Restriction on readLine()

Question

I just wanted to know if there is any restriction on the number of lines readLine method can read from a file in java.Any help will be grately appreciated.This is what I am talking about:

FileReader fr1=new FileReader("/homes/output_train_2000.txt");
BufferedReader br1=new BufferedReader(fr1);
while((line1=br1.readLine())!=null){ }  

Thanks.

Answer 1

使用缓冲读取器时，整个文件永远不会读入内存，因此它应该能够处理操作系统支持的任何大小的文件。

Answer 2

它可以读取任意多行。

Answer 3

Are you trying to restrict the number of lines read? If so then you can easily add some code to do that:

FileReader fr1=new FileReader("/homes/output_train_2000.txt");
BufferedReader br1=new BufferedReader(fr1);
int numLinesRead = 0;
int maxLines = 1000;
while((numLinesRead < maxLines) && (line1=br1.readLine())!=null){
  numLinesRead++;
  // other stuff
} 

Answer 4

No restriction that I know of. Here's a better way of doing it:

BufferedReader reader = null;  
try {  
    reader = new BufferedReader( new FileReader( "/homes/output_train_2000.txt") );  
    String line = null;  
    do {  
        line = reader.readLine();  
        if( line != null ) {  
            // Do something     
        }  
    } while( line != null );  
} catch (Exception e) {  
    e.printStackTrace();  
} finally {  
    if( reader != null )  
    try {  
        reader.close();  
    } catch (IOException e) {  
}