Java笔记7：最简单的网络请求Demo

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mob604756f9eb4d 2017-04-19 11:16:00

文章标签 java .net xml tomcat 服务器端 文章分类 代码人生

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

Java笔记7：最简单的网络请求Demo_java

Java笔记7：最简单的网络请求Demo_java_02

3 建立LoginServlet类，内容如下

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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

Java笔记7：最简单的网络请求Demo_服务器端_05

Java笔记7：最简单的网络请求Demo_tomcat_06

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

Java笔记7：最简单的网络请求Demo_服务器端_07

6 在WEB-INF目录下建立web.xml文件，内容如下：

[html] view plain copy

<?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>

Java笔记7：最简单的网络请求Demo_java_10

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。

Java笔记7：最简单的网络请求Demo_xml_11

二、客户端

1 Get请求

在MyRequest工程新建HttpGetRequest类，内容如下：

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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：

[java] view plain copy

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：

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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：

[java] view plain copy

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/"));
}
}