我是一个Spring新手，有一个看似简单的Spring问题。我在这个问题上工作了几个小时，但没有运气。下面是例外，后面是代码（提前感谢你）：

Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'graphiteWriterSession' defined in file [/home/user/resources/jmxtrans.graphite.xml]: Error setting property values; nested exception is org.springframework.beans.NotWritablePropertyException: Invalid property 'host' of bean class [com.example.ExampleClass]: Bean property 'host' is not writable or has an invalid setter method. Does the parameter type of the setter match the return type of the getter?

我的bean定义：

<bean id="graphiteWriterSession" class="com.example.ExampleClass">
    <property name="host" value="host.example.com" />
    <property name="port" value="2023" />
    <property name="namespacePrefix" value="apps.foo.bar" />
    <property name="debug" value="true" />
</bean>

<bean id="jmxtransSession" class="com.example.MainMethodClass" factory-method="getInstance">
    <property name="graphiteWriterSession" ref="graphiteWriterSession" />
</bean>

代码片段：

package com.example.ExampleClass;
import com.googlecode.jmxtrans.model.output.GraphiteWriter;

public class ExampleClass {

   private static final long   serialVersionUID = 1L;
   private String              host;
   private int                 port;
   private GraphiteWriter      gw;

  public ExampleClass() {
  }

  public GraphiteWriter getWriter() {
    gw = new GraphiteWriter();
    gw.addSetting(GraphiteWriter.PORT, port);
    gw.addSetting(GraphiteWriter.HOST, host);
    return gw;
  }

  // =====================================================
  // set/get methods for Carbon host.
  // Plugged into Spring application-context file.
  // =====================================================
  public void setCarbonHost( String host ) {
       this.host = host;
  }

  public String getCarbonHost() {
       return host;
  }
  // =====================================================

  // =====================================================
  // set/get methods for Carbon port.
  // Plugged into Spring application-context file.
  // =====================================================
  public void setCarbonPort( int port ) {
      this.port = port;
  }

  public int getCarbonPort() {
      return port;
  }
  // =====================================================
}

我没有在这里包含驱动程序（包含主方法）类。虽然驱动程序类依赖于上面的类，但驱动程序类本身没有问题（我不相信）。
上面的错误显示'host'属性有问题，但是，正如您所期望的，'port'属性也有同样的问题（碰巧'host'属性首先被评估）。
有谁能告诉我我哪里做错了吗？如果你愿意，请随意解释，因为我本身不是一个Spring的人。谢谢。