反射工具类——ReflectUtils-白红宇

反射工具类——ReflectUtils

阅读量：6883 次

发布时间：2019-06-27

本文共 10975 字，大约阅读时间需要 36 分钟。

测试方法：根据已知的方法名，来反射调用方法

package com.redmoon.forum.job;import java.util.ArrayList;import java.util.List;import com.common.utils.ReflectUtils;public class Test{    private String name;    public String getName()    {        return name;    }    public void setName(String name)    {        this.name = name;    }    public List
     
       ff()    {        List
      
        list = new ArrayList
       
        ();        list.add("111");        list.add("222");        return list;    }    public static void main(String[] args)    {        Test test = new Test();        Object list = ReflectUtils.invokeMethodByName(test, "ff", null);        List
        
          list2 = (List
         
          )list;        System.out.println(list);        ReflectUtils.setFieldValue(test,"name","panie");        String name = (String)ReflectUtils.getFieldValue(test,"name");        System.out.println(name);    }}

结果：

[111, 222]panie

反射工具类

package com.common.utils;import java.lang.reflect.Field;import java.lang.reflect.InvocationTargetException;import java.lang.reflect.Method;import java.lang.reflect.Modifier;import java.lang.reflect.ParameterizedType;import java.lang.reflect.Type;import java.util.Date;import org.apache.commons.lang3.StringUtils;import org.apache.commons.lang3.Validate;import org.slf4j.Logger;import org.slf4j.LoggerFactory;/** * 反射工具类. * 提供调用getter/setter方法, 访问私有变量, 调用私有方法, 获取泛型类型Class, 被AOP过的真实类等工具函数. * @author  * @version  */public class ReflectUtils {        private static final String SETTER_PREFIX = "set";    private static final String GETTER_PREFIX = "get";    private static final String CGLIB_CLASS_SEPARATOR = "$$";        private static Logger logger = LoggerFactory.getLogger(ReflectUtils.class);    /**     * 调用Getter方法.     * 支持多级，如：对象名.对象名.方法     */    public static Object invokeGetter(Object obj, String propertyName) {        Object object = obj;        for (String name : StringUtils.split(propertyName, ".")){            String getterMethodName = GETTER_PREFIX + StringUtils.capitalize(name);            object = invokeMethod(object, getterMethodName, new Class[] {}, new Object[] {});        }        return object;    }    /**     * 调用Setter方法, 仅匹配方法名。     * 支持多级，如：对象名.对象名.方法     */    public static void invokeSetter(Object obj, String propertyName, Object value) {        Object object = obj;        String[] names = StringUtils.split(propertyName, ".");        for (int i=0; i
     
      [] parameterTypes,            final Object[] args) {        Method method = getAccessibleMethod(obj, methodName, parameterTypes);        if (method == null) {            throw new IllegalArgumentException("Could not find method [" + methodName + "] on target [" + obj + "]");        }        try {            return method.invoke(obj, args);        } catch (Exception e) {            throw convertReflectionExceptionToUnchecked(e);        }    }    /**     * 直接调用对象方法, 无视private/protected修饰符，     * 用于一次性调用的情况，否则应使用getAccessibleMethodByName()函数获得Method后反复调用.     * 只匹配函数名，如果有多个同名函数调用第一个。     */    public static Object invokeMethodByName(final Object obj, final String methodName, final Object[] args) {        Method method = getAccessibleMethodByName(obj, methodName);        if (method == null) {            throw new IllegalArgumentException("Could not find method [" + methodName + "] on target [" + obj + "]");        }        try {            return method.invoke(obj, args);        } catch (Exception e) {            throw convertReflectionExceptionToUnchecked(e);        }    }    /**     * 循环向上转型, 获取对象的DeclaredField, 并强制设置为可访问.     *      * 如向上转型到Object仍无法找到, 返回null.     */    public static Field getAccessibleField(final Object obj, final String fieldName) {        Validate.notNull(obj, "object can't be null");        Validate.notBlank(fieldName, "fieldName can't be blank");        for (Class
       superClass = obj.getClass(); superClass != Object.class; superClass = superClass.getSuperclass()) {            try {                Field field = superClass.getDeclaredField(fieldName);                makeAccessible(field);                return field;            } catch (NoSuchFieldException e) {//NOSONAR                // Field不在当前类定义,继续向上转型                continue;// new add            }        }        return null;    }    /**     * 循环向上转型, 获取对象的DeclaredMethod,并强制设置为可访问.     * 如向上转型到Object仍无法找到, 返回null.     * 匹配函数名+参数类型。     *      * 用于方法需要被多次调用的情况. 先使用本函数先取得Method,然后调用Method.invoke(Object obj, Object... args)     */    public static Method getAccessibleMethod(final Object obj, final String methodName,            final Class
      ... parameterTypes) {        Validate.notNull(obj, "object can't be null");        Validate.notBlank(methodName, "methodName can't be blank");        for (Class
       searchType = obj.getClass(); searchType != Object.class; searchType = searchType.getSuperclass()) {            try {                Method method = searchType.getDeclaredMethod(methodName, parameterTypes);                makeAccessible(method);                return method;            } catch (NoSuchMethodException e) {                // Method不在当前类定义,继续向上转型                continue;// new add            }        }        return null;    }    /**     * 循环向上转型, 获取对象的DeclaredMethod,并强制设置为可访问.     * 如向上转型到Object仍无法找到, 返回null.     * 只匹配函数名。     *      * 用于方法需要被多次调用的情况. 先使用本函数先取得Method,然后调用Method.invoke(Object obj, Object... args)     */    public static Method getAccessibleMethodByName(final Object obj, final String methodName) {        Validate.notNull(obj, "object can't be null");        Validate.notBlank(methodName, "methodName can't be blank");        for (Class
       searchType = obj.getClass(); searchType != Object.class; searchType = searchType.getSuperclass()) {            Method[] methods = searchType.getDeclaredMethods();            for (Method method : methods) {                if (method.getName().equals(methodName)) {                    makeAccessible(method);                    return method;                }            }        }        return null;    }    /**     * 改变private/protected的方法为public，尽量不调用实际改动的语句，避免JDK的SecurityManager抱怨。     */    public static void makeAccessible(Method method) {        if ((!Modifier.isPublic(method.getModifiers()) || !Modifier.isPublic(method.getDeclaringClass().getModifiers()))                && !method.isAccessible()) {            method.setAccessible(true);        }    }    /**     * 改变private/protected的成员变量为public，尽量不调用实际改动的语句，避免JDK的SecurityManager抱怨。     */    public static void makeAccessible(Field field) {        if ((!Modifier.isPublic(field.getModifiers()) || !Modifier.isPublic(field.getDeclaringClass().getModifiers()) || Modifier                .isFinal(field.getModifiers())) && !field.isAccessible()) {            field.setAccessible(true);        }    }    /**     * 通过反射, 获得Class定义中声明的泛型参数的类型, 注意泛型必须定义在父类处     * 如无法找到, 返回Object.class.     * eg.     * public UserDao extends HibernateDao
      
