在Java中从文件读取并将其写回到文件（难以理解Java中的BufferedWriter write方法）

Question

I'm confused with the the java BufferedWriter write method. The java documents says that write takes int as an argument.

void write(int c) Writes a single character.

But I have used write method in my code, and I have passed String into it

BufferedReader br=new BufferedReader(file);
BufferedWriter bw=new BufferedWriter(file1);
String line=null;
while((line=br.readLine())!=null) 
{
  bw.write(line); // Why is this statement working?
  bw.write("\r\n");
}

I passing "line" to bw.write(line) and "line" is a string, why is this working?Is write 
method  overloaded?But I don't see it in docs.

Answer 1

因为存在一个接受字符串的write()和BufferedWriter “ IS-A” Writer子类，所以这就是它具有write(String)原因，因为Writer类具有它。

Answer 2

Api copy / paste : http://docs.oracle.com/javase/7/docs/api/java/io/BufferedWriter.html

Class BufferedWriter

java.lang.Object java.io.Writer <------ *has method write(String str) java.io.BufferedWriter

There is a write method which is capable to take a string as param and write it.

As Luis Alberto allready mentioned.