Java将url读取为字符串并读取所选字符串 [英] Java read url as string and read selected strings

问题描述

读取网址并选择列表项标签和标题的代码

Code that reads url and selects list items tag and title

import java.io.File;
import org.apache.commons.io.FileUtils;
import org.apache.commons.lang.StringUtils;

public class StringUtilitiesFromFile  {

	public static void main(String[] args) throws Exception {		
                 
                String url = "http://www.google.com";             

		String title = StringUtils.substringBetween(url, "<title>", "</title>");
		System.out.println("title:" + title); // good

		String[] tds = StringUtils.substringsBetween(url, "<li>", "</li>");
		for (String td : tds) {
			System.out.println(td); // good
		}		
	}
}

输出为

title：null

线程中的异常mainjava.lang.NullPointerException

at Strings.StringUtilitiesFromFile.main（StringUtilitiesFromFile.java:17）

.... \ ApplicationData \ NetBeans \Cache \8.2 \executor-snippets\run.xml：53：Java返回：1

BUILD FAILED（总时间） ：2秒）



我尝试了什么：



更改了网址



缓冲读取器并读取文件

The output is
title:null
Exception in thread "main" java.lang.NullPointerException
at Strings.StringUtilitiesFromFile.main(StringUtilitiesFromFile.java:17)
....\Application Data\NetBeans\Cache\8.2\executor-snippets\run.xml:53: Java returned: 1
BUILD FAILED (total time: 2 seconds)

What I have tried:

changed url

buffered reader and read as file

推荐答案

引用：

读取网址并选择列表项标签和标题的代码

Code that reads url and selects list items tag and title

否，此代码不读取网址。

No, this code do not read url.

// here you set an arbitrary string named url
String url = "http://www.google.com";
// here you try to find given substrings in string named url
// , not in the page aimed by url
String title = StringUtils.substringBetween(url, "<title>", "</title>");

您没有尝试阅读网址所针对的页面。

You didn't try to read the page aimed by url.

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