URLConnection发送HTTP请求的方法_动力节点Java学院整理
作者：nick-huang 发布时间：2023-09-20 16:08:17
标签：URLConnection,HTTP
如何通过Java发送HTTP请求，通俗点讲，如何通过Java（模拟浏览器）发送HTTP请求。
Java有原生的API可用于发送HTTP请求，即java.net.URL、java.net.URLConnection，这些API很好用、很常用，但不够简便；
所以，也流行有许多Java HTTP请求的framework，如，Apache的HttpClient。
目前项目主要用到Java原生的方式，所以，这里主要介绍此方式。
运用原生Java Api发送简单的Get请求、Post请求
HTTP请求粗分为两种，一种是GET请求，一种是POST请求。使用Java发送这两种请求的代码大同小异，只是一些参数设置的不同。步骤如下：
1.通过统一资源 * （java.net.URL）获取连接器（java.net.URLConnection）
2.设置请求的参数
3.发送请求
4.以输入流的形式获取返回内容
5.关闭输入流
简单的Get请求示例如下：
package com.bjpowernode.httprequestdemo;
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/OneHttpServer/");
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();
}
}
简单的Post请求示例如下：
package com.bjpowernode.httprequestdemo;
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/OneHttpServer/");
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();
}
}
简单封装
如果项目中有多处地方使用HTTP请求，我们适当对其进行封装，
可以大大减少代码量（不需每次都写一大段原生的请求Source code）
也可以使配置更灵活、方便（全局设置一些项目特有的配置，比如已商榷的time out时间、已确定的Proxy Server，避免以后改动繁琐）
以下简单封装成HttpRequestor，以便使用：
package com.bjpowernode.util.httprequestor;
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;
}
}
写一个调用的测试类：
package com.bjpowernode.util.httprequestor;
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", "Nick Huang");
dataMap.put("blog", "IT");
System.out.println(new HttpRequestor().doPost("http://localhost:8080/OneHttpServer/", dataMap));
/* Get Request */
System.out.println(new HttpRequestor().doGet("http://localhost:8080/OneHttpServer/"));
}
}
OK，完成！！
简单测试
以上的请求地址都是http://localhost:8080/OneHttpServer/
这是自己的一个用于测试的Web Application，就一个简单的Servlet和web.xml。毕竟需要测试请求参数是否能正常接收，处理超时的情况。
LoginServlet
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!");
}
}
web.xml
<?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>
0
投稿猜你喜欢
* 在JavaWeb开发中用得比较多Java Web开发中的 * （listener）就是application、session、requ- 泛型1、简单泛型泛型的主要目的之一就是用来指定容器要持有什么类型的对象，而且由编译器来保证类型的正确性。泛型暂时不指定类型，在使用时决定具体
- 一、什么是备忘录模式定义：在不破坏封闭的前提下，捕获一个对象的内部状态，并在该对象之外保存这个状态。这样以后就可将该对象恢复到原先保存的状态
- 前言短信验证码是通过发送验证码到手机的一种有效的验证码系统。主要用于验证用户手机的合法性及敏感操作的身份验证。现在市面上的短信服务平台有很多
- 实例如下：//选择文件，点击【浏览】，选择文件 private void button1_Click(object sender, Even
- AsyncTask，顾名思义，异步任务。说到异步，最简单的理解就是不同步。再复杂一点理解，就得举例子了。假设我要去火车站买票，刚到火车站我突
- 先要把word或ppt转换为pdf； 以pdf的格式展示，防止文件拷贝。转换方法1、安装Word、Excel、PowerPoint组件注意：
- [LeetCode] 9. Palindrome Number 验证回文数字Determine whether an integer is
- 效果如下：BitmapShader 的简单介绍关于 Shader是什么，Shader的种类有哪几种以及如何使用不属于本文范畴，对这方面不是很
- 前言：学习了SpringBoot分页查询的两种写法，一种是手动实现，另一种是使用框架实现。现在我将具体的实现流程分享一下。首先是手动实现分页
- 一、unity方向导航制作设计要求是方向导航随着鼠标旋转转换方向，效果图如下：具体的实现方法主要有两个步骤，分别为UI设计和脚本编写。我的设
- 一、线程组 /** * A thread group represents a set of threads. In addition,
- 本文实例为大家分享了C#生成唯一订单号的具体代码，供大家参考，具体内容如下根据GUID+DateTime.Now.Ticks生产唯一订单号/
- 在早期开发的时候，我们完成的都是静态页面也就是html页面，随着时间轴的发展，慢慢的引入了jsp页面，当在后端服务查询到数据之后可以转发到j
- 1.字节码增强技术字节码增强技术就是一类对现有字节码进行修改或者动态生成全新字节码文件的技术。参考地址2.常见技术技术分类类型静态增强Asp
- 本文实例为大家分享了java实现文件下载的具体代码，供大家参考，具体内容如下public HttpServletResponse downl
- spring mvc中的@PathVariable是用来获得请求url中的动态参数的，十分方便，复习下： @Controller publ
- 引言使用标准框架验证Java bean的基础知识 - JSR 380，也称为Bean Validation 2.0。当然，验证用户输入在大多
- 本文实例讲述了C#字符串加密解密方法。分享给大家供大家参考。具体如下：#region 加密解密static string encryptKe
- 普通校验导入依赖：默认的报错：没有提示具体的属性设置自己的错误信息提示：创建 ValidationMessages.properties内容
