http——post

最新推荐文章于 2024-10-19 15:06:34 发布

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最新推荐文章于 2024-10-19 15:06:34 发布

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分类专栏： android

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本文详细介绍了如何在Java Web应用中实现登录功能，并通过两种方式发送HTTP POST请求进行验证。第一种方式利用Servlet配置和JSP页面直接处理请求；第二种方式使用Java自带的包和Apache HttpClient库进行HTTP POST请求的发送。文章提供了完整的代码示例，包括URL路径设置、参数获取、编码设置以及响应结果处理。

服务器端：

servlet配置：

  <servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>LoginAction</servlet-name>
    <servlet-class>com.login.manager.LoginAction</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>LoginAction</servlet-name>
    <url-pattern>/servlet/LoginAction</url-pattern>
  </servlet-mapping>

在程序中调用该对象：

<%
String path = request.getContextPath();
%>

<form name="form1"  method="post" action="<%=path %>/servlet/LoginAction">

注意：此处为URL的路径

3 程序中必要的编码设置

response.setContentType("text/html;charset=utf-8");
		request.setCharacterEncoding("utf-8");
		response.setCharacterEncoding("utf-8");

4 获得参数的一般方法

PrintWriter out = response.getWriter();
		String username = request.getParameter("username");
		System.out.println("-username->>"+username);
		String pswd = request.getParameter("password");
		System.out.println("-password->>"+pswd);
		if(username.equals("admin")&&pswd.equals("123")){
			out.print("login is success!!!!");
		}else{
			out.print("login is fail!!!");
		}
		out.flush();
		out.close();

客户端：

方法一：使用java自带的包来处理

package com.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 HttpUtils {

	// 请求服务器端的url
	private static String PATH = "http://192.168.0.102:8080/myhttp/servlet/LoginAction";
	private static URL url;

	public HttpUtils() {
		// 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,0,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, 0, 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 = HttpUtils.sendPostMessage(params, "utf-8");
		System.out.println("--result->>" + result);
	}

}

方法二：使用apache的包来处理HTTP

http://blog.youkuaiyun.com/javavenus/article/details/6560997

引入的包：

package com.http.post;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;

public class HttpUtils {

	public HttpUtils() {
		// TODO Auto-generated constructor stub
	}

	public static String sendHttpClientPost(String path,
			Map<String, String> map, String encode) {
		List<NameValuePair> list = new ArrayList<NameValuePair>();
		if (map != null && !map.isEmpty()) {
			for (Map.Entry<String, String> entry : map.entrySet()) {
				list.add(new BasicNameValuePair(entry.getKey(), entry
						.getValue()));
			}
		}
		try {
			// 实现将请求的参数封装到表单中,请求体重
			UrlEncodedFormEntity entity = new UrlEncodedFormEntity(list, encode);
			// 使用Post方式提交数据
			HttpPost httpPost = new HttpPost(path);
			httpPost.setEntity(entity);
			// 指定post请求
			DefaultHttpClient client = new DefaultHttpClient();
			HttpResponse httpResponse = client.execute(httpPost);
			if (httpResponse.getStatusLine().getStatusCode() == 200) {
				return changeInputStream(httpResponse.getEntity().getContent(),
						encode);
			}
		} catch (UnsupportedEncodingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (ClientProtocolException 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
	 */
	public 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, 0, 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
		String path = "http://192.168.0.102:8080/myhttp/servlet/LoginAction";
		Map<String, String> params = new HashMap<String, String>();
		params.put("username", "admin");
		params.put("password", "123");
		String result = HttpUtils.sendHttpClientPost(path, params, "utf-8");
		System.out.println("-->>"+result);
	}

}