SpringBoot利用dag加速Spring beans初始化的方法示例
更新時(shí)間：2024年12月27日 10:56:27 作者：HBLOG
本文介紹了利用DAG加速SpringBoot中Spring beans初始化,先解釋了DAG 概念及特性,包括節(jié)點(diǎn)入度出度、拓?fù)渑判虻?接著闡述加速Spring Bean初始化的實(shí)現(xiàn)思路,如識(shí)別依賴關(guān)系構(gòu)建DAG、拓?fù)渑判颉⒉⑿谐跏蓟疊ean及與Spring集成,還展示了相關(guān)代碼工程、測(cè)試結(jié)果及引用
1.什么是Dag？
有向無環(huán)圖(Directed Acyclic Graph)，簡稱DAG，是一種有向圖，其中沒有從節(jié)點(diǎn)出發(fā)經(jīng)過若干條邊后再回到該節(jié)點(diǎn)的路徑。換句話說，DAG中不存在環(huán)路。這種數(shù)據(jù)結(jié)構(gòu)常用于表示并解決具有依賴關(guān)系的問題。
DAG的特性
- 首先，DAG中的節(jié)點(diǎn)可以有入度和出度。節(jié)點(diǎn)的入度是指指向該節(jié)點(diǎn)的邊的數(shù)量，而節(jié)點(diǎn)的出度是指由該節(jié)點(diǎn)指向其他節(jié)點(diǎn)的邊的數(shù)量。在DAG中，節(jié)點(diǎn)的入度可以是0或正整數(shù)，而出度可以是0或正整數(shù)，但不能同時(shí)為負(fù)數(shù)。
- DAG的另一個(gè)重要性質(zhì)是存在一個(gè)或多個(gè)拓?fù)渑判颉Ｍ負(fù)渑判蚴荄AG中節(jié)點(diǎn)的線性排列，滿足任意一條有向邊的起點(diǎn)在排序中都位于終點(diǎn)之前?？梢允褂蒙疃葍?yōu)先搜索(DFS)或?qū)挾葍?yōu)先搜索(BFS)算法來生成拓?fù)渑判颉?/li>
DAG的應(yīng)用
- 任務(wù)調(diào)度
- 編譯器優(yōu)化
- 數(shù)據(jù)流分析
- 電路設(shè)計(jì)
2.如何加速Spring Bean初始化？
在Spring框架中進(jìn)行DAG（有向無環(huán)圖）分析以實(shí)現(xiàn)并行初始化，可以有效提升應(yīng)用程序啟動(dòng)的性能。通常情況下，Spring應(yīng)用程序的Bean是按依賴順序初始化的，而通過DAG分析可以識(shí)別出哪些Bean之間沒有依賴關(guān)系，并行初始化這些Bean可以減少啟動(dòng)時(shí)間。以下是實(shí)現(xiàn)思路：
1. 識(shí)別依賴關(guān)系，構(gòu)建DAG
首先需要識(shí)別Spring Bean之間的依賴關(guān)系?？梢酝ㄟ^@DependsOn注解、構(gòu)造器注入或@Autowired等方式獲取Bean依賴。具體步驟：
- 遍歷Spring上下文中的所有Bean定義。
- 根據(jù)Bean的依賴關(guān)系構(gòu)建DAG，節(jié)點(diǎn)代表Bean，邊表示依賴關(guān)系。
Spring的ApplicationContext提供了getBeanDefinitionNames()方法可以列出所有的Bean，通過BeanDefinition可以分析出依賴。
2. 拓?fù)渑判?/h3>
通過拓?fù)渑判颍═opological Sorting）對(duì)DAG進(jìn)行排序，以確保Bean按依賴順序初始化。拓?fù)渑判蚩梢源_定哪些Bean可以并行初始化，哪些Bean必須在某些Bean之后初始化。 使用算法如Kahn’s Algorithm或DFS找到所有沒有依賴的Bean（入度為0的節(jié)點(diǎn)），這些節(jié)點(diǎn)可以并行初始化。
3. 并行初始化Bean
在完成拓?fù)渑判蚝螅褂枚嗑€程來并行初始化可以同時(shí)啟動(dòng)的Bean?？梢允褂肑ava的ExecutorService或類似的線程池機(jī)制來管理并發(fā)的Bean初始化過程。 步驟：
- 針對(duì)所有入度為0的節(jié)點(diǎn)，啟動(dòng)一個(gè)線程來初始化它們。
- 當(dāng)某個(gè)Bean初始化完成后，減少它所依賴的其他Bean的入度值。
- 當(dāng)某個(gè)Bean的入度為0時(shí)，可以在另一個(gè)線程中啟動(dòng)它的初始化。
4. Spring Integration
可以通過BeanFactoryPostProcessor或ApplicationContextInitializer來掛鉤到Spring的初始化流程中，分析Bean之間的依賴關(guān)系，并將并行化初始化邏輯集成到Spring容器的啟動(dòng)過程中。 具體方法：
- 實(shí)現(xiàn)
BeanFactoryPostProcessor，在Bean初始化之前分析Bean的依賴并構(gòu)建DAG。 - 在Bean初始化階段，使用多線程并行處理獨(dú)立的Bean。
3.代碼工程
整體的依賴關(guān)系如下：
實(shí)驗(yàn)?zāi)繕?biāo)
實(shí)現(xiàn)自定義Bean并行化加載
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>3.2.1</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>dag</artifactId>
<properties>
<maven.compiler.source>17</maven.compiler.source>
<maven.compiler.target>17</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-autoconfigure</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.jgrapht</groupId>
<artifactId>jgrapht-core</artifactId>
<version>1.5.1</version>
</dependency>
</dependencies>
<build>
<pluginManagement>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.1</version>
<configuration>
<fork>true</fork>
<failOnError>false</failOnError>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.22.2</version>
<configuration>
<forkCount>0</forkCount>
<failIfNoTests>false</failIfNoTests>
</configuration>
</plugin>
</plugins>
</pluginManagement>
</build>
</project>
Bean初始化
package com.et.config;
import org.jgrapht.graph.DefaultEdge;
import org.jgrapht.graph.DirectedAcyclicGraph;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.stereotype.Component;
import java.util.*;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.stream.Collectors;
@Component
public class DAGBeanInitializer implements BeanFactoryPostProcessor {
private final ExecutorService executorService = Executors.newFixedThreadPool(10);
@Override
public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
