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MyHttpServer\WEB-INF\classes，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!