.create(url + "?" + param));
        HttpResponse response = httpClient.execute(httpGet);
        String httpEntityContent = getHttpEntityContent(response);
        httpGet.abort();
        return httpEntityContent;
    }

    /**
     * 封装HTTP PUT方法
     *
     * @param
     * @param
     * @return
     * @throws ClientProtocolException
     * @throws IOException
     */
    public static String put(String url, Map paramMap) throws ClientProtocolException, IOException {
        HttpClient httpClient = HttpClients.createDefault();
        HttpPut httpPut = new HttpPut(url);
        //设置请求和传输超时时间
        RequestConfig requestConfig = RequestConfig.custom().setSocketTimeout(60000).setConnectTimeout(60000).build();
        httpPut.setConfig(requestConfig);
        List formparams = setHttpParams(paramMap);
        UrlEncodedFormEntity param = new UrlEncodedFormEntity(formparams, "UTF-8");
        httpPut.setEntity(param);
        HttpResponse response = httpClient.execute(httpPut);
        String httpEntityContent = getHttpEntityContent(response);
        httpPut.abort();
        return httpEntityContent;
    }

    /**
     * 封装HTTP DELETE方法
     *
     * @param
     * @return
     * @throws ClientProtocolException
     * @throws IOException
     */
    public static String delete(String url) throws ClientProtocolException, IOException {
        HttpClient httpClient = HttpClients.createDefault();
        HttpDelete httpDelete = new HttpDelete();
        //设置请求和传输超时时间
        RequestConfig requestConfig = RequestConfig.custom().setSocketTimeout(60000).setConnectTimeout(60000).build();
        httpDelete.setConfig(requestConfig);
        httpDelete.setURI(URI.create(url));
        HttpResponse response = httpClient.execute(httpDelete);
        String httpEntityContent = getHttpEntityContent(response);
        httpDelete.abort();
        return httpEntityContent;
    }

    /**
     * 封装HTTP DELETE方法
     *
     * @param
     * @param
     * @return
     * @throws ClientProtocolException
     * @throws IOException
     */
    public static String delete(String url, Map paramMap) throws ClientProtocolException, IOException {
        HttpClient httpClient = HttpClients.createDefault();
        HttpDelete httpDelete = new HttpDelete();
        //设置请求和传输超时时间
        RequestConfig requestConfig = RequestConfig.custom().setSocketTimeout(60000).setConnectTimeout(60000).build();
        httpDelete.setConfig(requestConfig);
        List formparams = setHttpParams(paramMap);
        String param = URLEncodedUtils.format(formparams, "UTF-8");
        httpDelete.setURI(URI.create(url + "?" + param));
        HttpResponse response = httpClient.execute(httpDelete);
        String httpEntityContent = getHttpEntityContent(response);
        httpDelete.abort();
        return httpEntityContent;
    }


    /**
     * 设置请求参数
     *
     * @param
     * @return
     */
    private static List setHttpParams(Map paramMap) {
        List formparams = new ArrayList();
        Set> set = paramMap.entrySet();
        for (Map.Entry entry : set) {
            formparams.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));
        }
        return formparams;
    }

    /**
     * 获得响应HTTP实体内容
     *
     * @param response
     * @return
     * @throws IOException
     * @throws UnsupportedEncodingException
     */
    public static String getHttpEntityContent(HttpResponse response) throws IOException, UnsupportedEncodingException {
        HttpEntity entity = response.getEntity();
        if (entity != null) {
            InputStream is = entity.getContent();
            BufferedReader br = new BufferedReader(new InputStreamReader(is, "UTF-8"));
            String line = br.readLine();
            StringBuilder sb = new StringBuilder();
            while (line != null) {
                sb.append(line + "\n");
                line = br.readLine();
            }
            return sb.toString();
        }
        return "";
    }
}

spring跨域请求数据:

