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    • com.taobao.hsf.util.ReflectUtils Maven / Gradle / Ivy

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    /*
 * Copyright 1999-2011 Alibaba Group.
 *  
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *  
 *      http://www.apache.org/licenses/LICENSE-2.0
 *  
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.taobao.hsf.util;

import java.lang.reflect.Array;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.GenericArrayType;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.ParameterizedType;
import java.net.URL;
import java.security.CodeSource;
import java.security.ProtectionDomain;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * ReflectUtils
 *
 * @author qian.lei
 * @author kongming.lrq
 */
public final class ReflectUtils {

    /**
     * void(V).
     */
    public static final char JVM_VOID = 'V';

    /**
     * boolean(Z).
     */
    public static final char JVM_BOOLEAN = 'Z';

    /**
     * byte(B).
     */
    public static final char JVM_BYTE = 'B';

    /**
     * char(C).
     */
    public static final char JVM_CHAR = 'C';

    /**
     * double(D).
     */
    public static final char JVM_DOUBLE = 'D';

    /**
     * float(F).
     */
    public static final char JVM_FLOAT = 'F';

    /**
     * int(I).
     */
    public static final char JVM_INT = 'I';

    /**
     * long(J).
     */
    public static final char JVM_LONG = 'J';

    /**
     * short(S).
     */
    public static final char JVM_SHORT = 'S';

    public static final Class[] EMPTY_CLASS_ARRAY = new Class[0];

    public static final String JAVA_IDENT_REGEX = "(?:[_$a-zA-Z][_$a-zA-Z0-9]*)";


    public static final String CLASS_DESC = "(?:L" + JAVA_IDENT_REGEX + "(?:\\/" + JAVA_IDENT_REGEX + ")*;)";

    public static final String ARRAY_DESC = "(?:\\[+(?:(?:[VZBCDFIJS])|" + CLASS_DESC + "))";

    public static final String DESC_REGEX = "(?:(?:[VZBCDFIJS])|" + CLASS_DESC + "|" + ARRAY_DESC + ")";

    public static final Pattern DESC_PATTERN = Pattern.compile(DESC_REGEX);

    public static final Pattern GETTER_METHOD_DESC_PATTERN = Pattern.compile(
            "get([A-Z][_a-zA-Z0-9]*)\\(\\)(" + DESC_REGEX + ")");

    public static final Pattern SETTER_METHOD_DESC_PATTERN = Pattern.compile(
            "set([A-Z][_a-zA-Z0-9]*)\\((" + DESC_REGEX + ")\\)V");

    public static final Pattern IS_HAS_CAN_METHOD_DESC_PATTERN = Pattern.compile(
            "(?:is|has|can)([A-Z][_a-zA-Z0-9]*)\\(\\)Z");

    private static final ConcurrentMap> DESC_CLASS_CACHE = new ConcurrentHashMap>();

    private static final ConcurrentMap> NAME_CLASS_CACHE = new ConcurrentHashMap>();

    private static final ConcurrentMap Signature_METHODS_CACHE = new ConcurrentHashMap();

    static private Map, Object> primitiveDefaults = new HashMap, Object>();

    static {
        primitiveDefaults.put(int.class, 0);
        primitiveDefaults.put(long.class, 0L);
        primitiveDefaults.put(byte.class, (byte) 0);
        primitiveDefaults.put(char.class, (char) 0);
        primitiveDefaults.put(short.class, (short) 0);
        primitiveDefaults.put(float.class, (float) 0);
        primitiveDefaults.put(double.class, (double) 0);
        primitiveDefaults.put(boolean.class, false);
        primitiveDefaults.put(void.class, null);
    }

    private ReflectUtils() {
    }

    /**
     * 
         * 根据方法获取对应的默认返回值
     * 
    
     *
     * @param m 方法
     * @return 如果是原型，返回对应的值，否则返回null
     */
    static public Object defaultReturn(Method m) {
        if (m.getReturnType().isPrimitive()) {
            return primitiveDefaults.get(m.getReturnType());
        } else {
            return null;
        }
    }

    /**
     * 根据类型确定默认返回值
     *
     * @param classType 类型
     * @return 默认值，如果是原型，返回对应的值，否则返回null
     */
    static public Object defaultReturn(Class classType) {
        if (classType != null && classType.isPrimitive()) {
            return primitiveDefaults.get(classType);
        } else {
            return null;
        }
    }

    /**
     * 递归判断当前类型是否原型
     *
     * @param cls 类型，如果是数组，则获取其元素类型
     * @return 是否原型
     */
    public static boolean isPrimitives(Class cls) {
        if (cls.isArray()) {
            return isPrimitives(cls.getComponentType());
        }
        return isPrimitive(cls);
    }

    /**
     * 
         * 是否原型
     *
     * 
  • java原型
    • 
     * 
  • 字符串java.lang.String
    • 
     * 
  • Boolean包装类型
    • 
     * 
  • Character包装
    • 
     * 
  • Number的子类型
    • 
     * 
  • java.util.Date
    • 
     *
     * 
    
     *
     * @param cls 类型
     * @return 是否原型
     */
    public static boolean isPrimitive(Class cls) {
        return cls.isPrimitive() || cls == String.class || cls == Boolean.class || cls == Character.class
                || Number.class.isAssignableFrom(cls) || Date.class.isAssignableFrom(cls);
    }

    /**
     * 获取类型的包装类型
     *
     * @param c 原型
     * @return 包装类型
     */
    public static Class getBoxedClass(Class c) {
        if (c == int.class)
            c = Integer.class;
        else if (c == boolean.class)
            c = Boolean.class;
        else if (c == long.class)
            c = Long.class;
        else if (c == float.class)
            c = Float.class;
        else if (c == double.class)
            c = Double.class;
        else if (c == char.class)
            c = Character.class;
        else if (c == byte.class)
            c = Byte.class;
        else if (c == short.class)
            c = Short.class;
        return c;
    }

    /**
     * is compatible.
     *
     * @param c class.
     * @param o instance.
     * @return compatible or not.
     */
    public static boolean isCompatible(Class c, Object o) {
        boolean pt = c.isPrimitive();
        if (o == null)
            return !pt;

        if (pt) {
            if (c == int.class)
                c = Integer.class;
            else if (c == boolean.class)
                c = Boolean.class;
            else if (c == long.class)
                c = Long.class;
            else if (c == float.class)
                c = Float.class;
            else if (c == double.class)
                c = Double.class;
            else if (c == char.class)
                c = Character.class;
            else if (c == byte.class)
                c = Byte.class;
            else if (c == short.class)
                c = Short.class;
        }
        if (c == o.getClass())
            return true;
        return c.isInstance(o);
    }

    /**
     * is compatible.
     *
     * @param cs class array.
     * @param os object array.
     * @return compatible or not.
     */
    public static boolean isCompatible(Class[] cs, Object[] os) {
        int len = cs.length;
        if (len != os.length)
            return false;
        if (len == 0)
            return true;
        for (int i = 0; i < len; i++)
            if (!isCompatible(cs[i], os[i]))
                return false;
        return true;
    }

    /**
     * 获取当前类型的位置
     *
     * @param cls 类型
     * @return 位置
     */
    public static String getCodeBase(Class cls) {
        if (cls == null)
            return null;
        ProtectionDomain domain = cls.getProtectionDomain();
        if (domain == null)
            return null;
        CodeSource source = domain.getCodeSource();
        if (source == null)
            return null;
        URL location = source.getLocation();
        if (location == null)
            return null;
        return location.getFile();
    }

    /**
     * 
         * get name. java.lang.Object[][].class => "java.lang.Object[][]"
     * java.lang.Object ==> "java.lang.Object"
     * 
    
     *
     * @param c class.
     * @return name.
     */
    public static String getName(Class c) {
        if (c.isArray()) {
            StringBuilder sb = new StringBuilder();
            do {
                sb.append("[]");
                c = c.getComponentType();
            } while (c.isArray());

            return c.getName() + sb.toString();
        }
        return c.getName();
    }

    /**
     * 获取实现接口上的泛型类型
     *
     * @param cls 类型
     * @return 实现接口的泛型
     */
    public static Class getGenericClass(Class cls) {
        return getGenericClass(cls, 0);
    }

    /**
     * 获取实现接口上的泛型类型
     *
     * @param cls 类型
     * @param i   第几个泛型参数
     * @return 实现接口的泛型
     */
    public static Class getGenericClass(Class cls, int i) {
        try {
            ParameterizedType parameterizedType = ((ParameterizedType) cls.getGenericInterfaces()[0]);
            Object genericClass = parameterizedType.getActualTypeArguments()[i];
            if (genericClass instanceof ParameterizedType) {
                return (Class) ((ParameterizedType) genericClass).getRawType();
            } else if (genericClass instanceof GenericArrayType) {
                return (Class) ((GenericArrayType) genericClass).getGenericComponentType();
            } else {
                return (Class) genericClass;
            }
        } catch (Throwable e) {
            throw new IllegalArgumentException(cls.getName() + " generic type undefined!", e);
        }
    }

    /**
     * 
         * get method name. "void do(int)", "void do()", "int do(java.lang.String,boolean)"
     *
     * 
    
     *
     * @param m method.
     * @return name.
     */
    public static String getName(final Method m) {
        StringBuilder ret = new StringBuilder();
        ret.append(getName(m.getReturnType())).append(' ');
        ret.append(m.getName()).append('(');
        Class[] parameterTypes = m.getParameterTypes();
        for (int i = 0; i < parameterTypes.length; i++) {
            if (i > 0)
                ret.append(',');
            ret.append(getName(parameterTypes[i]));
        }
        ret.append(')');
        return ret.toString();
    }

    /**
     * 获取一个方法的展示label
     *
     * @param methodName     方法名
     * @param parameterTypes 参数
     * @return 展示label
     */
    public static String getSignature(String methodName, Class[] parameterTypes) {
        StringBuilder sb = new StringBuilder(methodName);
        sb.append("(");
        if (parameterTypes != null && parameterTypes.length > 0) {
            boolean first = true;
            for (Class type : parameterTypes) {
                if (first) {
                    first = false;
                } else {
                    sb.append(",");
                }
                sb.append(type.getName());
            }
        }
        sb.append(")");
        return sb.toString();
    }

    /**
     * 
         * get constructor name. "()", "(java.lang.String,int)"
     * 
    
     *
     * @param c constructor.
     * @return name.
     */
    public static String getName(final Constructor c) {
        StringBuilder ret = new StringBuilder("(");
        Class[] parameterTypes = c.getParameterTypes();
        for (int i = 0; i < parameterTypes.length; i++) {
            if (i > 0)
                ret.append(',');
            ret.append(getName(parameterTypes[i]));
        }
        ret.append(')');
        return ret.toString();
    }

    /**
     * 
         * get class desc.
     * boolean[].class => "[Z"
     * Object.class => "Ljava/lang/Object;"
     * 获取类型的虚拟机表示形式
     *
     * 
    
     *
     * @param c class.
     * @return desc.
     */
    public static String getDesc(Class c) {
        StringBuilder ret = new StringBuilder();

        while (c.isArray()) {
            ret.append('[');
            c = c.getComponentType();
        }

        if (c.isPrimitive()) {
            String t = c.getName();
            if ("void".equals(t))
                ret.append(JVM_VOID);
            else if ("boolean".equals(t))
                ret.append(JVM_BOOLEAN);
            else if ("byte".equals(t))
                ret.append(JVM_BYTE);
            else if ("char".equals(t))
                ret.append(JVM_CHAR);
            else if ("double".equals(t))
                ret.append(JVM_DOUBLE);
            else if ("float".equals(t))
                ret.append(JVM_FLOAT);
            else if ("int".equals(t))
                ret.append(JVM_INT);
            else if ("long".equals(t))
                ret.append(JVM_LONG);
            else if ("short".equals(t))
                ret.append(JVM_SHORT);
        } else {
            ret.append('L');
            ret.append(c.getName().replace('.', '/'));
            ret.append(';');
        }
        return ret.toString();
    }

    /**
     * 
         * get class array desc.
     * [int.class, boolean[].class, Object.class] => "I[ZLjava/lang/Object;"
     * 
    
     *
     * @param cs class array.
     * @return desc.
     */
    public static String getDesc(final Class[] cs) {
        if (cs.length == 0)
            return "";

        StringBuilder sb = new StringBuilder(64);
        for (Class c : cs)
            sb.append(getDesc(c));
        return sb.toString();
    }

    /**
     * 
         * get method desc.
     * int do(int arg1) => "do(I)I"
     * void do(String arg1,boolean arg2) => "do(Ljava/lang/String;Z)V"
     * 
    
     *
     * @param m method.
     * @return desc.
     */
    public static String getDesc(final Method m) {
        StringBuilder ret = new StringBuilder(m.getName()).append('(');
        Class[] parameterTypes = m.getParameterTypes();
        for (int i = 0; i < parameterTypes.length; i++)
            ret.append(getDesc(parameterTypes[i]));
        ret.append(')').append(getDesc(m.getReturnType()));
        return ret.toString();
    }

    /**
     * 
         * get constructor desc.
     * public A() ==> "()V"
     * public A(String, int) ==> "(Ljava/lang/String;I)V"
     * 
    
     *
     * @param c constructor.
     * @return desc
     */
    public static String getDesc(final Constructor c) {
        StringBuilder ret = new StringBuilder("(");
        Class[] parameterTypes = c.getParameterTypes();
        for (int i = 0; i < parameterTypes.length; i++)
            ret.append(getDesc(parameterTypes[i]));
        ret.append(')').append('V');
        return ret.toString();
    }

    /**
     * 
         * get method desc. "(I)I", "()V", "(Ljava/lang/String;Z)V"
     * 
    
     *
     * @param m method.
     * @return desc.
     */
    public static String getDescWithoutMethodName(Method m) {
        StringBuilder ret = new StringBuilder();
        ret.append('(');
        Class[] parameterTypes = m.getParameterTypes();
        for (int i = 0; i < parameterTypes.length; i++)
            ret.append(getDesc(parameterTypes[i]));
        ret.append(')').append(getDesc(m.getReturnType()));
        return ret.toString();
    }

    /**
     * 
         * name to desc. java.util.Map[][] => "[[Ljava/util/Map;"
     * 
    
     *
     * @param name name.
     * @return desc.
     */
    public static String name2desc(String name) {
        StringBuilder sb = new StringBuilder();
        int c = 0, index = name.indexOf('[');
        if (index > 0) {
            c = (name.length() - index) / 2;
            name = name.substring(0, index);
        }
        while (c-- > 0)
            sb.append("[");
        if ("void".equals(name))
            sb.append(JVM_VOID);
        else if ("boolean".equals(name))
            sb.append(JVM_BOOLEAN);
        else if ("byte".equals(name))
            sb.append(JVM_BYTE);
        else if ("char".equals(name))
            sb.append(JVM_CHAR);
        else if ("double".equals(name))
            sb.append(JVM_DOUBLE);
        else if ("float".equals(name))
            sb.append(JVM_FLOAT);
        else if ("int".equals(name))
            sb.append(JVM_INT);
        else if ("long".equals(name))
            sb.append(JVM_LONG);
        else if ("short".equals(name))
            sb.append(JVM_SHORT);
        else
            sb.append('L').append(name.replace('.', '/')).append(';');
        return sb.toString();
    }

    /**
     * 
         * desc to name.
     * "[[I" => "int[][]"
     * 
    
     *
     * @param desc desc.
     * @return name.
     */
    public static String desc2name(String desc) {
        StringBuilder sb = new StringBuilder();
        int c = desc.lastIndexOf('[') + 1;
        if (desc.length() == c + 1) {
            switch (desc.charAt(c)) {
                case JVM_VOID: {
                    sb.append("void");
                    break;
                }
                case JVM_BOOLEAN: {
                    sb.append("boolean");
                    break;
                }
                case JVM_BYTE: {
                    sb.append("byte");
                    break;
                }
                case JVM_CHAR: {
                    sb.append("char");
                    break;
                }
                case JVM_DOUBLE: {
                    sb.append("double");
                    break;
                }
                case JVM_FLOAT: {
                    sb.append("float");
                    break;
                }
                case JVM_INT: {
                    sb.append("int");
                    break;
                }
                case JVM_LONG: {
                    sb.append("long");
                    break;
                }
                case JVM_SHORT: {
                    sb.append("short");
                    break;
                }
                default:
                    throw new RuntimeException();
            }
        } else {
            sb.append(desc.substring(c + 1, desc.length() - 1).replace('/', '.'));
        }
        while (c-- > 0)
            sb.append("[]");
        return sb.toString();
    }

    /**
     * 
         * 根据类名加载一个类型
     *
     * "boolean" => boolean.class
     * "java.common.Map[][]" => java.common.Map[][].class
     * 
    
     *
     * @param name 类名
     * @return 类型
     */
    public static Class forName(String name) {
        try {
            return name2class(name);
        } catch (ClassNotFoundException e) {
            throw new IllegalStateException("Not found class " + name + ", cause: " + e.getMessage(), e);
        }
    }

    /**
     * name to class. "boolean" => boolean.class "java.common.Map[][]" => java.common.Map[][].class
     *
     * @param name name.
     * @return Class instance.
     */
    public static Class name2class(String name) throws ClassNotFoundException {
        return null;
    }

    /**
     * name to class. "boolean" => boolean.class "java.common.Map[][]" => java.common.Map[][].class
     *
     * @param cl   ClassLoader instance.
     * @param name name.
     * @return Class instance.
     */
    private static Class name2class(ClassLoader cl, String name) throws ClassNotFoundException {

        return null;
    }

    /**
     * 
         * desc to class.
     * "[Z" => boolean[].class
     * "[[Ljava/common/Map;" => java.common.Map[][].class
     * 
    
     *
     * @param desc desc.
     * @return Class instance.
     * @throws ClassNotFoundException
     */
    public static Class desc2class(String desc) throws ClassNotFoundException {
        return null;
    }

    /**
     * desc to class. "[Z" => boolean[].class "[[Ljava/common/Map;" => java.common.Map[][].class
     *
     * @param cl   ClassLoader instance.
     * @param desc desc.
     * @return Class instance.
     * @throws ClassNotFoundException
     */
    private static Class desc2class(ClassLoader cl, String desc) throws ClassNotFoundException {

        return null;
    }

    /**
     * get class array instance.
     *
     * @param desc desc.
     * @return Class class array.
     * @throws ClassNotFoundException
     */
    public static Class[] desc2classArray(String desc) throws ClassNotFoundException {
        return null;
    }

    /**
     * get class array instance.
     *
     * @param cl   ClassLoader instance.
     * @param desc desc.
     * @return Class[] class array.
     * @throws ClassNotFoundException
     */
    private static Class[] desc2classArray(ClassLoader cl, String desc) throws ClassNotFoundException {
        if (desc.length() == 0)
            return EMPTY_CLASS_ARRAY;

        List> cs = new ArrayList>();
        Matcher m = DESC_PATTERN.matcher(desc);
        while (m.find())
            cs.add(desc2class(cl, m.group()));
        return cs.toArray(EMPTY_CLASS_ARRAY);
    }

    /**
     * 
         * 根据方法名称和参数类型名查找Method
     * 
    
     *
     * @param clazz          类型
     * @param methodName     方法名
     * @param parameterTypes 参数
     * @return method
     * @throws NoSuchMethodException
     * @throws ClassNotFoundException
     */
    public static Method findMethodByMethodSignature(Class clazz, String methodName, String[] parameterTypes)
            throws NoSuchMethodException, ClassNotFoundException {
        String signature = methodName;
        if (parameterTypes != null && parameterTypes.length > 0) {
            signature = methodName + org.apache.commons.lang.StringUtils.join(parameterTypes);
        }
        Method method = Signature_METHODS_CACHE.get(signature);
        if (method != null) {
            return method;
        }
        if (parameterTypes == null) {
            List finded = new ArrayList();
            for (Method m : clazz.getMethods()) {
                if (m.getName().equals(methodName)) {
                    finded.add(m);
                }
            }
            if (finded.isEmpty()) {
                throw new NoSuchMethodException("No such method " + methodName + " in class " + clazz);
            }
            if (finded.size() > 1) {
                String msg = String.format("Not unique method for method name(%s) in class(%s), find %d methods.",
                        methodName, clazz.getName(), finded.size());
                throw new IllegalStateException(msg);
            }
            method = finded.get(0);
        } else {
            Class[] types = new Class[parameterTypes.length];
            for (int i = 0; i < parameterTypes.length; i++) {
                types[i] = ReflectUtils.name2class(parameterTypes[i]);
            }
            method = clazz.getMethod(methodName, types);

        }
        Signature_METHODS_CACHE.put(signature, method);
        return method;
    }

    /**
     * 
         * 根据方法名称和参数类型名查找Method，没有参数的方法
     * 
    
     *
     * @param clazz      类型
     * @param methodName 方法名
     * @return 方法
     * @throws NoSuchMethodException
     * @throws ClassNotFoundException
     */
    public static Method findMethodByMethodName(Class clazz, String methodName) throws NoSuchMethodException,
            ClassNotFoundException {
        return findMethodByMethodSignature(clazz, methodName, null);
    }

    /**
     * 获取一个有参数的构造函数
     *
     * @param clazz     类型
     * @param paramType 参数类型
     * @return 构造函数
     * @throws NoSuchMethodException
     */
    public static Constructor findConstructor(Class clazz, Class paramType) throws NoSuchMethodException {
        Constructor targetConstructor;
        try {
            targetConstructor = clazz.getConstructor(new Class[]{paramType});
        } catch (NoSuchMethodException e) {
            targetConstructor = null;
            Constructor[] constructors = clazz.getConstructors();
            for (Constructor constructor : constructors) {
                if (Modifier.isPublic(constructor.getModifiers()) && constructor.getParameterTypes().length == 1
                        && constructor.getParameterTypes()[0].isAssignableFrom(paramType)) {
                    targetConstructor = constructor;
                    break;
                }
            }
            if (targetConstructor == null) {
                throw e;
            }
        }
        return targetConstructor;
    }

    /**
     * 当前实例是否实现了对应的接口
     *
     * @param obj                实例
     * @param interfaceClazzName 接口
     * @return true表示实现了
     */
    public static boolean isInstance(Object obj, String interfaceClazzName) {
        for (Class clazz = obj.getClass(); clazz != null && !clazz.equals(Object.class); clazz = clazz
                .getSuperclass()) {
            Class[] interfaces = clazz.getInterfaces();
            for (Class itf : interfaces) {
                if (itf.getName().equals(interfaceClazzName)) {
                    return true;
                }
            }
        }
        return false;
    }

    /**
     * 获取一个默认类型的默认对象
     *
     * @param returnType 类型
     * @return 默认对象
     */
    public static Object getEmptyObject(Class returnType) {
        return getEmptyObject(returnType, new HashMap, Object>(), 0);
    }

    private static Object getEmptyObject(Class returnType, Map, Object> emptyInstances, int level) {
        if (level > 2)
            return null;
        if (returnType == null) {
            return null;
        } else if (returnType == boolean.class || returnType == Boolean.class) {
            return false;
        } else if (returnType == char.class || returnType == Character.class) {
            return '\0';
        } else if (returnType == byte.class || returnType == Byte.class) {
            return (byte) 0;
        } else if (returnType == short.class || returnType == Short.class) {
            return (short) 0;
        } else if (returnType == int.class || returnType == Integer.class) {
            return 0;
        } else if (returnType == long.class || returnType == Long.class) {
            return 0L;
        } else if (returnType == float.class || returnType == Float.class) {
            return 0F;
        } else if (returnType == double.class || returnType == Double.class) {
            return 0D;
        } else if (returnType.isArray()) {
            return Array.newInstance(returnType.getComponentType(), 0);
        } else if (returnType.isAssignableFrom(ArrayList.class)) {
            return new ArrayList(0);
        } else if (returnType.isAssignableFrom(HashSet.class)) {
            return new HashSet(0);
        } else if (returnType.isAssignableFrom(HashMap.class)) {
            return new HashMap(0);
        } else if (String.class.equals(returnType)) {
            return "";
        } else if (!returnType.isInterface()) {
            try {
                Object value = emptyInstances.get(returnType);
                if (value == null) {
                    value = returnType.newInstance();
                    emptyInstances.put(returnType, value);
                }
                Class cls = value.getClass();
                while (cls != null && cls != Object.class) {
                    Field[] fields = cls.getDeclaredFields();
                    for (Field field : fields) {
                        Object property = getEmptyObject(field.getType(), emptyInstances, level + 1);
                        if (property != null) {
                            try {
                                if (!field.isAccessible()) {
                                    field.setAccessible(true);
                                }
                                field.set(value, property);
                            } catch (Throwable e) {
                            }
                        }
                    }
                    cls = cls.getSuperclass();
                }
                return value;
            } catch (Throwable e) {
                return null;
            }
        } else {
            return null;
        }
    }

    /**
     * 方法是否是get方法
     *
     * @param method 方法
     * @return 是否读方法
     */
    public static boolean isBeanPropertyReadMethod(Method method) {
        return method != null
                && Modifier.isPublic(method.getModifiers())
                && !Modifier.isStatic(method.getModifiers())
                && method.getReturnType() != void.class
                && method.getDeclaringClass() != Object.class
                && method.getParameterTypes().length == 0
                && ((method.getName().startsWith("get") && method.getName().length() > 3) || (method.getName()
                .startsWith("is") && method.getName().length() > 2));
    }

    public static String getPropertyNameFromBeanReadMethod(Method method) {
        if (isBeanPropertyReadMethod(method)) {
            if (method.getName().startsWith("get")) {
                return method.getName().substring(3, 4).toLowerCase() + method.getName().substring(4);
            }
            if (method.getName().startsWith("is")) {
                return method.getName().substring(2, 3).toLowerCase() + method.getName().substring(3);
            }
        }
        return null;
    }

    public static boolean isBeanPropertyWriteMethod(Method method) {
        return method != null && Modifier.isPublic(method.getModifiers()) && !Modifier.isStatic(method.getModifiers())
                && method.getDeclaringClass() != Object.class && method.getParameterTypes().length == 1
                && method.getName().startsWith("set") && method.getName().length() > 3;
    }

    public static String getPropertyNameFromBeanWriteMethod(Method method) {
        if (isBeanPropertyWriteMethod(method)) {
            return method.getName().substring(3, 4).toLowerCase() + method.getName().substring(4);
        }
        return null;
    }

    public static boolean isPublicInstanceField(Field field) {
        return Modifier.isPublic(field.getModifiers()) && !Modifier.isStatic(field.getModifiers())
                && !Modifier.isFinal(field.getModifiers()) && !field.isSynthetic();
    }
}    
    
    
    

    




    
    
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