In Spring, @Qualifier means, which bean is qualify to autowired on a field. See following scenario : Autowiring Example See below example, it will autowired a "person" bean into customer's person property. package com.mkyong.common; import org.s…

In last Spring auto-wiring in XML example, it will autowired the matched property of any bean in current Spring container. In most cases, you may need autowired property in a particular bean only. In Spring, you can use @Autowired annotation to auto…

In Spring, "Autowiring by AutoDetect", means chooses "autowire by constructor" if default constructor (argument with any data type), otherwise uses "autowire by type". See an example of Spring "auto wiring by autodetect&…

In Spring, "Autowiring by Constructor" is actually autowiring by Type in constructor argument. It means, if data type of a bean is same as the data type of other bean constructor argument, auto wire it. See a full example of Spring auto wiring b…

In Spring, "Autowiring by Name" means, if the name of a bean is same as the name of other bean property, auto wire it. For example, if a "customer" bean exposes an "address" property, Spring will find the "address"…

In Spring, "Autowiring by Type" means, if data type of a bean is compatible with the data type of other bean property, auto wire it. For example, a "person" bean exposes a property with data type of "ability" class, Spring wi…

In Spring framework, you can wire beans automatically with auto-wiring feature. To enable it, just define the "autowire" attribute in <bean>. <bean id="customer" class="com.mkyong.common.Customer" autowire="byNa…

@Autowired是根据类型进行自动装配的.如果当Spring上下文中存在不止一个UserDao类型的bean时,就会抛出BeanCreationException异常;如果Spring上下文中不存在UserDao类型的bean,也会抛出BeanCreationException异常.我们可以使用@Qualifier配合@Autowired来解决这些问题. 存在多个实现类的情况 @Autowired public void setUserDao(@Qualifier("userDao"…

在使用Spring框架中@Autowired标签时默认情况下使用 @Autowired 注释进行自动注入时,Spring 容器中匹配的候选 Bean 数目必须有且仅有一个.当找不到一个匹配的 Bean 时,Spring 容器将抛BeanCreationException 异常,并指出必须至少拥有一个匹配的 Bean. Spring 允许我们通过 @Qualifier 注释指定注入 Bean 的名称,这样歧义就消除了,可以通过下面的方法解决异常.@Qualifier("XXX") 中的…

近期在捯饬spring的注解,现将遇到的问题记录下来,以供遇到同样问题的童鞋解决~ 先说明下场景,代码如下: 有如下接口: public interface EmployeeService { public EmployeeDto getEmployeeById(Long id); } 同时有下述两个实现类 EmployeeServiceImpl和EmployeeServiceImpl1: @Service("service") public class EmployeeService…