Map<String, BeanDefinition> beanDefinitionMap = new HashMap<>();
for (String beanName : beanFactory.getBeanDefinitionNames()) {
BeanDefinition beanDefinition = beanFactory.getBeanDefinition(beanName);
beanDefinitionMap.put(beanName, beanDefinition);
}
// build DAG
DirectedAcyclicGraph<String, DefaultEdge> dag = buildDAG(beanDefinitionMap,beanFactory);
// bean layers
List<Set<String>> layers = getBeansByLayer(dag);
System.out.println("layers:"+layers);
// init bean by layers
initializeBeansInLayers(layers, beanFactory);
}
// DAG Bean
private DirectedAcyclicGraph<String, DefaultEdge> buildDAG(Map<String, BeanDefinition> beanDefinitionMap, ConfigurableListableBeanFactory beanFactory) {
DependencyResolver resolver = new DependencyResolver(beanFactory);
DirectedAcyclicGraph<String, DefaultEdge> dag = new DirectedAcyclicGraph<>(DefaultEdge.class);
for (String beanName : beanDefinitionMap.keySet()) {
if(shouldLoadBean(beanName)) {
dag.addVertex(beanName);
String[] dependencies = beanDefinitionMap.get(beanName).getDependsOn();
if (dependencies != null) {
for (String dependency : dependencies) {
dag.addEdge(dependency, beanName);
}
}
// get @Autowired dependencies
Set<String> autowireDependencies = resolver.getAllDependencies(beanName);
for (String autowireDependency : autowireDependencies) {
// convert beanName
String autowireBeanName = convertToBeanName(autowireDependency);
dag.addVertex(autowireBeanName);
dag.addEdge(autowireBeanName, beanName);
}
}
}
return dag;
}
private String convertToBeanName(String className) {
String simpleName = className.substring(className.lastIndexOf('.') + 1);
return Character.toLowerCase(simpleName.charAt(0)) + simpleName.substring(1);
}
private List<Set<String>> getBeansByLayer(DirectedAcyclicGraph<String,DefaultEdge> dag) {
List<Set<String>> layers = new ArrayList<>();
Map<String, Integer> inDegree = new HashMap<>();
Queue<String> queue = new LinkedList<>();
// init all nodes degree
for (String vertex : dag) {
int degree = dag.inDegreeOf(vertex);
inDegree.put(vertex, degree);
if (degree == 0) {
queue.offer(vertex); //zero degree as the first layer
}
}
// BFS process everyLayers
while (!queue.isEmpty()) {
Set<String> currentLayer = new HashSet<>();
int size = queue.size();
for (int i = 0; i < size; i++) {
String currentBean = queue.poll();
currentLayer.add(currentBean);
// iterator layers
for (String successor : getSuccessors(dag,currentBean)) {
inDegree.put(successor, inDegree.get(successor) - 1);
if (inDegree.get(successor) == 0) {
queue.offer(successor); // add next layer when the degress is zero
}
}
}
layers.add(currentLayer);
}
return layers;
}
// get next node
private Set<String> getSuccessors(DirectedAcyclicGraph<String, DefaultEdge> dag, String vertex) {
// get outgoingEdges
Set<DefaultEdge> outgoingEdges = dag.outgoingEdgesOf(vertex);
// find the next node
return outgoingEdges.stream()
.map(edge -> dag.getEdgeTarget(edge))
.collect(Collectors.toSet());
}
// init beans by layer
private void initializeBeansInLayers(List<Set<String>> layers, ConfigurableListableBeanFactory beanFactory) {
for (Set<String> layer : layers) {
// Beans of the same layer can be initialized in parallel
List<CompletableFuture<Void>> futures = new ArrayList<>();
for (String beanName : layer) {
// only load beans that wrote by yourself
if (shouldLoadBean(beanName)) {
CompletableFuture<Void> future = CompletableFuture.runAsync(() -> {
try {
beanFactory.getBean(beanName); // init Bean
} catch (Exception e) {
System.err.println("Failed to initialize bean: " + beanName);
e.printStackTrace();
}
}, executorService);
futures.add(future);
}
}
//Wait for all beans in the current layer to be initialized before initializing the next layer.
