ThinkSSL🔒 一键申购 5分钟快速签发 30天无理由退款 购买更放心 广告
# URL类 <h1 style="border: 0px; margin: 0px 0px 10px; padding: 0px; font-size: 2.1em; font-family: &#39;Open Sans&#39;, &#39;Helvetica Neue&#39;, Helvetica, Arial, STHeiti, &#39;Microsoft Yahei&#39;, sans-serif; white-space: normal; background-color: rgb(255, 255, 255);"> Java URL处理 </h1> <p style="border: 0px; margin-top: 0px; margin-bottom: 0px; padding: 0px; line-height: 2em; font-size: 12px; font-family: &#39;Microsoft Yahei&#39;, &#39;Helvetica Neue&#39;, Helvetica, Arial, sans-serif; color: rgb(51, 51, 51); white-space: normal; background-color: rgb(255, 255, 255);"> URL(Uniform Resource Locator)中文名为统一资源定位符,有时也被俗称为网页地址。表示为互联网上的资源,如网页或者FTP地址。 </p> <p style="border: 0px; margin-top: 0px; margin-bottom: 0px; padding: 0px; line-height: 2em; font-size: 12px; font-family: &#39;Microsoft Yahei&#39;, &#39;Helvetica Neue&#39;, Helvetica, Arial, sans-serif; color: rgb(51, 51, 51); white-space: normal; background-color: rgb(255, 255, 255);"> 本章节我们将介绍Java是如处理URL的。URL可以分为如下几个部分。 </p> <pre class="prettyprint" style="border-width: 1px 1px 1px 4px; border-style: solid; border-color: rgb(221, 221, 221); margin: 15px auto; padding: 10px 15px; font-stretch: normal; font-size: 12px; line-height: 20px; font-family: &#39;courier new&#39;; word-break: break-all; word-wrap: break-word; color: rgb(51, 51, 51); background-image: url(http://www.runoob.com/images/codecolorer_bg.gif); background-color: rgb(251, 251, 251); background-position: 50% 0%;">protocol://host:port/path?query#ref</pre> <p style="border: 0px; margin-top: 0px; margin-bottom: 0px; padding: 0px; line-height: 2em; font-size: 12px; font-family: &#39;Microsoft Yahei&#39;, &#39;Helvetica Neue&#39;, Helvetica, Arial, sans-serif; color: rgb(51, 51, 51); white-space: normal; background-color: rgb(255, 255, 255);"> protocols(协议)可以是 HTTP, HTTPS, FTP, 和File。port 为端口号。path为文件路径及文件名。 </p> <p style="border: 0px; margin-top: 0px; margin-bottom: 0px; padding: 0px; line-height: 2em; font-size: 12px; font-family: &#39;Microsoft Yahei&#39;, &#39;Helvetica Neue&#39;, Helvetica, Arial, sans-serif; color: rgb(51, 51, 51); white-space: normal; background-color: rgb(255, 255, 255);"> HTTP协议的URL实例如下: </p> <pre class="prettyprint" style="border-width: 1px 1px 1px 4px; border-style: solid; border-color: rgb(221, 221, 221); margin: 15px auto; padding: 10px 15px; font-stretch: normal; font-size: 12px; line-height: 20px; font-family: &#39;courier new&#39;; word-break: break-all; word-wrap: break-word; color: rgb(51, 51, 51); background-image: url(http://www.runoob.com/images/codecolorer_bg.gif); background-color: rgb(251, 251, 251); background-position: 50% 0%;">http://www.w3cschool.cc/index.html?language=cn#j2se</pre> <p style="border: 0px; margin-top: 0px; margin-bottom: 0px; padding: 0px; line-height: 2em; font-size: 12px; font-family: &#39;Microsoft Yahei&#39;, &#39;Helvetica Neue&#39;, Helvetica, Arial, sans-serif; color: rgb(51, 51, 51); white-space: normal; background-color: rgb(255, 255, 255);"> 以上URL实例并未指定端口,因为HTTP协议默认的端口号为80。 </p> <p> <br/> </p> <h2 style="border: 0px; margin: 2px 0px; padding: 0px; font-size: 1.8em; line-height: 1.8em; color: rgb(51, 51, 51); font-family: &#39;Open Sans&#39;, &#39;Helvetica Neue&#39;, Helvetica, Arial, STHeiti, &#39;Microsoft Yahei&#39;, sans-serif; white-space: normal; background-color: rgb(255, 255, 255);"> URL 类方法 </h2> <p style="border: 0px; margin-top: 0px; margin-bottom: 0px; padding: 0px; line-height: 2em; font-size: 12px; font-family: &#39;Microsoft Yahei&#39;, &#39;Helvetica Neue&#39;, Helvetica, Arial, sans-serif; color: rgb(51, 51, 51); white-space: normal; background-color: rgb(255, 255, 255);"> 在java.net包中定义了URL类,该类用来处理有关URL的内容。