throws ? catch checked unchecked

ThrowableClass

　　Error  (unchecked)

　　Exception

　　　　IOException (checked)

　　　　RuntimeException (unchecked)　　

public void read(String filename)
{
    try
    {
        InputStream in = new FileInputStream(filename);
        int b;
        while((b = in.read()) != -1){
            process input
        }
    }
    catch(IOException exception)
    {
        exception.printStackTrace();
    }
}

//较好
//read方法出现了错误，就让read方法的调用者去处理
public void read(String filename) throws IOException
{
    InputStream in = new FileInputStream(filename);
    int b;
    while((b = in.read()) != -1){
        process input
    }
}