Spring 没有解析适当的构造函数

Question

感恩：感谢您的支持。

问题描述：

我在尝试运行以下代码时遇到异常。一点头绪都没有。
如何编写 xml 定义以使用带有 int 参数的 @Autowired 构造函数来启动 Dependent class。

异常消息：

Exception in thread "main" org.springframework.beans.factory.BeanCreationException: 
Error creating bean with name 'dependent' defined in class path 
 resource [simple-context.xml]: 
Could not resolve matching constructor (hint: specify index/type/name arguments 
 for simple parameters to avoid type ambiguities)

文件名：spring-context.xml

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

   <context:component-scan base-package="com.learning.spring.constinjection" />

   <bean id="dependency" class="com.learning.spring.constinjection.Dependency"></bean>

   <bean id="dependent" class="com.learning.spring.constinjection.Dependent">
        <constructor-arg ref="dependency" name="dpcy" />
        <constructor-arg name="mesg" value="Hi this is a test mesg" />
   </bean> 

   <bean id="dependent2" class="com.learning.spring.constinjection.Dependent" 
        c:mesg="Hi, this is another test mesg" /> 


 </beans>

文件名：Dependent.java

public class Dependent {

    Dependency dpcy;

    Dependent(Dependency dpcy, String mesg){
      this.dpcy = dpcy;
      System.out.println("Message is: " + mesg);
    }

    Dependent(String mesg){
      System.out.println("Only Message is: " + mesg);
    }

    @Autowired
    Dependent(Integer ticketno){
      System.out.println("Ticket no is: " + ticketno);
    }

}

文件名：Dependency.java

public class Dependency {

  Dependency(){
      System.out.println("Dependency loaded successfully");
  }

}

文件名：ConstructorInjectionApp

public class ConstructorInjectionApp {
        public static void main(String[] args) {

        GenericXmlApplicationContext gen = new GenericXmlApplicationContext();
        gen.load("classpath:simplespringconstinjection.xml");
        gen.refresh();
        Dependent d = (Dependent) gen.getBean("dependent");
        Dependent d2 = (Dependent) gen.getBean("dependent2");   
}
}

Answer 1

通过改变这个：

<bean id="dependent" class="com.learning.spring.constinjection.Dependent">
        <constructor-arg ref="dependency" name="dpcy" />
        <constructor-arg name="mesg" value="Hi this is a test mesg" />
   </bean>

对此：

<bean id="dependent" class="com.learning.spring.constinjection.Dependent" 
        c:dpcy-ref="dependency" c:mesg="Hi, this is another test mesg" />

我能够让 ApplicationContext 正确初始化，没有错误。

有关 "c" 命名空间的信息，请参阅 this Spring doc。

带有@Autowired 注释的构造函数仍然存在问题。

Spring 没有解析适当的构造函数

Spring isn't resolving the appropriate constructor

java

spring

constructor-injection