Android 网络编程（一）

概述

一。Android平台网络相关API接口

　　1.java.net.*(标准Java接口)

　　　　java.net.*提供与联网有关的类，包括流、数据包套接字(socket)、Internet协议、常见Http处理等。比如：创建URL，以及URLConnection/HttpURLConnection对象、设置链接参数、链接到服务器、向服务器写数据、从服务器读取数据等通信。这些在Java网络编程中均有涉及。

　　

　　2.org.apache 接口

　　　　

　　　　对于大部分应用程序而言JDK本身提供的网络功能已远远不够，这时就需要Android提供的Apache HttpClient了。它是一个开源项目，功能更加完善，为客户端的Http编程提供高效、最新、功能丰富的工具包支持。

　　3.Android.net.*(Android网络接口)

　　　　常常使用此包下的类进行Android特有的网络编程，如：访问WiFi，访问Android联网信息，邮件等功能。

二。服务器端返回客户端的内容有三种方式

　　

　　1.以HTML代码的形式返回。

　　2.以XML字符串的形式返回，做Android开发时这种方式比较多。返回的数据需要通过XML解析（SAX、DOM，Pull,等）器进行解析（必备知识）。

　　3.以json对象的方式返回。

 

封装的工具类

•    发送GET请求；
•    发送POST请求；
•    发送文件上传请求；
• 　发送XML数据；

package com.kest.util;

import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.InetAddress;
import java.net.Socket;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLEncoder;
import java.util.Map;

/**
 * 
 *
 *         (1)发送GET请求；
 * 
 *         (2)发送POST请求；
 * 
 *         (3)发送文件上传请求；
 * 
 *         (4)发送XML数据；
 */

public class HttpRequestUtil {
    /**
     * 发送GET请求
     * 
     * @param url
     * @param params
     * @param headers
     * @return URLConnection
     * @throws Exception
     */
    public static URLConnection sendGetRequest(String url,
            Map<String, String> params, Map<String, String> headers)
            throws Exception {
        StringBuilder sb = new StringBuilder(url);
        // 如果是GET请求，则请求参数在URL中
        if (params != null && !params.isEmpty()) {
            sb.append("?");
            for (Map.Entry<String, String> entry : params.entrySet()) {
                sb.append(entry.getKey()).append("=")
                        .append(URLEncoder.encode(entry.getValue(), "UTF-8"))
                        .append("&");
            }
            sb.deleteCharAt(sb.length() - 1);
        }
        URL url1 = new URL(sb.toString());
        HttpURLConnection conn = (HttpURLConnection) url1.openConnection();
        conn.setRequestMethod("GET");
        // 设置请求头
        if (headers != null && !headers.isEmpty()) {
            for (Map.Entry<String, String> entry : headers.entrySet()) {
                conn.setRequestProperty(entry.getKey(), entry.getValue());
            }
        }
        conn.getResponseCode();
        return conn;
    }

    /**
     * 发送POST请求
     * 
     * @param url
     * @param params
     * @param headers
     * @return URLConnection
     * @throws Exception
     */
    public static URLConnection sendPostRequest(String url,
            Map<String, String> params, Map<String, String> headers)
            throws Exception {
        StringBuilder sb = new StringBuilder();
        // 如果存在参数，则放在HTTP请求体，形如name=aaa&age=10
        if (params != null && !params.isEmpty()) {
            for (Map.Entry<String, String> entry : params.entrySet()) {
                sb.append(entry.getKey()).append("=")
                        .append(URLEncoder.encode(entry.getValue(), "UTF-8"))
                        .append("&");
            }
            sb.deleteCharAt(sb.length() - 1);
        }
        URL url1 = new URL(url);
        HttpURLConnection conn = (HttpURLConnection) url1.openConnection();
        conn.setRequestMethod("POST");
        conn.setDoOutput(true);
        OutputStream out = conn.getOutputStream();
        out.write(sb.toString().getBytes("UTF-8"));
        if (headers != null && !headers.isEmpty()) {
            for (Map.Entry<String, String> entry : headers.entrySet()) {
                conn.setRequestProperty(entry.getKey(), entry.getValue());
            }
        }
        conn.getResponseCode(); // 为了发送成功
        return conn;
    }

