Spring @Async Demo
原创转载请注明出处:http://agilestyle.iteye.com/blog/2327025
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
<?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: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:
<!-- 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
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请求(send两次)
Console Output
Reference