春季批处理csv:将多个标头添加到csv
问题描述:
如何在csv中编写多头标头,以便第二个标头值应来自数据库
How to write mulitples header in csv such that the second header values should come from the database
//预期输出
personId,firstName,lastName,email,age
fullname,total // this is the second header which should come the database
kaa,karthi,sa,123@,34
//以下是用于春季批量写入csv的代码段
//below is the code snippet for spring batch writing to csv
@Bean(destroyMethod="")
public JdbcCursorItemReader<Person> reader(){
JdbcCursorItemReader<Person> cursorItemReader = new JdbcCursorItemReader<>();
cursorItemReader.setDataSource(dataSource);
cursorItemReader.setSql("SELECT person_id,first_name,last_name,email,age FROM springbatchdb.person");
cursorItemReader.setRowMapper(new PersonRowMapper());
return cursorItemReader;
}
@Bean(destroyMethod="")
public PersonItenProcessor processor(){
return new PersonItenProcessor();
}
@Bean(destroyMethod="")
public FlatFileItemWriter<Person> writer(){
FlatFileItemWriter<Person> writer = new FlatFileItemWriter<Person>();
String exportFileHeader = "personId,firstName,lastName,email,age";
StringHeaderWriter headerWriter = new StringHeaderWriter(exportFileHeader);
writer.setHeaderCallback(headerWriter);
writer.setResource(new ClassPathResource("person.csv"));
DelimitedLineAggregator<Person> lineAggregator = new DelimitedLineAggregator<Person>();
lineAggregator.setDelimiter(",");
BeanWrapperFieldExtractor<Person> fieldExtractor = new BeanWrapperFieldExtractor<Person>();
fieldExtractor.setNames(new String[]{"personId","firstName","lastName","email","age"});
lineAggregator.setFieldExtractor(fieldExtractor);
writer.setLineAggregator(lineAggregator);
return writer;
}
答
您可以在FlatFileHeaderCallback
中执行查询,并将结果附加到标题的第一行.
You can execute the query in a FlatFileHeaderCallback
and append the result to the first line of the header.