Android 最早使用的简单的网络请求

下面是最早从事android开发的时候写的网络请求的代码，简单高效，对于理解http请求有帮助。直接上代码，不用解释，因为非常简单。

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.util.List;
import java.util.Map;

import org.apache.http.entity.mime.content.FileBody;

import android.util.Log;

public class HttpRequest {
    
    public static final String UTF_8 = "UTF-8";
    
    private static String cookie = null;
    
    
    /**
     * GET请求
     * 
     * @param actionUrl
     * @param params
     * @return
     */
    public static String httpGet(String actionUrl, Map<String, String> params) {
        try{
            StringBuffer urlbuff = new StringBuffer(actionUrl);
            if (params != null && params.size() > 0) {
                if (actionUrl.indexOf("?") >= 0) {
                    urlbuff.append("&");
                } else {
                    urlbuff.append("?");
                }
                for (String key : params.keySet()) {
                    urlbuff.append(key).append("=").append(URLEncoder.encode(params.get(key), UTF_8)).append("&");
                }
                urlbuff.deleteCharAt(urlbuff.length() - 1);
                Log.v("---request---Get---", urlbuff.toString());
            }
            URL url = new URL(urlbuff.toString());
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setDoInput(true);// 允许输入
            conn.setDoOutput(false);// 允许输出
            conn.setUseCaches(false);// 不使用Cache
            conn.setRequestMethod("GET");
            conn.setRequestProperty("Charset", UTF_8);
            if (cookie != null) {
                conn.setRequestProperty("Cookie", cookie);
            }
            int cah = conn.getResponseCode();
            if (cah != 200)
                throw new RuntimeException("请求url失败");
            if (conn.getHeaderField("Set-Cookie") != null) {
                cookie = conn.getHeaderField("Set-Cookie");
            }
            Log.i("", "------------------cookie:" + cookie);
            Map<String, List<String>> keys =  conn.getHeaderFields();
            for(String key : keys.keySet()) {
                List<String> list = keys.get(key);
                for(String value : list) {
                    Log.i("", "header: key:" + key + "  values:" + value);
                }
            }
            
            InputStream is = conn.getInputStream();
            int ch;
            StringBuilder b = new StringBuilder();
            while ((ch = is.read()) != -1) {
                b.append((char) ch);
            }
            is.close();
            conn.disconnect();
            return b.toString();
        }catch(Exception e) {
            e.printStackTrace();
        }
        return null;
    }
    
    /**
     * post 带文件上传
     * @param actionUrl
     * @param params
     * @param files
     * @return
     */
    public static String httpPost(String actionUrl, Map<String, String> params, Map<String, FileBody> files) {
        String LINE_START = "--";
        String LINE_END = "
";
        String BOUNDRY =  "*****";
        
        try{
            HttpURLConnection conn = null;
            DataOutputStream dos = null;

            int bytesRead, bytesAvailable, bufferSize;
            long totalBytes;
            byte[] buffer;
            int maxBufferSize = 8096;

            URL url = new URL(actionUrl);
            conn = (HttpURLConnection) url.openConnection();
            
            // Allow Inputs
            conn.setDoInput(true);
            
            // Allow Outputs
            conn.setDoOutput(true);
            
            // Don't use a cached copy.
            conn.setUseCaches(false);
            
            // Use a post method.
            conn.setRequestMethod("POST");
            //if (files != null && files.size() > 0) {
                conn.setRequestProperty("Connection", "Keep-Alive");
                conn.setRequestProperty("Content-Type", "multipart/form-data;boundary="+BOUNDRY);
            //}
            
            Log.i("", "cookie:" + cookie);
            if (cookie != null) {
                conn.setRequestProperty("Cookie", cookie);
            }
//            // Set the cookies on the response
//            String cookie = CookieManager.getInstance().getCookie(server);
//            if (cookie != null) {
//                conn.setRequestProperty("Cookie", cookie);
//            }
            
//            // Should set this up as an option
//            if (chunkedMode) {
//                conn.setChunkedStreamingMode(maxBufferSize);
//            }
                
            dos = new DataOutputStream(conn.getOutputStream());

            // Send any extra parameters
            for (Object key : params.keySet()) {
                dos.writeBytes(LINE_START + BOUNDRY + LINE_END); 
                dos.writeBytes("Content-Disposition: form-data; name="" +  key.toString() + """ + LINE_END);
                dos.writeBytes(LINE_END); 
                dos.write(params.get(key).getBytes());
                dos.writeBytes(LINE_END); 
                
