Spring Batch在处理过程中遇到错误job默认会执行失败。为了提高应用程序的健壮性,我们需要处理临时异常造成失败。本文我们探讨如何配置Spring Batch的重试逻辑。
1. 应用示例
批处理应用读取csv文件
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sammy, 1234 , 31 / 10 / 2015 , 10000 john, 9999 , 3 / 12 / 2015 , 12321 |
然后,通过调用rest接口处理每条记录,获取用户的年龄和邮编属性,为了正确输出日期,可以在属性上增加@XmlJavaTypeAdapter(LocalDateTimeAdapter.class)注解:
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@XmlRootElement (name = “transactionRecord”) @Data public class Transaction { private String username; private int userId; private int age; private String postCode; private LocalDateTime transactionDate; private double amount; } |
处理类如下
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public class RetryItemProcessor implements ItemProcessor<Transaction, Transaction> { private static final Logger LOGGER = LoggerFactory.getLogger(RetryItemProcessor. class ); @Autowired private CloseableHttpClient closeableHttpClient; @Override public Transaction process(Transaction transaction) throws IOException, JSONException { LOGGER.info( "Attempting to process user with id={}" , transaction.getUserId()); HttpResponse response = fetchMoreUserDetails(transaction.getUserId()); //parse user's age and postCode from response and update transaction String result = EntityUtils.toString(response.getEntity()); JSONObject userObject = new JSONObject(result); transaction.setAge(Integer.parseInt(userObject.getString( "age" ))); transaction.setPostCode(userObject.getString( "postCode" )); return transaction; } private HttpResponse fetchMoreUserDetails( int id) throws IOException { final HttpGet request = new HttpGet( "http://www.testapi.com:81/user/" + id); return closeableHttpClient.execute(request); } } |
这里当然也可以使用RestTemplate进行调用,调用服务仅为了测试,读者可以搭建测试接口。
最终输出结果为
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< transactionRecord > < transactionRecord > < amount >10000.0</ amount > < transactionDate >2015-10-31 00:00:00</ transactionDate > < userId >1234</ userId > < username >sammy</ username > < age >10</ age > < postCode >430222</ postCode > </ transactionRecord > ... </ transactionRecord > |
2. 给处理增加重试功能
如果连接rest接口因为网络不稳定导致连接超时,那么批处理将失败。但这种错误并不是不能恢复,可以通过重试几次进行尝试。
因此我们配置批处理job在失败的情况下重试三次
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@Configuration @EnableBatchProcessing public class SpringBatchRetryConfig { private static final String[] tokens = { "username" , "userid" , "transactiondate" , "amount" }; private static final int TWO_SECONDS = 2000 ; @Autowired private JobBuilderFactory jobBuilderFactory; @Autowired private StepBuilderFactory stepBuilderFactory; @Value ( "input/recordRetry.csv" ) private Resource inputCsv; @Value ( "file:xml/retryOutput.xml" ) private Resource outputXml; public ItemReader<Transaction> itemReader(Resource inputData) throws ParseException { DelimitedLineTokenizer tokenizer = new DelimitedLineTokenizer(); tokenizer.setNames(tokens); DefaultLineMapper<Transaction> lineMapper = new DefaultLineMapper<>(); lineMapper.setLineTokenizer(tokenizer); lineMapper.setFieldSetMapper( new RecordFieldSetMapper()); FlatFileItemReader<Transaction> reader = new FlatFileItemReader<>(); reader.setResource(inputData); reader.setLinesToSkip( 1 ); reader.setLineMapper(lineMapper); return reader; } @Bean public CloseableHttpClient closeableHttpClient() { final RequestConfig config = RequestConfig.custom() .setConnectTimeout(TWO_SECONDS) .build(); return HttpClientBuilder.create().setDefaultRequestConfig(config).build(); } @Bean public ItemProcessor<Transaction, Transaction> retryItemProcessor() { return new RetryItemProcessor(); } @Bean public ItemWriter<Transaction> itemWriter(Marshaller marshaller) { StaxEventItemWriter<Transaction> itemWriter = new StaxEventItemWriter<>(); itemWriter.setMarshaller(marshaller); itemWriter.setRootTagName( "transactionRecord" ); itemWriter.setResource(outputXml); return itemWriter; } @Bean public Marshaller marshaller() { Jaxb2Marshaller marshaller = new Jaxb2Marshaller(); marshaller.setClassesToBeBound(Transaction. class ); return marshaller; } @Bean public Step retryStep( @Qualifier ( "retryItemProcessor" ) ItemProcessor<Transaction, Transaction> processor, ItemWriter<Transaction> writer) throws ParseException { return stepBuilderFactory.get( "retryStep" ) .