如何修复“使用 class 路径资源中定义的名称创建 bean 时出错”？

Question

我拿了一颗豆子class，在这个class里面我拿了一颗豆子。我已经在配置文件中配置了它们。但是，当我尝试运行我的 Java 应用程序时，它向我抛出异常，说 "Error creating bean with name 'id1' defined in class path resource [spconfig.xml]: Error setting property values; nested exception is org.springframework.beans.NotWritablePropertyException: Invalid property 'db' of bean class [SampleBean]: Bean property 'db' is not writable or has an invalid setter method. Did you mean 'DB'?" 为什么我不欢迎使用 inner bean？怎么办？

属性在配置文件中正确定义。

SampleBean.java

public class SampleBean {

    private DemoBean db;

    public void setDB(DemoBean db) {
        this.db=db;
    }

    public void show() {
        db.m1();
    }
}

DemoBean.java

public class DemoBean {

    public void m1() {
        System.out.println("Welcome to inner bean");
    }
}

spconfig.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN 2.0//EN"
        "http://www.springframework.org/dtd/spring-beans-2.0.dtd">

 <beans>
 <bean id="id1" class = "SampleBean">
 <property name="db">
 <bean class = "DemoBean"/>
 </property>
 </bean>
 </beans>

Client.java

import org.springframework.beans.factory.*;
import org.springframework.beans.factory.xml.*;
import org.springframework.core.io.*;
public class Client {
    public static void main(String[] args) {


    Resource res = new ClassPathResource("spconfig.xml");
    @SuppressWarnings("deprecation")
    BeanFactory factory = new XmlBeanFactory(res);
    Object o = factory.getBean("id1");
    SampleBean sb = (SampleBean)o;
    sb.show();
    }

}

Answer 1

Spring 使用 JavaBeans naming convention.

像

这样的字段

private DemoBean db;

和像

这样的声明

<property name="db">

Spring 需要一个名为 setDb 的 setter，而不是代码中的 setDB。将其更改为 setDb 并且您的 main 方法将正确打印

Welcome to inner bean

如何修复“使用 class 路径资源中定义的名称创建 bean 时出错”？

How to fix ''Error creating bean with name defined in class path resource"?

java

spring

inversion-of-control

setter-injection