1 package com.lovo.util; 2  3 import java.lang.reflect.Constructor; 4 import java.lang.reflect.Field; 5  6 public class MyUtil { 7     private MyUtil(){ 8         throw new AssertionError(); 9     }10     /**11      * 通过反射获取对象的字段值12      * @param target 目标对象13      * @param fieldName 字段名称14      * @return 字段的值或null15      */16     public static Object getValue(Object target,String fieldName) {17         Object value = http://www.mamicode.com/null;18         //用"."分割例如："car.engine"表示target对象的（Car类型）car属性的（Engine）engine属性值19         String[] strs = fieldName.split("\\.");20         for (int i = 0; i < strs.length; i++) {21             if (target != null) {22                 try {23                     Class<?> clazz = target.getClass();//得到target对象类的类类型对象（描述target对象类的类对象）24                     Field f = clazz.getDeclaredField(strs[i]);//得到属性25                     f.setAccessible(true);26                     if (i == strs.length - 1) {27                         value = http://www.mamicode.com/f.get(target);//得到属性值28                         return value;29                     } else {30                         target = f.get(target);//修改target31                     }32                 } catch (Exception e) {33                     throw new RuntimeException(e);34                 }35             }36         }37         return null;38     }39     /**40      * 设置属性值41      * @param target 目标对象42      * @param fieldName 属性43      * @param value 值44      */45     public static void setValue(Object target,String fieldName,Object value) {46         Class<?> clazz = target.getClass();47         String[] trs = fieldName.split("\\.");48         for (int i = 0; i < trs.length - 1; i++) {49             try {50                 Field f = clazz.getDeclaredField(trs[i]);51                 f.setAccessible(true);52 //                Object tempTarget = target;53 //                target = f.get(target);54                 if (f.get(target) == null) {55                     String type = f.getGenericType().toString();//得到值为null的属性的类型的字符串56                     String[] typeSplits = type.split(" ");57                     clazz = Class.forName(typeSplits[1]);//得到值为null的属性的类型的类类型对象58                     Constructor<?> con = clazz.getDeclaredConstructor();//得到属性的无参构造器59                     con.setAccessible(true); //有可能是private的所以设置可以访问60                     f.set(target, con.newInstance());//给null属性赋值61                 }62                 target = f.get(target);63                 clazz = target.getClass();64                 65             } catch (Exception e) {66                 e.printStackTrace();67                 throw new RuntimeException();68             } 69         }70         try {71             Field f = clazz.getDeclaredField(trs[trs.length - 1]);72             f.setAccessible(true);73             f.set(target, value);74             75         } catch (Exception e) {76             throw new RuntimeException();77         } 78     }79 }