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本篇内容介绍了“常见Bean拷贝框架的性能有哪些区别”的有关知识，在实际案例的操作过程中，不少人都会遇到这样的困境，接下来就让小编带领大家学习一下如何处理这些情况吧！希望大家仔细阅读，能够学有所成！
当业务量不大时，不管选择哪个框架都没什么问题，只要功能支持就ok了；但是当数据量大的时候，可能就需要考虑性能问题了；再实际的项目中，正好遇到了这个问题，不仅慢，还发现会有锁竞争，这特么就尼普了
项目中使用的是Spring的 BeanUtils， 版本 3.2.4.RELEASE， 版本相对较老，主要问题在于org.springframework.beans.CachedIntrospectionResults.forClass
/**
* Create CachedIntrospectionResults for the given bean class.
* <P>We don't want to use synchronization here. Object references are atomic,
* so we can live with doing the occasional unnecessary lookup at startup only.
* @param beanClass the bean class to analyze
* @return the corresponding CachedIntrospectionResults
* @throws BeansException in case of introspection failure
*/
static CachedIntrospectionResults forClass(Class beanClass) throws BeansException {
CachedIntrospectionResults results;
Object value;
synchronized (classCache) {
value = classCache.get(beanClass);
}
if (value instanceof Reference) {
Reference ref = (Reference) value;
results = (CachedIntrospectionResults) ref.get();
}
else {
results = (CachedIntrospectionResults) value;
}
if (results == null) {
if (ClassUtils.isCacheSafe(beanClass, CachedIntrospectionResults.class.getClassLoader()) ||
isClassLoaderAccepted(beanClass.getClassLoader())) {
results = new CachedIntrospectionResults(beanClass);
synchronized (classCache) {
classCache.put(beanClass, results);
}
}
else {
if (logger.isDebugEnabled()) {
logger.debug("Not strongly caching class [" + beanClass.getName() + "] because it is not cache-safe");
}
results = new CachedIntrospectionResults(beanClass);
synchronized (classCache) {
classCache.put(beanClass, new WeakReference<CachedIntrospectionResults>(results));
}
}
}
return results;
}看上面的实现，每次获取value都加了一个同步锁，而且还是锁的全局的classCache，这就有些过分了啊，微妙的是这段代码注释，谷歌翻译之后为
我们不想在这里使用同步。 对象引用是原子的，因此我们可以只在启动时进行偶尔的不必要查找。
这意思大概是说我就在启动的时候用一下，并不会频繁的使用，所以使用了同步代码块也问题不大...
但是在BeanUtils#copyProperties中就蛋疼了，每次都会执行这个方法，扎心了
当然我们现在一般用的Spring5+了，这段代码也早就做了改造了，新版的如下，不再存在上面的这个并发问题了
/**
* Create CachedIntrospectionResults for the given bean class.
