Spring Boot下Spring Batch入门实例

作者: output | 来源:发表于2018-04-11 07:24 被阅读1766次

一、About

Spring Batch是什么能干什么，网上一搜就有，但是就是没有入门实例，能找到的例子也都是2.0的，看文档都是英文无从下手~~~，使用当前最新的版本整合网络上找到的例子。

关于基础不熟悉的，推荐读一下Spring Batch 批处理框架这本书，虽然讲的是2.0但基本概念没变。

1.1 How Spring Batch works?

image

一个Job有1个或多个Step组成，Step有读、处理、写三部分操作组成；通过JobLauncher启动Job，启动时从JobRepository获取Job Execution；当前运行的Job及Step的结果及状态保存在JobRepository中。

二、Begin

下面举个小例子，就是这篇文章中的例子，下面的这个例子版本是最新的：

spring-boot:2.0.1.RELEASE
spring-batch-4.0.1.RELEASE(Spring-Boot 2.0.1就是依赖的此版本)

下面这个例子实现的是：从变量中读取3个字符串全转化大写并输出到控制台，加了一个监听，当任务完成时输出一个字符串到控制台，通过web端来调用。

下面是项目的目录结构：

image

2.1 pom.xml

<?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/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.javainuse</groupId>
    <artifactId>springboot-batch</artifactId>
    <version>0.0.1</version>
    <packaging>jar</packaging>

    <name>SpringBatch</name>
    <description>Spring Batch-Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.1.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-batch</artifactId>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

2.2 Item Reader

读取：从数组中读取3个字符串

package com.javainuse.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<String> {

    private String[] messages = { "javainuse.com", 
            "Welcome to Spring Batch Example",
            "We use H2 Database for this example" };

    private int count = 0;

    @Override
    public String read() throws Exception, UnexpectedInputException, ParseException, NonTransientResourceException {

        if (count < messages.length) {
            return messages[count++];
        } else {
            count = 0;
        }
        return null;
    }
    
}

2.3 Item Processor

处理：将字符串转为大写

package com.javainuse.step;

import org.springframework.batch.item.ItemProcessor;

public class Processor implements ItemProcessor<String, String> {
    
    @Override
    public String process(String data) throws Exception {
        return data.toUpperCase();
    }
    
}

2.4 Item Writer

输出：把转为大写的字符串输出到控制台

package com.javainuse.step;

import java.util.List;

import org.springframework.batch.item.ItemWriter;

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

2.5 Listener

监听：任务成功完成后往控制台输出一行字符串

package com.javainuse.listener;

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) {
        if (jobExecution.getStatus() == BatchStatus.COMPLETED) {
            System.out.println("BATCH JOB COMPLETED SUCCESSFULLY");
        }
    }
    
}

2.6 Config

Spring Boot配置：

package com.javainuse.config;

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;

import com.javainuse.listener.JobCompletionListener;
import com.javainuse.step.Processor;
import com.javainuse.step.Reader;
import com.javainuse.step.Writer;

@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())
                .flow(orderStep1()).end().build();
    }

    @Bean
    public Step orderStep1() {
        return stepBuilderFactory.get("orderStep1").<String, String> chunk(1)
                .reader(new Reader()).processor(new Processor())
                .writer(new Writer()).build();
    }

    @Bean
    public JobExecutionListener listener() {
        return new JobCompletionListener();
    }
    
}

2.7 Controller

控制器：配置web路由，访问/invokejob来调用任务

package com.javainuse.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";
    }
}

2.8 application.properties

配置：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

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

2.9 Application

Spring Boot入口类：加注解@EnableBatchProcessing

package com.javainuse;

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

@SpringBootApplication
@EnableBatchProcessing
public class SpringBatchApplication {

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

三、Run

启动这个Spring Boot项目，访问下面这个路径，会有如下输出

http://localhost:8080/invokejob

image

然后控制台会有如下输出：

image

我们可以使用H2-console来查看H2数据库，访问如下地址 http://localhost:8080/h2-console ，选择如下数据库，输入JDBC URL：jdbc:h2:file:./DB，这是上文配置的，不用输入密码，直接点击Connect就可以了。

[图片上传失败...(image-573293-1523402615194)]

连上后显示如下：

image

左侧那些表就是Spring Batch自动创建的，至于每个表都是什么意思，可参考下面的那本书，这些建表的脚本存在于哪呢？可在spring-batch-core-xxx.jar包下的org.springframework.batch.core包下找到

image

查看batch-h2.properties可以看到相关的默认配置:

image

四、Reference

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Spring Boot下Spring Batch入门实例

一、About

1.1 How Spring Batch works?

二、Begin

2.1 pom.xml

2.2 Item Reader

2.3 Item Processor

2.4 Item Writer

2.5 Listener

2.6 Config

2.7 Controller

2.8 application.properties

2.9 Application

三、Run

四、Reference

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