Question

我有4个文本文件a.txt，b.txt，c.txt和c.txt 我有一个从a.txt获取行的编码，如果条件如下，那么我还有另一个条件可以从b，c或d（它跟随条件）进一步获取

import java.io.*; 
public class Scholarship { 
public static void main(String[] args) {

    try{

        FileInputStream fstream1 = new  FileInputStream("a.txt"); 
        FileInputStream fstream2 = new  FileInputStream("b.txt"); 
        FileInputStream fstream3 = new  FileInputStream("c.txt"); 
        FileInputStream fstream4 = new  FileInputStream("d.txt");       
             DataInputStream in1 = new DataInputStream(fstream1);
             DataInputStream in2 = new DataInputStream(fstream2);
             DataInputStream in3 = new DataInputStream(fstream3);
             DataInputStream in4 = new DataInputStream(fstream4);
              BufferedReader br1 = new BufferedReader(new InputStreamReader(in1));
              BufferedReader br2 = new BufferedReader(new InputStreamReader(in2));
              BufferedReader br3 = new BufferedReader(new InputStreamReader(in3));
              BufferedReader br4 = new BufferedReader(new InputStreamReader(in4));

        String strLine1=null;
        String strLine2=null;
        String strLine3=null;
        String strLine4=null;

        while((strLine1 = br1.readLine()) != null){

           String[] column1 = strLine1.split("\\|");

           if(Integer.parseInt(column1[1])<5000) {   

                while((strLine2 = br2.readLine())!=null){
                   String[] column2 = strLine2.split("\\|");
                   if(  (column1[0].equals(column2[0]))&&(column2[2].equals("mumbai"))&&( (column2[3].equals("C"))||(column2[3].equals("D")) ) ){   
                     System.out.println(strLine2);

                   }//if ends                   
                }//while ends 

                while((strLine3 = br3.readLine())!=null){
                   String[] column3 = strLine3.split("\\|");
                   if(  (column1[0].equals(column3[0]))&&(column3[2].equals("mumbai"))&&( (column3[3].equals("C"))||(column3[3].equals("D")) ) ){   
                     System.out.println(strLine3);

                   }//if ends                   
                }//while ends 

                while((strLine4 = br4.readLine())!=null){
                   String[] column4 = strLine4.split("\\|");
                   if(  (column1[0].equals(column4[0]))&&(column4[2].equals("mumbai"))&&( (column4[3].equals("C"))||(column4[3].equals("D")) ) ){   
                     System.out.println(strLine4);

                   }//if ends                   
                }//while ends   


             }//if ends          
         }//while ends       

        in1.close();
        in2.close();
        in3.close();
        in4.close();
    }catch (Exception e){//Catch exception if any
        System.err.println("Error: " + e.getMessage());
    }
}
}

外部循环用于b，c和d的a.txt和内部3循环。代码仅在a.txt中满足第一个条件时打印。它不会检查a.txt中的线路。我用Scanner方法尝试过，但同样存在问题。

Answer 1

除非您有意阅读原始Java数据类型（参见http://docs.oracle.com/javase/7/docs/api/java/io/DataInputStream.html），否则不应使用DataInputStream。

您可以像这样实例化BufferedReader阅读器：

BufferedReader br1 = Files.newBufferedReader(Paths.get("a.txt"), StandardCharsets.UTF_8);

或传统上喜欢这样：

BufferedReader br1 = new BufferedReader(new FileReader("a.txt"));

最后，您可以关闭所有BufferedReaders。它们将隐式地关闭所有包含的流。

BufferedReader在第一行后无法读取

1 个答案: