Spring Batch ItemProcessor组件-自定义处理器

目录

引言

自定义ItemProcessor处理器

案例

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引言

接着上篇：Spring Batch ItemProcessor组件-默认处理器 了解Spring Batch ItemProcessor默认处理器后，接下来一起学习一下Spring Batch自定义处理器。

自定义ItemProcessor处理器

除去上面默认的几种处理器外，Spring Batch 也允许我们自定义，具体做法只需要实现ItemProcessor接口即可

案例

需求：自定义处理器，筛选出id为偶数的用户

1>定义读取文件user.txt

1#dafei#18
2#xiaofei#16
3#laofei#20
4#zhongfei#19
5#feifei#15

2>定义实体对象

@Getter
@Setter
@ToString
public class User {
    private Long id;
    private String name;
    private int age;
}

3>自定义处理器

//自定义
public class CustomizeItemProcessor implements ItemProcessor<User,User> {
    @Override
    public User process(User item) throws Exception {
        //id 为偶数的用户放弃
        //返回null时候 读入的item会被放弃，不会进入itemwriter
        return item.getId() % 2 != 0 ? item : null;
    }
}

4>完整代码

package com.langfeiyes.batch._30_itemprocessor_customize;

import org.springframework.batch.core.Job;
import org.springframework.batch.core.Step;
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.item.ItemWriter;
import org.springframework.batch.item.file.FlatFileItemReader;
import org.springframework.batch.item.file.builder.FlatFileItemReaderBuilder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.core.io.ClassPathResource;

import java.util.List;

@SpringBootApplication
@EnableBatchProcessing
public class CustomizeProcessorJob {
    @Autowired
    private JobBuilderFactory jobBuilderFactory;
    @Autowired
    private StepBuilderFactory stepBuilderFactory;


    @Bean
    public FlatFileItemReader<User> userItemReader(){
        return new FlatFileItemReaderBuilder<User>()
                .name("userItemReader")
                .resource(new ClassPathResource("users.txt"))
                .delimited().delimiter("#")
                .names("id", "name", "age")
                .targetType(User.class)
                .build();
    }

    @Bean
    public ItemWriter<User> itemWriter(){
        return new ItemWriter<User>() {
            @Override
            public void write(List<? extends User> items) throws Exception {
                items.forEach(System.err::println);
            }
        };
    }
    @Bean
    public CustomizeItemProcessor customizeItemProcessor(){
        return new CustomizeItemProcessor();
    }

    @Bean
    public Step step(){
        return stepBuilderFactory.get("step1")
                .<User, User>chunk(1)
                .reader(userItemReader())
                .processor(customizeItemProcessor())
                .writer(itemWriter())
                .build();

    }
    @Bean
    public Job job(){
        return jobBuilderFactory.get("customize-processor-job")
                .start(step())
                .build();
    }
    public static void main(String[] args) {
        SpringApplication.run(CustomizeProcessorJob.class, args);
    }
}

解析：非常简单操作，实现ItemProcessor，定制自己校验标准即可。

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看文字不过瘾可以切换视频版：Spring Batch高效批处理框架实战