使用Spring開啟@Async異步方式(javaconfig配置)

Posted on 2021-08-27 by WalkonNet

Spring開啟@Async異步(javaconfig配置)

在Spring中，基於@Async標註的方法，稱之為異步方法；這些方法將在執行的時候，將會在獨立的線程中被執行，調用者無需等待它的完成，即可繼續其他的操作。

應用場景

某些耗時較長的而用戶不需要等待該方法的處理結果
某些耗時較長的方法，後面的程序不需要用到這個方法的處理結果時

代碼

創建AsyncTask

/**
 * 異步任務
 *
 * @author Peng
 */
public class AsyncTask {
    @Async
    public void doAsyncTask() throws InterruptedException {
        // 假設執行一個很耗時的任務
        Thread.sleep(10 * 1000);
        System.out.println("執行完成，我執行瞭10秒");
    }
}

創建spring配置AppConfig

/**
 * spring 配置
 *
 * @author Peng
 */
@Configuration
@EnableAsync
public class AppConfig {
    /**
     * 聲明異步任務bean
     *
     * @return
     */
    @Bean
    public AsyncTask asyncTask() {
        return new AsyncTask();
    }
}

測試

/**
 * 異步測試
 *
 * @author Peng
 */
public class AppTest {
    public static void main(String[] args) throws InterruptedException {
        ApplicationContext ctx = new AnnotationConfigApplicationContext(AppConfig.class);
        AsyncTask task = ctx.getBean(AsyncTask.class);
        task.doAsyncTask();
        System.out.println("異步任務調用成功，返回客戶端執行成功，異步任務繼續執行");
    }
}

執行結果

異步任務調用成功，返回客戶端執行成功，異步任務繼續執行

執行完成，我執行瞭10秒

從結果可以看出，異步任務測試成功！

Spring @Async Demo

模擬一個業務場景：系統新用戶註冊成功後，異步發送郵件。

Project Directory

Maven Dependency

<?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/maven-v4_0_0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>org.fool.springasync</groupId>
	<artifactId>springasync</artifactId>
	<name>springasync</name>
	<packaging>war</packaging>
	<version>1.0.0-BUILD-SNAPSHOT</version>
	<properties>
		<org.springframework-version>4.2.8.RELEASE</org.springframework-version>
	</properties>
	<dependencies>
		<!-- Spring -->
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-context</artifactId>
			<version>${org.springframework-version}</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-webmvc</artifactId>
			<version>${org.springframework-version}</version>
		</dependency>
		<dependency>
			<groupId>com.fasterxml.jackson.core</groupId>
			<artifactId>jackson-databind</artifactId>
			<version>2.8.1</version>
		</dependency>
		<dependency>
			<groupId>com.google.guava</groupId>
			<artifactId>guava</artifactId>
			<version>19.0</version>
		</dependency>
		<dependency>
			<groupId>org.apache.commons</groupId>
			<artifactId>commons-lang3</artifactId>
			<version>3.4</version>
		</dependency>
		<!-- @Inject -->
		<dependency>
			<groupId>javax.inject</groupId>
			<artifactId>javax.inject</artifactId>
			<version>1</version>
		</dependency>
		<!-- Servlet -->
		<dependency>
			<groupId>javax.servlet</groupId>
			<artifactId>javax.servlet-api</artifactId>
			<version>3.1.0</version>
			<scope>provided</scope>
		</dependency>
		<dependency>
			<groupId>javax.servlet.jsp</groupId>
			<artifactId>javax.servlet.jsp-api</artifactId>
			<version>2.3.1</version>
			<scope>provided</scope>
		</dependency>
		<dependency>
			<groupId>javax.servlet</groupId>
			<artifactId>jstl</artifactId>
			<version>1.2</version>
		</dependency>
		<!-- Test -->
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>4.12</version>
			<scope>test</scope>
		</dependency>
	</dependencies>
	<build>
		<plugins>
			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-eclipse-plugin</artifactId>
				<version>2.10</version>
				<configuration>
					<additionalProjectnatures>
						<projectnature>org.springframework.ide.eclipse.core.springnature</projectnature>
					</additionalProjectnatures>
					<additionalBuildcommands>
						<buildcommand>org.springframework.ide.eclipse.core.springbuilder</buildcommand>
					</additionalBuildcommands>
					<downloadSources>true</downloadSources>
					<downloadJavadocs>true</downloadJavadocs>
				</configuration>
			</plugin>
			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-compiler-plugin</artifactId>
				<version>3.5.1</version>
				<configuration>
					<source>1.8</source>
					<target>1.8</target>
					<compilerArgument>-Xlint:all</compilerArgument>
					<showWarnings>true</showWarnings>
					<showDeprecation>true</showDeprecation>
				</configuration>
			</plugin>
			<plugin>
				<groupId>org.eclipse.jetty</groupId>
				<artifactId>jetty-maven-plugin</artifactId>
				<version>9.3.11.v20160721</version>
				<configuration>
					<scanIntervalSeconds>10</scanIntervalSeconds>
					<httpConnector>
						<port>8888</port>
					</httpConnector>
					<webApp>
						<contextPath>/springasync</contextPath>
					</webApp>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee"
	xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
	id="WebApp_ID" version="3.0">
	<!-- The definition of the Root Spring Container shared by all Servlets and Filters -->
	<context-param>
		<param-name>contextConfigLocation</param-name>
		<param-value>/WEB-INF/spring/root-context.xml</param-value>
	</context-param>
	<!-- Creates the Spring Container shared by all Servlets and Filters -->
	<listener>
		<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
	</listener>
	<!-- Processes application requests -->
	<servlet>
		<servlet-name>appServlet</servlet-name>
		<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
		<init-param>
			<param-name>contextConfigLocation</param-name>
			<param-value>/WEB-INF/spring/appServlet/servlet-context.xml</param-value>
		</init-param>
		<load-on-startup>1</load-on-startup>
	</servlet>
	<servlet-mapping>
		<servlet-name>appServlet</servlet-name>
		<url-pattern>/</url-pattern>
	</servlet-mapping>
</web-app>

