import java.io.*;
public class TestTransForm2 {
public static void main(String args[]) throws Exception{
InputStreamReader isr =
new InputStreamReader(System.in);
BufferedReader br = new BufferedReader(isr);FileWriter fw=new FileWriter("d:/fw.txt");
BufferedWriter bw= new BufferedWriter(fw);
String s = null;
try {
s = br.readLine();
while(s!=null){
if(s.equalsIgnoreCase("exit")) break;
System.out.println(s);
bw.write(s);
s = br.readLine();
}
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
} /*想通过键盘向fw文件里写东西,结果fw文件里什么也没有,
*/
public class TestTransForm2 {
public static void main(String args[]) throws Exception{
InputStreamReader isr =
new InputStreamReader(System.in);
BufferedReader br = new BufferedReader(isr);FileWriter fw=new FileWriter("d:/fw.txt");
BufferedWriter bw= new BufferedWriter(fw);
String s = null;
try {
s = br.readLine();
while(s!=null){
if(s.equalsIgnoreCase("exit")) break;
System.out.println(s);
bw.write(s);
s = br.readLine();
}
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
} /*想通过键盘向fw文件里写东西,结果fw文件里什么也没有,
*/
这是因为你没有对数据进行输出到文件的操作。查查API看这个方法就明白了
import java.io.*;
public class TestTransForm2 {
public static void main(String args[]) throws Exception{
InputStreamReader isr =new InputStreamReader(System.in);
BufferedReader br = new BufferedReader(isr);
FileWriter fw=new FileWriter("d:/fw.txt");
BufferedWriter bw= new BufferedWriter(fw);
String s = null;
try {
s = br.readLine();
// while(s!=null){
// if(s.equalsIgnoreCase("exit")) break;
// System.out.println(s);
// bw.write(s);
//// s = br.readLine();
// }
System.out.println(s);
bw.write(s);
br.close();
bw.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
public class TestTransForm2 {
public static void main(String args[]) throws Exception {
InputStreamReader isr = new InputStreamReader(System.in);
BufferedReader br = new BufferedReader(isr); FileWriter fw = new FileWriter("d:/fw.txt");
BufferedWriter bw = new BufferedWriter(fw); String s = null;
try {
s = br.readLine();
while (!"exit".equals(s)) {
if (s.equalsIgnoreCase("exit"))
break;
System.out.println(s);
bw.write(s);
s = br.readLine();
}
br.close();
bw.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
bw.close();
这样的话,实际上并没有运行while后面的代码,直接跳出了。
所以你在while后面写关闭是没用用的。
另外,你只关闭了读入流,并没有关闭输出流。所以,当然就不会有将内容写入到文件的处理。
所以我帮你做了上面的调整。