java reflections_Reflections.java反射工具类 | 学步园
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 org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.Validate;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.Assert;
/**
* 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.
*/
@SuppressWarnings("rawtypes")
public class Reflections {
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(Reflections.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
if(i
String getterMethodName = GETTER_PREFIX + StringUtils.capitalize(names[i]);
object = invokeMethod(object, getterMethodName, new Class[] {}, new Object[] {});
}else{
String setterMethodName = SETTER_PREFIX + StringUtils.capitalize(names[i]);
invokeMethodByName(object, setterMethodName, new Object[] { value });
}
}
}
/**
* 直接读取对象属性值, 无视private/protected修饰符, 不经过getter函数.
*/
public static Object getFieldValue(final Object obj, final String fieldName) {
Field field = getAccessibleField(obj, fieldName);
if (field == null) {
throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + obj + "]");
}
Object result = null;
try {
result = field.get(obj);
} catch (IllegalAccessException e) {
logger.error("不可能抛出的异常{}", e.getMessage());
}
return result;
}
/**
* 直接设置对象属性值, 无视private/protected修饰符, 不经过setter函数.
*/
public static void setFieldValue(final Object obj, final String fieldName, final Object value) {
Field field = getAccessibleField(obj, fieldName);
if (field == null) {
throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + obj + "]");
}
try {
field.set(obj, value);
} catch (IllegalAccessException e) {
logger.error("不可能抛出的异常:{}", e.getMessage());
}
}
/**
* 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getAccessibleMethod()函数获得Method后反复调用.
* 同时匹配方法名+参数类型，
*/
public static Object invokeMethod(final Object obj, final String methodName, final Class>[] 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) {
Assert.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);
}
}
法二：
import java.lang.reflect.Method;
import java.util.Hashtable;
import java.util.regex.Pattern;
/**
*
* @desc 通过反射来动态调用get 和 set 方法
*/
public class ReflectHelper {
private Class cls;
/**
* 传过来的对象
*/
private Object obj;
/**
* 存放get方法
*/
private Hashtable getMethods = null;
/**
* 存放set方法
*/
private Hashtable setMethods = null;
/**
* 定义构造方法 -- 一般来说是个pojo
*
* @param o
* 目标对象
*/
public ReflectHelper(Object o) {
obj = o;
initMethods();
}
/**
*
* @desc 初始化
*/
public void initMethods() {
getMethods = new Hashtable();
setMethods = new Hashtable();
cls = obj.getClass();
Method[] methods = cls.getMethods();
// 定义正则表达式，从方法中过滤出getter / setter 函数.
String gs = "get(\\w+)";
Pattern getM = Pattern.compile(gs);
String ss = "set(\\w+)";
Pattern setM = Pattern.compile(ss);
// 把方法中的"set" 或者 "get" 去掉
String rapl = "$1";
String param;
for (int i = 0; i < methods.length; ++i) {
Method m = methods[i];
String methodName = m.getName();
if (Pattern.matches(gs, methodName)) {
param = getM.matcher(methodName).replaceAll(rapl).toLowerCase();
getMethods.put(param, m);
} else if (Pattern.matches(ss, methodName)) {
param = setM.matcher(methodName).replaceAll(rapl).toLowerCase();
setMethods.put(param, m);
} else {
// System.out.println(methodName + " 不是getter,setter方法！");
}
}
}
/**
*
* @desc 调用set方法
*/
public boolean setMethodValue(String property,Object object) {
Method m = setMethods.get(property.toLowerCase());
if (m != null) {
try {
// 调用目标类的setter函数
m.invoke(obj, object);
return true;
} catch (Exception ex) {
System.out.println("invoke getter on " + property + " error: " + ex.toString());
return false;
}
}
return false;
}
/**
*
* @desc 调用set方法
*/
public Object getMethodValue(String property) {
Object value=null;
Method m = getMethods.get(property.toLowerCase());
if (m != null) {
try {
/**
* 调用obj类的setter函数
*/
value=m.invoke(obj, new Object[] {});
} catch (Exception ex) {
System.out.println("invoke getter on " + property + " error: " + ex.toString());
