从 Java 中的文本文件中读取行并拆分内容

Question

我有一个输入文件如下：

conf/iastedCSN/KangHPLNL06 Quoc V. Phung    
conf/iastedCSN/KangHPLNL06 Kungmeng Lo  
conf/iastedCSN/KangHPLNL06 Hoang Nam Nguyen 
conf/iastedCSN/KangHPLNL06 M. M. Lee    
series/sci/ZighedAB13 Djamel Abdelkader Zighed  
series/sci/ZighedAB13 Rafik Abdesselam  
series/sci/ZighedAB13 Ahmed Bounekkar   
series/sci/LermanG13 Isra챘l-C챕sar Lerman

我想用分隔符输出如下：

conf/iastedCSN/KangHPLNL06 | QuocV.Phung    
conf/iastedCSN/KangHPLNL06 | KungmengLo 
conf/iastedCSN/KangHPLNL06 | HoangNamNguyen 
conf/iastedCSN/KangHPLNL06 | M.M.Lee    
series/sci/ZighedAB13 | DjamelAbdelkaderZighed  
series/sci/ZighedAB13 | RafikAbdesselam 
series/sci/ZighedAB13 | AhmedBounekkar  
series/sci/LermanG13 | Isra챘l-C챕sarLerman

但是现在，我的结果中有很多行重复，我似乎无法找出原因。 我得到的输出如下：

conf/iastedCSN/KangHPLNL06 | QuocV.Phung    
conf/iastedCSN/KangHPLNL06 | KungmengLo 
conf/iastedCSN/KangHPLNL06 | HoangNamNguyen 
conf/iastedCSN/KangHPLNL06 | M.M.Lee    
conf/iastedCSN/KangHPLNL06 | M.M.Lee    
series/sci/ZighedAB13 | DjamelAbdelkaderZighed  
conf/iastedCSN/KangHPLNL06 | M.M.Lee    
series/sci/ZighedAB13 | RafikAbdesselam 
conf/iastedCSN/KangHPLNL06 | M.M.Lee    
series/sci/ZighedAB13 | AhmedBounekkar  
conf/iastedCSN/KangHPLNL06 | M.M.Lee    
series/sci/LermanG13 | Isra챘l-C챕sarLerman   
series/sci/ZighedAB13 | AhmedBounekkar  

以下是源代码：

package authorgraph;
import java.io.*;
import java.util.*;

public class graph {
    private static BufferedReader br;

    public static void main(String[] args)
    {
        try{
        br = new BufferedReader (new FileReader ("inproceedings-author-test1.txt"));
        Map<String, String>  items = new TreeMap<String, String>();
        String line;

        while (null != (line = br.readLine()))
        {
            String[] line_parts = line.split(" ");
            if (line_parts.length > 1)
            {
                StringBuilder name = new StringBuilder(line_parts[1]);
                for (int i = 2; i < line_parts.length; i++)
                {
                    name.append(line_parts[i]);
                }
                items.put(new String(line_parts[0]), name.toString());
            }
            for (String conf: items.keySet())
            {
                System.out.println(conf + " | " + items.get(conf));
            }
        }
        }
        catch (IOException e) {
            e.printStackTrace();
        }
    }
};

任何帮助将不胜感激

Answer 1

items.put(new String(line_parts[0]), name.toString()); 中的new String 没用。字符串是不可变的，如果你已经有一个字符串，就不需要创建一个新的。

你得到了重复，因为for 没有放在正确的位置：你每次读取一行时都在执行它。

        for (String conf: items.keySet())
        {
            System.out.println(conf + " | " + items.get(conf));
        }
      } // end of while

改为：将for 移到while 循环之外。

      } // end of while
        for (String conf: items.keySet())
        {
            System.out.println(conf + " | " + items.get(conf));
        }

不要在keySet()上循环，而是这样做：

        for (Map.Entry<String, String> entry : items.entrySet()) {
            System.out.println(entry.getKey() + " | " + entry.getValue());
        }

Map<K,V>.entrySet() 将返回一个Map.Entry<K,V>。条目是键与其值之间的关联。