Spring三种装配Bean的方式

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本文详细介绍了Spring框架的三种配置方式：基于XML的配置、基于注解的配置和基于Java类的配置。通过实例展示了每种配置方式的具体实现，包括POJO类定义、配置文件编写及测试验证。

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>


    <!--开启注解扫描-->
    <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

这里是引用

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>


    <!--开启注解扫描-->
    <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