来请教一个关于HTTPREQUEST和 HTTPRESPONSE问题

Question

现在我正在写一个小东西
直接用一个程序向一个应用发送一个 HTTPREQUEST 
然后接收HTTPRESPONSE过程中不用浏览器请大家给点指导意见%%%%%

Answer 1

如果是简单的请求，可以使用 java.net.URLConnection。如果是比较复杂的请求使用 Apache HttpComponent 会更好一些。

Answer 2

不知道你发出的是 GET 请求，还是 POST 请求？GET 的话方便一些，POST 的话稍微麻烦一点。

Answer 3

写了个测试，参考一下，实现了 GET 和 POST 请求。HTTP 服务端使用一个 Servlet 作为测试：import java.io.IOException;import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;public class UrlConnectionServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;    public UrlConnectionServlet() {
        super();
    }    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        request.setCharacterEncoding("gbk");
        response.setCharacterEncoding("gbk");
        String name = request.getParameter("name");
        String age = request.getParameter("age");
        ServletOutputStream out = response.getOutputStream();
        response.setContentType("text/plain");
        out.print("GET:name=" + name + ":age=" + age);
        out.flush();
    }    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        request.setCharacterEncoding("gbk");
        response.setCharacterEncoding("gbk");
        String name = request.getParameter("name");
        String age = request.getParameter("age");
        ServletOutputStream out = response.getOutputStream();
        response.setContentType("text/plain");
        out.print("POST:name=" + name + ":age=" + age);
        out.flush();
    }
}客户端调用如下：import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStreamWriter;
import java.io.Serializable;
import java.io.UnsupportedEncodingException;
import java.io.Writer;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;public class UrlConnection {    public static void main(String[] args) throws IOException {
        Student student = new Student("张三", 20);
        String url = "http://localhost:8080/web/UrlConnectionServlet";
        String charset = "gbk";
        String getResp = httpGet(student, url, charset);
        System.out.println(getResp);
        
        String postResp = httpPost(student, url, charset);
        System.out.println(postResp);
    }
    
    private static String httpGet(Student student, String address, String charset)
            throws IOException {
        // GET 请求直接将参数放到 URL 中去
        URL url = new URL(student.toUrlString(address, charset));
        HttpURLConnection httpConnection = null;
        try {
            httpConnection = (HttpURLConnection)url.openConnection();
            int responseCode = httpConnection.getResponseCode();
            System.out.println("请求响应: " + responseCode);
            InputStream in = httpConnection.getInputStream();
            return read(in, charset);
        } finally {
            if(httpConnection != null) {
                httpConnection.disconnect();
            }
        }
    }
    
    private static String httpPost(Student student, String address, String charset) throws IOException {
        // POST 请求的 URL 是一个地址，参数放在 HTTP 正文之中
        URL url = new URL(address);
        HttpURLConnection httpConnection = null;
        try {
            httpConnection = (HttpURLConnection)url.openConnection();
            int responseCode = sendPostRequest(student, httpConnection, charset);            
            System.out.println("请求响应: " + responseCode);
            InputStream in = httpConnection.getInputStream();
            return read(in, "gbk");
        } finally {
            if(httpConnection != null) {
                httpConnection.disconnect();
            }
        }
    }
    
    private static int sendPostRequest(Student student, HttpURLConnection httpConnection,
            String charset) throws IOException {
        Writer writer = null;
        try {
            httpConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
            // 打开 HTTP 输出流，允许向 HTTP 写入 content
            httpConnection.setDoOutput(true);
            writer = new OutputStreamWriter(httpConnection.getOutputStream(), charset);
            writer.write(student.toPostString(charset));            
        } finally {
            if(writer != null) {
                writer.close();
            }
        }
        httpConnection.connect();
        return httpConnection.getResponseCode();
    }
    
    private static String read(InputStream in, String charset) throws IOException {
        ByteArrayOutputStream ba = new ByteArrayOutputStream();
        byte[] bys = new byte[8 * 1024];
        for(int n = -1; (n = in.read(bys)) != -1; ) {
            ba.write(bys, 0, n);
        }
        return new String(ba.toByteArray(), charset);
    }
}class Student implements Serializable {    private static final long serialVersionUID = 5253657949062051574L;
    
    private String name;
    private int age;
    
    public Student(String name, int age) {
        this.name = name;
        this.age = age;
    }
    
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    
    public String toUrlString(String url, String charset) {
        StringBuilder sb = new StringBuilder();
        sb.append(url).append("?");
        sb.append("name=").append(NetUtil.urlEncode(name, "gbk"));
        sb.append("&age=").append(age);
        return sb.toString();
    }
    
    public String toPostString(String charset) {
        StringBuilder sb = new StringBuilder();
        sb.append("name=").append(NetUtil.urlEncode(name, "gbk"));
        sb.append("&age=").append(age);
        return sb.toString();
    }
}class NetUtil {
    
    public static String urlEncode(String str, String encoding) {
        try {
            return URLEncoder.encode(str, encoding);
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
            return null;
        }        
    }
}

Answer 4

sun.net.www.protocol.http.HttpURLConnection:http://localhost:8080/WEB/servlet/Test
java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(Unknown Source)
at java.io.BufferedInputStream.fill(Unknown Source)
at java.io.BufferedInputStream.read1(Unknown Source)
at java.io.BufferedInputStream.read(Unknown Source)
at sun.net.www.http.HttpClient.parseHTTPHeader(Unknown Source)
at sun.net.www.http.HttpClient.parseHTTP(Unknown Source)
at sun.net.www.http.HttpClient.parseHTTP(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
at java.net.HttpURLConnection.getResponseCode(Unknown Source)
at cn.imrobin.catcher.UrlCatcher.main(UrlCatcher.java:19)