对于URL类的创建和使用,下面分别进行介绍。 </p> <p style="border: 0px; margin-top: 0px; margin-bottom: 0px; padding: 0px; line-height: 2em; font-size: 12px; font-family: &#39;Microsoft Yahei&#39;, &#39;Helvetica Neue&#39;, Helvetica, Arial, sans-serif; color: rgb(51, 51, 51); white-space: normal; background-color: rgb(255, 255, 255);"> java.net.URL提供了丰富的URL构建方式,并可以通过java.net.URL来获取资源。 </p> <table class="reference" width="729"> <tbody style="border: 0px; margin: 0px; padding: 0px;"> <tr style="border: 0px; margin: 0px; padding: 0px; background-color: rgb(246, 244, 240);" class="firstRow"> <th style="border-color: rgb(85, 85, 85); margin: 0px; padding: 3px; color: rgb(255, 255, 255); vertical-align: top; background-color: rgb(85, 85, 85);"> 序号 </th> <th style="border-color: rgb(85, 85, 85); margin: 0px; padding: 3px; color: rgb(255, 255, 255); vertical-align: top; background-color: rgb(85, 85, 85);"> 方法描述 </th> </tr> <tr style="border: 0px; margin: 0px; padding: 0px;"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 1 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>public URL(String protocol, String host, int port, String file) throws MalformedURLException.</strong><br/>通过给定的参数(协议、主机名、端口号、文件名)创建URL。 </td> </tr> <tr style="border: 0px; margin: 0px; padding: 0px; background-color: rgb(246, 244, 240);"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 2 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>public URL(String protocol, String host, String file) throws MalformedURLException</strong><br/>使用指定的协议、主机名、文件名创建URL,端口使用协议的默认端口。 </td> </tr> <tr style="border: 0px; margin: 0px; padding: 0px;"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 3 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>public URL(String url) throws MalformedURLException</strong><br/>通过给定的URL字符串创建URL </td> </tr> <tr style="border: 0px; margin: 0px; padding: 0px; background-color: rgb(246, 244, 240);"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 4 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>public URL(URL context, String url) throws MalformedURLException</strong><br/>使用基地址和相对URL创建 </td> </tr> </tbody> </table> <p style="border: 0px; margin-top: 0px; margin-bottom: 0px; padding: 0px; line-height: 2em; font-size: 12px; font-family: &#39;Microsoft Yahei&#39;, &#39;Helvetica Neue&#39;, Helvetica, Arial, sans-serif; color: rgb(51, 51, 51); white-space: normal; background-color: rgb(255, 255, 255);"> URL类中包含了很多方法用于访问URL的各个部分,具体方法及描述如下: </p> <table class="reference" width="729"> <tbody style="border: 0px; margin: 0px; padding: 0px;"> <tr style="border: 0px; margin: 0px; padding: 0px; background-color: rgb(246, 244, 240);" class="firstRow"> <th style="border-color: rgb(85, 85, 85); margin: 0px; padding: 3px; color: rgb(255, 255, 255); vertical-align: top; background-color: rgb(85, 85, 85);"> 序号 </th> <th style="border-color: rgb(85, 85, 85); margin: 0px; padding: 3px; color: rgb(255, 255, 255); vertical-align: top; background-color: rgb(85, 85, 85);"> 方法描述 </th> </tr> <tr style="border: 0px; margin: 0px; padding: 0px;"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 1 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>public String getPath()</strong><br/>返回URL路径部分。 </td> </tr> <tr style="border: 0px; margin: 0px; padding: 0px; background-color: rgb(246, 244, 240);"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 2 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>public String getQuery()</strong><br/>返回URL查询部分。 </td> </tr> <tr style="border: 0px; margin: 0px; padding: 0px;"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 3 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>public String getAuthority()</strong><br/>获取此 URL 的授权部分。 </td> </tr> <tr style="border: 0px; margin: 0px; padding: 0px; background-color: rgb(246, 244, 240);"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 4 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>public int getPort()</strong><br/>返回URL端口部分 </td> </tr> <tr style="border: 0px; margin: 0px; padding: 0px;"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 5 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>public int getDefaultPort()</strong><br/>返回协议的默认端口号。 </td> </tr> <tr style="border: 0px; margin: 0px; padding: 0px; background-color: rgb(246, 244, 240);"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 6 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>public String getProtocol()</strong><br/>返回URL的协议 </td> </tr> <tr style="border: 0px; margin: 0px; padding: 0px;"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 7 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>public String getHost()</strong><br/>返回URL的主机 </td> </tr> <tr style="border: 0px; margin: 0px; padding: 0px; background-color: rgb(246, 244, 240);"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 8 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>public String getFile()</strong><br/>返回URL文件名部分 </td> </tr> <tr style="border: 0px; margin: 0px; padding: 0px;"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 9 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>public String getRef()</strong><br/>获取此 URL 的锚点(也称为&quot;引用&quot;)。 </td> </tr> <tr style="border: 0px; margin: 0px; padding: 0px; background-color: rgb(246, 244, 240);"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 10 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>public URLConnection openConnection() throws IOException</strong><br/>打开一个URL连接,并运行客户端访问资源。 </td> </tr> </tbody> </table> <h3 style="border: 0px; margin: 8px 0px; padding: 0px; font-size: 1.4em; color: rgb(51, 51, 51); font-family: &#39;Open Sans&#39;, &#39;Helvetica Neue&#39;, Helvetica, Arial, STHeiti, &#39;Microsoft Yahei&#39;, sans-serif; white-space: normal; background-color: rgb(255, 255, 255);"> 实例 </h3> <p style="border: 0px; margin-top: 0px; margin-bottom: 0px; padding: 0px; line-height: 2em; font-size: 12px; font-family: &#39;Microsoft Yahei&#39;, &#39;Helvetica Neue&#39;, Helvetica, Arial, sans-serif; color: rgb(51, 51, 51); white-space: normal; background-color: rgb(255, 255, 255);"> 以上实例演示了使用java.net的URL类获取URL的各个部分参数: </p> <pre class="prettyprint prettyprinted" style="border-width: 1px 1px 1px 4px; border-style: solid; border-color: rgb(221, 221, 221); margin: 15px auto; padding: 10px 15px; font-stretch: normal; font-size: 12px; line-height: 20px; font-family: &#39;courier new&#39;; word-break: break-all; word-wrap: break-word; color: rgb(51, 51, 51); background-image: url(http://www.runoob.com/images/codecolorer_bg.gif); background-color: rgb(251, 251, 251); background-position: 50% 0%;">// 文件名 : URLDemo.javaimport java.net.*;import java.io.*;public class URLDemo{ public static void main(String [] args) { try { URL url = new URL(&quot;http://www.w3cschool.cc/index.html?language=cn#j2se&quot;); System.out.println(&quot;URL is &quot; + url.toString()); System.out.println(&quot;protocol is &quot; + url.getProtocol()); System.out.println(&quot;authority is &quot; + url.getAuthority()); System.out.println(&quot;file name is &quot; + url.getFile()); System.out.println(&quot;host is &quot; + url.getHost()); System.out.println(&quot;path is &quot; + url.getPath()); System.out.println(&quot;port is &quot; + url.getPort()); System.out.println(&quot;default port is &quot; + url.getDefaultPort()); System.out.println(&quot;query is &quot; + url.getQuery()); System.out.println(&quot;ref is &quot; + url.getRef()); }catch(IOException e) { e.printStackTrace(); } }}</pre> <p style="border: 0px; margin-top: 0px; margin-bottom: 0px; padding: 0px; line-height: 2em; font-size: 12px; font-family: &#39;Microsoft Yahei&#39;, &#39;Helvetica Neue&#39;, Helvetica, Arial, sans-serif; color: rgb(51, 51, 51); white-space: normal; background-color: rgb(255, 255, 255);"> 以上实例编译运行结果如下: </p> <pre class="prettyprint prettyprinted" style="border-width: 1px 1px 1px 4px; border-style: solid; border-color: rgb(221, 221, 221); margin: 15px auto; padding: 10px 15px; font-stretch: normal; font-size: 12px; line-height: 20px; font-family: &#39;courier new&#39;; word-break: break-all; word-wrap: break-word; color: rgb(51, 51, 51); background-image: url(http://www.runoob.com/images/codecolorer_bg.gif); background-color: rgb(251, 251, 251); background-position: 50% 0%;">URL is http://www.w3cschool.cc/index.html?language=cn#j2seprotocol is http authority is www.w3cschool.cc file name is /index.htm?language=cn host is www.amrood.com path is /index.html port is -1default port is 80query is language=cnref is j2se</pre> <hr style="color: rgb(212, 212, 212); height: 1px; border: 0px; clear: both; font-family: &#39;Open Sans&#39;, &#39;Helvetica Neue&#39;, Helvetica, Arial, STHeiti, &#39;Microsoft Yahei&#39;, sans-serif; font-size: 12px; white-space: normal; background-color: rgb(212, 212, 212);"/> <h2 style="border: 0px; margin: 2px 0px; padding: 0px; font-size: 1.8em; line-height: 1.8em; color: rgb(51, 51, 51); font-family: &#39;Open Sans&#39;, &#39;Helvetica Neue&#39;, Helvetica, Arial, STHeiti, &#39;Microsoft Yahei&#39;, sans-serif; white-space: normal; background-color: rgb(255, 255, 255);"> URLConnections 类方法 </h2> <p style="border: 0px; margin-top: 0px; margin-bottom: 0px; padding: 0px; line-height: 2em; font-size: 12px; font-family: &#39;Microsoft Yahei&#39;, &#39;Helvetica Neue&#39;, Helvetica, Arial, sans-serif; color: rgb(51, 51, 51); white-space: normal; background-color: rgb(255, 255, 255);"> openConnection() 返回一个 java.net.URLConnection。 </p> <p style="border: 0px; margin-top: 0px; margin-bottom: 0px; padding: 0px; line-height: 2em; font-size: 12px; font-family: &#39;Microsoft Yahei&#39;, &#39;Helvetica Neue&#39;, Helvetica, Arial, sans-serif; color: rgb(51, 51, 51); white-space: normal; background-color: rgb(255, 255, 255);"> 例如: </p> <ul class="list list-paddingleft-2" style="list-style-type: none;"> <li> <p style="border: 0px; margin-top: 0px; margin-bottom: 0px; padding: 0px 10px; line-height: 2em; font-family: &#39;Microsoft Yahei&#39;, &#39;Helvetica Neue&#39;, Helvetica, Arial, sans-serif;"> 如果你连接HTTP协议的URL, openConnection() 方法返回 HttpURLConnection 对象。 </p> </li> <li> <p style="border: 0px; margin-top: 0px; margin-bottom: 0px; padding: 0px 10px; line-height: 2em; font-family: &#39;Microsoft Yahei&#39;, &#39;Helvetica Neue&#39;, Helvetica, Arial, sans-serif;"> 如果你连接的URL为一个 JAR 文件, openConnection() 方法将返回 JarURLConnection 对象。 </p> </li> <li> <p style="border: 0px; margin-top: 0px; margin-bottom: 0px; padding: 0px 10px; line-height: 2em; font-family: &#39;Microsoft Yahei&#39;, &#39;Helvetica Neue&#39;, Helvetica, Arial, sans-serif;"> 等等... </p> </li> </ul> <p style="border: 0px; margin-top: 0px; margin-bottom: 0px; padding: 0px; line-height: 2em; font-size: 12px; font-family: &#39;Microsoft Yahei&#39;, &#39;Helvetica Neue&#39;, Helvetica, Arial, sans-serif; color: rgb(51, 51, 51); white-space: normal; background-color: rgb(255, 255, 255);"> URLConnection 方法列表如下: </p> <table class="reference" width="729"> <tbody style="border: 0px; margin: 0px; padding: 0px;"> <tr style="border: 0px; margin: 0px; padding: 0px; background-color: rgb(246, 244, 240);" class="firstRow"> <th style="border-color: rgb(85, 85, 85); margin: 0px; padding: 3px; color: rgb(255, 255, 255); vertical-align: top; background-color: rgb(85, 85, 85);"> 序号 </th> <th style="border-color: rgb(85, 85, 85); margin: 0px; padding: 3px; color: rgb(255, 255, 255); vertical-align: top; background-color: rgb(85, 85, 85);"> 方法描述 </th> </tr> <tr style="border: 0px; margin: 0px; padding: 0px;"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 1 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>Object getContent()&nbsp;</strong><br/>检索URL链接内容 </td> </tr> <tr style="border: 0px; margin: 0px; padding: 0px; background-color: rgb(246, 244, 240);"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 2 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>Object getContent(Class[] classes)&nbsp;</strong><br/>检索URL链接内容 </td> </tr> <tr style="border: 0px; margin: 0px; padding: 0px;"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 3 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>String getContentEncoding()&nbsp;</strong><br/>返回头部 content-encoding 字段值。 </td> </tr> <tr style="border: 0px; margin: 0px; padding: 0px; background-color: rgb(246, 244, 240);"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 4 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>int getContentLength()&nbsp;</strong><br/>返回头部 content-length字段值 </td> </tr> <tr style="border: 0px; margin: 0px; padding: 0px;"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 5 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>String getContentType()&nbsp;</strong><br/>返回头部 content-type 字段值 </td> </tr> <tr style="border: 0px; margin: 0px; padding: 0px; background-color: rgb(246, 244, 240);"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 6 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>int getLastModified()&nbsp;</strong><br/>返回头部 last-modified 字段值。 </td> </tr> <tr style="border: 0px; margin: 0px; padding: 0px;"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 7 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>long getExpiration()&nbsp;</strong><br/>返回头部 expires 字段值。 </td> </tr> <tr style="border: 0px; margin: 0px; padding: 0px; background-color: rgb(246, 244, 240);"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 8 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>long getIfModifiedSince()&nbsp;</strong><br/>返回对象的 ifModifiedSince 字段值。 </td> </tr> <tr style="border: 0px; margin: 0px; padding: 0px;"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 9 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>public void setDoInput(boolean input)</strong><br/>URL 连接可用于输入和/或输出。如果打算使用 URL 连接进行输入,则将 DoInput 标志设置为 true;如果不打算使用,则设置为 false。默认值为 true。 </td> </tr> <tr style="border: 0px; margin: 0px; padding: 0px; background-color: rgb(246, 244, 240);"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 10 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>public void setDoOutput(boolean output)</strong><br/>URL 连接可用于输入和/或输出。