Spring开启@Async异步(javaconfig配置)
在Spring中，基于@Async标注的方法，称之为异步方法；这些方法将在执行的时候，将会在独立的线程中被执行，调用者无需等待它的完成，即可继续其他的操作。
应用场景
- 某些耗时较长的而用户不需要等待该方法的处理结果
- 某些耗时较长的方法，后面的程序不需要用到这个方法的处理结果时
代码
创建AsyncTask
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/** * 异步任务 * * @author Peng */public class AsyncTask { @Async public void doAsyncTask() throws InterruptedException { // 假设执行一个很耗时的任务 Thread.sleep(10 * 1000); System.out.println("执行完成，我执行了10秒"); }} |
创建spring配置AppConfig
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/** * spring 配置 * * @author Peng */@Configuration@EnableAsyncpublic class AppConfig { /** * 声明异步任务bean * * @return */ @Bean public AsyncTask asyncTask() { return new AsyncTask(); }} |
测试
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/** * 异步测试 * * @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("异步任务调用成功，返回客户端执行成功，异步任务继续执行"); }} |
执行结果
异步任务调用成功，返回客户端执行成功，异步任务继续执行
执行完成，我执行了10秒
从结果可以看出，异步任务测试成功！
Spring @Async Demo
模拟一个业务场景：系统新用户注册成功后，异步发送邮件。
Project Directory
Maven Dependency
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<?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
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<?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
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<?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
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<?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 ${webappRoot}/resources directory --> <resources mapping="/resources/**" location="/resources/" /> <!-- Resolves views selected for rendering by @Controllers to .jsp resources in the /WEB-INF/views directory --> <beans:bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <beans:property name="prefix" value="/WEB-INF/views/" /> <beans:property name="suffix" value=".jsp" /> </beans:bean> <context:component-scan base-package="org.fool.springasync" /></beans:beans> |
AsyncConfig.java
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package org.fool.springasync; import java.util.concurrent.Executor;import java.util.concurrent.ThreadPoolExecutor; import org.springframework.beans.factory.annotation.Value;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.context.annotation.PropertySource;import org.springframework.context.support.PropertySourcesPlaceholderConfigurer;import org.springframework.scheduling.annotation.EnableAsync;import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor; @Configuration@EnableAsync@PropertySource("classpath:async.properties")public class AsyncConfig { /** Set the ThreadPoolExecutor's core pool size. */ @Value("${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：当pool已经达到max size的时候，如何处理新任务 // CALLER_RUNS：不在新线程中执行任务，而是有调用者所在的线程来执行 executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy()); executor.initialize(); return executor; }} |
Note:
AsyncConfig使用Annotation进行Spring Async的配置，当然也可以用XML的方式进行配置，只需要在servlet-context.xml中添加task的命名空间，同时加下如下两行配置：
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<!-- Enables Spring Async --><task:annotation-driven executor="asyncExecutor"/><task:executor id="asyncExecutor" pool-size="2-4" queue-capacity="10"/> |
<task:executor />配置参数：
id：当配置多个executor时，被@Async("id")指定使用；也被作为线程名的前缀。
pool-size：
- core size：最小的线程数，缺省：1
- max size：最大的线程数，缺省：Integer.MAX_VALUE
queue-capacity：当最小的线程数已经被占用满后，新的任务会被放进queue里面，当这个queue的capacity也被占满之后，pool里面会创建新线程处理这个任务，直到总线程数达到了max size，这时系统会拒绝这个任务并抛出TaskRejectedException异常（缺省配置的情况下，可以通过rejection-policy来决定如何处理这种情况）。缺省值为：Integer.MAX_VALUE
keep-alive：超过core size的那些线程，任务完成后，再经过这个时长（秒）会被结束掉
rejection-policy：当pool已经达到max size的时候，如何处理新任务
- ABORT（缺省）：抛出TaskRejectedException异常，然后不执行
- DISCARD：不执行，也不抛出异常
- DISCARD_OLDEST：丢弃queue中最旧的那个任务
- CALLER_RUNS：不在新线程中执行任务，而是有调用者所在的线程来执行
MailService.java
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package org.fool.springasync; import org.springframework.scheduling.annotation.Async;import org.springframework.stereotype.Component; @Componentpublic 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
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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
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package org.fool.springasync; import javax.inject.Inject; import org.springframework.stereotype.Service; @Servicepublic 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
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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请求（send两次）
Console Output
以上为个人经验，希望能给大家一个参考，也希望大家多多支持服务器之家。
原文链接：https://retry.blog.csdn.net/article/details/79014329
