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package com.demo;import lombok.Data;import org.springframework.beans.BeanUtils;import java.util.Arrays;import java.util.List;/** * @author xiaobu * @version JDK1.8.0_171 * @date on 2019/10/8 10:04 * @description */public class BeanUtilsTest { @Data private static class CopyTest1 { private String outerName; private CopyTest1.InnerClass innerClass; private List clazz; @Data private static class InnerClass { public String innerName; } } @Data private static class CopyTest2 { private String outerName; private CopyTest2.InnerClass innerClass; private List clazz; @Data static class InnerClass { private String innerName; } } public static void main(String[] args) { CopyTest1 copyTest1 = new CopyTest1(); copyTest1.outerName = "outer xiaobu"; CopyTest1.InnerClass innerClass = new CopyTest1.InnerClass(); innerClass.innerName = "inner xiaobu"; copyTest1.innerClass = innerClass; copyTest1.clazz = Arrays.asList(1, 2, 3); System.out.println("copyTest1 = " + copyTest1); CopyTest2 copyTest2 = new CopyTest2(); //未copy内部类的属性 BeanUtils.copyProperties(copyTest1, copyTest2); System.out.println("copy内部类的属性前copyTest2 = " + copyTest2); CopyTest2.InnerClass innerClass2 = new CopyTest2.InnerClass(); copyTest2.innerClass = innerClass2; BeanUtils.copyProperties(innerClass, innerClass2); System.out.println("copy内部类的属性后copyTest2 = " + copyTest2); }}
总结
Spring的BeanUtils的CopyProperties方法需要对应的属性有getter和setter方法;
如果存在属性完全相同的内部类,但是不是同一个内部类,即分别属于各自的内部类,则spring会认为属性不同,不会copy;
泛型只在编译期起作用,不能依靠泛型来做运行期的限制;
最后,spring和apache的copy属性的方法源和目的参数的位置正好相反,所以导包和调用的时候都要注意一下。
泛型只在编译期起作用,不能依靠泛型来做运行期的限制
package com.demo;import java.lang.reflect.InvocationTargetException;import java.lang.reflect.Method;import java.util.ArrayList;/** * @author xiaobu * @version JDK1.8.0_171 * @date on 2019/10/8 14:54 * @description */public class Demo { public static void main(String[] args) throws ClassNotFoundException, NoSuchMethodException, InvocationTargetException, IllegalAccessException { ArrayListlist = new ArrayList (); list.add(111); list.add(222); list.add("xiaobu"); //编译器报错 Class clazz3 = Class.forName("java.util.ArrayList");//获取ArrayList的字节码文件 Method m = clazz3.getMethod("add", Object.class);//获取add() 方法,Object.class 代表任意对象类型的数据 m.invoke(list,"xiaobu");//通过反射添加字符串类型元素数据 System.out.println(list);//运行结果:[111, 222, xiaobu] }}
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