使用BeanUtils設置設置值

Question

我嘗試使用setter來設置值，但null會出現。請幫助我解決此問題，並告訴我是否還有其他更好的方法。

import org.apache.commons.beanutils.BeanUtils; 

public class TestSetter { 

    public static void main(String args[]) throws Exception 
    { 
     Test t = new Test(); 
     BeanUtils.setProperty(t,"te","teval"); 
     System.out.println("tevalue :"+t.getTe()); 
    } 
} 
class Test 
{ 
    String te; 

    public String getTe() { 
     return te; 
    } 

    public void setTe(String te) { 
     this.te = te; 
    } 

} 

例外：

Exception in thread "main" java.lang.reflect.InvocationTargetException: Cannot set te 
    at org.apache.commons.beanutils.BeanUtilsBean.setProperty(BeanUtilsBean.java:1025) 
    at org.apache.commons.beanutils.BeanUtils.setProperty(BeanUtils.java:313) 
    at test.reflection.TestSetter.main(TestSetter.java:10) 
Caused by: java.lang.NoSuchMethodException: Property 'te' has no setter method 
    at org.apache.commons.beanutils.PropertyUtilsBean.setSimpleProperty(PropertyUtilsBean.java:1746) 
    at org.apache.commons.beanutils.PropertyUtilsBean.setNestedProperty(PropertyUtilsBean.java:1648) 
    at org.apache.commons.beanutils.PropertyUtilsBean.setProperty(PropertyUtilsBean.java:1677) 
    at org.apache.commons.beanutils.BeanUtilsBean.setProperty(BeanUtilsBean.java:1022) 
    ... 2 more 

Answer 1

您的等級Test應該是public類，將Test移動到一個自己的文件，使其公開並重新運行您的代碼。

Answer 2

其設於字段的名稱：

BeanUtils.setProperty(t,"te","teval"); 

Documentation這裏

Answer 3

的setProperty()

的方法簽名210

public static void setProperty(Object bean, 
           String name, 
           Object value) 
         throws IllegalAccessException, 
           InvocationTargetException 

    Parameters: 
     bean - Bean on which setting is to be performed 
     name - Property name (can be nested/indexed/mapped/combo) 
     value - Value to be set 

name是屬性名稱「te」不是「setTe」。

BeanUtils.setProperty（t，「te」，「teval」）;

Answer 4

類必須是公共，並提供 接受任何參數的公共構造。這使得工具和應用程序 動態創建bean的新實例，而不必 知道什麼是Java類的名字將被提前使用，如：

 String className = ...; 
    Class beanClass = Class.forName(className); 
    Object beanInstance = beanClass.newInstance(); 

從http://commons.apache.org/proper/commons-beanutils/javadocs/v1.9.2/apidocs/org/apache/commons/beanutils/package-summary.html#FAQ.property