/**
 * 跨域请求数据
 * @param model
 * @param code
 * @return
 */
@RequestMapping(value = "/getDataFromCost")
public void getDataFromCost(ModelAndView model,Long eprjInfoId,Long cprjInfoId,Integer uploadType,String loginname,String t,String h,String eprjAuthMap){
	GenericIdentityBean identityBean = this.genGenericIdentity((IdentityBean)model.getModel().get(WebReviewParam.MODEL_IDENTITY));
	UserObject user = userSessionService.getUser(identityBean);
	Map postData = new HashMap<>();
	//costHost = "http://localhost:8080/cost";
	String url = costHost+"/token2";
	if(user != null) {
		Map paramsObject;
		try {
			paramsObject = this.goToCost(model, 1l);
			postData.put("loginname", paramsObject.get("loginname")+"");
			postData.put("t", paramsObject.get("t")+"");
			postData.put("h", paramsObject.get("h")+"");
			postData.put("eprjInfoId", "0");
			postData.put("uploadType", "50");
			postData.put("cprjInfoId", cprjInfoId+"");
			postData.put("isChina", "false");
			postData.put("remoteUrl", "down");
		} catch (Exception e1) {
			e1.printStackTrace();
		}
		String filename = "备份文件导出.hwp";
		if(!UnitChange.isEmpty(loginname)){
			try {
				filename = URLDecoder.decode(loginname, "utf-8");
			} catch (Exception e) {
			}
		}
		try {
			HttpResponse postForResponse = HttpClientUtil.postForResponse(url, postData);
			HttpEntity entity = postForResponse.getEntity();
			if(entity != null) {
				InputStream is = entity.getContent();
				HttpServletResponse response = ((ServletRequestAttributes) (RequestContextHolder.currentRequestAttributes())).getResponse();
				
				String contentType = "application/x-hwp";
				String contentDisposition="attachment;";				
				filename = URLEncoder.encode(filename, "UTF-8");
				contentDisposition+="filename=\""+filename+"\"";
				response.setContentType(contentType);
				response.setHeader("accept-ranges", "bytes");
				response.setHeader("Content-Disposition", contentDisposition);
				
				try {
					ServletOutputStream outputStream = response.getOutputStream();
					IOUtils.copy(is, outputStream);
					outputStream.flush();
					outputStream.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		} catch (ClientProtocolException e1) {
			e1.printStackTrace();
		} catch (IOException e1) {
			e1.printStackTrace();
		}
	}
}

//获取跨域跳转需要的一些参数

/**
* 跳转造价详细审核页面
* @return
* @throws Exception 
*/
@ResponseBody
@RequestMapping(value = "/goToCost")
public Map goToCost(ModelAndView model,Long eprjInfoId) throws Exception{
	GenericIdentityBean identityBean = this.genGenericIdentity((IdentityBean)model.getModel().get(WebReviewParam.MODEL_IDENTITY));
	UserObject user = userSessionService.getUser(identityBean);
	if(UnitChange.isEmpty(user.getSecretKey())) {
		user.setSecretKey(UuidUtil.uuid());
		userService.update(identityBean, user.getId(), user);
	}
	Map returnMap = new HashMap<>();
	returnMap.put("loginname", user.getUsername());
	long t = new Date().getTime();
	returnMap.put("t", t);
	String hash = MD5.encode16((user.getUsername()+user.getSecretKey()+t).getBytes(Charset.forName("UTF-8")));
	returnMap.put("h", hash);
	returnMap.put("costHost", costHost);
	returnMap.put("costHost2", GlobalParameters.getServerUrl()+"/cost");  //跳转造价路径直接取当前域名+/cost
	returnMap.put("returnCode",EprjParam.SUCCESS);
	return returnMap;
}

html页面和JS:

