java扫描包下所有类的完整路径

最近在完善微信公众号返利机器人订单轮训、跟踪。

业务逻辑是定时任务调用淘客API，按一定条件查询某时间段内的返利订单。定时任务框架用的quartz，原先定时任务写死在代码中，此次优化将定时任务做成可视化配置，更加灵活、通用。

今天暂不讨论、总结quartz定时任务可视化配置，有需要的同学可以参考《Springboot集成quartz定时任务可视化配置》。

用过quartz的应该知道，所有的定时任务都是直接或间接的继承Job类，我们把所有的job类放在同一个包下，做成可视化需要解决的就是扫描此包，获取包下所有的job类。

直接贴上扫描包下所有类代码

package com.gaoxiaobo.download.component;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.JarURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Enumeration;
import java.util.List;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import java.util.jar.JarInputStream;

/**
 * @Auther: gaoxiaobo
 * @Date: 2020/8/8 21:17
 * @Description:
 */
public class ClasspathPackageScanner {

    private static Logger logger = LoggerFactory.getLogger(ClasspathPackageScanner.class);
    private static ClassLoader cl = ClasspathPackageScanner.class.getClassLoader();



    /**
     *获取指定包下的所有字节码文件的全类名
     */
    public static List<String> getFullyQualifiedClassNameList(String basePackage) throws Exception {

        return doScan(basePackage, new ArrayList<>());
    }

    private static List<String> scanJar(String basePackage)throws Exception{
        List<String> clazz = new ArrayList<>();
        Enumeration<URL> urlEnumeration = Thread.currentThread().getContextClassLoader().getResources(basePackage.replace(".", "/"));
        while (urlEnumeration.hasMoreElements()) {
            URL url = urlEnumeration.nextElement();//得到的结果大概是：jar:file:/C:/Users/ibm/.m2/repository/junit/junit/4.12/junit-4.12.jar!/org/junit
            String protocol = url.getProtocol();//大概是jar
            System.out.println(protocol);
            if ("jar".equalsIgnoreCase(protocol)) {
                //转换为JarURLConnection
                JarURLConnection connection = (JarURLConnection) url.openConnection();
                if (connection != null) {
                    JarFile jarFile = connection.getJarFile();
                    if (jarFile != null) {
                        //得到该jar文件下面的类实体
                        Enumeration<JarEntry> jarEntryEnumeration = jarFile.entries();
                        while (jarEntryEnumeration.hasMoreElements()) {
                            /*entry的结果大概是这样：
                                    org/
                                    org/junit/
                                    org/junit/rules/
                                    org/junit/runners/*/
                            JarEntry entry = jarEntryEnumeration.nextElement();
                            String jarEntryName = entry.getName();
                            //这里我们需要过滤不是class文件和不在basePack包名下的类
                            if (jarEntryName.contains(".class") && jarEntryName.replaceAll("/",".").startsWith(basePackage)) {
                                String className = jarEntryName.substring(0, jarEntryName.lastIndexOf(".")).replace("/", ".");
                                clazz.add(className);
                            }
                        }
                    }
                }
            }
        }
        return clazz;
    }

    /**
     *doScan函数
     * @param basePackage
     * @param nameList
     * @return
     * @throws IOException
     */
    private static List<String> doScan(String basePackage, List<String> nameList) throws Exception {
        String classpath = ClasspathPackageScanner.class.getResource("/").getPath();
        if (classpath.startsWith("file")){
            return scanJar(basePackage);
        }
        String splashPath = dotToSplash(basePackage);
        URL url = cl.getResource(splashPath);   //file:/D:/WorkSpace/java/ScanTest/target/classes/com/scan
        String filePath = getRootPath(url);

        List<String> names = null; // contains the name of the class file. e.g., Apple.class will be stored as "Apple"
        if (isJarFile(filePath)) {// 先判断是否是jar包，如果是jar包，通过JarInputStream产生的JarEntity去递归查询所有类
            if (logger.isDebugEnabled()) {
                logger.debug("{} 是一个JAR包", filePath);
            }
            names = readFromJarFile(filePath, splashPath);
        } else {
            if (logger.isDebugEnabled()) {
                logger.debug("{} 是一个目录", filePath);
            }
            names = readFromDirectory(filePath);
        }
        for (String name : names) {
            if (isClassFile(name)) {
                nameList.add(toFullyQualifiedName(name, basePackage));
            } else {
                doScan(basePackage + "." + name, nameList);
            }
        }
        if (logger.isDebugEnabled()) {
            for (String n : nameList) {
                logger.debug("找到{}", n);
            }
        }
        return nameList;
    }

    private static String toFullyQualifiedName(String shortName, String basePackage) {
        StringBuilder sb = new StringBuilder(basePackage);
        sb.append('.');
        sb.append(trimExtension(shortName));
        //打印出结果
        System.out.println(sb.toString());
        return sb.toString();
    }

    private static List<String> readFromJarFile(String jarPath, String splashedPackageName) throws IOException {
        if (logger.isDebugEnabled()) {
            logger.debug("从JAR包中读取类: {}", jarPath);
        }
        JarInputStream jarIn = new JarInputStream(new FileInputStream(jarPath));
        JarEntry entry = jarIn.getNextJarEntry();
        List<String> nameList = new ArrayList<String>();
        while (null != entry) {
            String name = entry.getName();
            if (name.startsWith(splashedPackageName) && isClassFile(name)) {
                nameList.add(name);
            }

            entry = jarIn.getNextJarEntry();
        }

        return nameList;
    }

    private static List<String> readFromDirectory(String path) {
        File file = new File(path);
        String[] names = file.list();

        if (null == names) {
            return null;
        }

        return Arrays.asList(names);
    }

    private static boolean isClassFile(String name) {
        return name.endsWith(".class");
    }

    private static boolean isJarFile(String name) {
        return name.endsWith(".jar");
    }


    private static String getRootPath(URL url) {
        String fileUrl = url.getFile();
        int pos = fileUrl.indexOf('!');

        if (-1 == pos) {
            return fileUrl;
        }

        return fileUrl.substring(5, pos);
    }

    /**
     * "cn.fh.lightning" -> "cn/fh/lightning"
     * @param name
     * @return
     */
    private static String dotToSplash(String name) {
        return name.replaceAll("\\.", "/");
    }

    /**
     * "Apple.class" -> "Apple"
     */
    private static String trimExtension(String name) {
        int pos = name.indexOf('.');
        if (-1 != pos) {
            return name.substring(0, pos);
        }

        return name;
    }

    /**
     * /application/home -> /home
     * @param uri
     * @return
     */
    private static String trimURI(String uri) {
        String trimmed = uri.substring(1);
        int splashIndex = trimmed.indexOf('/');

        return trimmed.substring(splashIndex);
    }
}

 

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