                Log.i("", "-----key:" + key + "  value:" + params.get(key));
            }
            //-----------
            if (files != null && files.size() > 0) {
                for (String key : files.keySet()) {
                     Log.i("", "-----key:" + key + "  value:" + params.get(key));
                     FileBody fileBody = files.get(key);
                     dos.writeBytes(LINE_START + BOUNDRY + LINE_END);
                     dos.writeBytes("Content-Disposition: form-data; name="" + key + "";" + " filename="" + fileBody.getFilename() +""" + LINE_END);
                     dos.writeBytes("Content-Type: " + fileBody.getMimeType() + LINE_END); 
                      dos.writeBytes(LINE_END);
                    
                     // Get a input stream of the file on the phone
                     InputStream fileInputStream = new FileInputStream(fileBody.getFile());
                     bytesAvailable = fileInputStream.available();
                    bufferSize = Math.min(bytesAvailable, maxBufferSize);
                    buffer = new byte[bufferSize];
                    // read file and write it into form...
                    bytesRead = fileInputStream.read(buffer, 0, bufferSize);
                    totalBytes = 0;
                    while (bytesRead > 0) {
                        totalBytes += bytesRead;
                        //result.setBytesSent(totalBytes);
                        dos.write(buffer, 0, bufferSize);
                        bytesAvailable = fileInputStream.available();
                        bufferSize = Math.min(bytesAvailable, maxBufferSize);
                        bytesRead = fileInputStream.read(buffer, 0, bufferSize);
                    }
                    dos.writeBytes(LINE_END);
                    // close streams
                    fileInputStream.close();
                }
            }
            dos.writeBytes(LINE_START + BOUNDRY + LINE_START + LINE_END);
            dos.flush();
            dos.close(); 
             
            int statusCode = conn.getResponseCode();
            Log.i("", "---------------statusCode:" + statusCode);
            if (statusCode != 200) {
                throw new HttpRequestException("server error");
            }
             
            //------------------ read the SERVER RESPONSE
            InputStream is = conn.getInputStream();
            int ch;
            StringBuilder b = new StringBuilder();
            while ((ch = is.read()) != -1) {
                b.append((char) ch);
            }
            conn.disconnect();
            
            return b.toString();
        }catch(Exception e){
            Log.i("", "---------------" + e.getMessage(), e.fillInStackTrace());
            e.printStackTrace();
        }
        return null;
    }
    
    /**
     * post请求
     * @param actionUrl
     * @param params
     * @return
     */
    public static String httpPost(String actionUrl, Map<String, String> params){
        try{
            URL url = new URL(actionUrl);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();   
            //因为这个是post请求,设立需要设置为true   
            conn.setDoOutput(true);   
            conn.setDoInput(true);   
            // 设置以POST方式   
            conn.setRequestMethod("POST");   
            // Post 请求不能使用缓存   
            conn.setUseCaches(false);   
            conn.setInstanceFollowRedirects(true);   
            // 配置本次连接的Content-type，配置为application/x-www-form-urlencoded的   
            conn.setRequestProperty("Content-Type","application/x-www-form-urlencoded");   
            // 连接，从postUrl.openConnection()至此的配置必须要在connect之前完成，   
            // 要注意的是connection.getOutputStream会隐含的进行connect。   
            if (cookie != null) {
                conn.setRequestProperty("Cookie", cookie);
            }
            conn.connect();   
            //DataOutputStream流   
            DataOutputStream out = new DataOutputStream(conn.getOutputStream());   
            //要上传的参数 
            StringBuffer content = new StringBuffer();
            for (String key : params.keySet()) {
                //String content = "par=" + URLEncoder.encode("ABCDEFG", "gb2312"); 
                content.append(key).append("=").append(params.get(key)).append("&");
            }
            //将要上传的内容写入流中   
            out.writeBytes(content.toString());    
            //刷新、关闭   
            out.flush();   
            out.close();
            
            int statusCode = conn.getResponseCode();
            Log.i("", "---------------statusCode:" + statusCode);
            if (statusCode != 200) {
                throw new HttpRequestException("server error");
            }
            if (conn.getHeaderField("Set-Cookie") != null) {
                cookie = conn.getHeaderField("Set-Cookie");
            }
            //获取数据   
            InputStream is = conn.getInputStream();
            int ch;
            StringBuilder b = new StringBuilder();
            while ((ch = is.read()) != -1) {
                b.append((char) ch);
            }
            conn.disconnect();
            return b.toString();
        }catch(Exception e) {
            Log.i("", "---------------" + e.getMessage(), e.fillInStackTrace());
            e.printStackTrace();
        }  
        return null;
    }
    
