Question

我尝试使用setter设置值但是null来了。请帮我解决这个问题并给出其他更好的方法。

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

您的课程Test应为公开课程，将Test移至自己的文件，公开并重新运行您的代码。

Answer 2

将其设置为字段名称：

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

Documentation此处

Answer 3

setProperty()

的方法签名

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是属性名称“te”而不是“setTe”。

BeanUtils.setProperty（T， “TE”， “teval”）;

Answer 4

该类必须是 public ，并提供一个公共构造函数不接受任何参数。这允许工具和应用程序动态创建bean的新实例，但不一定知道将提前使用什么Java类名称，如下所示：

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

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

使用BeanUtils设置setter值

4 个答案: