java.lang.IllegalStateException: No primary or default constructor

springboot中报错如下：

springmvc也可以使用类似处理方法。其他参考：SrpingMVC通过JSON注入from数据到实体自定义(LocalDateTime,LocalDate,Boolean类型)字段的序列化、反序列化方法

java.lang.IllegalStateException: No primary or default constructor found for class java.time.LocalDate
    at org.springframework.web.method.annotation.ModelAttributeMethodProcessor.createAttribute(ModelAttributeMethodProcessor.java:212)
    at org.springframework.web.servlet.mvc.method.annotation.ServletModelAttributeMethodProcessor.createAttribute(ServletModelAttributeMethodProcessor.java:84)
    at org.springframework.web.method.annotation.ModelAttributeMethodProcessor.resolveArgument(ModelAttributeMethodProcessor.java:132)
    at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:124)
    at org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:161)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:131)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:877)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:783)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974)

解决方法：在maven添加如下依赖

让框架可以处理jsr310的新日期、时间类

<dependency>
     <groupId>com.fasterxml.jackson.datatype</groupId>
     <artifactId>jackson-datatype-jsr310</artifactId>
     <version>2.9.9</version>
</dependency>

任意一个带Configuration注解的类中添加以下代码

@Bean
    public Converter<String, String> StringConvert() {
        return new Converter<String, String>() {
            @Override
            public String convert(String source) {
                return StringUtils.trimToNull(source);
            }
        };
    }
 
 
 
    @Bean
    public Converter<String, LocalDate> LocalDateConvert() {
        return new Converter<String, LocalDate>() {
            @Override
            public LocalDate convert(String source) {
                if (StringUtils.isBlank(source)) {
                    return null;
                }
                return LocalDate.parse(source, DateTimeFormatter.ofPattern("yyyy-MM-dd"));
            }
 
        };
    }
 
    @Bean
    public Converter<String, LocalDateTime> LocalDateTimeConvert() {
        return new Converter<String, LocalDateTime>() {
            @Override
            public LocalDateTime convert(String source) {
                if (StringUtils.isBlank(source)) {
                    return null;
                }
                return LocalDateTime.parse(source, DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
            }
 
        };

Controller里面添加注解@RequestParam(required=false)

@RequestMapping(value = "/test")
    @ResponseBody
    public String test(@RequestParam(required = false) LocalDate startDate) {
        System.out.println(startDate);
        return "success";
    }