为什么在春季批处理中不使用FlatFileItemWriter创建文件？

Question

I am using spring batch to write a bean into csv file. But file is not getting created and I am not getting errors either. I tried using close() for fileWriter also. Following is my writer part of code.

public void writeToCSVFile(User user) throws IOException{
    Resource src = new FileSystemResource("output.csv");
    try{
        fileWriter.setResource(src);

        fileWriter.setAppendAllowed(true);
        fileWriter.setForceSync(true);
        fileWriter.setLineAggregator(new DelimitedLineAggregator<User>() {
            {
                setDelimiter(",");
                setFieldExtractor(new BeanWrapperFieldExtractor<User>() {
                    {
                        setNames(new String[] { "employeeId", "userName", "fullName"});
                    }
                });
            }
        });
    } catch(Exception e){
        System.out.println("Error in logging file" + e.getMessage());
    }
}

Answer 1

You have set the AppendAllowed flag to true, so probably the file already exists and hence it is not created.

Apart from that, I'm not sure your configuration is correct. You need to define your item writer as a bean and register it within a chunk-oriented step in a job. The step will open the writer, write some data, and close it when appropriate. You can find many samples in the spring-batch-samples module .

Otherwise, you need to open the writer, call the write method to write some data, and then close the writer yourself.