Java访问指定URL并获取网页源代码

1．编写useSourceViewer 类的基本框架，该类仅包括无返回值的main ()方法，该方法从参数中获取URL，通过输入缓冲和输出缓冲将该URL 原码输出。

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2．编写useSourceViewer 类，代码如下：

import java.net.*;

import java.io.*;

public class useSourceViewer

{

public static void main (String[] args)

{

if (args.length 0)

{

try

{

//读入URL

URL u = new URL(args[0]);

InputStream in = u.openStream( );

// 为增加性能存储输入流

in = new BufferedInputStream(in);

// 将输入流连接到阅读器

Reader r = new InputStreamReader(in);

int c;

while ((c = r.read( )) != -1)

{

System.out.print((char) c);

}

Object o = u.getContent( );

System.out.println("I got a " + o.getClass().getName( ));

}

catch (MalformedURLException e)

{

System.err.println(args[0] + " is not a parseable URL");

}

catch (IOException e)

{

System.err.println(e);

}

} // end if

} // end main

} // end SourceViewer}

java中如何根据一个网址获得该网页的源代码，急求

import java.io.BufferedReader;

import java.io.InputStreamReader;

import java.net.HttpURLConnection;

import java.net.URL;

public class HttpTest {

String urlString;

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

HttpTest client = new HttpTest(网址);

client.run();

}

public HttpTest(String urlString) {

this.urlString = urlString;

}

public void run() throws Exception {

//生成一个URL对象

URL url = new URL(urlString);

//打开URL

HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();

//得到输入流，即获得了网页的内容

BufferedReader reader = new BufferedReader(new InputStreamReader(urlConnection

.getInputStream()));

String line;

// 读取输入流的数据，并显示

while ((line = reader.readLine()) != null){

System.out.println(line);

}

}

}

java中如何根据一个网址获得该网页的源代码？

package test;

import java.io.BufferedReader;

import java.io.InputStreamReader;

import java.net.HttpURLConnection;

import java.net.URL;

public class HttpTest {

private String u;

private String encoding;

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

HttpTest client = new HttpTest("", "UTF-8");

client.run();

}

public HttpTest(String u, String encoding) {

this.u = u;

this.encoding = encoding;

}

public void run() throws Exception {

URL url = new URL(u);// 根据链接（字符串格式），生成一个URL对象

HttpURLConnection urlConnection = (HttpURLConnection) url

.openConnection();// 打开URL

BufferedReader reader = new BufferedReader(new InputStreamReader(

urlConnection.getInputStream(), encoding));// 得到输入流，即获得了网页的内容

String line; // 读取输入流的数据，并显示

while ((line = reader.readLine()) != null) {

System.out.println(line);

}

}

}

根据具体问题类型，进行步骤拆解／原因原理分析／内容拓展等。

具体步骤如下：／导致这种情况的原因主要是……

求一个Java实现自动下载的源代码

您好，这样的：

/**

*

*/

package com.b510.base.bean.install;

import java.io.File;

import java.io.FileWriter;

import java.text.SimpleDateFormat;

import java.util.Date;

/**

* @author hongten(hongtenzone@foxmail.com)

* @date 2013-2-24

*/

@SuppressWarnings("unchecked")

public class BeanUtils {

//公共部分

private static final String RT_1 = "\r\n";

private static final String RT_2 = RT_1+RT_1;

private static final String BLANK_1 =" ";

private static final String BLANK_4 =" ";

private static final String BLANK_8 =BLANK_4 + BLANK_4;

//注释部分

private static final String ANNOTATION_AUTHOR_PARAMTER = "@author ";

private static final String ANNOTATION_AUTHOR_NAME = "hongten(hongtenzone@foxmail.com)";

private static final String ANNOTATION_AUTHOR = ANNOTATION_AUTHOR_PARAMTER + ANNOTATION_AUTHOR_NAME;

private static final String ANNOTATION_DATE = "@date ";

private static final String ANNOTATION = "/**"+RT_1+BLANK_1+"*"+BLANK_1+ANNOTATION_AUTHOR +RT_1+BLANK_1+"*"+BLANK_1+ANNOTATION_DATE +getDate()+RT_1+BLANK_1+"*/"+RT_1;

