Using Multi‑Catch and Try‑with‑Resources in Java for Database Operations

The article explains two useful Java techniques for database‑related code: using a multi‑catch block to handle several exceptions in one clause, and leveraging the try‑with‑resources statement (available since JDK 1.7) to ensure resources are closed automatically.

1. Multi‑catch block syntax

Referencing the Nacos nacos-config BaseDatabaseOperate class, the following method shows a typical pattern:

default Boolean update(TransactionTemplate transactionTemplate, JdbcTemplate jdbcTemplate, List<ModifyRequest> contexts, BiConsumer<Boolean, Throwable> consumer) {
    try {
        return Boolean.TRUE;
    } catch (BadSqlGrammarException | DataIntegrityViolationException e) {
        FATAL_LOG.error("[db-error] sql : {}, args : {}, error : {}", errSql[0], args[0], e.toString());
        return Boolean.FALSE;
    }
}

When several exceptions require identical handling, the catch (XxxException | YyyException) form keeps the code concise and elegant.

2. Resource closing with try‑with‑resources

Since JDK 1.7, the try‑with‑resources mechanism simplifies resource management. The example below, taken from Nacos's batch‑upload configuration interface, shows how to read a file line‑by‑line while automatically closing the iterator:

try (DiskUtils.LineIterator iterator = DiskUtils.lineIterator(file)) {
    int batchSize = 1000;
    List<String> batchUpdate = new ArrayList<>(batchSize);
    List<CompletableFuture<Void>> futures = new ArrayList<>();
    List<Boolean> results = new CopyOnWriteArrayList<>();
    while (iterator.hasNext()) {
        String sql = iterator.next();
        if (StringUtils.isNotBlank(sql)) {
            batchUpdate.add(sql);
        }
        if (batchUpdate.size() == batchSize || !iterator.hasNext()) {
            List<ModifyRequest> sqls = batchUpdate.stream().map(s -> {
                ModifyRequest request = new ModifyRequest();
                request.setSql(s);
                return request;
            }).collect(Collectors.toList());
            futures.add(CompletableFuture.runAsync(() -> results.add(doDataImport(jdbcTemplate, sqls))));
            batchUpdate.clear();
        }
    }
    CompletableFuture.allOf(futures.toArray(new CompletableFuture[0])).join();
    return RestResult.<String>builder()
            .withCode(BooleanUtils.and(results.toArray(new Boolean[0])) ? 200 : 500)
            .withData("")
            .build();
} catch (Throwable ex) {
    LogUtil.DEFAULT_LOG.error("An exception occurred when external data was imported into Derby : {}", ex);
    return RestResultUtils.failed(ex.getMessage());
}

The snippet demonstrates that the try (DiskUtils.LineIterator iterator = DiskUtils.lineIterator(file)) construct automatically closes the file stream, eliminating the need for manual resource cleanup.

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Why Redis Slows Down: A Complete Guide to Diagnosing Redis Performance Issues

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Second‑Round Interview at Tencent: Does Redis Transaction Support ACID?

Discussing Distributed Locks – Redis and Redisson Approaches