Java笔记7：最简单的网络请求Demo

一、服务器端

 

 

1 新建一个工程，建立一个名为MyRequest的工程。

 

2 FileàProject StructureàModulesà点击最右侧的“+”àLibraryàJava

找到Tomcat中的lib目录下的servlet-api.jar，添加进来

 

 

3 建立LoginServlet类，内容如下

 

 

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class LoginServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    public LoginServlet() {
        super();
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String username = request.getParameter("username");
        String blog = request.getParameter("blog");

        System.out.println(username);
        System.out.println(blog);

        response.setContentType("text/plain; charset=UTF-8");
        response.setCharacterEncoding("UTF-8");
        response.getWriter().write("It is ok!");
    }

}

 

4 编译LoginServlet.java，得到LoginServlet.class

 

 

 

5 在Tomcat中的webapps中添加MyHttpServerWEB-INFclasses，并把上一步生成的LoginServlet.class拷进来

 

6 在WEB-INF目录下建立web.xml文件，内容如下：

 

 

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>OneHttpServer</display-name>
  <welcome-file-list>
    <welcome-file>LoginServlet</welcome-file>
  </welcome-file-list>

  <servlet>
    <description></description>
    <display-name>LoginServlet</display-name>
    <servlet-name>LoginServlet</servlet-name>
    <servlet-class>LoginServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>LoginServlet</servlet-name>
    <url-pattern>/LoginServlet</url-pattern>
  </servlet-mapping>

</web-app>

 

 

7 执行Tomcat下的bin目录下的startup.bat来启动Tomcat

 

 

8 在浏览器中输入http://localhost:8080/MyHttpServer，若见到页面显示“It is ok!”则表示服务器端配置成功。

 

二、客户端

1 Get请求

在MyRequest工程新建HttpGetRequest类，内容如下：

 

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;

public class HttpGetRequest {

    /**
     * Main
     * @param args
     * @throws Exception
     */
    public static void main(String[] args) throws Exception {
        System.out.println(doGet());
    }

    /**
     * Get Request
     * @return
     * @throws Exception
     */
    public static String doGet() throws Exception {
        URL localURL = new URL("http://localhost:8080/MyHttpServer/");
        URLConnection connection = localURL.openConnection();
        HttpURLConnection httpURLConnection = (HttpURLConnection)connection;

        httpURLConnection.setRequestProperty("Accept-Charset", "utf-8");
        httpURLConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");

        InputStream inputStream = null;
        InputStreamReader inputStreamReader = null;
        BufferedReader reader = null;
        StringBuffer resultBuffer = new StringBuffer();
        String tempLine = null;

        if (httpURLConnection.getResponseCode() >= 300) {
            throw new Exception("HTTP Request is not success, Response code is " + httpURLConnection.getResponseCode());
        }

        try {
            inputStream = httpURLConnection.getInputStream();
            inputStreamReader = new InputStreamReader(inputStream);
            reader = new BufferedReader(inputStreamReader);

            while ((tempLine = reader.readLine()) != null) {
                resultBuffer.append(tempLine);
            }

        } finally {

            if (reader != null) {
                reader.close();
            }

            if (inputStreamReader != null) {
                inputStreamReader.close();
            }

            if (inputStream != null) {
                inputStream.close();
            }

        }

        return resultBuffer.toString();
    }

}

运行结果：

It is ok!

 

2 Post请求

新建HttpPostRequest.java类，内容如下：

 

 

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;

public class HttpPostRequest {

    /**
     * Main
     * @param args
     * @throws Exception
     */
    public static void main(String[] args) throws Exception {
        System.out.println(doPost());
    }

    /**
     * Post Request
     * @return
     * @throws Exception
     */
    public static String doPost() throws Exception {
        String parameterData = "username=nickhuang&blog=http://www.cnblogs.com/nick-huang/";

