java - 在 Spring 中传递构造函数参数时遇到问题

Question

我在使用 Spring 将构造函数参数传递到我的项目中时遇到一些问题。我确信这是一件微不足道的事情，但我仍在努力学习 Spring。我这里有我的代码:

package com.WheelOfFortune.Client;

import java.util.ArrayList;

import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.FileSystemResource;
import org.springframework.stereotype.Controller;



@Controller
public class Spinner implements SpinnerInterface{

    private int balance;
    private String vacation;
    private String car;
    private ArrayList<String> spinWheel;

    //Methods can access same instance of factory
    BeanFactory factory = new XmlBeanFactory(new FileSystemResource(
            "src/main/resources/spring/SpinWheel.xml"));

    public Spinner(){}

    @Autowired
    public Spinner(int balance, String vacation, String car, ArrayList<String> spinWheel)
    {
        this.balance = balance;
        this.vacation = vacation;
        this.car = car;
        this.spinWheel = spinWheel;
    }

    //Setters and Getters
    public void setSpinWheel()
    {
        this.spinWheel = spinWheel;
    }
    public ArrayList<String> getSpinWheel(ArrayList<String> getSpinWheel)
    {
        return spinWheel;
    }
    public void setBalance()
    {
        this.balance = balance;
    }
    public void setVacation()
    {
        this.vacation = vacation;
    }
    public void setCar()
    {
        this.car = car;
    }
    public int getBalance(int balance)
    {
        return balance;
    }
    public String getVacation(String vacation)
    {
        return vacation;
    }
    public String getCar(String car)
    {
        return car;
    }

    public void spin() {
        Spinner spin = (Spinner) factory.getBean("spinWheel");

    }

    public void addToBank(boolean isCorrect) {
        // TODO Auto-generated method stub

    }

    public void deductFromBank() {
        // TODO Auto-generated method stub

    }

    public void vacation(boolean isCorrect) {
        Spinner vacation = (Spinner) factory.getBean("vacation");
        System.out.println(vacation);
    }
    public void car(boolean isCorrect){
        Spinner car = (Spinner) factory.getBean("car");
    }   
}

还有我的 xml 文件:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

    <bean id="balance" class="com.WheelOfFortune.Client.Spinner">
        <constructor-arg>
            <value>0</value>
        </constructor-arg>
    </bean>

    <bean id="vacation" class="com.WheelOfFortune.Client.Spinner">
        <constructor-arg value="You Won a Trip to Hawaii!!" />
    </bean>

    <bean id="car" class="com.WheelOfFortune.Client.Spinner">
        <constructor-arg value="You Won a brand new Corvette!!" />
    </bean>

    <bean id="spinWheel" class="com.WheelOfFortune.Client.Spinner">
        <property name="word">
            <list>
                <value>$100</value>
                <value>$150</value>
                <value>$275</value>
                <value>$400</value>
                <value>$500</value>
                <value>$750</value>
                <value>$1000</value>
                <value>Bankruptcy</value>
                <value>$5000</value>
                <value>Vacation</value>
                <value>Car</value>
            </list>
        </property>
    </bean>
</beans>

每当我尝试运行该项目时，我总是会得到堆栈跟踪:

Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'vacation' defined in file [/home/ryan/workspace/wheel/src/main/resources/spring/SpinWheel.xml]: Could not resolve matching constructor (hint: specify index/type/name arguments for simple parameters to avoid type ambiguities)
    at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:250)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1003)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:907)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:485)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:291)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:288)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:190)
    at com.WheelOfFortune.Client.Spinner.vacation(Spinner.java:74)
    at com.WheelOfFortune.Client.Client.main(Client.java:10)

我对 XML 文件进行了仔细研究，但找不到它产生此堆栈跟踪的任何原因。有什么建议吗？

Answer 1

您的配置中有多个错误的地方。

首先，关于您的 constructor-arg 问题，您在 XML 中使用单个 arg 构造函数:

<bean id="balance" class="com.WheelOfFortune.Client.Spinner">
    <constructor-arg>
        <value>0</value>
    </constructor-arg>
</bean>

但是你的 Java 只定义了带有 4 个参数的构造函数:

public Spinner(int balance, String vacation, String car, ArrayList<String> spinWheel);

你可以写的是:

<bean id="spinner" class="com.WheelOfFortune.Client.Spinner">
    <constructor-arg>
        <value>0</value>
    </constructor-arg>
    <constructor-arg ref="vacation">
    ...
</bean>

但在此之前，您需要更正您的 vacation bean(对于 car 和 spinWheel 也是如此)。您将其输入为 com.WheelOfFortune.Client.Spinner，但它是一个 String。

最终，您将混合注释和 XML 配置。这不是问题，但在启动 Spring 时可能会令人困惑，我建议要么全部在 XML 中完成，要么全部在注释中完成。

如果您需要更多详细信息，请随时询问;)

<小时/>

编辑:重新阅读您的文章，我实际上理解您想写的内容，如果您激活组件扫描，只需更正 bean 的类型就足够了。