* @param beanClass the bean class to analyze
* @return the corresponding CachedIntrospectionResults
* @throws BeansException in case of introspection failure
*/
@SuppressWarnings("unchecked")
static CachedIntrospectionResults forClass(Class<?> beanClass) throws BeansException {
CachedIntrospectionResults results = strongClassCache.get(beanClass);
if (results != null) {
return results;
}
results = softClassCache.get(beanClass);
if (results != null) {
return results;
}
results = new CachedIntrospectionResults(beanClass);
ConcurrentMap<Class<?>, CachedIntrospectionResults> classCacheToUse;
if (ClassUtils.isCacheSafe(beanClass, CachedIntrospectionResults.class.getClassLoader()) ||
isClassLoaderAccepted(beanClass.getClassLoader())) {
classCacheToUse = strongClassCache;
}
else {
if (logger.isDebugEnabled()) {
logger.debug("Not strongly caching class [" + beanClass.getName() + "] because it is not cache-safe");
}
classCacheToUse = softClassCache;
}
CachedIntrospectionResults existing = classCacheToUse.putIfAbsent(beanClass, results);
return (existing != null ? existing : results);
}接下来我们看一下几种常见的bean拷贝框架的使用姿势，以及对比测试
阿里规范中，明确说明了，不要使用它，idea安装阿里的代码规范插件之后，会有提示
使用姿势比较简单，引入依赖
<!-- https://mvnrepository.com/artifact/commons-beanutils/commons-beanutils --> <dependency> <groupId>commons-beanutils</groupId> <artifactId>commons-beanutils</artifactId> <version>1.9.4</version> </dependency>
属性拷贝
@Component
public class ApacheCopier {
public <K, T> T copy(K source, Class<T> target) throws IllegalAccessException, InstantiationException, InvocationTargetException {
T res = target.newInstance();
// 注意，第一个参数为target，第二个参数为source
// 与其他的正好相反
BeanUtils.copyProperties(res, source);
return res;
}
}cglib是通过动态代理的方式来实现属性拷贝的，与上面基于反射实现方式存在本质上的区别，这也是它性能更优秀的主因
在Spring环境下，一般不需要额外的引入依赖；或者直接引入spring-core
<!-- cglib --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>5.2.8.RELEASE</version> <scope>compile</scope> </dependency>
属性拷贝
@Component
public class SpringCglibCopier {
/**
* cglib 对象转换
*
* @param source
* @param target
* @param <K>
* @param <T>
* @return
* @throws IllegalAccessException
* @throws InstantiationException
*/
public <K, T> T copy(K source, Class<T> target) throws IllegalAccessException, InstantiationException {
BeanCopier copier = BeanCopier.create(source.getClass(), target, false);
T res = target.newInstance();
copier.copy(source, res, null);
return res;
}
}当然也可以直接使用纯净版的cglib，引入依赖
<dependency> <groupId>cglib</groupId> <artifactId>cglib</artifactId> <version>3.3.0</version> </dependency>
使用姿势和上面一模一样
@Component
public class PureCglibCopier {
/**
* cglib 对象转换
*
* @param source
* @param target
* @param <K>
* @param <T>
* @return
* @throws IllegalAccessException
* @throws InstantiationException
*/
public <K, T> T copy(K source, Class<T> target) throws IllegalAccessException, InstantiationException {
BeanCopier copier = BeanCopier.create(source.getClass(), target, false);
T res = target.newInstance();
copier.copy(source, res, null);
return res;
}
}这里使用的是spring 5.2.1.RELEASE， 就不要拿3.2来使用了，不然并发下的性能实在是感人
基于内省+反射，借助getter/setter方法实现属性拷贝，性能比apache高
核心依赖
<dependency> <groupId>org.springframework</groupId> <artifactId>spring-beans</artifactId> <version>5.2.1.RELEASE</version> <scope>compile</scope> </dependency>
属性拷贝
@Component
public class SpringBeanCopier {
/**
* 对象转换
*
* @param source
* @param target
* @param <K>
* @param <T>
* @return
* @throws IllegalAccessException
* @throws InstantiationException
*/
public <K, T> T copy(K source, Class<T> target) throws IllegalAccessException, InstantiationException {
T res = target.newInstance();
BeanUtils.copyProperties(source, res);
return res;
}
