Simple file manipulation tool class (File)

1. Solve the problem

Load all the classes under the package through the package name in the form: com.xxx.yyy.zzz

2. Code:

package com.chuyutech.rssp.openservice.service.data;

import java.io.File;
import java.io.FileFilter;
import java.io.IOException;
import java.net.URL;
import java.net.URLDecoder;
import java.util.Enumeration;
import java.util.LinkedHashSet;
import java.util.Set;

/**
 * @description: 简单的文件操作类,包含一些文件的基本操作
 * 
 * @author cwh
 *
 */
public class FileOpreation {

	/**
	 * 根据包名访问磁盘文件
	 * 
	 * @param packageName:形如com.xxx.yyy.zzz以点号分割
	 */
	public static Set<Class<?>> getClazz(String packageName) {
		// 是否递归
		boolean isRecursion = true;
		// 定义变量,保存class文件
		Set<Class<?>> clazz = new LinkedHashSet<Class<?>>();
		char dot = '.';
		char sprit = '/';
		try {
			// 根据当前线程获取ContextClassLoader类加载器 需注意:分隔符的转换
			// getResources方法定义的资源是 '/' 分隔符

			Enumeration<URL> resources = Thread.currentThread().getContextClassLoader()
					.getResources(packageName.replace(dot, sprit));
			// 遍历枚举
			while (resources.hasMoreElements()) {
				URL url = resources.nextElement();
// url:file:/E:/03.WorkSpaceToNew/soldier-openservice/target/classes/com/chuyutech/rssp/openservice/common/db/dao
				System.out.println("url:" + url.toString());
				// 获取协议名称
				String protocol = url.getProtocol();
				// 如果为文件类型 接下来就是File类的操作
				if (protocol.equals("file")) {
					//					使用特定的编码方案解码url
					String packagePath = URLDecoder.decode(url.getFile(), "UTF-8");
//					调用方法递归获取文件
					getClazzFromPath(packageName, packagePath, isRecursion, clazz);
				}
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
		return clazz;
	}

	/**
	 * 获取文件中class文件
	 * 
	 * @param packageName:包名;
	 *            packagePath:文件路径;isRecursion:是否递归
	 */
	public static void getClazzFromPath(String packageName, String packagePath, boolean isRecursion,
			Set<Class<?>> clazz) {
		char dot = '.';
		// 根据路径名获取File文件对象
		File file = new File(packagePath);

		if (!file.exists() || !file.isDirectory()) {
			return;
		}
		// 以File数组的形式列出所有的文件
		File[] files = file.listFiles(new FileFilter() {
			// 匿名内部类重写FIleFilter
			@Override
			public boolean accept(File pathName) {
	// 自定义过滤规则 如果可以循环(包含子目录) 或者是以.class结尾的文件(编译好的java类文件)
				return ((isRecursion && pathName.isDirectory()) || pathName.getName().endsWith(".class"));
			}
		});
		// 遍历files
		for (File destFile : files) {
			// 如果是目录 则继续扫描
			if (destFile.isDirectory()) {
				getClazzFromPath(packageName + dot + destFile.getName(), destFile.getAbsolutePath(), isRecursion,
						clazz);
			} else {
				// 如果是编译后java类文件 去掉后面的.class 只留下类名
				String fileName = destFile.getName().substring(0, destFile.getName().lastIndexOf(dot));
				// 添加到集合中去 通过完整包名+"."+文件名 加载class
				try {
					// Class<?> forName = Class.forName(packageName + dot +
					// className); 此方法在会初始化所加载类的static静态代码块
					Class<?> loadClass = Thread.currentThread().getContextClassLoader()
							.loadClass(packageName + dot + fileName);
					clazz.add(loadClass);
				} catch (ClassNotFoundException e) {
					e.printStackTrace();
				}
			}

		}
	}

	public static void main(String[] args) {
		String packageName = "com.chuyutech.rssp.openservice.common.db.dao";
		Set<Class<?>> clazz = getClazz(packageName);
		System.out.println(clazz.size());
		for (Class<?> class1 : clazz) {
			System.out.println(class1.getName());
		}
	}

}

3. Summary:

        3.1: The general logic of the implementation:

Obtain the ContextClassLoader class loader             according to the current thread , and obtain the URL corresponding to the package name through the getResources(String name) method of the class loader.

            Get the absolute path through the URL and use the java.io.listFiles(FileFilter filter) of the File class to list all files or directories

            Recursively call the file or directory obtained in the previous step, and finally
                            obtain the Class object through Thread.currentThread().getContextClassLoader() .loadClass(className) and save it to the set collection.

           3.2: Note: Conversion of separators: The resource defined by the getResources method is the '/' separator

4. Result print:

---------------------over-----------------------