java 文件读写

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

//文件读写
public class FileDemo {

	public static void main(String[] args) {
		StringBuffer line=null;
		try {
			FileReader fr = new FileReader("C:/test.txt");
			BufferedReader br =new BufferedReader(fr);
			 line=new StringBuffer();
			while (br.ready()) {
				line.append(br.readLine());
				
			}
			br.close();
			
		} catch (FileNotFoundException e) {
			// 
			e.printStackTrace();
		} catch (IOException e) {
			// 
			e.printStackTrace();
		}
		
		try {
			File f =new File("D:/test.txt");
			FileWriter fw = new FileWriter(f);
			BufferedWriter bw = new BufferedWriter(fw);
			bw.write(line.toString());
			bw.flush();
			bw.close();			
		} catch (IOException e) {
			// 
			e.printStackTrace();
		}
	}
}