}

1. application/x-www-form-urlencoded

最常见的 POST 提交数据的方式了。浏览器的原生 form 表单，如果不设置 enctype 属性，那么最终就会以 application/x-www-form-urlencoded方式提交数据。 
传递的key/val会经过URL转码，所以如果传递的参数存在中文或者特殊字符需要注意。

//例子
//b=曹,a=1

POST  HTTP/1.1(CRLF)
Host: www.example.com(CRLF)
Content-Type: application/x-www-form-urlencoded(CRLF)
Cache-Control: no-cache(CRLF)
(CRLF)
b=%E6%9B%B9&a=1(CRLF)
//这里b参数的值"曹"因为URL转码变成其他的字符串了

2. text/xml

//例子

POST http://www.example.com HTTP/1.1(CRLF) 
Content-Type: text/xml(CRLF)
(CRLF)
<?xml version="1.0"?>
<resource>
    <id>123</id>
    <params>
        <name>
            <value>homeway</value>
        </name>
        <age>
            <value>22</value>
        </age>
    </params>
</resource>

3.application/json

//例子
//传递json

POST  HTTP/1.1(CRLF)
Host: www.example.com(CRLF)
Content-Type: application/json(CRLF)
Cache-Control: no-cache(CRLF)
Content-Length: 24(CRLF)
(CRLF)
{
    "a":1,
    "b":"hello"
}

4. multipart/form-data

使用表单上传文件时，必须让 form 的 enctyped 等于这个值。 
并且Http协议会使用boundary来分割上传的参数

//例子
//a="曹",file1是一个文件

POST  HTTP/1.1(CRLF)
Host: www.example.com(CRLF)
//注意data;和boundary之间有一个空格,并且----WebKitFormBoundary7MA4YWxkTrZu0gW是可以自定义的
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW(CRLF)
Cache-Control: no-cache(CRLF)
Content-Length: 728
(CRLF)
//如果有Content-Length的话，则Content-Length指下面所有的字节总数，包括boundary
//这里用自定义的boundary来进行分割,注意会在头部加多"--"
------WebKitFormBoundary7MA4YWxkTrZu0gW(CRLF)
Content-Disposition: form-data; name="a"(CRLF)
(CRLF)
曹(CRLF)
------WebKitFormBoundary7MA4YWxkTrZu0gW(CRLF)
Content-Disposition: form-data; name="file1"; filename="1.jpg"
Content-Type: application/octet-stream(CRLF)
(CRLF)
//此处是参数file1 对应的文件的二进制数据
[654dfasalk;af&6…](CRLF)
//最后一个boundary会分别在头部和尾部加多"--"
------WebKitFormBoundary7MA4YWxkTrZu0gW--(CRLF)

//多个文件同时上传

POST  HTTP/1.1(CRLF)
Host: www.example.com(CRLF)
//注意data;和boundary之间有一个空格,并且----WebKitFormBoundary7MA4YWxkTrZu0gW是可以自定义的
Content-Type: multipart/form-data; boundary=---------------------------418888951815204591197893077
Cache-Control: no-cache(CRLF)
Content-Length: 12138(CRLF)
(CRLF)
-----------------------------418888951815204591197893077(CRLF)
// 文件1的头部boundary
Content-Disposition: form-data; name="userfile[]"; filename="文件1.md"(CRLF)
Content-Type: text/markdown(CRLF)
(CRLF)
// 文件1内容开始
// ...
// 文件1内容结束
-----------------------------418888951815204591197893077(CRLF)
// 文件2的头部boundary
Content-Disposition: form-data; name="userfile[]"; filename="文件2"(CRLF)
Content-Type: application/octet-stream(CRLF)
(CRLF)
// 文件2内容开始
// ...
// 文件2内容结束
-----------------------------418888951815204591197893077(CRLF)
// 文件3的头部boundary
Content-Disposition: form-data; name="userfile[]"; filename="文件3"(CRLF)
Content-Type: application/octet-stream(CRLF)
(CRLF)
// 文件3内容开始
// ...
// 文件3内容结束
-----------------------------418888951815204591197893077(CRLF)
// 参数username的头部boundary
Content-Disposition: form-data; name="username"(CRLF)
(CRLF)
zhangsan
-----------------------------418888951815204591197893077(CRLF)
// 参数password的头部boundary
Content-Disposition: form-data; name="password"(CRLF)
(CRLF)
zhangxx
-----------------------------418888951815204591197893077-- 
// 尾部boundary，表示结束

注意 ：(CRLF)指