java - 指定了 1 个构造函数参数，但在 bean 中找不到匹配的构造函数，为什么 Autowiring 名称不适用于构造函数参数

Question

如何设置 emp Id 及其地址，并且我还想保留 autowire = "byName"作为地址。

Please avoid answering by <constructor-arg ref="address">

下面是我的场景

spring-config.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:p="http://www.springframework.org/schema/p"
    xsi:schemaLocation="http://www.springframework.org/schema/beans   
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">


    <bean id="empBean" class="com.spring.SpringCoreIOC.autowiring.Employee"
        autowire="byName">
        <constructor-arg index="0" type="int" value="11111" />
    </bean>

    <bean id="address" class="com.spring.SpringCoreIOC.autowiring.Address">
        <constructor-arg value="Secret Chowk" />
    </bean>
</beans>  

地址.java

public class Address {
    private String place;

    public Address(String place) {
        super();
        this.place = place;
    }
    public String toString() {
        return place;
    }

Employee.java，类有自己的id、int类型和address地址类型

public class Employee {

    private Address address;
    private int id;

    public Employee(int id, Address address) {
        super();
        this.id = id;
        this.address = address;
    } }

我遇到的错误如下

Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'empBean' defined in class path resource [autowiring_byNameByTag.xml]: 1 constructor arguments specified but no matching constructor found in bean 'empBean' (hint: specify index and/or type arguments for simple parameters to avoid type ambiguities)

提前致谢!!.

Answer 1

如果您使用 autowire="byName" 并希望将 id 参数传递给构造函数，那么您应该使用仅包含 id 的构造函数> 参数:public Employee(int id) 并通过 setter 设置您的地址:

public class Employee {

    private Address address;
    private int id;

    public Employee(int id) {
        super();
        this.id = id;
    } 

    public Address getAddress() {
        return address;
    }
    public void setAddress(Address address) {
        this.address = address;
    }
}

因为 autowire="byName" 不适用于构造函数参数，但 autowire="constructor" 可以。