root-context.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
	
	<!-- Root Context: defines shared resources visible to all other web components -->		
</beans>

servlet-context.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans:beans xmlns="http://www.springframework.org/schema/mvc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:beans="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context"
	xmlns:task="http://www.springframework.org/schema/task" 
	xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
		http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task.xsd">
	<!-- DispatcherServlet Context: defines this servlet's request-processing infrastructure -->
	
	<!-- Enables the Spring MVC @Controller programming model -->
	<annotation-driven />
	<!-- Handles HTTP GET requests for /resources/** by efficiently serving up static resources in the ${webappRoot}/resources 
		directory -->
	<resources mapping="/resources/**" location="/resources/" />
	<!-- Resolves views selected for rendering by @Controllers to .jsp resources in the /WEB-INF/views directory -->
	<beans:bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<beans:property name="prefix" value="/WEB-INF/views/" />
		<beans:property name="suffix" value=".jsp" />
	</beans:bean>
	<context:component-scan base-package="org.fool.springasync" />
</beans:beans>

AsyncConfig.java

package org.fool.springasync; 
import java.util.concurrent.Executor;
import java.util.concurrent.ThreadPoolExecutor; 
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import org.springframework.context.support.PropertySourcesPlaceholderConfigurer;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
 
@Configuration
@EnableAsync
@PropertySource("classpath:async.properties")
public class AsyncConfig {
	/** Set the ThreadPoolExecutor's core pool size. */ 
	@Value("${core.pool.size}")
    private Integer corePoolSize;
	
    /** Set the ThreadPoolExecutor's maximum pool size. */
	@Value("${max.pool.size}")
    private Integer maxPoolSize;
	
    /** Set the capacity for the ThreadPoolExecutor's BlockingQueue. */
	@Value("${queue.capacity}")
    private Integer queueCapacity;  
  
	@Value("${thread.name.prefix}")
    private String ThreadNamePrefix;
	
	@Bean  
    public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfig() {  
        return new PropertySourcesPlaceholderConfigurer();  
    } 
    
    @Bean  
    public Executor getAsyncExecutor() {  
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();  
        executor.setCorePoolSize(corePoolSize);  
        executor.setMaxPoolSize(maxPoolSize);  
        executor.setQueueCapacity(queueCapacity);  
        executor.setThreadNamePrefix(ThreadNamePrefix);  
  
        // rejection-policy：當pool已經達到max size的時候，如何處理新任務  
        // CALLER_RUNS：不在新線程中執行任務，而是有調用者所在的線程來執行  
        executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());  
        executor.initialize();         
        return executor;  
    }
}

Note:

AsyncConfig使用Annotation進行Spring Async的配置，當然也可以用XML的方式進行配置，隻需要在servlet-context.xml中添加task的命名空間，同時加下如下兩行配置：

<!-- Enables Spring Async -->
<task:annotation-driven executor="asyncExecutor"/>
<task:executor id="asyncExecutor" pool-size="2-4" queue-capacity="10"/>

<task:executor />配置參數：

id：當配置多個executor時，被@Async(“id”)指定使用；也被作為線程名的前綴。

pool-size：

core size：最小的線程數，缺省：1
max size：最大的線程數，缺省：Integer.MAX_VALUE

queue-capacity：當最小的線程數已經被占用滿後，新的任務會被放進queue裡面，當這個queue的capacity也被占滿之後，pool裡面會創建新線程處理這個任務，直到總線程數達到瞭max size，這時系統會拒絕這個任務並拋出TaskRejectedException異常（缺省配置的情況下，可以通過rejection-policy來決定如何處理這種情況）。缺省值為：Integer.MAX_VALUE

keep-alive：超過core size的那些線程，任務完成後，再經過這個時長（秒）會被結束掉

rejection-policy：當pool已經達到max size的時候，如何處理新任務

ABORT（缺省）：拋出TaskRejectedException異常，然後不執行
DISCARD：不執行，也不拋出異常
DISCARD_OLDEST：丟棄queue中最舊的那個任務
CALLER_RUNS：不在新線程中執行任務，而是有調用者所在的線程來執行

MailService.java

package org.fool.springasync; 
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Component; 
@Component
public class MailService {
 
	@Async
	public void sendMail(String username) {
		System.out.println("Send Mail initialization...");
		System.out.println("Execute method asynchronously - " + Thread.currentThread().getName());
 
		try {
			Thread.sleep(5000);
			System.out.println("Welcome " + username);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
 
		System.out.println("Send Mail Async done!!!");
	} 
}

User.java

package org.fool.springasync; 
import org.apache.commons.lang3.builder.ToStringBuilder;
import org.apache.commons.lang3.builder.ToStringStyle; 
public class User {
	private Long id;
	private String username;
	private String password; 
	public User() { 
	}
 
	public User(Long id, String username, String password) {
		this.id = id;
		this.username = username;
		this.password = password;
	}
 
	public Long getId() {
		return id;
	}
 
	public void setId(Long id) {
		this.id = id;
	}
 
	public String getUsername() {
		return username;
	}
 
	public void setUsername(String username) {
		this.username = username;
	}
 
	public String getPassword() {
		return password;
	}
 
	public void setPassword(String password) {
		this.password = password;
	}
 
	@Override
	public String toString() {
		return ToStringBuilder.reflectionToString(this, ToStringStyle.SHORT_PREFIX_STYLE);
	}
}

UserService.java

package org.fool.springasync; 
import javax.inject.Inject; 
import org.springframework.stereotype.Service; 
@Service
public class UserService {	
	@Inject
	private MailService mailService;	
	public void registerUser(User user) {
		System.out.println("insert user to db..."); 
		mailService.sendMail(user.getUsername()); 
		System.out.println("register done, please check the email later!!!");
	}	
}

UserController.java

package org.fool.springasync; 
import javax.inject.Inject; 
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
 
@Controller
@RequestMapping("/user")
public class UserController {	
	@Inject
	private UserService userService;	
	@RequestMapping(value = "/testasync", method = RequestMethod.POST)
	@ResponseBody
	public User register(@RequestBody User user) {
		System.out.println(user);		
		userService.registerUser(user);		
		return user;
	} 
}

Test

http://localhost:8888/springasync/user/testasync

POST請求（send兩次）

Console Output

以上為個人經驗，希望能給大傢一個參考，也希望大傢多多支持WalkonNet。

使用Spring開啟@Async異步方式(javaconfig配置)

目錄

Spring開啟@Async異步(javaconfig配置)

應用場景

創建AsyncTask

創建spring配置AppConfig

測試

Spring @Async Demo

推薦閱讀：

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近期文章

目錄

Spring開啟@Async異步(javaconfig配置)

應用場景

創建AsyncTask

創建spring配置AppConfig

測試

Spring @Async Demo

推薦閱讀：

發佈留言 取消回覆

近期文章

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