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  • Spring属性注入、构造方法注入、工厂注入以及注入参数（转）

    Spring 是一个开源框架.

    Spring 为简化企业级应用开发而生（对比EJB2.0来说）. 使用 Spring 可以使简单的 JavaBean 实现以前只有 EJB 才能实现的功能。
    Spring 是一个 IOC(DI) 和 AOP 容器框架。

    具体描述 Spring:
    轻量级：Spring 是非侵入性的 - 基于 Spring 开发的应用中的对象可以不依赖于 Spring 的 API
    控制反转（依赖注入） (IOC----inverse of control 、DI --- dependency injection)
    面向切面编程(AOP --- aspect oriented programming)
    容器: Spring 是一个容器, 因为它包含并且管理应用对象的生命周期
    框架: Spring 实现了使用简单的组件配置组合成一个复杂的应用. 在 Spring 中可以使用 XML 和 Java 注解组合这些对象
    一站式：在 IOC 和 AOP 的基础上可以整合各种企业应用的开源框架和优秀的第三方类库 （实际上 Spring 自身也提供了展现层的 SpringMVC 和 持久层的 Spring JDBC）

    所需jar包

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    <?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://www.springframework.org/schema/beans
            http://www.springframework.org/schema/beans/spring-beans.xsd">
     
        <bean name="dog" class="com.zhiqi.entity.Dog"></bean>
         
    </beans>

    　　装配一个Bean

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    package com.zhiqi.entity;
     
    public class Dog {
     
        private String name;
     
        public String getName() {
            return name;
        }
        public void setName(String name) {
            this.name = name;
        }
     
    }

    　　

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    package com.zhiqi.test;
     
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
     
    import com.zhiqi.entity.Dog;
     
    public class T {
     
        public static void main(String[] args) {
            ApplicationContext ac=new ClassPathXmlApplicationContext("beans.xml");
            Dog dog=(Dog)ac.getBean("dog");
            System.out.println(dog.getName());
        }
    }

    　　

    此时装配了Dog这个类，但是为null

    需要进行依赖注入（属性注入、构造方法注入，工厂注入）

    1、属性注入：

    装配一个员工类

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    package com.zhiqi.entity;
     
    public class Employee {
     
        private int id;
        private String name;
        private String sex;
        public int getId() {
            return id;
        }
        public void setId(int id) {
            this.id = id;
        }
        public String getName() {
            return name;
        }
        public void setName(String name) {
            this.name = name;
        }
        public String getSex() {
            return sex;
        }
        public void setSex(String sex) {
            this.sex = sex;
        }
    }

    　　

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    package com.zhiqi.test;
     
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
     
    import com.zhiqi.entity.Dog;
    import com.zhiqi.entity.Employee;
     
    public class T {
     
        public static void main(String[] args) {
            ApplicationContext ac=new ClassPathXmlApplicationContext("beans.xml");
            Employee employee=(Employee)ac.getBean("employee");
            System.out.println(employee.getName());
        }
    }

    　　

    属性注入如下：<property name="" value=""></property>

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    <bean name="employee" class="com.zhiqi.entity.Employee">
            <property name="id" value="10050"></property>
            <property name="name" value="小鲜肉"></property>
            <property name="sex" value="男"></property>
        </bean>

    构造方法注入一（通过类型）：<constructor-arg type="" value=""></constructor-arg>

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    <bean name="employee" class="com.zhiqi.entity.Employee">
            <constructor-arg type="int" value="10010"></constructor-arg>
            <constructor-arg type="String" value="小萝莉"></constructor-arg>
            <constructor-arg type="String" value="女"></constructor-arg>
        </bean>

    　　此时需要写构造函数否则会报错：

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    public class Employee {
     
        private int id;
        private String name;
        private String sex;
         
        public Employee() {
            super();
            // TODO Auto-generated constructor stub
        }
        public Employee(int id, String name, String sex) {
            super();
            this.id = id;
            this.name = name;
            this.sex = sex;
        }
    }

    　　

    构造方法注入二（通过索引）：<constructor-arg index="" value=""></constructor-arg>   索引从0开始

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    <bean name="employee" class="com.zhiqi.entity.Employee">
            <constructor-arg index="0" value="10010"></constructor-arg>
            <constructor-arg index="1" value="小萝莉"></constructor-arg>
            <constructor-arg index="2" value="女"></constructor-arg>
        </bean>

    　可以混合使用　类型+索引

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    <bean name="employee" class="com.zhiqi.entity.Employee">
            <constructor-arg type="int" index="0" value="10010"></constructor-arg>
            <constructor-arg type="String" index="1" value="小萝莉"></constructor-arg>
            <constructor-arg type="String" index="2" value="女"></constructor-arg>
        </bean>

    通过工厂注入：<bean name="employee" factory-bean="" factory-method=""></bean>

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    package com.zhiqi.factory;
     
    import com.zhiqi.entity.Employee;
     
    public class EmployeeFactory {
     
        public Employee createEmployee(){
            Employee employee=new Employee();
            employee.setId(10080);
            employee.setName("小霸王");
            employee.setSex("男");
            return employee;
        }
    }

    　　

