Android中使用HttpURLConnection实现GET POST JSON数据与下载图片
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2024-02-15 10:21:22
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httpurlc...
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。
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