@ConstructorProperties注釋不適用於&#39;name&#39;屬性 <constructor-arg> 標簽

Question

第19頁的Spring 5.1.6文檔建議使用'name'屬性為構造函數注入值，應使用@ConstructorProperties注釋。

在我的工作區中，我正在嘗試以下課程

ConstDICls.java

package src.spring.core;

import java.beans.ConstructorProperties;

public class ConstDICls 
{
    private boolean flag;
    private String str;

    @ConstructorProperties({"flag", "str"})
    ConstDICls(boolean flag, String str)
    {
        this.flag = flag;
        this.str = str;
    }

    public void constMeth()
    {
        System.out.println("flag : "+flag+" str : "+str);
    }
}

spring1.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="constdi" class="src.spring.core.ConstDICls">
        <constructor-arg name="flag" value="true"/>
        <constructor-arg name="str" value="Spring5"/>
    </bean>
</beans>

SpringCheck.java

package src.spring.core;

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

public class SpringCheck
{
    public static void main(String[] args) 
    {
        ApplicationContext context = new ClassPathXmlApplicationContext("spring1.xml");
        ConstDICls constdi = (ConstDICls)context.getBean("constdi");
        constdi.constMeth();
    }
}

在運行SpringCheck.java時，我收到了以下錯誤

Exception in thread "main" org.springframework.beans.factory.xml.XmlBeanDefinitionStoreException: Line 7 in XML document from class path resource [spring1.xml] is invalid; nested exception is org.xml.sax.SAXParseException; lineNumber: 7; columnNumber: 46; Attribute "name" must be declared for element type "constructor-arg".

完整錯誤日志如下

Exception in thread "main" org.springframework.beans.factory.xml.XmlBeanDefinitionStoreException: Line 7 in XML document from class path resource [spring1.xml] is invalid; nested exception is org.xml.sax.SAXParseException; lineNumber: 7; columnNumber: 46; Attribute "name" must be declared for element type "constructor-arg".
    at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.doLoadBeanDefinitions(XmlBeanDefinitionReader.java:404)
    at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:336)
    at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:304)
    at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:188)
    at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:224)
    at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:195)
    at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:257)
    at org.springframework.context.support.AbstractXmlApplicationContext.loadBeanDefinitions(AbstractXmlApplicationContext.java:128)
    at org.springframework.context.support.AbstractXmlApplicationContext.loadBeanDefinitions(AbstractXmlApplicationContext.java:94)
    at org.springframework.context.support.AbstractRefreshableApplicationContext.refreshBeanFactory(AbstractRefreshableApplicationContext.java:133)
    at org.springframework.context.support.AbstractApplicationContext.obtainFreshBeanFactory(AbstractApplicationContext.java:636)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:521)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:144)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:85)
    at src.spring.core.SpringCheck.main(SpringCheck.java:10)
Caused by: org.xml.sax.SAXParseException; lineNumber: 7; columnNumber: 46; Attribute "name" must be declared for element type "constructor-arg".
    at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(Unknown Source)
    at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.error(Unknown Source)
    at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(Unknown Source)
    at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(Unknown Source)
    at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(Unknown Source)
    at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.addDTDDefaultAttrsAndValidate(Unknown Source)
    at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.handleStartElement(Unknown Source)
    at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.emptyElement(Unknown Source)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanStartElement(Unknown Source)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(Unknown Source)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(Unknown Source)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
    at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(Unknown Source)
    at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(Unknown Source)
    at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(Unknown Source)
    at org.springframework.beans.factory.xml.DefaultDocumentLoader.loadDocument(DefaultDocumentLoader.java:77)
    at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.doLoadDocument(XmlBeanDefinitionReader.java:434)
    at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.doLoadBeanDefinitions(XmlBeanDefinitionReader.java:392)
    ... 14 more

請告訴我如何解決這個問題。

謝謝Jay

Answer 1

您正在使用一種非常古老的方法來驗證XML文檔DTD。 由於DTD的文件名表明它是為Spring 2.0編寫的，后者當時沒有name屬性。

您不應該使用DTD，而是使用XSD驗證XML的更新方法。

<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 https://www.springframework.org/schema/beans/spring-beans.xsd">

這將具有適當的XML模式。