CompletableFuture<Void> allOf = CompletableFuture.allOf(futures.toArray(new CompletableFuture[0]));
allOf.join(); // make sure to be done on current layer
}
}
private boolean shouldLoadBean(String beanName) {
return beanName.startsWith("helloWorldController")
||beanName.startsWith("serviceOne")
||beanName.startsWith("serviceTwo")
||beanName.startsWith("serviceThree");
}
}
獲取bean@Autowired依賴
package com.et.config;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import java.lang.reflect.Field;
import java.util.HashSet;
import java.util.Set;
@Component
public class DependencyResolver {
private final ConfigurableListableBeanFactory beanFactory;
@Autowired
public DependencyResolver(ConfigurableListableBeanFactory beanFactory) {
this.beanFactory = beanFactory;
}
public Set<String> getAllDependencies(String beanName) {
Set<String> dependencies = new HashSet<>();
// get Bean definite
BeanDefinition beanDefinition = beanFactory.getBeanDefinition(beanName);
// reflect
try {
Class<?> beanClass = Class.forName(beanDefinition.getBeanClassName());
Field[] fields = beanClass.getDeclaredFields();
for (Field field : fields) {
if (field.isAnnotationPresent(Autowired.class)) {
dependencies.add(field.getType().getName());
}
}
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
return dependencies;
}
}
controller
package com.et.controller;
import com.et.service.ServiceTwo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import com.et.service.*;
import java.util.HashMap;
import java.util.Map;
@RestController
public class HelloWorldController {
@Autowired
ServiceOne ServiceOne;
@Autowired
ServiceTwo ServiceTwo;
@RequestMapping("/hello")
public Map<String, Object> showHelloWorld(){
Map<String, Object> map = new HashMap<>();
map.put("msg", "HelloWorld");
return map;
}
}
service
package com.et.service;
import org.springframework.stereotype.Service;
/**
* @author liuhaihua
* @version 1.0
* @ClassName ServiceOne
* @Description todo
* @date 2024/09/20/ 14:01
*/
@Service
public class ServiceOne {
private void sayhi(){
System.out.println("this is service one sayhi");
}
}
package com.et.service;
import org.springframework.stereotype.Service;
/**
* @author liuhaihua
* @version 1.0
* @ClassName ServiceOne
* @Description todo
* @date 2024/09/20/ 14:01
*/
@Service
public class ServiceThree {
private void sayhi(){
System.out.println("this is service three sayhi");
}
}
package com.et.service;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
/**
* @author liuhaihua
* @version 1.0
* @ClassName ServiceOne
* @Description todo
* @date 2024/09/20/ 14:01
*/
@Service
public class ServiceTwo {
@Autowired
ServiceThree serviceThree;
private void sayhi(){
System.out.println("this is service two sayhi");
}
}
只是一些關(guān)鍵代碼
4.測(cè)試
啟動(dòng)Spring Boot工程，查看bean加載順序如下
2024-09-20T15:51:27.081+08:00 INFO 33188 --- [ main] com.et.DemoApplication : Starting DemoApplication using Java 17.0.9 with PID 33188 (D:\IdeaProjects\ETFramework\dag\target\classes started by Dell in D:\IdeaProjects\ETFramework) 2024-09-20T15:51:27.085+08:00 INFO 33188 --- [ main] com.et.DemoApplication : No active profile set, falling back to 1 default profile: "default" layers:[[serviceOne, serviceThree], [serviceTwo], [helloWorldController]] 2024-09-20T15:51:28.286+08:00 INFO 33188 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port 8088 (http) 2024-09-20T15:51:28.297+08:00 INFO 33188 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat] 2024-09-20T15:51:28.297+08:00 INFO 33188 --- [ main] o.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/10.1.17] 2024-09-20T15:51:28.373+08:00 INFO 33188 --- [ main] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext 2024-09-20T15:51:28.374+08:00 INFO 33188 --- [ main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 1198 ms 2024-09-20T15:51:28.725+08:00 INFO 33188 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port 8088 (http) with context path '' 2024-09-20T15:51:28.732+08:00 INFO 33188 --- [ main] com.et.DemoApplication
以上就是SpringBoot利用dag加速Spring beans初始化的方法示例的詳細(xì)內(nèi)容，更多關(guān)于SpringBoot dag加速beans初始化的資料請(qǐng)關(guān)注腳本之家其它相關(guān)文章！
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