Java反射之从对象获取值

我们在开发的过程中，可能会遇到需要动态地通过字符串获取某个值，该值来自于某个对象。

利用反射可以，方便获取。该类可提取为工具类，供众多类调用。

getValueFormObject方法就是从Object对象中获取该对象的属性名称当中，与fileName相同的值。

ReflectUtil.java

import java.lang.reflect.Field;public class ReflectUtil {public static Object getValueFormObject(Object object, String fieldName) {if (object==null){ // LOG.error("the fields is wrong,object is null,fieldName is "+fieldName);System.out.println("the fields is wrong,object is null,fieldName is "+fieldName);return null;}if(fieldName==null||fieldName=="") { // LOG.error("the fields is wrong,object is null,object is "+object.toString());System.out.println("the fields is wrong,object is null,fieldName is "+fieldName);return null;}Field field;try {field = object.getClass().getDeclaredField(fieldName);if (field != null) {field.setAccessible(true);return field.get(object);}} catch (NoSuchFieldException | IllegalAccessException e) { // LOG.error("Get Value Form Object Wrong");System.out.println("Get Value Form Object Wrong");}return null;}public static void main(String[] args) {Student student = new Student(1,"kangyucheng");Object obj1 = ReflectUtil.getValueFormObject(student, "name");Object obj2 = ReflectUtil.getValueFormObject(student, "id");System.out.println(obj1.toString());System.out.println(obj2.toString());}}

 在测试当中我们用到的学生类：

Student.java

public class Student {private Integer id;private String name;public Student(Integer id, String name) {this.id = id;this.name = name;}public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}}

测试结果：

kangyucheng 1

 

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