function downloadFile(url,paramObj){
    var xhr = new XMLHttpRequest();
    // xhr.open('GET', url, true);        // 使用GET方式比较简单，参数直接附在URL上
    xhr.open('POST', url, true); 		//POST的格式相对比较灵活，参数可以有比较多的形式，例如JSON，表单FORM等   
    xhr.responseType = "blob";    // 返回类型blob 
//    xhr.setRequestHeader("Content-Type","application/json");//提交的数据为json格式
    xhr.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
    //后台有使用JWT的token验证,会从请求头中读取"X-token"的值,所以这里在请求头加入"X-token"
    xhr.setRequestHeader("X-token", 'Bearer ' + localStorage.getItem(SAVE_AUTH));
    // 定义请求完成的处理函数
    xhr.onload = function () {
    	jQuery.messager.progress('close');
        // 请求完成
        if (this.status === 200) {
            // 返回200
            var blob = this.response;
            var reader = new FileReader();
            reader.readAsDataURL(blob);    // 转换为base64，可以直接放入a表情href
            reader.onload = function (e) {
                // 转换完成，创建一个a标签用于下载
                var a = document.createElement('a');
                a.download = paramObj["cprjName"]+".hwp";
                //可以通过导出空文件确认文件最小的长度为700000,如果长度过小,则表示远程抛出异常
                if(e.target.result.indexOf("data:application/x-hwp") != -1 &&
 e.target.result.length > 700000){
                	a.href = e.target.result;
                	$("body").append(a);    // 修复firefox中无法触发click
                	a.click();
                	$(a).remove();
                }else{
                	$.messager.show({ icon: "info", msg: "备份文件大小异常,可重新尝试备份操作！", position: "topCenter" ,timeout:1000, height:80});
                }
            }
        }else{
        	 $.messager.show({ icon: "info", msg: "备份文件大小异常,可重新尝试备份操作！", position: "topCenter" ,timeout:1000, height:80});
        }
    };
    // 发送ajax请求,案例中我们使用POST的请求格式，参数类型为JSON
    var param = {};
    xhr.send(null);
    jQuery.messager.progress({ title:'请稍候...',   text:'正在备份导出,请稍候...', interval:800  });
}

function myDownFun(paramObj){
	var url = "./iface/getDataFromCost?cprjInfoId="+paramObj["cprjInfoId"];
	var rowData = $('#gcxh').treegrid('getSelected');
	url += "&loginname="+encodeURIComponent(encodeURIComponent(rowData.name));
	var postData = {};
	postData["cprjName"] = rowData.cprjNameText;
	downloadFile(url,postData);
//	openPostWindow(url,data);
}

//本来可以使用form表单提交的方式,或者a连接的href进行导出,只是这两种方式不好捕捉和处理远程请求的异常exception
//下载
function openPostWindow(url,obj) {
    var formStr = '';
    //设置样式为隐藏，打开新标签再跳转页面前，如果有可现实的表单选项，用户会看到表单内容数据
    formStr  = '';
    formStr += '';
    formStr += '';
    formStr += '';
    formStr += '';
    $('body').append(formStr);
    $('#downTable')[0].submit();
    $('#downTable').remove();
}

跨域访问的方法struts2
 

	 
		text/html
		returnCode,message,data.*
		false
		true
	
	
		${contentDisposition}
		${contentType}
		inputStream
	
	/default

java(struts2):

public String token2(){
	if(VerifyString.isEmpty(loginname) || eprjInfoId == null) {
		return "login";
	}
    if (t
struts2的xml请求配置文件

	
		${contentDisposition}
		${contentType}
		inputStream
	
文件流:
/**
 * 导出文件
 * @return
 */
@Permission(authorize=Permission.AUTHORIZE_EXPORT)
public String download() 
{
	Boolean isError=false;
	ActionContext context=ActionContext.getContext();
	if (context==null)
	{
		return ActionSupport.ERROR;				
	}
	
	Integer fileLength=0;
	HttpServletRequest request=(HttpServletRequest)context.get(ServletActionContext.HTTP_REQUEST);
	HttpServletResponse response=(HttpServletResponse)context.get(ServletActionContext.HTTP_RESPONSE);;
	try
	{
		String filename = "";
		switch (this.uploadType) {
		case 50:// 建设项目 工程项目备份导出
			{
				this.inputStream=cprjInfoService.backup(cprjInfoId, eprjInfoId);
				if(this.inputStream != null){ 
					fileLength=this.inputStream.available();
					int minLength=700000;//普通工程大小
                    //备份的建设项目或工程项目小于700000，代表备份文件有异常，报错
				    if(fileLength");
			out.println("");
			out.println(""+this.message+"");
			out.println("");
			out.println("");
			 out.flush();
		} catch (Exception e1) {
		}
		
		return ERROR;
	}
	finally
	{
		if(progress != null && userObject != null)
		{
			progress.put("progressValue", 102);
			progress.put("progressText", "");
			userService.notsupSetProgressInfo(userObject, progress);
		}
	}
	if(!isError)
		return SUCCESS;
	else
		return ERROR;
到此，相信大家对“HttpClient远程请求struts2的文件流并实现下载的方法”有了更深的了解，不妨来实际操作一番吧！这里是创新互联网站，更多相关内容可以进入相关频道进行查询，关注我们，继续学习！
            
            
                        

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