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– Start

假设我们有如下表。

CREATE TABLE PEOPLE(    ID    NUMBER(8,0),     NAME  VARCHAR2(30));

我们需要把表中的数据导出到如下的定长文件中，有标题行和结尾行。

id        name         1                      zhangsan         2                          lisi         3                        wangwuTotal line3

让我们来看看代码吧。

package shangbo.springbatch.example5;public class People implements java.io.Serializable{	private static final long serialVersionUID = 8904705906008476310L;		private Integer id;	private String name;	public Integer getId() {		return id;	}	public void setId(Integer id) {		this.id = id;	}	public String getName() {		return name;	}	public void setName(String name) {		this.name = name;	}}

package shangbo.springbatch.example5;import java.io.IOException;import java.io.Writer;import java.util.List;import org.springframework.batch.item.ExecutionContext;import org.springframework.batch.item.ItemStreamException;import org.springframework.batch.item.ItemStreamWriter;import org.springframework.batch.item.file.FlatFileFooterCallback;import org.springframework.batch.item.file.FlatFileHeaderCallback;public class MyFileItemWriter implements FlatFileFooterCallback, FlatFileHeaderCallback, ItemStreamWriter
   
     {	private ItemStreamWriter
    
      delegate;	private String header;	private int totalLine = 0;	// Override from FlatFileHeaderCallback	@Override	public void writeHeader(Writer writer) throws IOException {		writer.write(header);	}	// Override from FlatFileFooterCallback	@Override	public void writeFooter(Writer writer) throws IOException {		writer.write("Total line" + totalLine);	}	// Override from ItemStreamWriter	@Override	public void write(List
      items) throws Exception {		totalLine += items.size();		delegate.write(items);	}	@Override	public void open(ExecutionContext executionContext) throws ItemStreamException {		delegate.open(executionContext);	}	@Override	public void update(ExecutionContext executionContext) throws ItemStreamException {		delegate.update(executionContext);	}	@Override	public void close() throws ItemStreamException {		delegate.close();	}	// Setter	public void setDelegate(ItemStreamWriter
     
       delegate) {		this.delegate = delegate;	}	public void setHeader(String header) {		this.header = header;	}}
     
    
   

package shangbo.springbatch.example5;import java.util.HashMap;import java.util.Map;import org.springframework.batch.core.Job;import org.springframework.batch.core.JobParameter;import org.springframework.batch.core.JobParameters;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.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class App {	public static void main(String[] args) throws JobExecutionAlreadyRunningException, JobRestartException, JobInstanceAlreadyCompleteException, JobParametersInvalidException {		ApplicationContext context = new ClassPathXmlApplicationContext("shangbo/springbatch/example5/ExtractFileJob.xml");		// job 和 job 参数		Map
   
     parameters = new HashMap<>();		parameters.put("business_date", new JobParameter("20170721"));		JobParameters jobParameters = new JobParameters(parameters);		Job job = context.getBean(Job.class);		// 运行 job		JobLauncher jobLauncher = context.getBean(JobLauncher.class);		jobLauncher.run(job, jobParameters);	}}
   

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