异步调用

SpringBoot使用@Async实现异步调用

SpringBoot使用@Async实现异步调用

Posted by John Doe on 2020-08-08
Words 368 and Reading Time 1 Minutes
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背景

在写项目时，有个需求为前端使用用户下载数据库备份压缩文件，其中涉及多表多条件dump备份

部分代码

类似方法有4个，未异步调用耗时较长影响用户体验。

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public void entIdSqlDumpOne(String path, String dateString, String ent_id,String entTableName,String user, String password, String hostIP, String exportDatabaseName){
    String folderName_1 = "ZYK_" + ent_id + "_BackupENT_" + dateString + ".sql";
    PrintWriter printWriter = null;
    BufferedReader bufferedReader = null;
    //Lock lock = new ReentrantLock();
    try {
        //lock.lock();
        printWriter = new PrintWriter(new OutputStreamWriter(new FileOutputStream(path + folderName_1), "utf8"));
        Process process = Runtime.getRuntime().exec(" mysqldump -h" + hostIP + " -u" + user + " -p" + password + " --set-charset=UTF8 " + exportDatabaseName +" --tables "+entTableName+" "+"--where=\"ent_id='"+ ent_id + "'\"");
        InputStreamReader inputStreamReader = new InputStreamReader(process.getInputStream(), "utf8");
        bufferedReader = new BufferedReader(inputStreamReader);
        String line;
        while ((line = bufferedReader.readLine()) != null) {
            printWriter.println(line);
        }
        printWriter.flush();
        if (process.waitFor() != 0) {
            throw new CustomException("线程未正常中止");
        }
    } catch (Exception e) {
        e.printStackTrace();
        throw new CustomException("备份sql操作失败");
    } finally {
        try {
            if (bufferedReader != null) {
                bufferedReader.close();
            }
            if (printWriter != null) {
                printWriter.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

设置异步调用

步骤

  1. springboot application类中配置@EnableAsync

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    @SpringBootApplication 
    @EnableAsync 
    public class SpringbootAsyncApplication {
        public static void main(String[] args) {        
     		SpringApplication.run(SpringbootAsyncApplication.class, args);    
     	}
    }

  2. 在需要异步调用的方法头加@Async注解

  3. 异步调用备份方法

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   public void testTask() throws Exception{
long start = System.currentTimeMillis();
        Future<String> task1 = myTask.entIdSqlDumpOne();
        Future<String> task2 = myTask.entIdSqlDumpTwo();
        Future<String> task3 = myTask.entIdSqlDumpThree();
        while(true) {
            if(task1.isDone() && task2.isDone() && task3.isDone()) {
                // 三个任务都调用完成，退出循环等待，无法调度完成抛出异常
                break;
           }
            Thread.sleep(1000);
       }
	long end = System.currentTimeMillis();
}

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