import java.io.File;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

import org.junit.Test;

public class ListFile {
	public void listJavaFile(String fileName) {
		File file = new File(fileName);
		if (file.isDirectory()) {
			File[] files = file.listFiles();
			for (int i = 0; i < files.length; i++) {
				String name = files[i].getName();
				if (name.trim().toLowerCase().endsWith(".java")) {
					System.out.println(name + "\t");
				}
				if (files[i].isDirectory()) {
					String path = files[i].getPath();
					listJavaFile(path);
				}
			}
		}
	}

	@Test
	public void testListJavaFile() throws Exception {
		listJavaFile(".");
	}
}

运行测试，输出：

TestAction.java
TestSpring.java
ListFile.java
Multiple.java