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为什么阿里巴巴禁止使用Apache Beanutils进行属性的copy?
如我们经常在代码中会对一个数据结构封装成DO、SDO、DTO、VO等,而这些Bean中的大部分属性都是一样的,所以使用属性拷贝类工具可以帮助我们节省大量的set和get操作。市面上有很多类似的工具类,比较常用的有1、Spring BeanUtils 2、Cglib BeanCopier 3、Apache BeanUtils 4、Apache PropertyUtils 5、Dozer那么,我们到底应该选择哪种工具类更加合适呢?为什么阿里巴巴Java开发手册中提到禁止使用Apache BeanUtils呢?
由于篇幅优先,关于这几种工具类的用法及区别,还有到底是什么是浅拷贝和深拷贝不在本文的讨论范围内。
本文主要聚焦于对比这几个类库的性能问题。
性能对比No Data No BB,我们就来写代码来对比下这几种框架的性能情况。代码示例如下:首先定义一个PersonDO类:
public class PersonDO { private Integer id;
private String name;
private Integer age;
private Date birthday;
//省略setter/getter }
再定义一个PersonDTO类:
public class PersonDTO {
private String name;
private Integer age;
private Date birthday;
}
然后进行测试类的编写:使用Spring BeanUtils进行属性拷贝:
private void mappingBySpringBeanUtils(PersonDO personDO, int times) {
StopWatch stopwatch = new StopWatch();
stopwatch.start();
for (int i = 0; i < times; i++) {
PersonDTO personDTO = new PersonDTO();
org.springframework.beans.BeanUtils.copyProperties(personDO, personDTO);
}
stopwatch.stop();
System.out.println("mappingBySpringBeanUtils cost :" + stopwatch.getTotalTimeMillis());
}
其中的StopWatch用于记录代码执行时间,方便进行对比。使用Cglib BeanCopier进行属性拷贝:
private void mappingByCglibBeanCopier(PersonDO personDO, int times) {
StopWatch stopwatch = new StopWatch();
stopwatch.start();
for (int i = 0; i < times; i++) {
PersonDTO personDTO = new PersonDTO();
BeanCopier copier = BeanCopier.create(PersonDO.class, PersonDTO.class, false);
copier.copy(personDO, personDTO, null);
}
stopwatch.stop();
System.out.println("mappingByCglibBeanCopier cost :" + stopwatch.getTotalTimeMillis());
}
使用Apache BeanUtils进行属性拷贝:
private void mappingByApacheBeanUtils(PersonDO personDO, int times)
throws InvocationTargetException, IllegalAccessException {
StopWatch stopwatch = new StopWatch();
stopwatch.start();
for (int i = 0; i < times; i++) {
PersonDTO personDTO = new PersonDTO();
BeanUtils.copyProperties(personDTO, personDO);
}
stopwatch.stop();
System.out.println("mappingByApacheBeanUtils cost :" + stopwatch.getTotalTimeMillis());
}
使用Apache PropertyUtils进行属性拷贝:
private void mappingByApachePropertyUtils(PersonDO personDO, int times)
throws InvocationTargetException, IllegalAccessException, NoSuchMethodException {
StopWatch stopwatch = new StopWatch();
stopwatch.start();
for (int i = 0; i < times; i++) {
PersonDTO personDTO = new PersonDTO();
PropertyUtils.copyProperties(personDTO, personDO);
}
stopwatch.stop();
System.out.println("mappingByApachePropertyUtils cost :" + stopwatch.getTotalTimeMillis());
}
然后执行以下代码:
public static void main(String[] args) throws InvocationTargetException, IllegalAccessException, NoSuchMethodException {
PersonDO personDO = new PersonDO();
personDO.setName("Hollis");
personDO.setAge(26);
personDO.setBirthday(new Date());
personDO.setId(1);
MapperTest mapperTest = new MapperTest();
mapperTest.mappingBySpringBeanUtils(personDO, 100);
mapperTest.mappingBySpringBeanUtils(personDO, 1000);
mapperTest.mappingBySpringBeanUtils(personDO, 10000);
mapperTest.mappingBySpringBeanUtils(personDO, 100000);
mapperTest.mappingBySpringBeanUtils(personDO, 1000000);
mapperTest.mappingByCglibBeanCopier(personDO, 100);
mapperTest.mappingByCglibBeanCopier(personDO, 1000);
mapperTest.mappingByCglibBeanCopier(personDO, 10000);
mapperTest.mappingByCglibBeanCopier(personDO, 100000);
mapperTest.mappingByCglibBeanCopier(personDO, 1000000);
mapperTest.mappingByApachePropertyUtils(personDO, 100);
mapperTest.mappingByApachePropertyUtils(personDO, 1000);
mapperTest.mappingByApachePropertyUtils(personDO, 10000);
mapperTest.mappingByApachePropertyUtils(personDO, 100000);
mapperTest.mappingByApachePropertyUtils(personDO, 1000000);
mapperTest.mappingByApacheBeanUtils(personDO, 100);
mapperTest.mappingByApacheBeanUtils(personDO, 1000);
mapperTest.mappingByApacheBeanUtils(personDO, 10000);
mapperTest.mappingByApacheBeanUtils(personDO, 100000);
mapperTest.mappingByApacheBeanUtils(personDO, 1000000);
得到结果如下:
画了一张折线图更方便大家进行对比
综上,我们基本可以得出结论,在性能方面,Spring BeanUtils和Cglib BeanCopier表现比较不错,而Apache PropertyUtils、Apache BeanUtils以及Dozer则表现的很不好。
所以,如果考虑性能情况的话,建议大家不要选择Apache PropertyUtils、Apache BeanUtils以及Dozer等工具类。很多人会不理解,为什么大名鼎鼎的Apache开源出来的的类库性能确不高呢?这不像是Apache的风格呀,这背后导致性能低下的原因又是什么呢?其实,是因为Apache BeanUtils力求做得完美, 在代码中增加了非常多的校验、兼容、日志打印等代码,过度的包装导致性能下降严重。
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