Question

你好，我的问题是如何按列过滤文本文件，我的意思是我想从行之间的范围内剪切文件。我的文件包含此类数据：

284015160747447; 8935901990807474474;
  284015160747448; 8935901990807474482;
  284015160747449; 8935901990807474490;
  284015160747450; 8935901990807474508;
  284015160747451; 8935901990807474516;
  284015160747452; 8935901990807474524;
  284015160747453; 8935901990807474532;
  284015160747454; 8935901990807474540;
  284015160747455; 8935901990807474557;
  284015160747456; 8935901990807474565;
  284015160747457; 8935901990807474573;
  284015160747458; 8935901990807474581;
  284015160747459; 8935901990807474599;
  284015160747460; 8935901990807474607;
  284015160747461; 8935901990807474615;
  284015160747462; 8935901990807474623;
  284015160747463; 8935901990807474631;

我希望用户能够过滤要从原始文件写入新创建的内容：例如，从8935901990807474490到8935901990807474532，对于此数字，开始行和最后一行都在此范围内。

public class Test_read_file {
    public static List<String> readFile() throws IOException {
        try (BufferedReader br = new BufferedReader(new FileReader("C:\\\\\\\\Users\\\\\\\\Admin\\\\\\\\Desktop\\\\\\\\Work Files\\\\\\\\314-WO0000001133814\\\\\\\\Cards\\\\\\\\MBD10760_182.out"))) {
            List<String> listOfData = new ArrayList<>();
            String d;
            while ((d = br.readLine()) != null) {
                listOfData.add(d);
            }
            return listOfData;
        }
    }

    public static void writeFile(List<String> listOfData) throws IOException {
        try (BufferedWriter bw = new BufferedWriter(new FileWriter("C:\\\\\\\\Users\\\\\\\\Admin\\\\\\\\Desktop\\\\\\\\Work Files\\\\\\\\314-WO0000001133814\\\\\\\\Cards\\\\\\\\MBD10760_187.out"))) {
            for (String str : listOfData) {
                bw.write(str);
                bw.newLine();
            }
        }
    }

    public static void main(String[] args) throws IOException {
        List<String> data = readFile();
        writeFile(data);
    }
}

Answer 1

对代码进行以下更改：

使用扫描仪接受将要过滤的值：

public static void main(String[] args) throws IOException {
    List<String> data = readFile();         
    Scanner sc = new Scanner(System.in);        
    System.out.println("Enter range");      
    long num1 = sc.nextLong();      
    long num2 = sc.nextLong();      
    writeFile(data, num1, num2);
    sc.close();     
}

由于只希望第二列写入列，因此将其拆分使用;，然后仅将第一个索引添加到列表中。这样可以确保仅将第二列的数字添加到列表中。

public static List<String> readFile() throws IOException {      
    try (BufferedReader br = new BufferedReader(new FileReader(PATH))) {
        List<String> listOfData = new ArrayList<>();            
        String d;
        while ((d = br.readLine()) != null) {
            String[] split = d.split(";");  // <-- change made here
            listOfData.add(split[1]);           
        }           
        return listOfData;      
     }  
}

使用传入的范围，它将仅写入掉落的数字在这个范围内。

public static void writeFile(List<String> listOfData, long num1, long num2) 
   throws IOException {
   try (BufferedWriter bw = new BufferedWriter(new FileWriter(OUT))) {          
        for (String str : listOfData) {
            // change made here
            if (Long.valueOf(str) >= num1 && Long.valueOf(str) <= num2) {
                bw.write(str);
                bw.newLine();
            }           
        }       
    }   
}

如何通过Java

1 个答案: