在上面的几个例子中可以看到当程序启动的时候，Job 会自动执行，但是在真实的场景中，往往需要某些条件触发，比如银行清算系统，需要检查到银联下发了SFTP 文件之后才能运行Job 等……
那么如何实现Job 的调度？
在pom.xml 引入web 依赖，用于实现由Controller 触发Job 的执行
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
在application.yml 中关闭任务自动执行
spring:
batch:
job:
enabled: false
Controller 代码如下，在收到请求时调度Job
package com.xum.controller;
import org.springframework.batch.core.Job;
import org.springframework.batch.core.JobParameters;
import org.springframework.batch.core.JobParametersBuilder;
import org.springframework.batch.core.JobParametersInvalidException;
import org.springframework.batch.core.launch.JobLauncher;
import org.springframework.batch.core.repository.JobExecutionAlreadyRunningException;
import org.springframework.batch.core.repository.JobInstanceAlreadyCompleteException;
import org.springframework.batch.core.repository.JobRestartException;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class StartJobController
{
@Autowired
private JobLauncher jobLauncher;
// 注入Job Bean
@Autowired
private Job launchStartJob;
@RequestMapping("/job/{msg}")
public String runJob(@PathVariable String msg) throws JobExecutionAlreadyRunningException,
JobRestartException,
JobInstanceAlreadyCompleteException,
JobParametersInvalidException
{
// 把参数值传给任务
JobParameters params = new JobParametersBuilder()
.addString("msg", msg)
.toJobParameters();
// 启动任务，并传递参数
jobLauncher.run(launchStartJob, params);
return "success";
}
}
定义Job 的代码如下
package com.xum.batch;
import java.util.Map;
import org.springframework.batch.core.ExitStatus;
import org.springframework.batch.core.Job;
import org.springframework.batch.core.JobParameter;
import org.springframework.batch.core.Step;
import org.springframework.batch.core.StepContribution;
import org.springframework.batch.core.StepExecution;
import org.springframework.batch.core.StepExecutionListener;
import org.springframework.batch.core.configuration.annotation.EnableBatchProcessing;
import org.springframework.batch.core.configuration.annotation.JobBuilderFactory;
import org.springframework.batch.core.configuration.annotation.StepBuilderFactory;
import org.springframework.batch.core.scope.context.ChunkContext;
import org.springframework.batch.core.step.tasklet.Tasklet;
import org.springframework.batch.repeat.RepeatStatus;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
@EnableBatchProcessing
public class JobLauncherDemo implements StepExecutionListener
{
@Autowired
private JobBuilderFactory jobBuilderFactory;
@Autowired
private StepBuilderFactory stepBuilderFactory;
// 这里并未考虑线程安全问题，只是展示其使用
private Map<String, JobParameter> params;
// 在Step 执行之前
public void beforeStep(StepExecution stepExecution) {
params = stepExecution.getJobParameters().getParameters();
}
// 在Step 执行之后
public ExitStatus afterStep(StepExecution stepExecution)
{
// TODO Auto-generated method stub
return null;
}
@Bean
public Job launchStartJob()
{
return jobBuilderFactory.get("launchStartJob")
.start(launchStep1())
.next(launchStep2())
.build();
}
@Bean
public Step launchStep1()
{
return stepBuilderFactory.get("launchStep1")
.listener(this)
.tasklet(new Tasklet() {
public RepeatStatus execute(StepContribution arg0, ChunkContext arg1) throws Exception {
System.out.println("launchStep1: " + params.get("msg").getValue());
return RepeatStatus.FINISHED;
}
})
.build();
}
@Bean
public Step launchStep2()
{
return stepBuilderFactory.get("launchStep2")
.listener(this)
.tasklet(new Tasklet() {
public RepeatStatus execute(StepContribution arg0, ChunkContext arg1) throws Exception {
System.out.println("launchStep2: " + params.get("msg").getValue());
return RepeatStatus.FINISHED;
}
})
.build();
}
}
在浏览器中输入 http://localhost:8080/job/test 回车
看到程序执行输出：
