简单介绍Java网络编程中的HTTP请求
HTTP请求的细节――请求行 例: http_get import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.net.HttpURLConnection; import java.net.MalformedURLException; import java.net.URL; public class Http_Get { private static String URL_PATH = "http://192.168.1.125:8080/myhttp/pro1.png"; public Http_Get() { // TODO Auto-generated constructor stub } public static void saveImageToDisk() { InputStream inputStream = getInputStream(); byte[] data = new byte[1024]; int len = 0; FileOutputStream fileOutputStream = null; try { fileOutputStream = new FileOutputStream("C:test.png"); while ((len = inputStream.read(data)) != -1) { fileOutputStream.write(data,len); } } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } finally { if (inputStream != null) { try { inputStream.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } if (fileOutputStream != null) { try { fileOutputStream.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } } /** * 获得服务器端的数据,以InputStream形式返回 * @return */ public static InputStream getInputStream() { InputStream inputStream = null; HttpURLConnection httpURLConnection = null; try { URL url = new URL(URL_PATH); if (url != null) { httpURLConnection = (HttpURLConnection) url.openConnection(); // 设置连接网络的超时时间 httpURLConnection.setConnectTimeout(3000); httpURLConnection.setDoInput(true); // 表示设置本次http请求使用GET方式请求 httpURLConnection.setRequestMethod("GET"); int responseCode = httpURLConnection.getResponseCode(); if (responseCode == 200) { // 从服务器获得一个输入流 inputStream = httpURLConnection.getInputStream(); } } } catch (MalformedURLException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } return inputStream; } public static void main(String[] args) { // 从服务器获得图片保存到本地 saveImageToDisk(); } } Http_Post import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.UnsupportedEncodingException; import java.net.HttpURLConnection; import java.net.MalformedURLException; import java.net.URL; import java.net.URLEncoder; import java.util.HashMap; import java.util.Map; public class Http_Post { // 请求服务器端的url private static String PATH = "http://192.168.1.125:8080/myhttp/servlet/LoginAction"; private static URL url; public Http_Post() { // TODO Auto-generated constructor stub } static { try { url = new URL(PATH); } catch (MalformedURLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } /** * @param params * 填写的url的参数 * @param encode * 字节编码 * @return */ public static String sendPostMessage(Map<String,String> params,String encode) { // 作为StringBuffer初始化的字符串 StringBuffer buffer = new StringBuffer(); try { if (params != null && !params.isEmpty()) { for (Map.Entry<String,String> entry : params.entrySet()) { // 完成转码操作 buffer.append(entry.getKey()).append("=").append( URLEncoder.encode(entry.getValue(),encode)) .append("&"); } buffer.deleteCharAt(buffer.length() - 1); } // System.out.println(buffer.toString()); // 删除掉最有一个& System.out.println("-->>"+buffer.toString()); HttpURLConnection urlConnection = (HttpURLConnection) url .openConnection(); urlConnection.setConnectTimeout(3000); urlConnection.setRequestMethod("POST"); urlConnection.setDoInput(true);// 表示从服务器获取数据 urlConnection.setDoOutput(true);// 表示向服务器写数据 // 获得上传信息的字节大小以及长度 byte[] mydata = buffer.toString().getBytes(); // 表示设置请求体的类型是文本类型 urlConnection.setRequestProperty("Content-Type","application/x-www-form-urlencoded"); urlConnection.setRequestProperty("Content-Length",String.valueOf(mydata.length)); // 获得输出流,向服务器输出数据 OutputStream outputStream = urlConnection.getOutputStream(); outputStream.write(mydata,mydata.length); outputStream.close(); // 获得服务器响应的结果和状态码 int responseCode = urlConnection.getResponseCode(); if (responseCode == 200) { return changeInputStream(urlConnection.getInputStream(),encode); } } catch (UnsupportedEncodingException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } return ""; } /** * 将一个输入流转换成指定编码的字符串 * * @param inputStream * @param encode * @return */ private static String changeInputStream(InputStream inputStream,String encode) { // TODO Auto-generated method stub ByteArrayOutputStream outputStream = new ByteArrayOutputStream(); byte[] data = new byte[1024]; int len = 0; String result = ""; if (inputStream != null) { try { while ((len = inputStream.read(data)) != -1) { outputStream.write(data,len); } result = new String(outputStream.toByteArray(),encode); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } return result; } /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub Map<String,String> params = new HashMap<String,String>(); params.put("username","admin"); params.put("password","123"); String result = Http_Post.sendPostMessage(params,"utf-8"); System.out.println("--result->>" + result); } }
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