//文件 地址

//private static final String BEAN_PATH = "com/b510/base/bean";

private static final String DAO_PATH = "com/b510/base/dao";

private static final String DAO_IMPL_PATH = "com/b510/base/dao/impl";

private static final String SERVICE_PATH = "com/b510/base/service";

private static final String SERVICE_IMPL_PATH = "com/b510/base/service/impl";

//包名

private static final String BEAN_URL = "com.b510.base.bean";

private static final String DAO_URL = "com.b510.base.dao";

private static final String DAO_IMPL_URL = "com.b510.base.dao.impl";

private static final String SERVICE_URL = "com.b510.base.service";

private static final String SERVICE_IMPL_URL = "com.b510.base.service.impl";

//基本类名称

private static final String BASE_DAO_NAME = DAO_URL + ".BaseDao";

private static final String ABSTRACT_BASE_DAO_IMPL_NAME = DAO_IMPL_URL + ".AbstractBaseDaoImpl";

private static final String BASE_SERVICE_NAME = SERVICE_URL + ".BaseService";

private static final String ABSTRACT_BASE_SERVICE_IMPL_NAME = SERVICE_IMPL_URL + ".AbstractBaseServiceImpl";

/**

* 创建bean的Daobr

*

* @param c

* @throws Exception

*/

public void createBeanDao(Class c) throws Exception {

String cName = c.getName();

String fileName = System.getProperty("user.dir") + "/src/" + DAO_PATH

+ "/" + getLastChar(cName) + "Dao.java";

File f = new File(fileName);

FileWriter fw = new FileWriter(f);

fw.write("package "+DAO_URL+";"+RT_2+ANNOTATION+"public interface " +

getLastChar(cName) + "Dao extends "+BASE_DAO_NAME+" " + cName + " {"+RT_2+"}");

fw.flush();

fw.close();

showInfo(fileName);

}

/**

* 创建bean的Dao的实现类

* @param c

* @throws Exception

*/

public void createBeanDaoImpl(Class c) throws Exception{

String cName = c.getName();

String fileName = System.getProperty("user.dir") + "/src/" + DAO_IMPL_PATH

+ "/" + getLastChar(cName) + "DaoImpl.java";

File f = new File(fileName);

FileWriter fw = new FileWriter(f);

fw.write("package "+DAO_IMPL_URL+";"+RT_2+ANNOTATION+"public class " +

getLastChar(cName) + "DaoImpl extends "+ABSTRACT_BASE_DAO_IMPL_NAME+"" +

cName + " implements "+DAO_URL+"."+getLastChar(cName)+"Dao{"+RT_2+"}");

fw.flush();

fw.close();

showInfo(fileName);

}

/**

* 创建bean的service

* @param c

* @throws Exception

*/

public void createBeanService(Class c) throws Exception{

String cName = c.getName();

String fileName = System.getProperty("user.dir") + "/src/" + SERVICE_PATH

+ "/" + getLastChar(cName) + "Service.java";

File f = new File(fileName);

FileWriter fw = new FileWriter(f);

fw.write("package "+SERVICE_URL+";"+RT_2+ANNOTATION+"public interface " +

getLastChar(cName) + "Service extends "+BASE_SERVICE_NAME+""+ cName +"{"+RT_2+"}");

fw.flush();

fw.close();

showInfo(fileName);

}

/**

* 创建bean的service的实现类

* @param c

* @throws Exception

*/

public void createBeanServiceImpl(Class c) throws Exception{

String cName = c.getName();

String fileName = System.getProperty("user.dir") + "/src/" + SERVICE_IMPL_PATH

+ "/" +getLastChar(cName)+"ServiceImpl.java";

File f = new File(fileName);

FileWriter fw = new FileWriter(f);

fw.write("package "+SERVICE_IMPL_URL+";"+RT_2+ANNOTATION+"public class "

+ getLastChar(cName) + "ServiceImpl extends "+ABSTRACT_BASE_SERVICE_IMPL_NAME+""+ cName

