请大侠们指教一下，这个程序的问题啊，我是准备把E:/java目录下的所以文本文件的内容合并到一个文件中。
import java.io.*;
public class TestFile {
static boolean indexC = true;
static int index = 50;
public static void main(String[] args) throws Exception{
File file = new File("E:/java"); // 读取目录
File[] f = file.listFiles();
BufferedWriter bw = new BufferedWriter(new FileWriter("D:/3.txt",true)); //存取文件
fileIO(f,bw);
}
public static void fileIO(File[] f,BufferedWriter bw) throws FileNotFoundException {
for(int i=0;i<f.length;i++){
if(f[i].isDirectory()){
File[] f2 = f[i].listFiles();
fileIO(f2,bw);
continue;
}
BufferedReader br = new BufferedReader(new FileReader((f[i])));
IO(br,bw);
//System.out.println(f[i].getName());
}
}
public static void IO(BufferedReader input,BufferedWriter output){
try{
int ch = 0;
while((ch = input.read()) != -1) {
output.write(ch);
}
} catch(Exception e) {
e.printStackTrace();
System.out.print("程序出错了");
}
}
}