【Spring】 No qualifying bean of type ‘java.lang.String‘ available: expected at least 1 bean which qua

1、问题所在

在使用spring框架中controller依赖user实体类，重载了其默认的构造方法。重载之后默认的构造方法就会被覆盖。

@Controller
@RequestMapping(value="/user")
public class HelloController{@Resourceprivate User user;@RequestMapping(value="/hello")public ModelAndView hello() {System.out.println("Hello,Annotation Spring MVC!");  user.setName("abc");System.out.print(user.getName());ModelAndView mv=new ModelAndView();mv.addObject("msg","ccc");mv.setViewName("first");return mv;}
}

@Component(value = "user")
public class User {private String name;private String password;public User(String name, String password) {this.name = name;this.password = password;}//省略set,get方法
}

2、出现的错误

Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'java.lang.String' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations:

3、分析错误

原因是springioc容器加载bean默认使用无参构造进行初始化。这里我们可以看到提示显示的是没有找到NoSuchBeanDefinition ，就是因为没有定义user的默认构造方法！！！

注意：
spring实例化bean对象，默认是无参构造方法实例化的，这时就需要bean类中存在无参构造方法。

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【Spring】 No qualifying bean of type ‘java.lang.String‘ available: expected at least 1 bean which qua

1、问题所在

2、出现的错误

3、分析错误

【Spring】 No qualifying bean of type ‘java.lang.String‘ available: expected at least 1 bean which qua相关推荐

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