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这里对Spring Batch 进行批处理实践。

介绍

本文将会讲述SpringBatch 如何搭建并运行起来的。
本教程，将会介绍从磁盘读取文件，并写入MySql 中。

什么是Spring Batch

Spring Batch 是Spring的子项目，基于Spring的批处理的框架，通过其可以构建出批量的批处理框架。

官方地址：github.com/spring-projects/spring-batch

入门案例

新建Spring Boot 项目

选择Spring Batch

继续等待

pom 依赖如下

4.0.0org.springframework.boot
        spring-boot-starter-parent
        2.3.1.RELEASEcom.example
    demo
    0.0.1-SNAPSHOTdemoDemo project for Spring Boot1.8org.springframework.boot
            spring-boot-starter-batch
        org.springframework.boot
            spring-boot-starter-web
        org.springframework.boot
            spring-boot-starter-test
            testorg.junit.vintage
                    junit-vintage-engine
                org.springframework.batch
            spring-batch-test
            testorg.springframework.boot
                spring-boot-maven-plugin
            

什么是 Spring Batch works

一个job有读写处理这三个部分组成。
通过JobLauncher启动Job
步骤为 读、处理、写 三个步骤

一个例子

初始化目录结构如下

读取

从数组中读取三个字符

package com.example.demo.step;

import org.springframework.batch.item.ItemReader;
import org.springframework.batch.item.NonTransientResourceException;
import org.springframework.batch.item.ParseException;
import org.springframework.batch.item.UnexpectedInputException;

public class Reader implements ItemReader {
    private String[] message = {"ming", "mingming", "mingmingming"};
    
    private int count = 0;
    
    @Override
    public String read() throws Exception, UnexpectedInputException, ParseException, NonTransientResourceException {
        if(count 

每次将会调用reader 方法，进行读取一个，

处理

字符串转为大写

package com.example.demo.step;

import org.springframework.batch.item.ItemProcessor;

public class Processor implements ItemProcessor {
    @Override
    public String process(String s) throws Exception {
        return s.toUpperCase();
    }
}

字符串将会调用其方法将其处理为大写

写

package com.example.demo.step;

import org.springframework.batch.item.ItemWriter;

import java.util.List;

public class Writer implements ItemWriter {
    @Override
    public void write(List extends String> list) throws Exception {
        for (String s : list) {
            System.out.println("Writing the data " + s);
        }
    }
}

监听

任务成功完成后往控制台输出一行字符串

package com.example.demo.step;

import org.springframework.batch.core.BatchStatus;
import org.springframework.batch.core.JobExecution;
import org.springframework.batch.core.listener.JobExecutionListenerSupport;

public class JobCompletionListener extends JobExecutionListenerSupport {
    @Override
    public void afterJob(JobExecution jobExecution) {
        // 项目完成以后调用
        if(jobExecution.getStatus() == BatchStatus.COMPLETED){
            System.out.println("项目已经完成");
        }
    }
}

Config

对项目进行配置

package com.example.demo.config;

import com.example.demo.step.JobCompletionListener;
import com.example.demo.step.Processor;
import com.example.demo.step.Reader;
import com.example.demo.step.Writer;
import org.springframework.batch.core.Job;
import org.springframework.batch.core.JobExecutionListener;
import org.springframework.batch.core.Step;
import org.springframework.batch.core.configuration.annotation.JobBuilderFactory;
import org.springframework.batch.core.configuration.annotation.StepBuilderFactory;
import org.springframework.batch.core.launch.support.RunIdIncrementer;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;


@Configuration
public class BatchConfig {
    @Autowired
    public JobBuilderFactory jobBuilderFactory;

    @Autowired
    public StepBuilderFactory stepBuilderFactory;

    @Bean
    public Job processJob() {
        return jobBuilderFactory.get("processJob")
                .incrementer(new RunIdIncrementer()).listener(listener())// 监听
                .flow(orderStep1()).end().build(); // 创建步骤1 
    }

    @Bean
    // 步骤1 bean 先读再写
    public Step orderStep1() {
        return stepBuilderFactory.get("orderStep1"). chunk(1)
                .reader(new Reader()).processor(new Processor())    // 读取。处理
                .writer(new Writer()).build();  // 最后写
    }

    @Bean
    public JobExecutionListener listener() {
        return new JobCompletionListener(); // 创建监听
    }

}

配置Controller

用来启动应用

package com.example.demo.controller;

import org.springframework.batch.core.Job;
import org.springframework.batch.core.JobParameters;
import org.springframework.batch.core.JobParametersBuilder;
import org.springframework.batch.core.launch.JobLauncher;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;


@RestController
public class JobInvokerController {
    @Autowired
    JobLauncher jobLauncher;

    @Autowired
    Job processJob;

    @RequestMapping("/invokejob")
    public String handle() throws Exception {

        JobParameters jobParameters = new JobParametersBuilder().addLong("time", System.currentTimeMillis())
                .toJobParameters();
        jobLauncher.run(processJob, jobParameters);

        return "Batch job has been invoked";
    }

}

配置文件

spring:
  batch:
    job:
      enabled: false
  datasource:
    url: jdbc:h2:file:./DB
  jpa:
    properties:
      hibernate:
        hbm2ddl:
          auto: update

Spring Batch在加载的时候job默认都会执行，把spring.batch.job.enabled置为false，即把job设置成不可用，应用便会根据jobLauncher.run来执行。下面2行是数据库的配置，不配置也可以，使用的嵌入式数据库h2

添加注解

Spring Boot入口类：加注解@EnableBatchProcessing

package com.example.demo;

import org.springframework.batch.core.configuration.annotation.EnableBatchProcessing;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
@EnableBatchProcessing
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }

}

Run

此时项目run
访问 http://localhost:8080/invokejob 项目已经启动

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Spring Batch之批处理实践

标签：入口   com   dep   ted   xtend   row   UNC   launcher   time   

原文地址：https://www.cnblogs.com/melovemingming/p/13153873.html