大家好:
它 println 出的最後一行是 "null"
請問為什麼? try{
File file=new File("list.txt");
LineNumberReader linereader = new LineNumberReader(new FileReader(file));
try{
String str=linereader.readLine();
System.out.println(str);
while(str != null){
str=linereader.readLine();
System.out.println(str);
} //end while
}catch(IOException io){} }catch(FileNotFoundException f){}
它 println 出的最後一行是 "null"
請問為什麼? try{
File file=new File("list.txt");
LineNumberReader linereader = new LineNumberReader(new FileReader(file));
try{
String str=linereader.readLine();
System.out.println(str);
while(str != null){
str=linereader.readLine();
System.out.println(str);
} //end while
}catch(IOException io){} }catch(FileNotFoundException f){}
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub try {
File file = new File("D:\\temp\\list.txt");
LineNumberReader linereader = new LineNumberReader(new FileReader(file));
// String str = linereader.readLine();
// System.out.println(str);
String str = "";
while ((str = linereader.readLine()) != null) {
// str = linereader.readLine();
System.out.println(str);
} // end while
} catch (Exception e) {
e.printStackTrace();
}
}}
一行一行地读用 BufferedReader 足够了。改了一下,把 str 的作用范围再缩小,呵呵。for(String str = null; (str = linereader.readLine()) != null; ) {
System.out.println(str);
}