大家需要注意BeanUtils工具类在spring-bean-4.3.12.RELEASE.jar和commons-beanutils.jar包中都有,但是两个类的参数是不一样的。
同时发现网对这个知识点讲解上大部分是错误的。希望我们的程序猿们对自己的博客都用心一点!!!
spring-bean-4.3.12.RELEASE.jar
/** * Copy the property values of the given source bean into the target bean. * <p>Note: The source and target classes do not have to match or even be derived * from each other, as long as the properties match. Any bean properties that the * source bean exposes but the target bean does not will silently be ignored. * <p>This is just a convenience method. For more complex transfer needs, * consider using a full BeanWrapper. * @param source the source bean * @param target the target bean * @throws BeansException if the copying failed * @see BeanWrapper */ public static void copyProperties(Object source, Object target) throws BeansException { copyProperties(source, target, null, (String[]) null); }
第一个参数是待拷贝的对象,第二个参数是目标对象
commons-beanutils.jar
/** * <p>Copy property values from the origin bean to the destination bean * for all cases where the property names are the same.</p> * * <p>For more details see <code>BeanUtilsBean</code>.</p> * * @param dest Destination bean whose properties are modified * @param orig Origin bean whose properties are retrieved * * @throws IllegalAccessException if the caller does not have * access to the property accessor method * @throws IllegalArgumentException if the <code>dest</code> or * <code>orig</code> argument is null or if the <code>dest</code> * property type is different from the source type and the relevant * converter has not been registered. * @throws InvocationTargetException if the property accessor method * throws an exception * @see BeanUtilsBean#copyProperties */ public static void copyProperties(final Object dest, final Object orig) throws IllegalAccessException, InvocationTargetException { BeanUtilsBean.getInstance().copyProperties(dest, orig); }
首先我们先看spring-bean-4.3.12.RELEASE.jar提供的工具类
import org.springframework.beans.BeanUtils; public class Test { public static void main(String ... args){ A a = new A(); a.setName("tom"); a.setAge(123); B b = new B(); BeanUtils.copyProperties(a,b); System.out.println(b); } } class A{ private String name; private Integer age; public String getName() { return name; } public void setName(String name) { this.name = name; } public Integer getAge() { return age; } public void setAge(Integer age) { this.age = age; } @Override public String toString() { return "A{" + "name='" + name + '\'' + ", age=" + age + '}'; } } class B{ private String name; private Integer age; public String getName() { return name; } public void setName(String name) { this.name = name; } public Integer getAge() { return age; } public void setAge(Integer age) { this.age = age; } @Override public String toString() { return "B{" + "name='" + name + '\'' + ", age=" + age + '}'; } }
输出结果
B{name='tom', age=123} Process finished with exit code 0
在我想尝试使用commons-beanutils工具包进行测试的时候,发现阿里已经不推荐使用,所以不再进行测试