最近遇到SpringMVC写个controller类，传一个空串的字符类型过来，正常情况是会自动转成date类型的，因为数据表对应类类型就是date的
解决方法是在controller类的后面加个注解：
@InitBinder
protected void initDateFormatBinder(WebDataBinder binder) {
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
binder.registerCustomEditor(Date.class, new CustomDateEditor(dateFormat, true));
}
注意，上面的代码CustomDateEditor构造函数要传个true参数，表示允许传空字符串来进行日期类型转换
CustomDateEditor 里源码
public class CustomDateEditor extends PropertyEditorSupport {
private final DateFormat dateFormat;
private final boolean allowEmpty;
private final int exactDateLength;
public CustomDateEditor(DateFormat dateFormat, boolean allowEmpty) {
this.dateFormat = dateFormat;
this.allowEmpty = allowEmpty;
this.exactDateLength = -1;
}
....
}
Spring Bean类的装载是通过BeanWrapperImpl来实现，可以写个简单的例子，验证这个问题，DispatchInfoModel 类是我自己的测试类，里面有signDate这个date类型的参数
设置为true的情况，是可以正常运行的
public class mytest {
public static void main(String[] args) {
DispatchInfoModel tm = new DispatchInfoModel();
BeanWrapper bw = new BeanWrapperImpl(tm);
bw.registerCustomEditor(Date.class, new CustomDateEditor(new SimpleDateFormat("yyyy-MM-dd"), true));
bw.setPropertyValue("signDate", "");
System.out.println(tm.getSignDate());
}
}
设置为false的情况，会抛出异常：
public class mytest {
public static void main(String[] args) {
DispatchInfoModel tm = new DispatchInfoModel();
BeanWrapper bw = new BeanWrapperImpl(tm);
bw.registerCustomEditor(Date.class, new CustomDateEditor(new SimpleDateFormat("yyyy-MM-dd"), false));
bw.setPropertyValue("signDate", "");
System.out.println(tm.getSignDate());
}
}
