75.Java异常处理机制throws

package testDate;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
public class TestReadFile {
    public static void main(String[] args) {
        String str = null;
        try {
            str = new TestReadFile().openFile();
        } catch (IOException e){
            e.printStackTrace();
        }
        System.out.println(str);
    }
    String openFile() throws FileNotFoundException,IOException{
        FileReader reader = new FileReader("d:/a.txt");
        char c= (char) reader.read();
        System.out.println(c);
        return "";
    }
}