Java基本IO操作
03 Dec 2013
public class IODemo {
public static void main(String[] args) {
try {
// 1a.Reading input by lines
BufferedReader in = new BufferedReader(new FileReader(args[0]));
String s, s2 = new String();
while ((s = in.readLine()) != null) {
s2 += s + "\n";
}
in.close();
// 1b.Reading standard input
BufferedReader stdin = new BufferedReader(new InputStreamReader(
System.in));
System.out.println("Enter a line: ");
System.out.println(stdin.readLine());
// 2.Input from memory
StringReader in2 = new StringReader(s2);
int c;
while ((c = in2.read()) != -1) {
System.out.print((char) c);
}
// 3. Formatted memory input
try {
DataInputStream in3 = new DataInputStream(
new StringBufferInputStream(s2));
while (true) {
System.out.print((char) in3.readByte());
}
} catch (EOFException e) {
System.out.println("End of stream");
}
// 4. Line number reading & file output
try {
LineNumberReader li = new LineNumberReader(new StringReader(s2));
BufferedReader in4 = new BufferedReader(li);
PrintWriter out1 = new PrintWriter(new BufferedWriter(
new FileWriter("IODemo.out")));
while ((s = in4.readLine()) != null) {
out1.println("Line " + li.getLineNumber() + " " + s);
}
out1.close();
} catch (EOFException e) {
System.out.println("End of stream");
}
// 5. Storing & recovering data
try {
DataOutputStream out2 = new DataOutputStream(
new BufferedOutputStream(new FileOutputStream(
"Data.txt")));
out2.writeDouble(3.1415926);
out2.writeBytes("It is a pi");
out2.close();
DataInputStream in5 = new DataInputStream(
new BufferedInputStream(new FileInputStream("Data.txt")));
BufferedReader in5br = new BufferedReader(
new InputStreamReader(in5));
System.out.println(in5.readDouble());
System.out.println(in5br.readLine());
} catch (EOFException e) {
System.out.println("End of stream");
}
} catch (FileNotFoundException e) {
System.out.println("File Not Found: " + args[1]);
} catch (IOException e) {
System.out.println("IO Exception");
}
}
}