<Transaction, Transaction>chunk( 10 ) .reader(itemReader(inputCsv)) .processor(processor) .writer(writer) .faultTolerant() .retryLimit( 3 ) .retry(ConnectTimeoutException. class ) .retry(DeadlockLoserDataAccessException. class ) .build(); } @Bean (name = "retryBatchJob" ) public Job retryJob( @Qualifier ( "retryStep" ) Step retryStep) { return jobBuilderFactory .get( "retryBatchJob" ) .start(retryStep) .build(); } |
这里调用faultTolerant()方法启用重试功能,并设置重试次数和对应异常。
3. 测试重试功能
我们测试场景,期望接口在一定时间内返回年龄和邮编。前两次调用API抛出异常ConnectTimeoutException
第三次成功调用
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@RunWith (SpringRunner. class ) @SpringBatchTest @EnableAutoConfiguration @ContextConfiguration (classes = { SpringBatchRetryConfig. class }) public class SpringBatchRetryIntegrationTest { private static final String TEST_OUTPUT = "xml/retryOutput.xml" ; private static final String EXPECTED_OUTPUT = "src/test/resources/output/batchRetry/retryOutput.xml" ; @Autowired private JobLauncherTestUtils jobLauncherTestUtils; @MockBean private CloseableHttpClient closeableHttpClient; @Mock private CloseableHttpResponse httpResponse; @Test public void whenEndpointAlwaysFail_thenJobFails() throws Exception { when(closeableHttpClient.execute(any())) .thenThrow( new ConnectTimeoutException( "Endpoint is down" )); JobExecution jobExecution = jobLauncherTestUtils.launchJob(defaultJobParameters()); JobInstance actualJobInstance = jobExecution.getJobInstance(); ExitStatus actualJobExitStatus = jobExecution.getExitStatus(); assertThat(actualJobInstance.getJobName(), is( "retryBatchJob" )); assertThat(actualJobExitStatus.getExitCode(), is( "FAILED" )); assertThat(actualJobExitStatus.getExitDescription(), containsString( "org.apache.http.conn.ConnectTimeoutException" )); } @Test public void whenEndpointFailsTwicePasses3rdTime_thenSuccess() throws Exception { FileSystemResource expectedResult = new FileSystemResource(EXPECTED_OUTPUT); FileSystemResource actualResult = new FileSystemResource(TEST_OUTPUT); //前两次调用失败,第三次继续执行 when(httpResponse.getEntity()) .thenReturn( new StringEntity( "{ \"age\":10, \"postCode\":\"430222\" }" )); when(closeableHttpClient.execute(any())) .thenThrow( new ConnectTimeoutException( "Timeout count 1" )) .thenThrow( new ConnectTimeoutException( "Timeout count 2" )) .thenReturn(httpResponse); JobExecution jobExecution = jobLauncherTestUtils.launchJob(defaultJobParameters()); JobInstance actualJobInstance = jobExecution.getJobInstance(); ExitStatus actualJobExitStatus = jobExecution.getExitStatus(); assertThat(actualJobInstance.getJobName(), is( "retryBatchJob" )); assertThat(actualJobExitStatus.getExitCode(), is( "COMPLETED" )); AssertFile.assertFileEquals(expectedResult, actualResult); } private JobParameters defaultJobParameters() { JobParametersBuilder paramsBuilder = new JobParametersBuilder(); paramsBuilder.addString( "jobID" , String.valueOf(System.currentTimeMillis())); return paramsBuilder.toJobParameters(); } } |
job成功执行
从日志可以看到两次失败,最终调用成功。
19:06:57.758 [main] INFO o.b.batch.service.RetryItemProcessor - Attempting to process user with id=1234
19:06:57.758 [main] INFO o.b.batch.service.RetryItemProcessor - Attempting to process user with id=1234
19:06:57.758 [main] INFO o.b.batch.service.RetryItemProcessor - Attempting to process user with id=1234
19:06:57.758 [main] INFO o.b.batch.service.RetryItemProcessor - Attempting to process user with id=9999
19:06:57.773 [main] INFO o.s.batch.core.step.AbstractStep - Step: [retryStep] executed in 31ms
同时也定义了另一个测试,重试多次并失败,抛出异常 ConnectTimeoutException。
4. 总结
本文我们学习如何配置Spring Batch的重试逻辑。通过示例学习配置并机型测试,仅为个人经验,希望能给大家一个参考,也希望大家多多支持服务器之家。
原文链接:https://blog.csdn.net/neweastsun/article/details/109264179