在 Spring 中使用表达式语言时出错

Question

Failed to convert property value of type [java.lang.String] to required type [com.spring.first.Item] for property 'item'; nested exception is java.lang.IllegalArgumentException: Cannot convert value of type [java.lang.String] to required type [com.spring.first.Item] for property 'item': no matching editors or conversion strategy found

server.java

package com.spring.first;
public class Server {
    private Item item;
    private String itemName;
    public Item getItem()
    {
        return item; 
    }

    public String getItemName()
    {
        return itemName;
    }
    public void setItem(Item item)
    {
        this.item=item;
    }
    public void setItemName(String str)
    {
        this.itemName=str;
    }
    @Override
    public String toString()
    {
        return "Server [item ="+item+", itemName ="+itemName+"]";
    }
}

Item.java

public class Item {
    private String name;
    private int qty;
    public String getName()
    {
        return name;
    }
    public int getQty()
    {
        return qty;
    }
    public void setName(String name)
    {
        this.name=name;
    }
    public void setQty(int x)
    {
        this.qty=x;
    }
    @Override
    public String toString()
    {
        return "Item [ name ="+name+", Qty ="+qty+"];";
    }

}

我的配置文件

<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-3.0.xsd">

<bean id="itemBean" class="com.spring.first.Item">
        <property name="name" value="itemA" />
        <property name="qty" value="10" />
    </bean>
    <bean id="serverBean" class="com.spring.first.Server">
        <property name="item" value="#{itemBean}" />
        <property name="itemName" value="#{itemBean.name}" />
    </bean>

</beans>

我正在使用 Spring 2.5.6.

Answer 1

Spring Expression Language (SPEL) 是在Spring 3 中引入的（参考new features introduced in Spring 3），因此无法在Spring 2.5 中使用SPEL .6.

您需要将 Spring 版本至少升级到 3（最好是最新版本，目前为 4.2.2）。您拥有的配置是正确的并且可以工作（see SPEL reference）。

Answer 2

尝试如下更改配置文件

<bean id="itemBean" class="com.spring.first.Item">
    <property name="name" value="itemA" />
    <property name="qty" value="10" />
</bean>
<bean id="serverBean" class="com.spring.first.Server">
    <property name="item" ref="itemBean" />
    <property name="itemName" value="itemBean.name" />
</bean>

在 Spring 中使用表达式语言时出错

Error in using Expression Language in Spring

java

spring

spring-mvc

maven

spring-2.5