            *     * @param clazz The class to introspect     * @return the first generic declaration, or Object.class if cannot be determined     */    @SuppressWarnings("unchecked")    public static 
       
         Class
        
          getClassGenricType(final Class clazz) {        return getClassGenricType(clazz, 0);    }    /**     * 通过反射, 获得Class定义中声明的父类的泛型参数的类型.     * 如无法找到, 返回Object.class.     *      * 如public UserDao extends HibernateDao
         
               *     * @param clazz clazz The class to introspect     * @param index the Index of the generic ddeclaration,start from 0.     * @return the index generic declaration, or Object.class if cannot be determined     */    public static Class getClassGenricType(final Class clazz, final int index) {        Type genType = clazz.getGenericSuperclass();        if (!(genType instanceof ParameterizedType)) {            logger.warn(clazz.getSimpleName() + "'s superclass not ParameterizedType");            return Object.class;        }        Type[] params = ((ParameterizedType) genType).getActualTypeArguments();        if (index >= params.length || index < 0) {            logger.warn("Index: " + index + ", Size of " + clazz.getSimpleName() + "'s Parameterized Type: "                    + params.length);            return Object.class;        }        if (!(params[index] instanceof Class)) {            logger.warn(clazz.getSimpleName() + " not set the actual class on superclass generic parameter");            return Object.class;        }        return (Class) params[index];    }        public static Class
           getUserClass(Object instance) {        Validate.notNull(instance, "Instance must not be null");        Class clazz = instance.getClass();        if (clazz != null && clazz.getName().contains(CGLIB_CLASS_SEPARATOR)) {            Class
           superClass = clazz.getSuperclass();            if (superClass != null && !Object.class.equals(superClass)) {                return superClass;            }        }        return clazz;    }        /**     * 将反射时的checked exception转换为unchecked exception.     */    public static RuntimeException convertReflectionExceptionToUnchecked(Exception e) {        if (e instanceof IllegalAccessException || e instanceof IllegalArgumentException                || e instanceof NoSuchMethodException) {            return new IllegalArgumentException(e);        } else if (e instanceof InvocationTargetException) {            return new RuntimeException(((InvocationTargetException) e).getTargetException());        } else if (e instanceof RuntimeException) {            return (RuntimeException) e;        }        return new RuntimeException("Unexpected Checked Exception.", e);    }        /**     * 判断属性是否为日期类型     *      * @param clazz     *            数据类型     * @param fieldName     *            属性名     * @return 如果为日期类型返回true，否则返回false     */    public static 
          
            boolean isDateType(Class
           
             clazz, String fieldName) { boolean flag = false; try { Field field = clazz.getDeclaredField(fieldName); Object typeObj = field.getType().newInstance(); flag = typeObj instanceof Date; } catch (Exception e) { // 把异常吞掉直接返回false } return flag; } /** * 根据类型将指定参数转换成对应的类型 * * @param value * 指定参数 * @param type * 指定类型 * @return 返回类型转换后的对象 */ public static 
            
              Object parseValueWithType(String value, Class
              type) { Object result = null; try { // 根据属性的类型将内容转换成对应的类型 if (Boolean.TYPE == type) { result = Boolean.parseBoolean(value); } else if (Byte.TYPE == type) { result = Byte.parseByte(value); } else if (Short.TYPE == type) { result = Short.parseShort(value); } else if (Integer.TYPE == type) { result = Integer.parseInt(value); } else if (Long.TYPE == type) { result = Long.parseLong(value); } else if (Float.TYPE == type) { result = Float.parseFloat(value); } else if (Double.TYPE == type) { result = Double.parseDouble(value); } else { result = (Object) value; } } catch (Exception e) { // 把异常吞掉直接返回null } return result; }}