常見Bean拷貝框架使用姿式及性能對比

常見Bean拷貝框架使用姿式及性能對比

Bean屬性拷貝，主要針對幾個經常使用的拷貝框架進行性能對比，以及功能擴展支持

選用的框架

• cglib (直接使用Spring封裝的BeanCopier)
• apache
• MapStruct
• Spring
• HuTool

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I.背景

當業務量不大時，無論選擇哪一個框架都沒什麼問題，只要功能支持就ok了；可是當數據量大的時候，可能就須要考慮性能問題了；再實際的項目中，正好遇到了這個問題，不只慢，還發現會有鎖競爭，這特麼就尼普了

項目中使用的是Spring的 BeanUtils， 版本 3.2.4.RELEASE， 版本相對較老，主要問題在於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;
}

看上面的實現，每次獲取value都加了一個同步鎖，並且仍是鎖的全局的classCache，這就有些過度了啊，微妙的是這段代碼註釋，谷歌翻譯以後爲

咱們不想在這裏使用同步。 對象引用是原子的，所以咱們能夠只在啓動時進行偶爾的沒必要要查找。

這意思大概是說我就在啓動的時候用一下，並不會頻繁的使用，因此使用了同步代碼塊也問題不大...

可是在BeanUtils#copyProperties中就蛋疼了，每次都會執行這個方法，扎心了

---

固然咱們如今通常用的Spring5+了，這段代碼也早就作了改造了，新版的以下，再也不存在上面的這個併發問題了

/**
 * 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);
}

II. 不一樣框架使用姿式

接下來咱們看一下幾種常見的bean拷貝框架的使用姿式，以及對比測試

1. apache BeanUtils

阿里規範中，明確說明了，不要使用它，idea安裝阿里的代碼規範插件以後，會有提示

使用姿式比較簡單，引入依賴

<!-- https://mvnrepository.com/artifact/commons-beanutils/commons-beanutils -->
<dependency>
    <groupId>commons-beanutils</groupId>
    <artifactId>commons-beanutils</artifactId>
    <version>1.9.4</version>
</dependency>

屬性拷貝

@Component
public class ApacheCopier {
    public <K, T> T copy(K source, Class<T> target) throws IllegalAccessException, InstantiationException, InvocationTargetException {
        T res = target.newInstance();
        // 注意，第一個參數爲target，第二個參數爲source
        // 與其餘的正好相反 
        BeanUtils.copyProperties(res, source);
        return res;
    }
}

2. cglib BeanCopier

cglib是經過動態代理的方式來實現屬性拷貝的，與上面基於反射實現方式存在本質上的區別，這也是它性能更優秀的主因

在Spring環境下，通常不須要額外的引入依賴；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>

屬性拷貝

@Component
public class SpringCglibCopier {
    /**
     * cglib 對象轉換
     *
     * @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;
    }
}

固然也能夠直接使用純淨版的cglib，引入依賴

<dependency>
    <groupId>cglib</groupId>
    <artifactId>cglib</artifactId>
    <version>3.3.0</version>
</dependency>

使用姿式和上面如出一轍

@Component
public class PureCglibCopier {
    /**
     * cglib 對象轉換
     *
     * @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;
    }
}

3. spring BeanUtils

這裏使用的是spring 5.2.1.RELEASE， 就不要拿3.2來使用了，否則併發下的性能實在是感人

基於內省+反射，藉助getter/setter方法實現屬性拷貝，性能比apache高

核心依賴

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-beans</artifactId>
    <version>5.2.1.RELEASE</version>
    <scope>compile</scope>
</dependency>

屬性拷貝

@Component
public class SpringBeanCopier {

    /**
     * 對象轉換
     *
     * @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;
    }
}

4. hutool BeanUtil

hutool 提供了不少的java工具類，從測試效果來看它的性能比apache會高一點，當低於spring

引入依賴

<dependency>
    <groupId>cn.hutool</groupId>
    <artifactId>hutool-core</artifactId>
    <version>5.6.0</version>
</dependency>

使用姿式

@Component
public class HutoolCopier {

    /**
     * bean 對象轉換
     *
     * @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);
    }
}

5. MapStruct

MapStruct 性能更強悍了，缺點也比較明顯，須要聲明bean的轉換接口，自動代碼生成的方式來實現拷貝，性能媲美直接的get/set

引入依賴

<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>

使用姿式

@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);
    }
}

缺點也比較明顯，須要顯示的接口轉換聲明

6. 測試

定義兩個Bean，用於轉換測試，兩個bean的成員屬性名，類型徹底一致

@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;
}

6.1 功能測試

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);
}

輸出結果以下，知足預期

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)

6.2 性能測試

接下來咱們關注一下不一樣的工具包，實現屬性拷貝的性能對比狀況如何

public void test() throws Exception {
    // 第一次用於預熱
    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;
}

輸出結果以下

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

上面的測試中，存在一個不一樣的變量，即不是用相同的source對象來測試不一樣的工具轉換狀況，可是這個不一樣並不會太影響不一樣框架的性能對比，基本上從上面的運行結果來看

• mapstruct, cglib, spring 表現最好
• apache 表現最差

基本趨勢至關於:

apache -> 10 hutool -> 28 spring -> 45 cglib -> 83 mapstruct

若是咱們須要實現簡單的bean拷貝，選擇cglib或者spring的是個不錯選擇

III. 其餘

1. 一灰灰Blog： https://blog.hhui.top

一灰灰的我的博客，記錄全部學習和工做中的博文，歡迎你們前去逛逛

• 項目源碼: https://github.com/liuyueyi/spring-boot-demo/tree/master/spring-boot/004-bean-util

2. 聲明

盡信書則不如，以上內容，純屬一家之言，因我的能力有限，不免有疏漏和錯誤之處，如發現bug或者有更好的建議，歡迎批評指正，不吝感激

• 微博地址: 小灰灰Blog
• QQ： 一灰灰/3302797840
• 微信公衆號: 一灰灰blog

3. 掃描關注

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