    /**
     * 直接通过HTTP协议提交数据到服务器,实现如下面表单提交功能: <FORM METHOD=POST
     * ACTION="http://192.168.0.200:8080/ssi/fileload/test.do"
     * enctype="multipart/form-data"> <INPUT TYPE="text" NAME="name"> <INPUT
     * TYPE="text" NAME="id"> <input type="file" name="imagefile"/> <input
     * type="file" name="zip"/> </FORM>
     * 
     * @param path
     *            
     * @param params
     *            请求参数 key为参数名,value为参数值
     * @param file
     *            上传文件
     */
    public static boolean uploadFiles(String path, Map<String, String> params,
            FormFile[] files) throws Exception {
        final String BOUNDARY = "---------------------------7da2137580612"; // 数据分隔线
        final String endline = "--" + BOUNDARY + "--\r\n";// 数据结束标志

        int fileDataLength = 0;
        if (files != null && files.length != 0) {
            for (FormFile uploadFile : files) {// 得到文件类型数据的总长度
                StringBuilder fileExplain = new StringBuilder();
                fileExplain.append("--");
                fileExplain.append(BOUNDARY);
                fileExplain.append("\r\n");
                fileExplain.append("Content-Disposition: form-data;name=\""
                        + uploadFile.getParameterName() + "\";filename=\""
                        + uploadFile.getFilname() + "\"\r\n");
                fileExplain.append("Content-Type: "
                        + uploadFile.getContentType() + "\r\n\r\n");
                fileExplain.append("\r\n");
                fileDataLength += fileExplain.length();
                if (uploadFile.getInStream() != null) {
                    fileDataLength += uploadFile.getFile().length();
                } else {
                    fileDataLength += uploadFile.getData().length;
                }
            }
        }
        StringBuilder textEntity = new StringBuilder();
        if (params != null && !params.isEmpty()) {
            for (Map.Entry<String, String> entry : params.entrySet()) {// 构造文本类型参数的实体数据
                textEntity.append("--");
                textEntity.append(BOUNDARY);
                textEntity.append("\r\n");
                textEntity.append("Content-Disposition: form-data; name=\""
                        + entry.getKey() + "\"\r\n\r\n");
                textEntity.append(entry.getValue());
                textEntity.append("\r\n");
            }
        }
        // 计算传输给服务器的实体数据总长度
        int dataLength = textEntity.toString().getBytes().length
                + fileDataLength + endline.getBytes().length;

