1.发送get、post携带参数以及post请求接受JSON数据:
package cn.qlq.utils;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.net.URI;import java.util.ArrayList;import java.util.HashMap;import java.util.Iterator;import java.util.List;import java.util.Map;import org.apache.http.HttpEntity;import org.apache.http.HttpResponse;import org.apache.http.HttpStatus;import org.apache.http.NameValuePair;import org.apache.http.StatusLine;import org.apache.http.client.HttpClient;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.StringEntity;import org.apache.http.impl.client.CloseableHttpClient;import org.apache.http.impl.client.DefaultHttpClient;import org.apache.http.impl.client.HttpClients;import org.apache.http.message.BasicNameValuePair;import org.apache.http.params.HttpParams;import org.apache.http.protocol.HTTP;import org.apache.http.util.EntityUtils;import org.slf4j.Logger;import org.slf4j.LoggerFactory;/** * http工具类的使用 * * @author Administrator * */public class HttpUtils { private static Logger logger = LoggerFactory.getLogger(HttpUtils.class); /** * 测试代码 * @param args */ public static void main(String[] args) { Map params = new HashMap (); params.put("entityClazz", "com.ebuytech.business.model.dto.v2.pms.PmsCampaign"); params.put("idField", "campaignId"); params.put("textField", "campaignName"); System.out.println(HttpUtils.doGetWithParams("http://xiaoe.e-buychina.com/common/widgetdata", params )); } /** * get请求 * * @return */ public static String doGet(String url, Map params) { try { HttpClient client = new DefaultHttpClient(); // 发送get请求 HttpGet request = new HttpGet(url); HttpResponse response = client.execute(request); /** 请求发送成功，并得到响应 **/ if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) { /** 读取服务器返回过来的json字符串数据 **/ String strResult = EntityUtils.toString(response.getEntity(),"utf-8"); return strResult; } } catch (IOException e) { logger.debug("get data error"); } return null; } /** * get请求携带参数(注意只能是英文参数) * * @return */ public static String doGetWithParams(String url, Map params) { try { HttpClient client = new DefaultHttpClient(); //如果携带参数，重新拼接get参数 if(params !=null && params.size()>0){ StringBuffer sb = new StringBuffer(url); sb.append("?"); for(Object key : params.keySet() ){ sb.append(key+"="+params.get(key)+"&"); } url = sb.toString().substring(0, sb.length()-1); } // 发送get请求 HttpGet request = new HttpGet(url); HttpResponse response = client.execute(request); /** 请求发送成功，并得到响应 **/ if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) { /** 读取服务器返回过来的json字符串数据 **/ String strResult = EntityUtils.toString(response.getEntity(),"utf-8"); return strResult; } } catch (IOException e) { logger.debug("get data error"); } return null; } /** * post请求(用于key-value格式的参数) * * @param url * @param params * @return */ public static String doPost(String url, Map params) { BufferedReader in = null; try { // 定义HttpClient HttpClient client = new DefaultHttpClient(); // 实例化HTTP方法 HttpPost request = new HttpPost(); request.setURI(new URI(url)); // 设置参数 List nvps = new ArrayList (); for (Iterator iter = params.keySet().iterator(); iter.hasNext();) { String name = (String) iter.next(); String value = String.valueOf(params.get(name)); nvps.add(new BasicNameValuePair(name, value)); } request.setEntity(new UrlEncodedFormEntity(nvps, HTTP.UTF_8)); HttpResponse response = client.execute(request); int code = response.getStatusLine().getStatusCode(); if (code == 200) { // 请求成功 in = new BufferedReader(new InputStreamReader(response.getEntity().getContent(), "utf-8")); StringBuffer sb = new StringBuffer(""); String line = ""; String NL = System.getProperty("line.separator"); while ((line = in.readLine()) != null) { sb.append(line + NL); } in.close(); return sb.toString(); } else { // System.out.println("状态码：" + code); return null; } } catch (Exception e) { e.printStackTrace(); return null; } } /** * post请求（用于请求json格式的参数） * * @param url * @param params * @return */ public static String doPost(String url, String params) throws Exception { CloseableHttpClient httpclient = HttpClients.createDefault(); HttpPost httpPost = new HttpPost(url);// 创建httpPost httpPost.setHeader("Accept", "application/json"); httpPost.setHeader("Content-Type", "application/json"); String charSet = "UTF-8"; StringEntity entity = new StringEntity(params, charSet); httpPost.setEntity(entity); CloseableHttpResponse response = null; try { response = httpclient.execute(httpPost); StatusLine status = response.getStatusLine(); int state = status.getStatusCode(); if (state == HttpStatus.SC_OK) { HttpEntity responseEntity = response.getEntity(); String jsonString = EntityUtils.toString(responseEntity); return jsonString; } else { logger.error("请求返回:" + state + "(" + url + ")"); } } finally { if (response != null) { try { response.close(); } catch (IOException e) { e.printStackTrace(); } } try { httpclient.close(); } catch (IOException e) { e.printStackTrace(); } } return null; }}
补充:get请求可以指定对返回数据的编码格式防止中文乱码:
String strResult = EntityUtils.toString(response.getEntity(),"utf-8");
2.上传文件，可以携带参数
import java.io.BufferedReader;import java.io.File;import java.io.IOException;import java.io.InputStreamReader;import java.nio.charset.Charset;import org.apache.http.HttpEntity;import org.apache.http.client.ClientProtocolException;import org.apache.http.client.methods.CloseableHttpResponse;import org.apache.http.client.methods.HttpPost;import org.apache.http.entity.ContentType;import org.apache.http.entity.mime.HttpMultipartMode;import org.apache.http.entity.mime.MultipartEntity;import org.apache.http.entity.mime.MultipartEntityBuilder;import org.apache.http.entity.mime.content.FileBody;import org.apache.http.impl.client.CloseableHttpClient;import org.apache.http.impl.client.HttpClientBuilder;import org.apache.http.protocol.HTTP;import org.apache.http.util.EntityUtils;/** * httpclient上传文件(测试没问题) * * @author Administrator * */public class HttpClientUploadFile { public static void main(String[] args) throws ClassNotFoundException, ClientProtocolException, IOException { CloseableHttpClient httpclient = HttpClientBuilder.create().build(); CloseableHttpResponse response = null; try { HttpPost httppost = new HttpPost("http://localhost/document/doUpload.html;jsessionid=512F7F701BD1DF6F2D73010094A42EC8"); //可以选择文件，也可以选择附加的参数 HttpEntity req = MultipartEntityBuilder.create() .setMode(HttpMultipartMode.BROWSER_COMPATIBLE) .addPart("docUpload", new FileBody(new File("C:\\Users\\Administrator\\Desktop\\changelog-20180626(4).txt")))//上传文件,如果不需要上传文件注掉此行 .addTextBody("folderId", "5") .addTextBody("trainPlanFormUpload", "false",ContentType.create(HTTP.PLAIN_TEXT_TYPE, HTTP.UTF_8))//最后的ContentType是防止中文参数乱码 .build(); httppost.setEntity(req); System.out.println("executing request: " + httppost.getRequestLine()); response = httpclient.execute(httppost); HttpEntity re = response.getEntity(); System.out.println(response.getStatusLine()); if (re != null) { System.out.println("Response content: " + new BufferedReader(new InputStreamReader(re .getContent())).readLine()); } EntityUtils.consume(re); } finally { try { response.close(); } catch (Exception e) { e.printStackTrace(); } } }}
补充:HttpClient包中还有一个类使用方法类似于Map，存放键值对信息，如下:
NameValuePair name = new NameValuePair("xxx", "value"); System.out.println(name.getName()); System.out.println(name.getValue()); 结果:
xxx
value查看源码发现内部维护一个name和value属性，如下:
public NameValuePair(String name, String value) { this.name = name; this.value = value; }