Jackson在处理字符串时存在长度限制，是否可以添加配置项，供业务控制其所能解析的字符传长度？

[yanghao605]

当前遇到一个问题，是服务端返回的响应消息中，字符串长度过长，导致jackson解析失败

Caused by: com.fasterxml.jackson.core.exc.StreamConstraintsException: String length (20051112) exceeds the maximum length (20000000)
	at com.fasterxml...core.StreamReadConstraints.validateStringLength:324
	at com.fasterxml...util.ReadConstrainedTextBuffer.validateStringLength:27
	at com.fasterxml...util.TextBuffer.finishCurrentSegment:939
	at com.fasterxml...json.UTF8StreamJsonParser._finishString2:2584
	at com.fasterxml...json.UTF8StreamJsonParser._finishAndReturnString:2560
	at com.fasterxml...json.UTF8StreamJsonParser.getText:335
	at com.fasterxml...jsonorg.JSONObjectDeserializer.deserialize:51
	at com.fasterxml...jsonorg.JSONObjectDeserializer.deserialize:48
	at com.fasterxml...jsonorg.JSONObjectDeserializer.deserialize:14
	at com.fasterxml...deser.DefaultDeserializationContext.readRootValue:323
	at com.fasterxml...databind.ObjectMapper._readMapAndClose:4825mas
	at com.fasterxml...databind.ObjectMapper.readValue:3825
	at org.apache...produce.ProduceJsonProcessor.doDecodeResponse:64
	at org.apache...produce.ProduceProcessor.decodeResponse:76
	at org.apache...http.DefaultHttpClientFilter.extractResponse:105
	at org.apache...http.DefaultHttpClientFilter.afterReceiveResponse:139
	at org.apache...http.RestClientInvocation.lambda$processResponseBody$7:251

20000000是jackson提供的默认值；从chassis源码中来看，并没有提供配置该长度的配置项，是否可以加一个

[liubao68]

老版本可以通过RestObjectMapperFactory处理。 配置项应该可以在新版本增加。

[yanghao605]

OK

[liubao68]

如果需要，可以按照下面的方式定制:

  @Test
  public void test() throws Exception {
    RestObjectMapperFactory.getRestObjectMapper().getFactory()
        .setStreamReadConstraints(StreamReadConstraints.builder().maxStringLength(20).build());
    RestObjectMapperFactory.getRestObjectMapper().readValue("\"dddddddddddddddddddddddddddddddddd\"", String.class);
  }