用纯java编写一个程序查找某个.java文件里的class后的类名及extends后的类名

用纯java编写一个程序查找某个.java文件里的class后的类名及extends后的类名
并输出这两个类名(其它文件内容就不输出了);
可以参考一下下面的程序:

Java code

import java.io.*;
import java.util.StringTokenizer;

class A {

}

public class Read extends A {

    public static void phase(String fileName) {
        String className = "";
        String superClassName = "";
        try {
            FileReader fis = new FileReader(fileName);
            BufferedReader reader = new BufferedReader(fis);
            String line;
            while ((line = reader.readLine()) != null) {
                if (line.contains("class")) {
                    StringTokenizer tokenizer = new StringTokenizer(line);
                    while (tokenizer.hasMoreElements()) {
                        String word = tokenizer.nextToken();
                        if (word.equals("class")) {
                            if (tokenizer.hasMoreElements()) {
                                className = tokenizer.nextToken();
                            }
                        } else if (word.equals("extends")) {
                            if (tokenizer.hasMoreElements()) {
                                superClassName = tokenizer.nextToken();
                            }
                        }
                    }
                }
            }
        } catch (IOException ioex) {
            ioex.printStackTrace();
        }

        System.out.println("ClassName: " + className
                           + ", SuperClassName: "
                           + superClassName);
    }

    /**
     * @param args
     */
    public static void main(String[] args) {
        Read.phase("Read.java");
    }

}

用正则表达式匹配吧！
可以匹配
public class Test
public class Test extends Object {");
public class Test extends Object implements Runnable  {");

Java code

    Pattern p = Pattern.compile("class\\s*(\\w+)(\\s+extends\\s+(\\w+)(\\s+.*?)?)?\\s*\\{",Pattern.DOTALL);
    Matcher m = p.matcher("public class Test extends Object implements Runnable  {");
    if(m.find()) {
      System.out.println(m.group(1));
      System.out.println(m.group(3));
    }