從txt文件中刪除空行

Question

我設法讓這段代碼正常工作。它用大約10000個字讀取test.txt（每個字在它自己的行中），並將它們按字母順序排列，第二個按字節排列。然而，當我打開sort.txt之後，我首先得到了很多空行，然後這些單詞格式正確。我的問題是如何刪除thos空行，因爲他們不能在那裏。 .trim會工作嗎？

package test; 

import java.io.BufferedReader; 
import java.io.FileReader; 
import java.io.FileWriter; 
import java.io.PrintWriter; 
import java.util.ArrayList; 
import java.util.Collections; 
import java.util.Comparator; 
import java.util.List; 

public class sort { 
public static class MyComparator implements Comparator<String>{ 
    @Override 
    public int compare(String o1, String o2) { 
     if (o1.length() > o2.length()) { 
     return 1; 
     } else if (o1.length() < o2.length()) { 
     return -1; 
     } 
     return o1.compareTo(o2); 
    } 
} 
public static void main(String[] args) throws Exception { 

    String inputFile = "test.txt"; 
    String outputFile = "sort.txt"; 

    FileReader fileReader = new FileReader(inputFile); 
    BufferedReader bufferedReader = new BufferedReader(fileReader); 
    String inputLine; 
    List<String> lineList = new ArrayList<String>(); 
    while ((inputLine = bufferedReader.readLine()) != null) { 
     lineList.add(inputLine); 
    } 
    fileReader.close(); 

    Collections.sort(lineList,String.CASE_INSENSITIVE_ORDER); 

    FileWriter fileWriter = new FileWriter(outputFile); 
    PrintWriter out = new PrintWriter(fileWriter); 
    for (String outputLine : lineList) { 
     out.println(outputLine); 
    } 

    Collections.sort(lineList, new MyComparator()); 

    FileWriter Fw = new FileWriter(outputFile); 
    PrintWriter pw = new PrintWriter(fileWriter); 
    for (String outputLine : lineList) { 
     out.println(outputLine); 
    }  
    out.flush(); 
    out.close(); 
    fileWriter.close(); 

} 
} 

Answer 1

只是不添加這些空行：

while ((inputLine = bufferedReader.readLine()) != null) { 
    if (!inputLine.isEmpty()) { 
     lineList.add(inputLine); 
    } 
} 

Answer 2

所有你需要的是

for (String outputLine : lineList) { 
    if (!"".equals(outputLine.trim())) 
     out.println(outputLine); 
    //... 

不能使用.trim()依靠自己的力量解決問題，因爲它只是黑客關閉在開頭和結尾處有空格。它會保留一個空的String不變。我在這裏用它來確保你也省略不爲空，但確實有在短短的空白行。

Answer 3

你可以處理它時，你實際上是添加字符串列表，這將是很好的方法類似

while (!StringUtils.isEmpty(inputLine = bufferedReader.readLine())) { 

Answer 4

管理使其工作。這是解決方案。感謝您的回覆。

package test; 

import java.io.BufferedReader; 
import java.io.FileReader; 
import java.io.FileWriter; 
import java.io.PrintWriter; 
import java.util.ArrayList; 
import java.util.Collections; 
import java.util.Comparator; 
import java.util.List; 

public class sort { 
public static class MyComparator implements Comparator<String>{ 
    @Override 
    public int compare(String o1, String o2) { 
     if (o1.trim().length() > o2.trim().length()) { 
     return 1; 
     } else if (o1.trim().length() < o2.trim().length()) { 
     return -1; 
     } 
     return o1.compareTo(o2); 
    } 
} 
public static void main(String[] args) throws Exception { 

    String inputFile = "test.txt"; 
    String outputFile = "sort.txt"; 

    FileReader fileReader = new FileReader(inputFile); 
    BufferedReader bufferedReader = new BufferedReader(fileReader); 
    String inputLine; 
    List<String> lineList = new ArrayList<String>(); 
    while ((inputLine = bufferedReader.readLine()) != null) { 
     lineList.add(inputLine); 
    } 

    Collections.sort(lineList,String.CASE_INSENSITIVE_ORDER); 
    Collections.sort(lineList, new MyComparator()); 

    FileWriter fileWriter = new FileWriter(outputFile); 
    PrintWriter out = new PrintWriter(fileWriter); 
    FileWriter Fw = new FileWriter(outputFile); 
    PrintWriter pw = new PrintWriter(Fw); 
    for (String outputLine : lineList) { 
     if (!"".equals(outputLine.trim())) 
      out.println(outputLine);  }  
    out.flush(); 
    out.close(); 
    fileWriter.close(); 

} 
}