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    <?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://www.springframework.org/schema/beans
            http://www.springframework.org/schema/beans/spring-beans.xsd">
     
        <bean name="dog" class="com.zhiqi.entity.Dog"></bean>
         
        <bean name="employeeFactory" class="com.zhiqi.factory.EmployeeFactory"></bean>
        <bean name="employee" factory-bean="employeeFactory" factory-method="createEmployee"></bean>
         
    </beans>

    　　

    通过静态工厂注入：

    注入参数：

    1、基本类型值

    2、注入bean

    3、内部bean

    4、null值

    5、级联属性

    6、集合注入（List、Set、Map）

    员工有一辆车

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    <bean id="employee" class="com.zhiqi.entity.Employee">
            <property name="id" value="10060"></property>
            <property name="name" value="脑残粉"></property>
            <property name="sex" value="女"></property>
            <property name="car" ref="car"></property>
        </bean>
        <bean id="car" class="com.zhiqi.entity.Car">
            <property name="name" value="别克"></property>
        </bean>

    　　

    一辆车只属于某员工，内部bean

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    <bean id="employee" class="com.zhiqi.entity.Employee">
            <property name="id" value="10060"></property>
            <property name="name" value="脑残粉"></property>
            <property name="sex" value="女"></property>
            <property name="car">
                <bean class="com.zhiqi.entity.Car">
                    <property name="name" value="雪佛兰"></property>
                </bean>
            </property>
        </bean>

    　　

    有一个员工没有车

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    <bean id="employee" class="com.zhiqi.entity.Employee">
            <property name="id" value="10060"></property>
            <property name="name" value="脑残粉"></property>
            <property name="sex" value="女"></property>
            <property name="car">
                <null></null>
            </property>
        </bean>

    　　

     级联

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    <bean id="employee" class="com.zhiqi.entity.Employee">
            <property name="id" value="10060"></property>
            <property name="name" value="脑残粉"></property>
            <property name="sex" value="女"></property>
            <property name="car.name" value="好车"></property>
        </bean>

    　　此时在Car中new一个

    一个员工有多个girlFriend

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    private int id;
        private String name;
        private String sex;
        private Car car;
        private List<String> girlFriend=new ArrayList<String>();

    　　

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    <?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://www.springframework.org/schema/beans
            http://www.springframework.org/schema/beans/spring-beans.xsd">
         
        <bean id="employee" class="com.zhiqi.entity.Employee">
            <property name="id" value="10060"></property>
            <property name="name" value="脑残粉"></property>
            <property name="sex" value="女"></property>
            <property name="car" value="宾利"></property>
            <property name="girlFriend">
                <list>
                    <value>琪琪</value>
                    <value>丽丽</value>
                    <value>小莫</value>
                </list>
            </property>
        </bean>
     
    </beans>

    　　

    一个员工有多套房子

    private Set<String> house=new HashSet<String>();

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    <?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://www.springframework.org/schema/beans
            http://www.springframework.org/schema/beans/spring-beans.xsd">
         
        <bean id="employee" class="com.zhiqi.entity.Employee">
            <property name="id" value="10060"></property>
            <property name="name" value="脑残粉"></property>
            <property name="sex" value="女"></property>
            <property name="car" value="宾利"></property>
            <property name="girlFriend">
                <list>
                    <value>琪琪</value>
                    <value>丽丽</value>
                    <value>小莫</value>
                </list>
            </property>
            <property name="house">
                <set>
                    <value>房子1</value>
                    <value>别墅2</value>
                </set>
            </property>
        </bean>
     
    </beans>

    　　一个员工的工作

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    <?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://www.springframework.org/schema/beans
            http://www.springframework.org/schema/beans/spring-beans.xsd">
         
        <bean id="employee" class="com.zhiqi.entity.Employee">
            <property name="id" value="10060"></property>
            <property name="name" value="脑残粉"></property>
            <property name="sex" value="女"></property>
            <property name="car" value="宾利"></property>
            <property name="girlFriend">
                <list>
                    <value>琪琪</value>
                    <value>丽丽</value>
                    <value>小莫</value>
                </list>
            </property>
            <property name="house">
                <set>
                    <value>房子1</value>
                    <value>别墅2</value>
                </set>
            </property>
            <property name="works">
                <map>
                    <entry>
                        <key><value>上午</value></key>
                        <value>撸代码</value>
                    </entry>
                    <entry>
                        <key><value>下午</value></key>
                        <value>找BUG</value>
                    </entry>
                </map>
            </property>
        </bean>
     
    </beans>

    　　

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    package com.zhiqi.test;
     
    import java.util.Iterator;
     
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
     
    import com.zhiqi.entity.Employee;
     
    public class T {
     
        public static void main(String[] args) {
            ApplicationContext ac=new ClassPathXmlApplicationContext("beans.xml");
            Employee employee=(Employee)ac.getBean("employee");
            for(String str:employee.getHouse()){
                System.out.println(str);
            }
            //entrySet()将map转为set，然后迭代器遍历
            Iterator it=employee.getWorks().entrySet().iterator();
            while(it.hasNext()){
                System.out.println(it.next());
            }
        }
    }
    • 　　
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  • 原文地址：https://www.cnblogs.com/hq233/p/6625218.html
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