}hutool 提供了很多的java工具类，从测试效果来看它的性能比apache会高一点，当低于spring
引入依赖
<dependency> <groupId>cn.hutool</groupId> <artifactId>hutool-core</artifactId> <version>5.6.0</version> </dependency>
使用姿势
@Component
public class HutoolCopier {
/**
* bean 对象转换
*
* @param source
* @param target
* @param <K>
* @param <T>
* @return
*/
public <K, T> T copy(K source, Class<T> target) throws Exception {
return BeanUtil.toBean(source, target);
}
}MapStruct 性能更强悍了，缺点也比较明显，需要声明bean的转换接口，自动代码生成的方式来实现拷贝，性能媲美直接的get/set
引入依赖
<dependency> <groupId>org.mapstruct</groupId> <artifactId>mapstruct</artifactId> <version>1.4.2.Final</version> </dependency> <dependency> <groupId>org.mapstruct</groupId> <artifactId>mapstruct-processor</artifactId> <version>1.4.2.Final</version> </dependency>
使用姿势
@Mapper
public interface MapStructCopier {
Target copy(Source source);
}
@Component
public class MapsCopier {
private MapStructCopier mapStructCopier = Mappers.getMapper(MapStructCopier.class);
public Target copy(Source source, Class<Target> target) {
return mapStructCopier.copy(source);
}
}缺点也比较明显，需要显示的接口转换声明
定义两个Bean，用于转换测试，两个bean的成员属性名，类型完全一致
@Data
public class Source {
private Integer id;
private String user_name;
private Double price;
private List<Long> ids;
private BigDecimal marketPrice;
}
@Data
public class Target {
private Integer id;
private String user_name;
private Double price;
private List<Long> ids;
private BigDecimal marketPrice;
}private Random random = new Random();
public Source genSource() {
Source source = new Source();
source.setId(random.nextInt());
source.setIds(Arrays.asList(random.nextLong(), random.nextLong(), random.nextLong()));
source.setMarketPrice(new BigDecimal(random.nextFloat()));
source.setPrice(random.nextInt(120) / 10.0d);
source.setUser_name("一灰灰Blog");
return source;
}
private void copyTest() throws Exception {
Source s = genSource();
Target ta = apacheCopier.copy(s, Target.class);
Target ts = springBeanCopier.copy(s, Target.class);
Target tc = springCglibCopier.copy(s, Target.class);
Target tp = pureCglibCopier.copy(s, Target.class);
Target th = hutoolCopier.copy(s, Target.class);
Target tm = mapsCopier.copy(s, Target.class);
System.out.println("source:\t" + s + "\napache:\t" + ta + "\nspring:\t" + ts
+ "\nsCglib:\t" + tc + "\npCglib:\t" + tp + "\nhuTool:\t" + th + "\nmapStruct:\t" + tm);
}输出结果如下，满足预期
source: Source(id=1337715455, user_name=一灰灰Blog, price=7.1, ids=[7283949433132389385, 3441022909341384204, 8273318310870260875], marketPrice=0.04279220104217529296875) apache: Target(id=1337715455, user_name=一灰灰Blog, price=7.1, ids=[7283949433132389385, 3441022909341384204, 8273318310870260875], marketPrice=0.04279220104217529296875) spring: Target(id=1337715455, user_name=一灰灰Blog, price=7.1, ids=[7283949433132389385, 3441022909341384204, 8273318310870260875], marketPrice=0.04279220104217529296875) sCglib: Target(id=1337715455, user_name=一灰灰Blog, price=7.1, ids=[7283949433132389385, 3441022909341384204, 8273318310870260875], marketPrice=0.04279220104217529296875) pCglib: Target(id=1337715455, user_name=一灰灰Blog, price=7.1, ids=[7283949433132389385, 3441022909341384204, 8273318310870260875], marketPrice=0.04279220104217529296875) huTool: Target(id=1337715455, user_name=一灰灰Blog, price=7.1, ids=[7283949433132389385, 3441022909341384204, 8273318310870260875], marketPrice=0.04279220104217529296875) mapStruct: Target(id=1337715455, user_name=一灰灰Blog, price=7.1, ids=[7283949433132389385, 3441022909341384204, 8273318310870260875], marketPrice=0.04279220104217529296875)
接下来我们关注一下不同的工具包，实现属性拷贝的性能对比情况如何
public void test() throws Exception {
// 第一次用于预热
autoCheck(Target2.class, 10000);
autoCheck(Target2.class, 10000);
autoCheck(Target2.class, 10000_0);
autoCheck(Target2.class, 50000_0);
autoCheck(Target2.class, 10000_00);
}
private <T> void autoCheck(Class<T> target, int size) throws Exception {
StopWatch stopWatch = new StopWatch();
runCopier(stopWatch, "apacheCopier", size, (s) -> apacheCopier.copy(s, target));
runCopier(stopWatch, "springCglibCopier", size, (s) -> springCglibCopier.copy(s, target));
runCopier(stopWatch, "pureCglibCopier", size, (s) -> pureCglibCopier.copy(s, target));
runCopier(stopWatch, "hutoolCopier", size, (s) -> hutoolCopier.copy(s, target));
runCopier(stopWatch, "springBeanCopier", size, (s) -> springBeanCopier.copy(s, target));
runCopier(stopWatch, "mapStruct", size, (s) -> mapsCopier.copy(s, target));
System.out.println((size / 10000) + "w -------- cost: " + stopWatch.prettyPrint());
}
private <T> void runCopier(StopWatch stopWatch, String key, int size, CopierFunc func) throws Exception {
stopWatch.start(key);
for (int i = 0; i < size; i++) {
Source s = genSource();
func.apply(s);
}
stopWatch.stop();
}
@FunctionalInterface
public interface CopierFunc<T> {
T apply(Source s) throws Exception;
}输出结果如下
1w -------- cost: StopWatch '': running time = 583135900 ns --------------------------------------------- ns % Task name --------------------------------------------- 488136600 084% apacheCopier 009363500 002% springCglibCopier 009385500 002% pureCglibCopier 053982900 009% hutoolCopier 016976500 003% springBeanCopier 005290900 001% mapStruct 10w -------- cost: StopWatch '': running time = 5607831900 ns --------------------------------------------- ns % Task name --------------------------------------------- 4646282100 083% apacheCopier 096047200 002% springCglibCopier 093815600 002% pureCglibCopier 548897800 010% hutoolCopier 169937400 003% springBeanCopier 052851800 001% mapStruct 50w -------- cost: StopWatch '': running time = 27946743000 ns --------------------------------------------- ns % Task name --------------------------------------------- 23115325200 083% apacheCopier 481878600 002% springCglibCopier 475181600 002% pureCglibCopier 2750257900 010% hutoolCopier 855448400 003% springBeanCopier 268651300 001% mapStruct 100w -------- cost: StopWatch '': running time = 57141483600 ns --------------------------------------------- ns % Task name --------------------------------------------- 46865332600 082% apacheCopier 1019163600 002% springCglibCopier 1033701100 002% pureCglibCopier 5897726100 010% hutoolCopier 1706155900 003% springBeanCopier 619404300 001% mapStruct
| - | 1w | 10w | 50w | 100w |
|---|---|---|---|---|
| apache | 0.488136600s / 084% | 4.646282100s / 083% | 23.115325200s / 083% | 46.865332600s / 083% |
| spring cglib | 0.009363500s / 002% | 0.096047200s / 002% | 0.481878600s / 002% | 1.019163600s / 002% |
| pure cglibg | 0.009385500s / 002% | 0.093815600s / 002% | 0.475181600s / 002% | 1.033701100s / 002% |
| hutool | 0.053982900s / 009% | 0.548897800s / 010% | 2.750257900s / 010% | 5.897726100s / 010% |
| spring | 0.016976500s / 003% | 0.169937400s / 003% | 0.855448400s / 003% | 1.706155900s / 003% |
| mapstruct | 0.005290900s / 001% | 0.052851800s / 001% | 0.268651300s / 001% | 0.619404300s / 001% |
| total | 0.583135900s | 5.607831900s | 27.946743000s | 57.141483600s |
上面的测试中，存在一个不同的变量，即不是用相同的source对象来测试不同的工具转换情况，但是这个不同并不会太影响不同框架的性能对比，基本上从上面的运行结果来看
mapstruct, cglib, spring 表现最好
apache 表现最差
基本趋势相当于:
apache -> 10 * hutool -> 28 * spring -> 45 * cglib -> 83 * mapstruct
如果我们需要实现简单的bean拷贝，选择cglib或者spring的是个不错选择
“常见Bean拷贝框架的性能有哪些区别”的内容就介绍到这里了，感谢大家的阅读。如果想了解更多行业相关的知识可以关注亿速云网站，小编将为大家输出更多高质量的实用文章！
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