HttpClient的简单使用，get、post、上传、下载

package com.zhang; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.nio.charset.Charset; import java.util.LinkedList; import java.util.List; import java.util.Map; import java.util.Map.Entry; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; 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.client.utils.URLEncodedUtils; import org.apache.http.entity.ContentType; import org.apache.http.entity.StringEntity; import org.apache.http.entity.mime.HttpMultipartMode; 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; public class HttpUtils { public static void main(String[] args) { Donwload("http://127.0.0.1:8888/HttpServer/img/aaa.jpg","C://ayy哈哈a.jpg"); /*Map<String, Object> map=new HashMap<String, Object>(); map.put("employee_no", 18811); Upload("http://127.0.0.1:8888/HttpServer/Upload","C://aa.jpg" , map);*/ /* Map<String, String> map=new HashMap<String, String>(); map.put("id", "哈哈哈"); String json=GetData("http://127.0.0.1:8888/HttpServer/getUser",map); System.out.println(json);*/ /*JSONObject json =new JSONObject(); json.put("name", "哈哈"); String j=PostData("http://127.0.0.1:8888/HttpServer/saveUser",json.toJSONString()); System.out.println(j);*/ } public static String GetData(String url,Map<String, String> map) { String result=""; CloseableHttpClient httpclient = HttpClients.createDefault(); CloseableHttpResponse response = null; try { //先将参数放入List，再对参数进行URL编码 List<BasicNameValuePair> params = new LinkedList<BasicNameValuePair>(); for (Entry<String, String> entry : map.entrySet()) { params.add(new BasicNameValuePair(entry.getKey(), entry.getValue())); } String param = "?"+URLEncodedUtils.format(params, "utf-8"); //对参数编码 HttpGet httpget = new HttpGet(url+param); // 创建httpget. response = httpclient.execute(httpget); // 执行get请求. HttpEntity entity = response.getEntity(); // 获取响应实体 int StatusCode=response.getStatusLine().getStatusCode(); // 打印响应状态码 if (StatusCode==200 && entity != null) { result=EntityUtils.toString(entity,"UTF-8"); // 打印响应内容 /* JSONObject jsonObject = JSONObject.parseObject(result); System.out.println(jsonObject.get("success")); User user= JsonUtils.JsonToBean(jsonObject.get("user").toString()); System.out.println(user); System.out.println(JsonUtils.ToJson(user));*/ } } catch (Exception e) { e.printStackTrace(); } finally { try { response.close(); httpclient.close(); } catch (IOException e) { e.printStackTrace(); } } return result; } public static String PostData(String url, String jsonString) { String result=""; CloseableHttpResponse response = null; CloseableHttpClient httpclient = HttpClients.createDefault();// 创建默认的httpClient实例 HttpPost httppost = new HttpPost(url); // 创建httppost StringEntity stringEntity = new StringEntity(jsonString,"utf-8");//解决中文乱码问题 stringEntity.setContentEncoding("UTF-8"); stringEntity.setContentType("application/json"); httppost.setEntity(stringEntity); try { response = httpclient.execute(httppost); HttpEntity entity = response.getEntity(); int StatusCode=response.getStatusLine().getStatusCode(); if (StatusCode == 200 && entity != null) { result = EntityUtils.toString(entity, "UTF-8"); }else{ result = EntityUtils.toString(entity, "UTF-8"); } } catch (Exception e) { e.printStackTrace(); } finally { try { response.close(); httpclient.close(); } catch (IOException e) { e.printStackTrace(); } } return result; } public static String Upload(String url,String fileName,Map<String, Object> map) { String result=""; CloseableHttpClient httpclient = HttpClients.createDefault(); try { HttpPost httppost = new HttpPost(url); MultipartEntityBuilder builder=MultipartEntityBuilder.create(); builder.setCharset(Charset.forName("UTF-8"));//设置请求的编码格式 builder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);//设置浏览器兼容模式 FileBody bin = new FileBody(new File(fileName)); builder.addPart("file",bin); //文件流参数 ContentType contentType = ContentType.create("text/plain", Charset.forName("UTF-8")); for (Entry<String, Object> entry : map.entrySet()) { builder.addPart(entry.getKey(),new StringBody(entry.getValue().toString(), contentType));//普通的参数 } HttpEntity reqEntity= builder.build(); httppost.setEntity(reqEntity); CloseableHttpResponse response = httpclient.execute(httppost); try { int status=response.getStatusLine().getStatusCode(); HttpEntity resEntity = response.getEntity(); if (status==200 && resEntity != null) { result= EntityUtils.toString(resEntity,"UTF-8"); } } finally { response.close(); } } catch (Exception e) { e.printStackTrace(); } finally { try { httpclient.close(); } catch (IOException e) { e.printStackTrace(); } } return result; } public static void Donwload(String url, String destFileName) { InputStream in = null; CloseableHttpClient httpclient = HttpClients.createDefault(); try { HttpGet httpget = new HttpGet(url); HttpResponse response = httpclient.execute(httpget); HttpEntity entity = response.getEntity(); in = entity.getContent(); File file = new File(destFileName); FileOutputStream fout = new FileOutputStream(file); int l = -1; byte[] tmp = new byte[1024]; while ((l = in.read(tmp)) != -1) { fout.write(tmp, 0, l); // 注意这里如果用OutputStream.write(buff)的话，图片会失真 } fout.flush(); fout.close(); }catch (Exception e) { e.printStackTrace(); } finally { try { in.close(); httpclient.close(); } catch (IOException e) { e.printStackTrace(); } } } }