这里在网上找了一份ReflectionUtils
package com.litian.jdbc; /** * @author: Li Tian * @contact: [email protected] * @software: IntelliJ IDEA * @file: ReflectionUtils.java * @time: 2020/3/26 18:57 * @desc: |JDBC 查询得到属性字段 反射机制返回到 JavaBean中相同类属性名的对象中 */ import java.lang.reflect.*; public class ReflectionUtils { /** * 使 filed 变为可访问 * * @param field */ public static void makeAccessible(Field field) { if (!Modifier.isPublic(field.getModifiers())) { field.setAccessible(true); } } /** * 直接设置对象的属性，忽略 private/protected 修饰符, 也不经过 setter * * @param object * @param fieldName 属性名称 * @param value */ public static void setFieldValue(Object object, String fieldName, Object value) { Field field = getDeclaredField(object, fieldName); if (field == null) throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + object + "]"); // 让 private 元素变得可以访问,field.setAccessible(); makeAccessible(field); try { field.set(object, value); } catch (IllegalArgumentException | IllegalAccessException e) { // TODO Auto-generated catch block e.printStackTrace(); } } /** * 循环向上转型, 获取对象的 DeclaredField * * @param object * @param filedName * @return */ public static Field getDeclaredField(Object object, String filedName) { // 一步步的循环得到 获取声明对象的祖宗类 for (Class<?> superClass = object.getClass(); superClass != Object.class; superClass = superClass.getSuperclass()) { try { return superClass.getDeclaredField(filedName); } catch (NoSuchFieldException | SecurityException e) { // TODO Auto-generated catch block e.printStackTrace(); } } return null; } /** * 直接读取对象的属性值, 忽略 private/protected 修饰符, 也不经过 getter * * @param object * @param fieldName * @return */ public static Object getFieldValue(Object object, String fieldName) { Field field = getDeclaredField(object, fieldName); if (field == null) throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + object + "]"); makeAccessible(field); Object result = null; try { result = field.get(object); } catch (IllegalArgumentException | IllegalAccessException e) { // TODO Auto-generated catch block e.printStackTrace(); } return result; } /** * 循环向上转型, 获取对象的 DeclaredMethod * * @param object * @param methodName * @param parameterTypes: 指定特定成员方法有重载可能性，必须指定特定的类型变量 * @return */ public static Method getDeclaredMethod(Object object, String methodName, Class<?>[] parameterTypes) { for (Class<?> superClass = object.getClass(); superClass != Object.class; superClass = superClass.getSuperclass()) { try { //superClass.getMethod(methodName, parameterTypes); return superClass.getDeclaredMethod(methodName, parameterTypes); } catch (NoSuchMethodException e) { //Method 不在当前类定义, 继续向上转型 } //.. } return null; } /** * 直接调用对象方法, 而忽略修饰符(private, protected) * * @param object * @param methodName * @param parameterTypes * @param parameters * @return * @throws InvocationTargetException * @throws IllegalArgumentException */ public static Object invokeMethod(Object object, String methodName, Class<?>[] parameterTypes, Object[] parameters) throws InvocationTargetException { Method method = getDeclaredMethod(object, methodName, parameterTypes); if (method == null) throw new IllegalArgumentException("Could not find method [" + methodName + "] on target [" + object + "]"); method.setAccessible(true); // 使用 method.invoke()方法进行运行 try { method.invoke(object, parameters); } catch (IllegalAccessException | IllegalArgumentException e) { // TODO Auto-generated catch block e.printStackTrace(); } return method; } /** * 通过反射, 获得定义 Class 时声明的父类的泛型参数的类型 * 如: public EmployeeDao extends BaseDao<Employee, String> * * @param clazz * @return */ public static Class getSuperClassGenricType(Class clazz, int index) { Type genType = clazz.getGenericSuperclass(); // 判定s是否是ParameterType相对应的 if (!(genType instanceof ParameterizedType)) return Object.class; // 强制转换 获取超类泛型参数实际类型，返回genType 是类的接口，基本类型或者void Type[] params = ((ParameterizedType) genType).getActualTypeArguments(); if (index >= params.length || index < 0) return Object.class; if (!(params[index] instanceof Class)) return Object.class; return (Class) params[index]; } /** * 通过反射,获得Class定义中声明的父类的泛型参数的类型. * eg. * public UserDao extends HibernateDao<User> * * @param clazz The class to introspect * @return the first generic declaration, or Object.class if cannot be determined */ @SuppressWarnings("unchecked") public static <T> Class<T> getSuperClassGenricType(final Class clazz) { return getSuperClassGenricType(clazz, 0); } }
JAVA类属性
在JAVAEE中，JAVA类的属性通过getter，setter来定义：get（set）方法：去除get（或set）后，首字母小写即为该类的属性。
而之前的属性，即成员变量称之为字段。
操作java类的属性有一个工具包：beanutils（需要结合logging来用）
BeanUtils.setProperty()
BeanUtils.getProperty()
一般情况下，字段名和属性名都一致
通过该工具包可以将之前的ReflectionUtil替换为：BeanUtils.setProperty(entity, propertyName, value);
BeanUtils测试代码
package com.litian.jdbc; import org.apache.commons.beanutils.BeanUtils; import java.lang.reflect.InvocationTargetException; /** * @author: Li Tian * @contact: [email protected] * @software: IntelliJ IDEA * @file: BeanUtilsTest.java * @time: 2020/3/27 15:37 * @desc: |测试工具包beanutils */ public class BeanUtilsTest { public static void main(String[] args) throws InvocationTargetException, IllegalAccessException, NoSuchMethodException { // 测试赋值操作 Object obj = new User(); System.out.println(obj); BeanUtils.setProperty(obj, "username", "二哈"); System.out.println(obj); // 测试获取操作 Object val = BeanUtils.getProperty(obj, "username"); System.out.println(val); } }
————————————————
版权声明：本文为CSDN博主「李英俊小朋友」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.csdn.net/qq_21579045/article/details/105386353