错误信息：
2019-02-19 09:17:58,678 [http-nio-8080-exec-1] WARN org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver - Failed to read HTTP message: org.springframework.http.converter.HttpMessageNotReadableException: JSON parse error: No suitable constructor found for type [simple type, class com.findsoft.policy.api.param.web.caseexperiment.CreateOrUpdateCaseDepartmentStepRequest]: can not instantiate from JSON object (missing default constructor or creator, or perhaps need to add/enable type information?); nested exception is com.fasterxml.jackson.databind.JsonMappingException: No suitable constructor found for type [simple type, class com.findsoft.policy.api.param.web.caseexperiment.CreateOrUpdateCaseDepartmentStepRequest]: can not instantiate from JSON object (missing default constructor or creator, or perhaps need to add/enable type information?) at [Source: java.io.PushbackInputStream@53fb391e; line: 2, column: 3]
报错原因：由于实体类写有参构造函数，但是未补充无参构造函数，引发报错。
Java构造函数详解 可访问：https://blog.csdn.net/qq_33642117/article/details/51909346
JSON parse error: No suitable constructor found for type
原文：https://www.cnblogs.com/qishen/p/10400120.html