java 多线程写入文件处理

# 1. ***多线程的配置文件 AsyncConfiguration***

	
@Configuration
@EnableAsync
public class AsyncConfiguration {

    @Bean("doExecutor")
    public Executor doExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        // 核心线程数：线程池创建时候初始化的线程数
        executor.setCorePoolSize(10);
        // 最大线程数：线程池最大的线程数，只有在缓冲队列满了之后才会申请超过核心线程数的线程
        executor.setMaxPoolSize(20);
        // 缓冲队列：用来缓冲执行任务的队列
        executor.setQueueCapacity(500);
        // 允许线程的空闲时间60秒：当超过了核心线程之外的线程在空闲时间到达之后会被销毁
        executor.setKeepAliveSeconds(60);
        // 线程池名的前缀：设置好了之后可以方便我们定位处理任务所在的线程池
        executor.setThreadNamePrefix("do-executor-");
        // 缓冲队列满了之后的拒绝策略：由调用线程处理（一般是主线程）
        executor.setRejectedExecutionHandler(new ThreadPoolExecutor.DiscardPolicy());
        executor.initialize();
        return executor;
    }
}

## 2. 方法调用只需在该方法上添加注解，命名和注入bean相同即可 @Async("doExecutor")

	
@Slf4j
@Service
public class AsyncBasicService extends baseController {

    @Autowired
    SftpConfiguration sftpConfiguration;

    @Async("doExecutor")
    @Transactional(rollbackFor = Exception.class)
    public FTPClient getFileWriter( Long classId, List fieldDtoList, List> tableData,String userId) {
        String fileName = DateUtils.format(new Date(), DateUtils.DATE_EXPORT_PATTERN) + ".txt";
        File directory = new File(sftpConfiguration.getSourceDirectory());
        if (!directory.exists()) {
            directory.mkdir();
        }
        FTPClient ftpClient = null;
        FileWriter fw = null;
        try {
            File file = new File(sftpConfiguration.getSourceDirectory() + fileName);
            fw = new FileWriter(file);
            log.info("每次写入文件的数据量是---------------------------------" + tableData.size());
            //拼接写入数据
            for (Map tableDatum : tableData) {
                int size = fieldDtoList.size();
                StringBuilder str = new StringBuilder();
             
                str.append("rn");
                fw.write(str.toString());
            }
            fw.flush();
         file.getName());
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            if (fw != null) {
                try {
                    fw.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return ftpClient;
    }
}

## 方法调用


    private void upload()  {
    asyncBasicService.getFileWriter(newDataset.getClassId(), fieldDtoList, 				tableData,newDataset.getUserId());
    }