前后台日期类型转换错误

谁借莪１个温暖的怀抱￠ 2022-02-16 09:57 191阅读 0赞

今天在完成项目的时候遇到了下面的异常信息：

04-Aug-2014 15:49:27.894 SEVERE \[http-apr-8080-exec-5\] org.apache.catalina.core.StandardWrapperValve.invoke Servlet.service() for servlet \[cms\] in context with path \[/cms\] threw exception \[Request processing failed; nested exception is org.springframework.validation.BindException: org.springframework.validation.BeanPropertyBindingResult: 6 errors  
Field error in object ‘carContractSearchBox’ on field ‘createEndDate’: rejected value \[\]; codes \[typeMismatch.carContractSearchBox.createEndDate,typeMismatch.createEndDate,typeMismatch.java.util.Date,typeMismatch\]; arguments \[org.springframework.context.support.DefaultMessageSourceResolvable: codes \[carContractSearchBox.createEndDate,createEndDate\]; arguments \[\]; default message \[createEndDate\]\]; default message \[Failed to convert property value of type ‘java.lang.String’ to required type ‘java.util.Date’ for property ‘createEndDate’; nested exception is java.lang.IllegalStateException: Cannot convert value of type \[java.lang.String\] to required type \[java.util.Date\] for property ‘createEndDate’: no matching editors or conversion strategy found\]  
先说明一下，我们的项目使用的是Spring MVC。相应的功能是一个简单的form表单查询功能，里面有一些日期字段的查询。

相应的解决办法为：

在对应的controller中增加属性编辑器：

@InitBinder  
protected void initBinder(WebDataBinder binder) \{  
SimpleDateFormat dateFormat = new SimpleDateFormat(“yyyy-MM-dd”);  
binder.registerCustomEditor(Date.class, new CustomDateEditor(dateFormat, true));  
\}  
注意这块的new CustomDateEditor(dateFormat, true)中的true，查看CustomDateEditor源码可以看到：

/\*\*

*  Create a new CustomDateEditor instance, using the given DateFormat
 *  for parsing and rendering.
 *  The "allowEmpty" parameter states if an empty String should
 *  be allowed for parsing, i.e. get interpreted as null value.
 *  Otherwise, an IllegalArgumentException gets thrown in that case.
 *  @param dateFormat DateFormat to use for parsing and rendering
 *  @param allowEmpty if empty strings should be allowed  
    \*/  
    public CustomDateEditor(DateFormat dateFormat, boolean allowEmpty) \{  
    this.dateFormat = dateFormat;  
    this.allowEmpty = allowEmpty;  
    this.exactDateLength = -1;  
    \}  
    当allowEmpty字段为true的时候form表单传递的值可以为空。否则会出现""字符串解析为date报错。