问题内容所示：求解~~~

[xxxlopyou]

如下，有这样的一堆连接，按照每一行一个连接存储在txt文档中。

http://123.com/uiudoa=jf123&dfd=123456
http://123.com/doa=jf123&dfd=123456
http://baolaoda.com/jiioa123fd=123456
http://123.com/jiioa123fd=123456
http://123.com/jiioa123fd=123456
http://46.com/jiidoa=jf56
http://xxrbz.com/jiioa123fd=123456
http://liumangtu.com/jiioa123fd=123456
http://123.com/jiioa123fd=123456

首先，这些链接按照每行一个链接存储在txt文本文档中。
然后，导入txt文件，对这些链接中做如下处理：
将只要出现了相同的域名，那么就只保留其中的任意一条，其他的全部删除。
最后，将处理后的结果保存。（也就是更新文本内容后保存）

PS:我是菜鸟级别，求各位大哥大姐详细点拨~~~Thanks very much!!

[qybao]

for example

BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream("test.txt")));
PrintStream ps = new PrintStream(new FileOutputStream("test_new.txt"));
String buf;
Set<String> domain = new HashSet<String>();
while ((buf=br.readLine()) != null) {
    if (buf.matches("(?i)http[s]?[:]//(www[.])?(.*?)/.*")) {
        String key = buf.replaceAll("(?i)http[s]?[:]//(www[.])?(.*?)/.*", "$2");
        if (domain.contains(key)) {
            continue;
        }
        domain.add(key);
        ps.println(buf);
    }
}
ps.close();
br.close();

[柯本]

完整的EX,利用HashMap,去掉重复的域名:

import java.io.*;
import java.util.regex.*;
import java.util.*;
public class filetest1 {

	/**
	 * @param args
	 * @throws IOException 
	 */
	public static void main(String[] args) throws IOException {
		// TODO Auto-generated method stub
		BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream("d:\\temp\\t.txt")));
		String data = null;
		String domain=null;
		HashMap map=new HashMap();  
		while((data = br.readLine())!=null)
		{
			Pattern pattern = Pattern.compile("(http://)(.*\\w+\\.\\w+)/.*");
			Matcher matcher = pattern.matcher(data);
			if (matcher.find()) {
		    domain=matcher.group(2).toString();
		    map.put(domain,data);
			}
		}
		br.close();
	    FileWriter fw = new FileWriter("d:\\temp\\t1.txt");  

		Iterator iter = map.entrySet().iterator(); 
		while (iter.hasNext()) { 
		    Map.Entry entry = (Map.Entry) iter.next(); 
		    Object val = entry.getValue();
		    data=val.toString()+"\n";
			fw.write(data,0,data.length());  
		} 
       fw.close();

	}

}

[niuniu20008]

香香结贴吧，我写的这个，代码量很多啊

package xiang;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.nio.charset.Charset;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

public class Demo {

	public Map readFromTxt(String fileName) {
		File file = new File(fileName);

		// (一):建立【读】的管子
		FileInputStream input = null;
		InputStreamReader insr = null;
		BufferedReader read = null;

		Map map = new HashMap();// 存储域名和链接的map
		String line = "";
		try {
			input = new FileInputStream(file);// 读
			insr = new InputStreamReader(input, Charset.forName("UTF-8"));// 按照UTF-8字符集的方式读，也可以不写Charset.forName("UTF-8");
			read = new BufferedReader(insr);

			// (二)：读取一行，也就是一行一行的读
			line = read.readLine();
			while (line != null) { // 如果line==null证明已经读完了，如果line!=null证明没有读完
				// (二)：读取一行，也就是一行一行的读
				String realmName = getRealmName(line);
				if (map.size() == 0) {
					map.put(realmName, line);
				} else {
					// 遍历map，看map中是否已经存在这个域名。
					Set set = map.keySet();
					Iterator it = set.iterator();

					String key = "";// 用来存域名
					String value = "";// 用来存链接字符串
					while (it.hasNext()) {
						String n = (String) it.next();
						if (n.equals(realmName)) {
							break;// 如果已经存在，就跳出循环
						} else {
							// 如果不存在，就把域名和这一行字符串赋值给key,value
							key = realmName;
							value = line;
						}
					}
					if (!"".equals(key) && !"".equals(value)) {
						map.put(key, value);
						key = "";
						value = "";
					}
				}
				line = read.readLine();// 继续读
			}
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			try {
				// (三)：关闭流
				if (input != null) {
					input.close();
				}
				if (insr != null) {
					insr.close();
				}
				if (read != null) {
					read.close();
				}
			} catch (IOException e) {
				e.printStackTrace();
			}
		}

		return map;
	}

	/**
	 * 截取字符串中的域名 详细解析看RealmNameDemo
	 * */
	public String getRealmName(String line) {

		int begin = -1;
		int end = -1;
		int times = 1;
		for (int i = 0; i < line.length(); i++) {
			char c = line.charAt(i);
			if ('/' == c && times == 2) {
				begin = i;
				times++;
			} else if ('/' == c && times == 3) {
				end = i;
				break;
			} else if ('/' == c) {
				times++;
			}
		}
		String realmName = line.substring(begin + 1, end);
		return realmName;
	}

	/**
	 * 往新的txt文件中写
	 * */
	public void writeToTxt(String fileName, Map map) {
		File file = new File(fileName);
		if (file.exists()) {// 如果这个文件不存在，就新建一个
			file.mkdirs();
		}
		// (一):建立【写】的管子
		FileOutputStream output = null;
		OutputStreamWriter outsw = null;
		BufferedWriter buffWriter = null;
		PrintWriter write = null;

		try {
			output = new FileOutputStream(file);
			outsw = new OutputStreamWriter(output);
			buffWriter = new BufferedWriter(outsw);
			write = new PrintWriter(buffWriter,true);

			Set set = map.keySet();
			Iterator it = set.iterator();
			while (it.hasNext()) {
				String key = (String) it.next();
				String line = (String) map.get(key);
				write.println(line);// 写入
			}
			write.flush();// 刷新下管道
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} finally {
			try {
				if (write != null) {
					write.close();
				}
				if (buffWriter != null) {
					buffWriter.close();
				}
				if (outsw != null) {
					outsw.close();
				}
				if (output != null) {
					output.close();
				}
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}

	public static void main(String[] args) {
		String readFileName = "F:\\MyWorkSpaces\\exerworkspace\\Struts2Web\\src\\xiang\\old.txt";
		Demo demo = new Demo();
		Map map = demo.readFromTxt(readFileName);

		String writeFileName = "F:\\MyWorkSpaces\\exerworkspace\\Struts2Web\\src\\xiang\\new.txt";
		demo.writeToTxt(writeFileName, map);
	}
}