        URL localURL = new URL("http://localhost:8080/MyHttpServer/");
        URLConnection connection = localURL.openConnection();
        HttpURLConnection httpURLConnection = (HttpURLConnection)connection;

        httpURLConnection.setDoOutput(true);
        httpURLConnection.setRequestMethod("POST");
        httpURLConnection.setRequestProperty("Accept-Charset", "utf-8");
        httpURLConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
        httpURLConnection.setRequestProperty("Content-Length", String.valueOf(parameterData.length()));

        OutputStream outputStream = null;
        OutputStreamWriter outputStreamWriter = null;
        InputStream inputStream = null;
        InputStreamReader inputStreamReader = null;
        BufferedReader reader = null;
        StringBuffer resultBuffer = new StringBuffer();
        String tempLine = null;

        try {
            outputStream = httpURLConnection.getOutputStream();
            outputStreamWriter = new OutputStreamWriter(outputStream);

            outputStreamWriter.write(parameterData.toString());
            outputStreamWriter.flush();

            if (httpURLConnection.getResponseCode() >= 300) {
                throw new Exception("HTTP Request is not success, Response code is " + httpURLConnection.getResponseCode());
            }

            inputStream = httpURLConnection.getInputStream();
            inputStreamReader = new InputStreamReader(inputStream);
            reader = new BufferedReader(inputStreamReader);

            while ((tempLine = reader.readLine()) != null) {
                resultBuffer.append(tempLine);
            }

        } finally {

            if (outputStreamWriter != null) {
                outputStreamWriter.close();
            }

            if (outputStream != null) {
                outputStream.close();
            }

            if (reader != null) {
                reader.close();
            }

            if (inputStreamReader != null) {
                inputStreamReader.close();
            }

            if (inputStream != null) {
                inputStream.close();
            }

        }

        return resultBuffer.toString();
    }
}

 

运行结果：

It is ok!

 

3 对Get和Post进行封装

封装类：

 

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.InetSocketAddress;
import java.net.Proxy;
import java.net.URL;
import java.net.URLConnection;
import java.util.Iterator;
import java.util.Map;


public class HttpRequestor {

    private String charset = "utf-8";
    private Integer connectTimeout = null;
    private Integer socketTimeout = null;
    private String proxyHost = null;
    private Integer proxyPort = null;

    /**
     * Do GET request
     * @param url
     * @return
     * @throws Exception
     * @throws IOException
     */
    public String doGet(String url) throws Exception {

        URL localURL = new URL(url);

        URLConnection connection = openConnection(localURL);
        HttpURLConnection httpURLConnection = (HttpURLConnection)connection;

        httpURLConnection.setRequestProperty("Accept-Charset", charset);
        httpURLConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");

        InputStream inputStream = null;
        InputStreamReader inputStreamReader = null;
        BufferedReader reader = null;
        StringBuffer resultBuffer = new StringBuffer();
        String tempLine = null;

        if (httpURLConnection.getResponseCode() >= 300) {
            throw new Exception("HTTP Request is not success, Response code is " + httpURLConnection.getResponseCode());
        }

        try {
            inputStream = httpURLConnection.getInputStream();
            inputStreamReader = new InputStreamReader(inputStream);
            reader = new BufferedReader(inputStreamReader);

            while ((tempLine = reader.readLine()) != null) {
                resultBuffer.append(tempLine);
            }

        } finally {

            if (reader != null) {
                reader.close();
            }

            if (inputStreamReader != null) {
                inputStreamReader.close();
            }

            if (inputStream != null) {
                inputStream.close();
            }

        }

        return resultBuffer.toString();
    }

    /**
     * Do POST request
     * @param url
     * @param parameterMap
     * @return
     * @throws Exception
     */
    public String doPost(String url, Map parameterMap) throws Exception {

        /* Translate parameter map to parameter date string */
        StringBuffer parameterBuffer = new StringBuffer();
        if (parameterMap != null) {
            Iterator iterator = parameterMap.keySet().iterator();
            String key = null;
            String value = null;
            while (iterator.hasNext()) {
                key = (String)iterator.next();
                if (parameterMap.get(key) != null) {
                    value = (String)parameterMap.get(key);
                } else {
                    value = "";
                }

                parameterBuffer.append(key).append("=").append(value);
                if (iterator.hasNext()) {
                    parameterBuffer.append("&");
                }
            }
        }