        URL url = new URL(path);
        int port = url.getPort() == -1 ? 80 : url.getPort();
        Socket socket = new Socket(InetAddress.getByName(url.getHost()), port);
        OutputStream outStream = socket.getOutputStream();
        // 下面完成HTTP请求头的发送
        String requestmethod = "POST " + url.getPath() + " HTTP/1.1\r\n";
        outStream.write(requestmethod.getBytes());
        String accept = "Accept: image/gif, image/jpeg, image/pjpeg, image/pjpeg, application/x-shockwave-flash, application/xaml+xml, application/vnd.ms-xpsdocument, application/x-ms-xbap, application/x-ms-application, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*\r\n";
        outStream.write(accept.getBytes());
        String language = "Accept-Language: zh-CN\r\n";
        outStream.write(language.getBytes());
        String contenttype = "Content-Type: multipart/form-data; boundary="
                + BOUNDARY + "\r\n";
        outStream.write(contenttype.getBytes());
        String contentlength = "Content-Length: " + dataLength + "\r\n";
        outStream.write(contentlength.getBytes());
        String alive = "Connection: Keep-Alive\r\n";
        outStream.write(alive.getBytes());
        String host = "Host: " + url.getHost() + ":" + port + "\r\n";
        outStream.write(host.getBytes());
        // 写完HTTP请求头后根据HTTP协议再写一个回车换行
        outStream.write("\r\n".getBytes());
        // 把所有文本类型的实体数据发送出来
        outStream.write(textEntity.toString().getBytes());
        // 把所有文件类型的实体数据发送出来
        if (files != null && files.length != 0) {
            for (FormFile uploadFile : files) {
                StringBuilder fileEntity = new StringBuilder();
                fileEntity.append("--");
                fileEntity.append(BOUNDARY);
                fileEntity.append("\r\n");
                fileEntity.append("Content-Disposition: form-data;name=\""
                        + uploadFile.getParameterName() + "\";filename=\""
                        + uploadFile.getFilname() + "\"\r\n");
                fileEntity.append("Content-Type: "
                        + uploadFile.getContentType() + "\r\n\r\n");
                outStream.write(fileEntity.toString().getBytes());
                if (uploadFile.getInStream() != null) {
                    byte[] buffer = new byte[1024];
                    int len = 0;
                    while ((len = uploadFile.getInStream()
                            .read(buffer, 0, 1024)) != -1) {
                        outStream.write(buffer, 0, len);
                    }
                    uploadFile.getInStream().close();
                } else {
                    outStream.write(uploadFile.getData(), 0,
                            uploadFile.getData().length);
                }
                outStream.write("\r\n".getBytes());
            }
        }
        // 下面发送数据结束标志，表示数据已经结束
        outStream.write(endline.getBytes());
        BufferedReader reader = new BufferedReader(new InputStreamReader(
                socket.getInputStream()));
        if (reader.readLine().indexOf("200") == -1) {// 读取web服务器返回的数据，判断请求码是否为200，如果不是200，代表请求失败
            return false;
        }
        outStream.flush();
        outStream.close();
        reader.close();
        socket.close();
        return true;
    }

    /**
     * 提交数据到服务器
     * 
     * @param path
     *            
     * @param params
     *            请求参数 key为参数名,value为参数值
     * @param file
     *            上传文件
     */
    public static boolean uploadFile(String path, Map<String, String> params,
            FormFile file) throws Exception {
        return uploadFiles(path, params, new FormFile[] { file });
    }

    /**
     * 将输入流转为字节数组
     * 
     * @param inStream
     * @return
     * @throws Exception
     */
    public static byte[] read2Byte(InputStream inStream) throws Exception {
        ByteArrayOutputStream outSteam = new ByteArrayOutputStream();
        byte[] buffer = new byte[1024];
        int len = 0;
        while ((len = inStream.read(buffer)) != -1) {
            outSteam.write(buffer, 0, len);
        }
        outSteam.close();
        inStream.close();
        return outSteam.toByteArray();
    }

    /**
     * 将输入流转为字符串
     * 
     * @param inStream
     * @return
     * @throws Exception
     */
    public static String read2String(InputStream inStream) throws Exception {
        ByteArrayOutputStream outSteam = new ByteArrayOutputStream();
        byte[] buffer = new byte[1024];
        int len = 0;
        while ((len = inStream.read(buffer)) != -1) {
            outSteam.write(buffer, 0, len);
        }
        outSteam.close();
        inStream.close();
        return new String(outSteam.toByteArray(), "UTF-8");
    }

    /**
     * 发送xml数据
     * 
     * @param path
     *            请求地址
     * @param xml
     *            xml数据
     * @param encoding
     *            编码
     * @return
     * @throws Exception
     */
    public static byte[] postXml(String path, String xml, String encoding)
            throws Exception {
        byte[] data = xml.getBytes(encoding);
        URL url = new URL(path);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setRequestMethod("POST");
        conn.setDoOutput(true);
        conn.setRequestProperty("Content-Type", "text/xml; charset=" + encoding);
        conn.setRequestProperty("Content-Length", String.valueOf(data.length));
        conn.setConnectTimeout(5 * 1000);
        OutputStream outStream = conn.getOutputStream();
        outStream.write(data);
        outStream.flush();
        outStream.close();
        if (conn.getResponseCode() == 200) {
            return read2Byte(conn.getInputStream());
        }
        return null;
    }
}