如何过滤文本文件并将结果保存到新文件 java

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。我的文件是这样的数据：

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从原始文件到新创建的文件要写入的内容：例如从 8935901990807474490 到 8935901990807474532，对于这个数字，开始行和最后一行都在这个范围内。

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

对您的代码进行以下更改：

使用扫描仪接受要过滤的值：

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();     
}

因为你只希望第2列写的列拆分它使用 ; 然后仅将第一个索引添加到列表中。这确保只有第二列的数字被添加到列表中。

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，只写落在的数字在此范围内。

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();
            }           
        }       
    }   
}

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