}
}
return value;
}
}
再一个:
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.Arrays;
public class ClassReflectUtil {
/**
* 根据类名反射创建对象
* @param name 类名
* @return 对象
* @throws Exception
*/
public static Object getInstance(String name) throws Exception {
Class> cls = Class.forName(name);
return cls.newInstance();
}
/**
* 反射方法，打印对象的属性，方法，构造器属性
* @param obj 被反射对象
*/
public static void reflect(Object obj) {
Class> cls = obj.getClass();
System.out.println("************构 造 器************");
Constructor>[] constructors = cls.getConstructors();
for (Constructor> constructor : constructors) {
System.out.println("构造器名称:" + constructor.getName() + "\t"+ " "
+ "构造器参数类型:"
+ Arrays.toString(constructor.getParameterTypes()));
}
System.out.println("************属 性************");
Field[] fields = cls.getDeclaredFields();
// cls.getFields() 该方法只能访问共有的属性
// cls.getDeclaredFields() 可以访问私有属性
for (Field field : fields) {
System.out.println("属性名称:" + field.getName() + "\t"+ "属性类型:"
+ field.getType()+"\t");
}
System.out.println("************方 法************");
Method[] methods = cls.getMethods();
for (Method method : methods) {
System.out.println("方法名:" + method.getName() + "\t" + "方法返回类型："
+ method.getReturnType() + "\t"+ "方法参数类型:"
+ Arrays.toString(method.getParameterTypes()));
}
}
/**
*
* @param obj 访问对象
* @param filedname 对象的属性
* @return 返回对象的属性值
* @throws Exception
*/
public static Object getFieldValue(Object obj,String filedname) throws Exception{
//反射出类型
Class> cls = obj.getClass();
Field field = null;
//反射出类型字段
try {
field = cls.getDeclaredField(filedname);
} catch (Exception e) {
e.printStackTrace();
System.out.println("没有这个字段："+filedname);
}
//获取属性时，压制Java对访问修饰符的检查
field.setAccessible(true);
//在对象obj上读取field属性的值
Object val = field.get(obj);
return val;
}
/**
*
* @param obj 访问对象
* @param filedname 对象的属性
* @return 返回对象的属性值
* @throws Exception
*/
public static Object setIdKeyValue(Object obj,String filedname,String value) throws Exception{
//反射出类型
Class> cls = obj.getClass();
Field field = null;
//反射出类型字段
try {
field = cls.getDeclaredField(filedname);
} catch (Exception e) {
e.printStackTrace();
System.out.println("没有这个字段："+filedname);
}
if(field==null){
return null;
}
//获取属性时，压制Java对访问修饰符的检查
field.setAccessible(true);
//---------------------------------------------------
//针对表主键为字符类型进行赋值UUID,如果为int类型采用自增方式
if(!field.getType().getName().contains("Integer")){
field.set(obj, value);
}
//---------------------------------------------------
//在对象obj上读取field属性的值
Object val = field.get(obj);
field.setAccessible(false);
return val;
}
/**
*
* @param obj 访问对象
* @param filedname 对象的属性
* @return 返回对象的属性值
* @throws Exception
*/
public static Object setFieldValue(Object obj,String filedname,String value) throws Exception{
//反射出类型
Class> cls = obj.getClass();
Field field = null;
//反射出类型字段
try {
field = cls.getDeclaredField(filedname);
} catch (Exception e) {
e.printStackTrace();
System.out.println("没有这个字段："+filedname);
}
if(field==null){
return null;
}
//获取属性时，压制Java对访问修饰符的检查
field.setAccessible(true);
//在对象obj上读取field属性的值
Object val = field.get(obj);
field.setAccessible(false);
return val;
}
/**
* 反射调用对象的方法
* @param obj 对象
* @param methodName 方法名称
* @param paramType 参数类型 new Class[]{int.class,double.class}
* @param params 参数值 new Object[]{2,3.5}
* @return
* @throws Exception
*/
public static Object readObjMethod(Object obj,String methodName,Class>[] paramTypes,Object[] params) throws Exception{
//发现类型
Class> cls = obj.getClass();
//发现方法
Method method = cls.getDeclaredMethod(methodName, paramTypes);
//访问方法时,压制Java对访问修饰符的检查
method.setAccessible(true);
Object val = method.invoke(obj, params);
return val;
}
public static void main(String[] args) {
person p = new person();
p.setName("12");
try {
System.out.println(setFieldValue(p,"names","100"));
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
class person{
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}