Spring三种装配Bean的方式

曾经终败给现在 2021-11-26 08:34 437阅读 0赞

## 1基于XML的配置 ##

pojo

package com.baidu.pojo;
    
    import java.util.List;
    
    public class Car2 {
    
        private  String  name;
        private  double price;
        public Car2() {
    
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        public double getPrice() {
            return price;
        }
    
        public void setPrice(double price) {
            this.price = price;
        }

xml配置

<?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:context="http://www.springframework.org/schema/context"
           xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans.xsd
           http://www.springframework.org/schema/context
            http://www.springframework.org/schema/context/spring-context.xsd">
    
    
    
    <bean id="car" class="com.baidu.pojo.Car2">
    
        <property name="name" value="本次"></property>
        <property name="price" value="2.0"></property>
    
    
    </bean>
    
    </beans>

test

package com.baidu.test;
    
    
    import com.baidu.pojo.Car2;
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    
    public class TestCar2 {
        public static void main(String[] args) {
    
            ApplicationContext applicationContext = new ClassPathXmlApplicationContext
                    ("applicationContext.xml");
            Car2 car2 = applicationContext.getBean(Car2.class);
    
            System.out.println(car2.getName());
            System.out.println(car2.getPrice());
    
        }
    }

结果

本次
    2.0
    
    Process finished with exit code 0

## 2基于注解的配置 ##

1bb.Xml文件（未配置）

<?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:context="http://www.springframework.org/schema/context"
           xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans.xsd
           http://www.springframework.org/schema/context
            http://www.springframework.org/schema/context/spring-context.xsd">
        <import resource="applicationContext.xml"></import>
    
    
        
        <context:component-scan base-package="com.baidu"></context:component-scan>
    
    </beans>

Controller层

package com.baidu.Controller;
    
    import com.baidu.Service.DeptService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Repository;
    
    @Repository
    public class DeptController {
        @Autowired
       private DeptService deptService;
       public  String findName(){
    
           return  deptService.findName();
       }
    
    
    
    }

Dao层

package com.baidu.Dao;
    
    import org.springframework.stereotype.Repository;
    
    @Repository
    public class DeptDao {
    
        public String queryName() {
            return "lisi";
        }
    }

service层

package com.baidu.Service;
    
    
    import com.baidu.Dao.DeptDao;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    
    @Service
    
    public class DeptService {
    
        @Autowired
        /*@Qualifier(value = "deptDao")
        *///与@AutoWired一起使用
        private DeptDao deptDao;
        public  String findName(){
    
            return deptDao.queryName();
    
        }
    }

test类

package com.baidu.test;
    
    import com.baidu.Service.DeptService;
    import com.baidu.pojo.Car;
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    
    public class TestDeptService {
        public static void main(String[] args) {
    
            ApplicationContext applicationContext = new ClassPathXmlApplicationContext
                    ("bb.xml");
    
            DeptService deptService = applicationContext.getBean(DeptService.class);
    
    
            System.out.println(deptService.findName());
    
        }
    }

结果

lisi
    
    Process finished with exit code 0

## 3基于Java类的配置 ##

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1Xml文件（未配置）

<?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:context="http://www.springframework.org/schema/context"
           xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans.xsd
           http://www.springframework.org/schema/context
            http://www.springframework.org/schema/context/spring-context.xsd">
        <import resource="applicationContext.xml"></import>
    
    
        
        <context:component-scan base-package="com.baidu"></context:component-scan>
    
    </beans>

2新建配置文件包com.baidu.Config

package com.baidu.Config;
    
    import com.baidu.pojo.Student;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    @Configuration
    public class Beanconfig {
    @Bean
    
        public  Student student(){
    
    
            return   new Student();
        }
    }

3创建pojo

package com.baidu.pojo;
    
    public class Student {
    
    }

4创建测试类

package com.baidu.test;
    
    import com.baidu.pojo.Student;
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    
    public class TestStudent {
        public static void main(String[] args) {
    
            ApplicationContext applicationContext = new ClassPathXmlApplicationContext
                    ("bb.xml");
    
            Student student = applicationContext.getBean(Student.class);
    
    
            System.out.println(student);
    
        }
    }

5运行结果

com.baidu.test.TestStudent
    com.baidu.pojo.Student@1460a8c0                          //-----成功------//
    
    Process finished with exit code 0

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