        System.out.println("POST parameter : " + parameterBuffer.toString());

        URL localURL = new URL(url);

        URLConnection connection = openConnection(localURL);
        HttpURLConnection httpURLConnection = (HttpURLConnection)connection;

        httpURLConnection.setDoOutput(true);
        httpURLConnection.setRequestMethod("POST");
        httpURLConnection.setRequestProperty("Accept-Charset", charset);
        httpURLConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
        httpURLConnection.setRequestProperty("Content-Length", String.valueOf(parameterBuffer.length()));

        OutputStream outputStream = null;
        OutputStreamWriter outputStreamWriter = null;
        InputStream inputStream = null;
        InputStreamReader inputStreamReader = null;
        BufferedReader reader = null;
        StringBuffer resultBuffer = new StringBuffer();
        String tempLine = null;

        try {
            outputStream = httpURLConnection.getOutputStream();
            outputStreamWriter = new OutputStreamWriter(outputStream);

            outputStreamWriter.write(parameterBuffer.toString());
            outputStreamWriter.flush();

            if (httpURLConnection.getResponseCode() >= 300) {
                throw new Exception("HTTP Request is not success, Response code is " + httpURLConnection.getResponseCode());
            }

            inputStream = httpURLConnection.getInputStream();
            inputStreamReader = new InputStreamReader(inputStream);
            reader = new BufferedReader(inputStreamReader);

            while ((tempLine = reader.readLine()) != null) {
                resultBuffer.append(tempLine);
            }

        } finally {

            if (outputStreamWriter != null) {
                outputStreamWriter.close();
            }

            if (outputStream != null) {
                outputStream.close();
            }

            if (reader != null) {
                reader.close();
            }

            if (inputStreamReader != null) {
                inputStreamReader.close();
            }

            if (inputStream != null) {
                inputStream.close();
            }

        }

        return resultBuffer.toString();
    }

    private URLConnection openConnection(URL localURL) throws IOException {
        URLConnection connection;
        if (proxyHost != null && proxyPort != null) {
            Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress(proxyHost, proxyPort));
            connection = localURL.openConnection(proxy);
        } else {
            connection = localURL.openConnection();
        }
        return connection;
    }

    /**
     * Render request according setting
     * @param request
     */
    private void renderRequest(URLConnection connection) {

        if (connectTimeout != null) {
            connection.setConnectTimeout(connectTimeout);
        }

        if (socketTimeout != null) {
            connection.setReadTimeout(socketTimeout);
        }

    }

    /*
     * Getter & Setter
     */
    public Integer getConnectTimeout() {
        return connectTimeout;
    }

    public void setConnectTimeout(Integer connectTimeout) {
        this.connectTimeout = connectTimeout;
    }

    public Integer getSocketTimeout() {
        return socketTimeout;
    }

    public void setSocketTimeout(Integer socketTimeout) {
        this.socketTimeout = socketTimeout;
    }

    public String getProxyHost() {
        return proxyHost;
    }

    public void setProxyHost(String proxyHost) {
        this.proxyHost = proxyHost;
    }

    public Integer getProxyPort() {
        return proxyPort;
    }

    public void setProxyPort(Integer proxyPort) {
        this.proxyPort = proxyPort;
    }

    public String getCharset() {
        return charset;
    }

    public void setCharset(String charset) {
        this.charset = charset;
    }

}

 

客户端测试代码：

 

 

import java.util.HashMap;
import java.util.Map;

public class Call {

    public static void main(String[] args) throws Exception {

        /* Post Request */
        Map dataMap = new HashMap();
        dataMap.put("username", "Zheng");
        dataMap.put("blog", "IT");
        System.out.println(new HttpRequestor().doPost("http://localhost:8080/MyHttpServer/", dataMap));

        /* Get Request */
        System.out.println(new HttpRequestor().doGet("http://localhost:8080/MyHttpServer/"));
    }
}

 

运行结果：

POST parameter : blog=IT&username=Zheng

It is ok!

It is ok!