Android中使用HttpURLConnection实现GET POST JSON数据与下载图片

android6.0中把apache http client所有的包与类都标记为deprecated不再建议使用所有跟http相关的数据请求与提交操作都通过httpurlconnection类实现，现实是很多android开发者一直都apache http client来做andoird客户端与后台http接口数据交互，小编刚刚用httpurlconnection做了一个android的app，不小心踩到了几个坑，总结下最常用的就通过httpurlconnection来post提交json数据与get请求json数据。此外就是下载图片，下载图片分为显示进度与不显示进度两种。其中提交数据的时候涉及中文一定要先把中文转码成utf-8之后在post提交，否则就会一直遇到http 400的错误。

一、get请求json数据的例子

public userdto execute(string... params) { 
 inputstream inputstream = null; 
 httpurlconnection urlconnection = null; 
 
 try { 
  // read responseurlencoder.encode(para, "gbk"); 
  string urlwithparams = domain_address + member_request_token_url + "?username=" + java.net.urlencoder.encode(params[0],"utf-8") + "&password=" + params[1]; 
  url url = new url(urlwithparams); 
  urlconnection = (httpurlconnection) url.openconnection(); 
 
  /* optional request header */ 
  urlconnection.setrequestproperty("content-type", "application/json; charset=utf-8"); 
 
  /* optional request header */ 
  urlconnection.setrequestproperty("accept", "application/json"); 
 
  /* for get request */ 
  urlconnection.setrequestmethod("get"); 
  int statuscode = urlconnection.getresponsecode(); 
 
  /* 200 represents http ok */ 
  if (statuscode == 200) { 
   inputstream = new bufferedinputstream(urlconnection.getinputstream()); 
   string response = httputil.convertinputstreamtostring(inputstream); 
   gson gson = new gson(); 
   userdto dto = gson.fromjson(response, userdto.class); 
   if (dto != null && dto.gettoken() != null) { 
    log.i("token", "find the token = " + dto.gettoken()); 
   } 
   return dto; 
  } 
 
 } catch (exception e) { 
  e.printstacktrace(); 
 } finally { 
  if (inputstream != null) { 
   try { 
    inputstream.close(); 
   } catch (ioexception e) { 
    e.printstacktrace(); 
   } 
  } 
  if (urlconnection != null) { 
   urlconnection.disconnect(); 
  } 
 } 
 return null; 
} 

二、post提交json数据

public map<string, string> execute(notificationdto dto) { 
 inputstream inputstream = null; 
 httpurlconnection urlconnection = null; 
 try { 
  url url = new url(geturl); 
  urlconnection = (httpurlconnection) url.openconnection(); 
 
  /* optional request header */ 
  urlconnection.setrequestproperty("content-type", "application/json; charset=utf-8"); 
 
  /* optional request header */ 
  urlconnection.setrequestproperty("accept", "application/json"); 
  dto.setcreator(java.net.urlencoder.encode(dto.getcreator(), "utf-8")); 
   
  // read response 
  /* for get request */ 
  urlconnection.setrequestmethod("post"); 
  urlconnection.setdooutput(true); 
  dataoutputstream wr = new dataoutputstream(urlconnection.getoutputstream()); 
  gson gson = new gson(); 
  string jsonstring = gson.tojson(dto); 
  wr.writebytes(jsonstring); 
  wr.flush(); 
  wr.close(); 
  // try to get response 
  int statuscode = urlconnection.getresponsecode(); 
  if (statuscode == 200) { 
   inputstream = new bufferedinputstream(urlconnection.getinputstream()); 
   string response = httputil.convertinputstreamtostring(inputstream); 
   map<string, string> resultmap = gson.fromjson(response, map.class); 
   if (resultmap != null && resultmap.size() > 0) { 
    log.i("applydesigner", "please check the map with key"); 
   } 
   return resultmap; 
  } 
 } 
 catch(exception e) 
 { 
  e.printstacktrace(); 
 } 
 finally 
 { 
  if (inputstream != null) { 
   try { 
    inputstream.close(); 
   } catch (ioexception e) { 
    e.printstacktrace(); 
   } 
  } 
  if (urlconnection != null) { 
   urlconnection.disconnect(); 
  } 
 } 
 return null; 
} 

三、下载图片显示下载进度

package com.example.demo; 
 
import java.io.bytearrayinputstream; 
import java.io.bytearrayoutputstream; 
import java.io.ioexception; 
import java.io.inputstream; 
import java.net.httpurlconnection; 
import java.net.url; 
 
import android.graphics.bitmap; 
import android.graphics.bitmapfactory; 
import android.os.asynctask; 
import android.os.handler; 
import android.os.message; 
import android.util.log; 
 
public class imageloadtask extends asynctask<string, void, bitmap> { 
 private handler handler; 
 
 public imageloadtask(handler handler) { 
  this.handler = handler; 
 } 
 
 protected void onpostexecute(bitmap result) { 
  message msg = new message(); 
  msg.obj = result; 
  handler.sendmessage(msg); 
 } 
 
 protected bitmap doinbackground(string... geturls) { 
  inputstream inputstream = null; 
  httpurlconnection urlconnection = null; 
 
  try { 
   // open connection 
   url url = new url(geturls[0]); 
   urlconnection = (httpurlconnection) url.openconnection(); 
   /* for get request */ 
   urlconnection.setrequestmethod("get"); 
   int filelength = urlconnection.getcontentlength(); 
   int statuscode = urlconnection.getresponsecode(); 
   if (statuscode == 200) { 
    inputstream = urlconnection.getinputstream(); 
    byte data[] = new byte[4096]; 
    long total = 0; 
    int count; 
    bytearrayoutputstream output = new bytearrayoutputstream(); 
    while ((count = inputstream.read(data)) != -1) { 
     total += count; 
     // publishing the progress.... 
     if (filelength > 0 && handler != null) { 
      handler.sendemptymessage(((int) (total * 100 / filelength)) - 1); 
     } 
     output.write(data, 0, count); 
    } 
    bytearrayinputstream bufferinput = new bytearrayinputstream(output.tobytearray()); 
    bitmap bitmap = bitmapfactory.decodestream(bufferinput); 
    inputstream.close(); 
    bufferinput.close(); 
    output.close(); 
    log.i("image", "already get the image by uuid : " + geturls[0]); 
    handler.sendemptymessage(100); 
    return bitmap; 
   } 
  } catch (exception e) { 
   e.printstacktrace(); 
  } finally { 
   if (inputstream != null) { 
    try { 
     inputstream.close(); 
    } catch (ioexception e) { 
     e.printstacktrace(); 
    } 
   } 
   if (urlconnection != null) { 
    urlconnection.disconnect(); 
   } 
  } 
  return null; 
 } 
 
} 

总结：使用httpurlconnection提交json数据的时候编码方式为utf-8所有中文字符请一定要预先转码为utf-8，然后在后台服务器对应的api中解码为utf-8，不然就会报错http 400。

以上就是本文的全部内容，希望对大家的学习android软件编程有所帮助。