Spring Batch 步骤对象-步骤监听器

目录

引言

概述

需求：演示StepExecutionListener 用法

转视频版

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引言

接着上篇：Spring Batch 步骤对象-Chunk Tasklet，了解step步骤逻辑处理模式后，本篇再来讲解spring batch中步骤监听器，看这个步骤监听器与作业监听器有何异同？

概述

前面我们讲了作业的监听器，步骤也有监听器，也是执行步骤执行前监听，步骤执行后监听。

步骤监听器有2个分别是：StepExecutionListener ChunkListener 意义很明显，就是step执行前后，chunk块执行前后监听。

先看下StepExecutionListener接口

public interface StepExecutionListener extends StepListener {
	void beforeStep(StepExecution stepExecution);
	@Nullable
	ExitStatus afterStep(StepExecution stepExecution);
}

需求：演示StepExecutionListener 用法

自定义监听接口

public class MyStepListener implements StepExecutionListener {
    @Override
    public void beforeStep(StepExecution stepExecution) {
        System.out.println("-----------beforeStep--------->");
    }

    @Override
    public ExitStatus afterStep(StepExecution stepExecution) {
        System.out.println("-----------afterStep--------->");
        return stepExecution.getExitStatus();  //不改动返回状态
    }
}

package com.langfeiyes.batch._09_step_listener;

import org.springframework.batch.core.Job;
import org.springframework.batch.core.Step;
import org.springframework.batch.core.StepContribution;
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.launch.JobLauncher;
import org.springframework.batch.core.launch.support.RunIdIncrementer;
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.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
@EnableBatchProcessing
public class StepListenerJob {
    @Autowired
    private JobLauncher jobLauncher;
    @Autowired
    private JobBuilderFactory jobBuilderFactory;
    @Autowired
    private StepBuilderFactory stepBuilderFactory;
    @Bean
    public Tasklet tasklet(){
        return new Tasklet() {
            @Override
            public RepeatStatus execute(StepContribution contribution, ChunkContext chunkContext) throws Exception {
                System.out.println("------>" + System.currentTimeMillis());
                return RepeatStatus.FINISHED;
            }
        };
    }


    @Bean
    public MyStepListener stepListener(){
        return new MyStepListener();
    }
    @Bean
    public Step step1(){
        return stepBuilderFactory.get("step1")
                .tasklet(tasklet())
                .listener(stepListener())  
                .build();
    }
    //定义作业
    @Bean
    public Job job(){
        return jobBuilderFactory.get("step-listener-job1")
                .start(step1())
                .incrementer(new RunIdIncrementer())
                .build();
    }
    public static void main(String[] args) {
        SpringApplication.run(StepListenerJob.class, args);
    }

}

在step1方法中，加入：.listener(stepListener()) 即可

同理ChunkListener 操作跟上面一样

public interface ChunkListener extends StepListener {
	static final String ROLLBACK_EXCEPTION_KEY = "sb_rollback_exception";
	void beforeChunk(ChunkContext context);
	void afterChunk(ChunkContext context);
	void afterChunkError(ChunkContext context);
}

唯一的区别是多了一个afterChunkError 方法，表示当chunk执行失败后回调。

到这，本篇就结束了，欲知后事如何，请听下回分解~

转视频版

看文字不过瘾可以切换视频版：Spring Batch高效批处理框架实战