+ " implements "+SERVICE_URL+"."+getLastChar(cName)+"Service{"+RT_2+BLANK_4

+"private "+DAO_URL+"."+getLastChar(cName)+"Dao "+getLowercaseChar(getLastChar(cName))

+"Dao;"+RT_2+BLANK_4+"public void set"+getLastChar(cName)+"Dao("+DAO_URL+"."+getLastChar(cName)+"Dao "

+getLowercaseChar(getLastChar(cName))+"Dao){"+RT_1+BLANK_8+"this."+getLowercaseChar(getLastChar(cName))+"Dao = "

+getLowercaseChar(getLastChar(cName))+"Dao;"+RT_1+BLANK_4+"}"+RT_2+BLANK_4+"@Override"+RT_1+BLANK_4

+"public "+DAO_URL+"."+"BaseDao"+BEAN_URL+"."+getLastChar(cName)+" getBaseDao(){"+RT_1+BLANK_8

+"return "+getLowercaseChar(getLastChar(cName))+"Dao;"+RT_1+BLANK_4+"}"+RT_2+"}");

fw.flush();

fw.close();

showInfo(fileName);

}

/**

* 获取路径的最后面字符串br

* 如：br

* codestr = "com.b510.base.bean.User"/codebr

* code return "User";code

* @param str

* @return

*/

public String getLastChar(String str) {

if ((str != null) (str.length() 0)) {

int dot = str.lastIndexOf('.');

if ((dot -1) (dot (str.length() - 1))) {

return str.substring(dot + 1);

}

}

return str;

}

/**

* 把第一个字母变为小写br

* 如：br

* codestr = "UserDao";/codebr

* codereturn "userDao";/code

* @param str

* @return

*/

public String getLowercaseChar(String str){

return str.substring(0,1).toLowerCase()+str.substring(1);

}

/**

* 显示信息

* @param info

*/

public void showInfo(String info){

System.out.println("创建文件："+ info+ "成功！");

}

/**

* 获取系统时间

* @return

*/

public static String getDate(){

SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd");

return simpleDateFormat.format(new Date());

}

}

java 获取网页源代码---有效防止乱码

前段时间做过这类功能，如何有效防止乱码，我们必须先知道一个网页的编码方式，是utf-8,还是gbk。

1.HttpURLConnection.getContentType();直接读取，效率高，但有很多时候读不到。只是text/html就完事了，没有charset.

2.使用第三方的HttpClient,执行效率较高。但读取网页头header也只适用部分站，很多网站服务段不设置，结果就读成了null.

3.最没有效率的判断方法就是使用inputStreamReader先把正页的html源码读取出来，之后截取charset后面编码。得到编码之后重新再读取一遍。但是效率很低。

做个总结：

/**

* 取得页面编码

*

* @param url

* @return

*/

public String getCharset(String url) throws Exception {

// log.info("进入读页面的关键词:" + keyword);

String charset = "";

int c;

HttpURLConnection httpurlcon = null;

// log.info("url:"+url);

// log.info("charset:"+charset);

log.info("url:" + url);

URL httpurl = new URL(url);

// System.out.println(url+str);

httpurlcon = (HttpURLConnection) httpurl.openConnection();

// google需要身份

httpurlcon.setRequestProperty("User-agent", "Mozilla/4.0");

charset = httpurlcon.getContentType();

log.info("charset1:" + charset);

// 如果可以找到

if (charset.indexOf("charset=") != -1)

charset = charset.substring(charset.indexOf("charset=")

+ "charset=".length(), charset.length());

// 否则读取response.Header头

else {

charset = this.getContentCharset();

log.info("charset2:" + charset);

}

// 如果charset还是为空,那么直接读网页来截取

if (charset == null) {

charset = this.readPageCharset(url);

log.info("charset31:" + charset);

}

return charset;

}

如何用java中HTMLPraser提取网页源代码中的某些链接

使用正则表达式去匹配就行了。

第一步：下载你需要分析的网页的源码

第二步：在程序中使用正则表达式去匹配源码，保存匹配成功的链接地址就行。

可以在网上搜一下匹配网址的正则表达式

新闻名称：java下载网页源代码,java获取网页源代码
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