java - 无法将 java.lang.String 类型的属性值转换为所需的类型 double

Question

每当我在文本框中输入一个空字符串并尝试保存它时，我都会遇到这个错误 我遇到了这个错误:

Failed to convert property value of type java.lang.String to 
   required type double for property customerAcctSetting.maxAllowableAmount; 
nested exception is java.lang.IllegalArgumentException: Cannot convert value of 
    type [java.lang.String] to required type [double] for 
    property maxAllowableAmount:
PropertyEditor [bp.ar.util.NumberFormatUtil$CustomerDoubleEditor] returned
    inappropriate value

但是当我输入一个无效的数字格式如“ddd”时我有这个错误:

Failed to convert property value of type java.lang.String to required
    type double for property customerAcctSetting.maxAllowableAmount; 
nested exception is java.lang.NumberFormatException: For input string: "ddd"

我的 Controller 中有这个 Binder :

@InitBinder
public void initBinder(WebDataBinder binder) {
    NumberFormatUtil.registerDoubleFormat(binder);
}

我有一个实现静态函数registerDoubleFormat(binder)的类NumberFormatUtil.java:

NumberFormatUtil.java

public static void registerDoubleFormat (WebDataBinder binder) {
    binder.registerCustomEditor(Double.TYPE, new CustomerDoubleEditor());
}

private static class CustomerDoubleEditor extends PropertyEditorSupport{    
    public String getAsText() { 
        Double d = (Double) getValue(); 
        return d.toString(); 
    } 

    public void setAsText(String str) { 
        if( str == "" || str == null ) 
            setValue(0); 
        else 
            setValue(Double.parseDouble(str)); 
    } 
}

我使用的是 Spring 3.0.1。我对 java 和其他相关技术(如 spring)非常陌生。请帮忙。提前致谢。

Answer 1

像这里一样改变你的 setAsText() 方法，

   public void setAsText(String str) { 
       if(str == null || str.trim().equals("")) {
           setValue(0d); // you want to return double
       } else {
           setValue(Double.parseDouble(str)); 
       }
  }