共计 4223 个字符，预计需要花费 11 分钟才能阅读完成。
[TOC]
BeansException 的子接口
| 异样类型 | 触发条件 (举例) | 场景举例 |
|---|---|---|
| NoSuchBeanDefinitionException | 当查找 Bean 不存在于 IoC 容器时 | BeanFactory#getBean ObjectFactory#getObject |
| NoUniqueBeanDefinitionException | 类型依赖查找时，IoC 容器存在多 个 Bean 实例 | BeanFactory#getBean(Class) |
| BeanInstantiationException | 当 Bean 所对应的类型非具体类时 | BeanFactory#getBean |
| BeanCreationException | 当 Bean 初始化过程中 | Bean 初始化办法执行异样 时 |
| BeanDefinitionStoreException | 当 BeanDefinition 配置元信息非法 时 | XML 配置资源无奈关上时 |
Rumenz.java 实体类
package com.rumenz;
import org.springframework.beans.factory.InitializingBean;
public class Rumenz implements InitializingBean {
private Integer id;
private String name;
@Override
public void afterPropertiesSet() throws Exception {throw new Exception("初始化异样。。。。");
}
@Override
public String toString() {
return "Rumenz{" +
"id=" + id +
", name='" + name + '\'' +
'}';
}
public Integer getId() {return id;}
public void setId(Integer id) {this.id = id;}
public String getName() {return name;}
public void setName(String name) {this.name = name;}
}
NoSuchBeanDefinitionException 不存在要查找的 Bean
package com.rumenz;
import java.util.Map;
public class DemoApplication {public static void main(String[] args) {AnnotationConfigApplicationContext ac=new AnnotationConfigApplicationContext();
ac.register(DemoApplication.class); // 不注册 Rumenz
ac.refresh();
//NoSuchBeanDefinitionException 不存在要查找的 Bean
byBeanFactory(ac);
ac.close();}
//NoSuchBeanDefinitionException 不存在要查找的 Bean
private static void byBeanFactory(AnnotationConfigApplicationContext ac) {ac.getBean(Rumenz.class);
}
}输入
Exception in thread "main" org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.rumenz.Rumenz' available
NoUniqueBeanDefinitionException 容器中存在多个同类型的 Bean
配置 Bean 的
注册了两个 Rumenz
package com.rumenz;
import org.springframework.context.annotation.Bean;
public class Config {
@Bean
public Rumenz rumenz1(){Rumenz r=new Rumenz();
r.setId(456);
r.setName("入门小站");
return r;
}
@Bean
public Rumenz rumenz(){Rumenz r=new Rumenz();
r.setId(123);
r.setName("入门小站");
return r;
}
}
案例
package com.rumenz;
import org.springframework.beans.factory.ObjectProvider;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import java.util.Map;
public class DemoApplication {public static void main(String[] args) {AnnotationConfigApplicationContext ac=new AnnotationConfigApplicationContext();
ac.register(Config.class); // 注册 Rumenz
ac.refresh();
// NoUniqueBeanDefinitionException 要查找的 Bean 不惟一
byBeanFactory(ac);
ac.close();}
// NoUniqueBeanDefinitionException 要查找的 Bean 不惟一
private static void byBeanFactory(AnnotationConfigApplicationContext ac) {ac.getBean(Rumenz.class);
}
}输入
Exception in thread "main" org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type 'com.rumenz.Rumenz' available: expected single matching bean but found 2: rumenz1,rumenz
BeanInstantiationException 不能被实例化
package com.rumenz;
public class DemoApplication {public static void main(String[] args) {AnnotationConfigApplicationContext ac=new AnnotationConfigApplicationContext();
BeanDefinitionBuilder bb=BeanDefinitionBuilder.genericBeanDefinition(BeanFactory.class);
ac.registerBeanDefinition("err",bb.getBeanDefinition());
ac.refresh();
ac.close();}
}输入
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.beans.factory.BeanFactory]: Specified class is an interface
BeanCreationException Bean 初始化异样
package com.rumenz;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.ObjectProvider;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import java.util.Map;
public class DemoApplication {public static void main(String[] args) {AnnotationConfigApplicationContext ac=new AnnotationConfigApplicationContext();
// 4.BeanCreationException Bean 初始化异样
BeanDefinitionBuilder bb=BeanDefinitionBuilder.genericBeanDefinition(Rumenz.class);
ac.registerBeanDefinition("err",bb.getBeanDefinition());
ac.refresh();
ac.close();}
}BeanDefinitionStoreException 配置元谬误
Beanss.xml 不存在就会触发 BeanDefinitionStoreException
ApplicationContext acc=new ClassPathXmlApplicationContext("Beanss.xml");
输入
Exception in thread "main" org.springframework.beans.factory.BeanDefinitionStoreException: IOException parsing XML document from class path resource [Beanss.xml]; nested exception is java.io.FileNotFoundException: class path resource [Beanss.xml] cannot be opened because it does not exist
正文完
