java获取包下面的自定义注解

自定义了Controller和RequestMapping两个注解，先去扫描加了@Controller注解的类，接着扫描这些类下面加了@RequestMapping注解的方法，然后通过java的反射invoke方法去调用加了RequestMapping注解的方法。

（1）该工程的目录结构如下

完整的工程代码下载链接如下：https://github.com/HelloKittyNII/JavaCustomAnnotation

（2）annotation包下面自定义了两个注解。

Controller.java

package com.huawi.annotation;import java.lang.annotation.ElementType;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;import java.lang.annotation.Target;/** * Created by wzj on 2016/10/1. */@Target(ElementType.TYPE)@Retention(RetentionPolicy.RUNTIME)public @interface Controller{    String value() default "";}

package com.huawi.annotation;import java.lang.annotation.ElementType;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;import java.lang.annotation.Target;/** * Created by wzj on 2016/10/1. */@Target({ElementType.METHOD, ElementType.TYPE})@Retention(RetentionPolicy.RUNTIME)public @interface RequestMapping{    String value() default "";}

（3）bean包下面定义了一个存放RequestMapping注解方法的对象

ExecutorBean.java

package com.huawi.bean;import java.lang.reflect.Method;import java.util.Objects;/** * Created by wzj on 2016/10/1. */public class ExecutorBean{    private Object object;    private Method method;    public Object getObject()    {        return object;    }    public void setObject(Object object)    {        this.object = object;    }    public Method getMethod()    {        return method;    }    public void setMethod(Method method)    {        this.method = method;    }}

（4）controller包下面定义了几个类，其中有两个类使用了自定义的Controller注解

CatController.java

package com.huawi.controller;import com.huawi.annotation.Controller;import com.huawi.annotation.RequestMapping;/** * Created by wzj on 2016/10/1. */@Controllerpublic class CatController{    @RequestMapping(value = "/test1")    public void test1()    {        System.out.println("CatController->test1()");    }    @RequestMapping(value = "/test2")    public void test2()    {        System.out.println("CatController->test2()");    }}

DogController.java

package com.huawi.controller;import com.huawi.annotation.Controller;import com.huawi.annotation.RequestMapping;/** * Created by wzj on 2016/10/1. */@Controllerpublic class DogController{    @RequestMapping(value = "/test3")    public void test3()    {        System.out.println("DogController->test3()");    }    @RequestMapping(value = "/test4")    public void test4()    {        System.out.println("DogController->test4()");    }}

Rabbit.java

package com.huawi.controller;import com.huawi.annotation.RequestMapping;/** * Created by wzj on 2016/10/5. */public class Rabbit{    @RequestMapping    public void test1()    {        System.out.println("Rabbit->test1()");    }}

(5)util包下面定义了一个工具类，来对包进行扫描获取自定义注解的类和方法

AnnoManageUtil.java

package com.huawi.util;import com.huawi.annotation.RequestMapping;import com.huawi.bean.ExecutorBean;import java.io.File;import java.io.FileFilter;import java.io.IOException;import java.io.UnsupportedEncodingException;import java.lang.annotation.Annotation;//import java.lang.reflect.Method;import java.lang.reflect.Method;import java.net.URL;import java.net.URLDecoder;import java.nio.file.DirectoryStream;import java.nio.file.Files;import java.nio.file.Path;import java.nio.file.Paths;import java.util.ArrayList;import java.util.Enumeration;import java.util.List;import java.util.Map;/** * Created by wzj on 2016/10/1. */public final class AnnoManageUtil{    /**     * 获取当前包路径下指定的Controller注解类型的文件     * @param packageName 包名     * @param annotation 注解类型     * @return 文件     */    public static  List<Class<?>> getPackageController(String packageName, Class<? extends Annotation> annotation)    {        List<Class<?>> classList = new ArrayList<Class<?>>();        String packageDirName = packageName.replace('.', '/');        Enumeration<URL> dirs = null;        //获取当前目录下面的所有的子目录的url        try        {            dirs = Thread.currentThread().getContextClassLoader().getResources(packageDirName);        }        catch (IOException e)        {            e.printStackTrace();        }        while (dirs.hasMoreElements())        {            URL url = dirs.nextElement();            //得到但钱url的类型            String protocol = url.getProtocol();            //如果当前类型是文件类型            if ("file".equals(protocol))            {                //获取包的物理路径                String filePath = null;                try                {                    filePath = URLDecoder.decode(url.getFile(), "UTF-8");                }                catch (UnsupportedEncodingException e)                {                    e.printStackTrace();                }                filePath = filePath.substring(1);                getFilePathClasses(packageName,filePath,classList,annotation);            }        }            return classList;    }    /**     * 从指定的包下面找到文件名     * @param packageName     * @param filePath     * @param classList     * @param annotation 注解类型     */    private static void getFilePathClasses(String packageName,String filePath,List<Class<?>> classList,                                           Class<? extends Annotation> annotation)    {        Path dir = Paths.get(filePath);        DirectoryStream<Path> stream = null;        try        {            //获得当前目录下的文件的stream流            stream = Files.newDirectoryStream(dir);        }        catch (IOException e)        {            e.printStackTrace();        }        for(Path path : stream)        {            String fileName = String.valueOf(path.getFileName());            String className = fileName.substring(0, fileName.length() - 6);            Class<?> classes = null;            try            {                classes = Thread.currentThread().getContextClassLoader().loadClass(packageName + "." + className);            }            catch (ClassNotFoundException e)            {                e.printStackTrace();            }            //判断该注解类型是不是所需要的类型            if (null != classes && null != classes.getAnnotation(annotation))            {                //把这个文件加入classlist中                classList.add(classes);            }        }    }    /**     * 获取classList下面的RequestMapping方法保存在mapp中     * @param classList 保存加了Controller的类     * @param mapp  存放url和ExecutorBean的对应关系     */    public static void getRequestMappingMethod(List<Class<?>> classList, Map<String,ExecutorBean> mapp)    {        for (Class classes : classList)        {            //得到该类下面的所有方法            Method[] methods = classes.getDeclaredMethods();            for (Method method : methods)            {                //得到该类下面的RequestMapping注解                RequestMapping requestMapping = method.getAnnotation(RequestMapping.class);                if (null != requestMapping)                {                    ExecutorBean executorBean = new ExecutorBean();                    try                    {                        executorBean.setObject(classes.newInstance());                    }                    catch (InstantiationException e)                    {                        e.printStackTrace();                    }                    catch (IllegalAccessException e)                    {                        e.printStackTrace();                    }                    executorBean.setMethod(method);                    mapp.put(requestMapping.value(),executorBean);                }            }        }    }}

(6)test包下面是一个测试的类

main.java

package com.huawi.test;import com.huawi.annotation.Controller;import com.huawi.bean.ExecutorBean;import com.huawi.util.AnnoManageUtil;import java.io.IOException;import java.lang.reflect.InvocationTargetException;import java.util.HashMap;import java.util.List;import java.util.Map;public class Main {    public static void main(String[] args)    {        List<Class<?>> classesList = null;        classesList = AnnoManageUtil.getPackageController("com.huawi.controller",Controller.class);        Map<String,ExecutorBean> mmap = new HashMap<String,ExecutorBean>();        AnnoManageUtil.getRequestMappingMethod(classesList,mmap);        ExecutorBean bean = mmap.get("/test1");        try {            bean.getMethod().invoke(bean.getObject());        } catch (IllegalAccessException e) {            e.printStackTrace();        } catch (InvocationTargetException e) {            e.printStackTrace();        }    }}