spring错误:bean实例类中的属性类型与spring配置文件中的构造器属性类型不对应

错误原因：bean实例类中的属性类型与spring配置文件中的构造器属性类型不对应所导致，这种情况多出在使用类型指定构造器参数；org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userId' defined in class path resource [com/java/f_xml/a_constructor/beans.xml]: Unsatisfied dependency expressed through constructor argument with index 0 of type [int]: Ambiguous constructor argument types - did you specify the correct bean references as constructor arguments?Related cause: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userId' defined in class path resource [com/java/f_xml/a_constructor/beans.xml]: Unsatisfied dependency expressed through constructor argument with index 1 of type [int]: Ambiguous constructor argument types - did you specify the correct bean references as constructor arguments? 这种错误是因为构造器中的type属性不会自动对应拆箱装箱属性类型，简单点说就是类中使用的是基本数据类型，配置文件中对应的type属性值就要是基本数据类型；类中使用的是类类型，配置文件中对应的type属性值就要是包名加上类类型；public class User { private String username; private int id;//可以为private Integer id;对应的配置文件type="java.lang.Integer",返回数据库字段值是null的话，int类型会报错。int是基本数据类型，其声明的是变量，而null则是对象。所以建议用integer； private int age; public User(int id, int age) { super(); this.id = id; this.age = age; } public User(String username, int id) { super(); this.username = username; this.id = id; } }xml:<bean id="userId" class="com.java.f_xml.a_constructor.User" > <constructor-arg index="0" type="java.lang.String" value="jack"></constructor-arg> <constructor-arg index="1" type="int" value="123"></constructor-arg> </bean>
参考文档：http://blog.csdn.net/u013493841/article/details/51944022https://www.2cto.com/kf/201305/211728.html