获取org.springframework.beans.NotWritablePropertyException

Question

我现在正在学习春天。我正处于依赖注入主题中，我正在尝试通过DI向setter中注入引用、遵从into。但我正面临着一个问题。

Client.java

package bean.driver;

import bean.Car;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Client {

    public static void main(String [] args)
    {
        String files[] = new String[]{"engine.xml","car.xml"};
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext(files);

        Car car = (Car) applicationContext.getBean("car");
        //car.printdata();
        car.printcardata();

    }
}

Car.java

package bean;

public class Car {

    private String carname;
    private Engine engine;
    private int cost;
    private int yearofRelease;
    private int maxspeed;
    private Inventory inventory;
    private String engineversion;


    /*Car(String carname, Engine engine)
    {
        this.carname = carname;
        this.engine = engine;
    }*/
    Car(String name,Engine engine,Inventory inventory, int maxspeed)
    {
        this.carname = name;
        this.maxspeed = maxspeed;
        this.engine = engine;
        this.inventory = inventory;
    }

    public void setCost(int cost)
    {
        this.cost = cost;
    }
    public void setYearofRelease(int yearofRelease)
    {
        this.yearofRelease = yearofRelease;
        System.out.println(engine.getEngineversion());
    }
    /*public void setEngine(Engine engine2)
    {
        this.engineversion = engine2.getEngineversion();
    }
    public String getEngineversion()
    {
        return engineversion;
    }*/

    public void setEngineVersion(Engine engine)
    {
        this.engineversion = engine.getEngineversion();
    }
    public void printdata()
    {
        System.out.println(carname + " "+ engine.getModel() +" "+cost+" "+yearofRelease);
    }

    public void printcardata()
    {
        System.out.println("Carname:-"+carname+"\n"+"Cost:-"+cost+"\n"+"MaxSpeed:-"+maxspeed+"\n"+
                "Year of Release:-"+yearofRelease+"\n"+"Engine model:-"+engine.getModel()+"\n"+
                "No of Units:-"+inventory.getNoofinitalunits()+"\n"+"Engine Version:-"+engineversion);
    }

}

Engine.java

package bean;

public class Engine {

    private String model;
    private String engineversion;

    Engine(String model)
    {
        this.model = model;
    }

    public void setEngineversion(String engineversion) {
        this.engineversion = engineversion;
    }

    public String getModel()
    {
        return model;
    }

    public String getEngineversion()
    {
        return engineversion;
    }
}

car.xml

<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN 2.0//EN"
        "https://www.springframework.org/dtd/spring-beans-2.0.dtd">

<beans>


    <bean id="car" class="bean.Car">

        <!--dependecy injection through constructor of secondary type-->
         <constructor-arg ref="engine"/><!-- we are passing object as a reference -->

         <constructor-arg>
         <ref bean="inventory"></ref>
        </constructor-arg><!-- passing object as a refernece -->

        <!-- pass object as a value -->

        <!--<constructor-arg>
            <bean class="bean.Engine">
                <constructor-arg>
                    <value>S10</value></constructor-arg>
            </bean>
        </constructor-arg>-->

        <!--dependency injection through constructor of primary type-->
        <constructor-arg value="Suzuki"/>
        <constructor-arg>
            <value>230</value>
        </constructor-arg>

        <!--dependency injection through setters of primary type-->
        <property name="cost" value="10"/>
        <property name="yearofRelease">
            <value>1994</value>
        </property>

        <!--dependecy injection through setter of secondary type-->

        <property name="engine" ref="engine"></property>


    </bean>

    <bean id="inventory" class="bean.Inventory">
        <constructor-arg>
            <value>1000</value>
        </constructor-arg>
    </bean>

    <bean id="engine2" class="bean.Engine">
        <constructor-arg value="S88"/>
        <property name="engineversion" value="V11"/>
    </bean>
</beans>

engine.xml

<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN 2.0//EN"
        "https://www.springframework.org/dtd/spring-beans-2.0.dtd">

<beans>

    <bean id="engine" class="bean.Engine">

        <constructor-arg value="S88"/>
        <property name="engineversion" value="V11"/>


    </bean>

    <bean id="engine2" class="bean.Engine">

        <constructor-arg value="S88"/>
        <property name="engineversion" value="V11"/>


    </bean>

</beans>

错误

"C:\Program Files\Java\jdk-15.0.1\bin\java.exe" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA Community Edition 2020.2.3\lib\idea_rt.jar=51693:C:\Program Files\JetBrains\IntelliJ IDEA Community Edition 2020.2.3\bin" -Dfile.encoding=UTF-8 -classpath D:\Spring-2\target\classes;C:\Users\chris\Downloads\spring-beans-5.3.15.jar;C:\Users\chris\Downloads\spring-context-5.3.15.jar;C:\Users\chris\Downloads\spring-core-5.3.15.jar;C:\Users\chris\Downloads\spring-expression-5.3.15.jar;C:\Users\chris\Downloads\commons-logging-1.2.jar bean.driver.Client
V11
Feb 06, 2022 1:53:20 PM org.springframework.context.support.ClassPathXmlApplicationContext refresh
WARNING: Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'car' defined in class path resource [car.xml]: Error setting property values; nested exception is org.springframework.beans.NotWritablePropertyException: Invalid property 'engine' of bean class [bean.Car]: Bean property 'engine' is not writable or has an invalid setter method. Does the parameter type of the setter match the return type of the getter?
Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'car' defined in class path resource [car.xml]: Error setting property values; nested exception is org.springframework.beans.NotWritablePropertyException: Invalid property 'engine' of bean class [bean.Car]: Bean property 'engine' is not writable or has an invalid setter method. Does the parameter type of the setter match the return type of the getter?
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1744)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1452)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:619)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542)
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:953)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:918)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:144)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:95)
    at bean.driver.Client.main(Client.java:12)
Caused by: org.springframework.beans.NotWritablePropertyException: Invalid property 'engine' of bean class [bean.Car]: Bean property 'engine' is not writable or has an invalid setter method. Does the parameter type of the setter match the return type of the getter?
    at org.springframework.beans.BeanWrapperImpl.createNotWritablePropertyException(BeanWrapperImpl.java:243)
    at org.springframework.beans.AbstractNestablePropertyAccessor.processLocalProperty(AbstractNestablePropertyAccessor.java:432)
    at org.springframework.beans.AbstractNestablePropertyAccessor.setPropertyValue(AbstractNestablePropertyAccessor.java:278)
    at org.springframework.beans.AbstractNestablePropertyAccessor.setPropertyValue(AbstractNestablePropertyAccessor.java:266)
    at org.springframework.beans.AbstractPropertyAccessor.setPropertyValues(AbstractPropertyAccessor.java:104)
    at org.springframework.beans.AbstractPropertyAccessor.setPropertyValues(AbstractPropertyAccessor.java:79)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1740)
    

Process finished with exit code 1

请参见属性名称是engine，并且在我提到的xml文档中也只作为engine。但还是会犯错误。

Answer 1

Xml配置是旧的，您最好阅读新的xml配置。您应该按照下面的代码更改xml文件。

Car.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans:beans
        xmlns:beans="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.xsd">

    <beans:bean id="car" class="com.example.stackoverfollw.Car">

        <beans:constructor-arg index="0" value="220"/>
        <beans:constructor-arg index="1" ref="engine"/>
        <beans:constructor-arg index="2" ref="inventory"/>
        <beans:constructor-arg index="3" value="650"/>
    </beans:bean>


    <beans:bean id="engine" class="com.example.stackoverfollw.Engine">
        <beans:constructor-arg value="V11"/>
    </beans:bean>

    <beans:bean id="inventory" class="com.example.stackoverfollw.Inventory">
    </beans:bean>


</beans:beans>

Engine.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans:beans
        xmlns:beans="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.xsd">

    <beans:bean id="engine" class="com.example.stackoverfollw.Engine">
        <beans:constructor-arg value="v22"/>
    </beans:bean>


</beans:beans>

有关bean的更多信息

• https://www.tutorialspoint.com/spring/spring_bean_definition.htm#:~:text=A%20bean%20is%20an%20object,seen%20in%20the%20previous%20chapters

• https://docs.spring.io/spring-framework/docs/4.2.x/spring-framework-reference/html/xsd-configuration.html