如果打算使用 URL 连接进行输出,则将 DoOutput 标志设置为 true;如果不打算使用,则设置为 false。默认值为 false。 </td> </tr> <tr style="border: 0px; margin: 0px; padding: 0px;"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 11 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>public InputStream getInputStream() throws IOException</strong><br/>返回URL的输入流,用于读取资源 </td> </tr> <tr style="border: 0px; margin: 0px; padding: 0px; background-color: rgb(246, 244, 240);"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 12 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>public OutputStream getOutputStream() throws IOException</strong><br/>返回URL的输出流, 用于写入资源。 </td> </tr> <tr style="border: 0px; margin: 0px; padding: 0px;"> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> 13 </td> <td style="border-color: rgb(212, 212, 212); margin: 0px; padding: 7px 5px; font-size: 1em; vertical-align: top;"> <strong>public URL getURL()</strong><br/>返回 URLConnection 对象连接的URL </td> </tr> </tbody> </table> <h3 style="border: 0px; margin: 8px 0px; padding: 0px; font-size: 1.4em; color: rgb(51, 51, 51); font-family: &#39;Open Sans&#39;, &#39;Helvetica Neue&#39;, Helvetica, Arial, STHeiti, &#39;Microsoft Yahei&#39;, sans-serif; white-space: normal; background-color: rgb(255, 255, 255);"> 实例 </h3> <p style="border: 0px; margin-top: 0px; margin-bottom: 0px; padding: 0px; line-height: 2em; font-size: 12px; font-family: &#39;Microsoft Yahei&#39;, &#39;Helvetica Neue&#39;, Helvetica, Arial, sans-serif; color: rgb(51, 51, 51); white-space: normal; background-color: rgb(255, 255, 255);"> 以下实例中URL采用了HTTP 协议。 openConnection 返回HttpURLConnection对象。 </p> <pre class="prettyprint prettyprinted" style="border-width: 1px 1px 1px 4px; border-style: solid; border-color: rgb(221, 221, 221); margin: 15px auto; padding: 10px 15px; font-stretch: normal; font-size: 12px; line-height: 20px; font-family: &#39;courier new&#39;; word-break: break-all; word-wrap: break-word; color: rgb(51, 51, 51); background-image: url(http://www.runoob.com/images/codecolorer_bg.gif); background-color: rgb(251, 251, 251); background-position: 50% 0%;">// 文件名 : URLConnDemo.javaimport java.net.*;import java.io.*;public class URLConnDemo{ public static void main(String [] args) { try { URL url = new URL(&quot;http://www.w3cschool.cc&quot;); URLConnection urlConnection = url.openConnection(); HttpURLConnection connection = null; if(urlConnection instanceof HttpURLConnection) { connection = (HttpURLConnection) urlConnection; } else { System.out.println(&quot;Please enter an HTTP URL.&quot;); return; } BufferedReader in = new BufferedReader( new InputStreamReader(connection.getInputStream())); String urlString = &quot;&quot;; String current; while((current = in.readLine()) != null) { urlString += current; } System.out.println(urlString); }catch(IOException e) { e.printStackTrace(); } }}</pre> <p style> 以上实例编译运行结果如下: </p> <pre class="prettyprint prettyprinted" style="border-width: 1px 1px 1px 4px; border-style: solid; border-color: rgb(221, 221, 221); margin: 15px auto; padding: 10px 15px; font-stretch: normal; font-size: 12px; line-height: 20px; font-family: &#39;courier new&#39;; word-break: break-all; word-wrap: break-word; color: rgb(51, 51, 51); background-image: url(http://www.runoob.com/images/codecolorer_bg.gif); background-color: rgb(251, 251, 251); background-position: 50% 0%;">$ java URLConnDemo.....a complete HTML content of home page of amrood.com.....</pre> <p> <br/> </p>