Spring依赖注入的方式、类型、Bean的作用域、自动注入、在Spring配置文件中引入属性文件

时间：2023-03-09 15:40:52
Spring依赖注入的方式、类型、Bean的作用域、自动注入、在Spring配置文件中引入属性文件

1.Spring依赖注入的方式

  1. 通过set方法完成依赖注入
  2. 通过构造方法完成依赖注入

2.依赖注入的类型

  1. 基本数据类型和字符串 使用value属性
  2. 如果是指向另一个对象的引入 使用ref属性

User类

package com.alibaba.wlq.bean;

public class User {

	private String name;

	private Integer age;

	private String phone;

	private Student student;

	public Student getStudent() {

		return student;

	}

	public void setStudent(Student student) {

		this.student = student;

	}

	public String getName() {

		return name;

	}

	public void setName(String name) {

		this.name = name;

	}

	public Integer getAge() {

		return age;

	}

	public void setAge(Integer age) {

		this.age = age;

	}

	public String getPhone() {

		return phone;

	}

	public void setPhone(String phone) {

		this.phone = phone;

	}

	public User(String name, String phone) {

		super();

		this.name = name;

		this.phone = phone;

		System.out.println("调用两个参的构造函数");

	}

	public User(String name, Integer age, String phone) {

		super();

		this.name = name;

		this.age = age;

		this.phone = phone;

	}

	public User() {

		super();

		System.out.println("调用无参的构造函数");

	}

	@Override

	public String toString() {

		return "User [name=" + name + ", age=" + age + ", phone=" + phone + ", student=" + student + "]";

	}

	public void show() {

		System.out.println("调用了show方法");

	}

}

Student类

package com.alibaba.wlq.bean;

public class Student {

	private String address;

	public String getAddress() {

		return address;

	}

	public void setAddress(String address) {

		this.address = address;

	}

	@Override

	public String toString() {

		return "Student [address=" + address + "]";

	}

}

配置文件

	<bean id="stu" class="com.alibaba.wlq.bean.Student">

		<property name="address" value="南京"></property>

	</bean>

	<bean id="user" class="com.alibaba.wlq.bean.User">

		<property name="name" value="刘亦菲"></property>

		<property name="age" value="18"></property>

		<property name="phone" value="10086"></property>

		<property name="student" ref="stu"></property>

	</bean>

测试类

package com.alibaba.wlq.test;

import org.omg.CORBA.portable.ApplicationException;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.alibaba.wlq.bean.User;

public class Test {

	public static void main(String[] args) {

		// TODO Auto-generated method stub

		ApplicationContext app = new ClassPathXmlApplicationContext("app.xml");

		User u = (User) app.getBean("user");

		u.show();

		System.out.println(u);

	}

}
  1. 如果类对象注入的属性类型为List类型

在User类中增加如下代码

private List<String> list;

	public List<String> getList() {

		return list;

	}

	public void setList(List<String> list) {

		this.list = list;

	}

配置文件中User类的配置改变

<bean id="user" class="com.alibaba.wlq.bean.User">

		<property name="name" value="刘亦菲"></property>

		<property name="age" value="18"></property>

		<property name="phone" value="10086"></property>

		<property name="student" ref="stu"></property>

		<property name="list">

			<list>

				<value>1</value>

				<value>2</value>

				<value>3</value>

				<value>4</value>

			</list>

		</property>

	</bean>

测试类中间部分

	public static void main(String[] args) {

		// TODO Auto-generated method stub

		ApplicationContext app = new ClassPathXmlApplicationContext("app.xml");

		User u = (User) app.getBean("user");

		List<String> list = u.getList();

		for (String string : list) {

			System.out.println(string);

		}

		u.show();

		System.out.println(u);

	}

打印结果

调用无参的构造函数

1

2

3

4

调用了show方法

User [name=刘亦菲, age=18, phone=10086, student=Student [address=南京]]
  1. 如果类对象注入的属性类型为Map类型

在User类中添加如下代码

	private Map<String, String> map;

	public Map<String, String> getMap() {

		return map;

	}

	public void setMap(Map<String, String> map) {

		this.map = map;

	}

配置文件

	<bean id="user" class="com.alibaba.wlq.bean.User">

		<property name="name" value="刘亦菲"></property>

		<property name="age" value="18"></property>

		<property name="phone" value="10086"></property>

		<property name="student" ref="stu"></property>

		<property name="list">

			<list>

				<value>1</value>

				<value>2</value>

				<value>3</value>

				<value>4</value>

			</list>

		</property>

		<property name="map">

			<map>

				<entry key="lyf" value="刘亦菲"></entry>

				<entry key="jsy" value="江疏影"></entry>

				<entry key="lye" value="林允儿"></entry>

			</map>

		</property>

	</bean>

测试类

	public static void main(String[] args) {

		// TODO Auto-generated method stub

		ApplicationContext app = new ClassPathXmlApplicationContext("app.xml");

		User u = (User) app.getBean("user");

		List<String> list = u.getList();

		for (String string : list) {

			System.out.println(string);

		}

		Map<String, String> map = u.getMap();

		for (String k : map.keySet()) {

			System.out.println(k+"===="+map.get(k));

		}

		u.show();

		System.out.println(u);

	}

打印结果

调用无参的构造函数

1

2

3

4

lyf====刘亦菲

jsy====江疏影

lye====林允儿

调用了show方法

User [name=刘亦菲, age=18, phone=10086, student=Student [address=南京]]

3.Bean的作用域

Bean的作用域默认为单例模式

Strust2：该框架要求非单例

bean标签中有scope属性，不写默认为单例，scope属性表示Bean的作用域，非单例：scope="prototype"

4.自动注入

Service类

package com.alibaba.wlq.service;

import com.alibaba.wlq.bean.Product;

public class ProductService {

	private Product product;

	public void fun(){

		product.find();

	}

	public Product getProduct() {

		return product;

	}

	public void setProduct(Product product) {

		this.product = product;

	}

}

Product类

package com.alibaba.wlq.bean;

public class Product {

	private String name;

	private int num;

	public String getName() {

		return name;

	}

	public void setName(String name) {

		this.name = name;

	}

	public int getNum() {

		return num;

	}

	public void setNum(int num) {

		this.num = num;

	}

	public void find() {

		System.out.println("======find=====");

	}

	@Override

	public String toString() {

		return "Product [name=" + name + ", num=" + num + "]";

	}

}

配置文件

<?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"

	default-autowire="byName">

	<bean id="pService" class="com.alibaba.wlq.service.ProductService" autowire="default">

	</bean>

	<bean id="product" class="com.alibaba.wlq.bean.Product">

		<property name="name" value="5700xt"></property>

		<property name="num" value="2"></property>

	</bean>

</beans>

测试代码

package com.alibaba.wlq.test;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.alibaba.wlq.bean.Product;

import com.alibaba.wlq.service.ProductService;

public class Test2 {

	public static void main(String[] args) {

		// TODO Auto-generated method stub

		ApplicationContext app = new ClassPathXmlApplicationContext("app2.xml");

		ProductService pService = (ProductService) app.getBean("pService");

		pService.fun();

		Product product = (Product) app.getBean("product");

		System.out.println(product);

	}

}

打印结果

======find=====

Product [name=5700xt, num=2]

5.在Spring配置文件中引入属性文件

  1. 在resources源文件夹下创建properties文件

    p.name=3700x
    
p.num=99

  2. 在配置文件中引用properties文件

    <context:property-placeholder location="classpath:my.properties"/>
    
	<!-- 引入属性文件，如果要引入多个那就在后面加， -->
    
	<bean id="pService" class="com.alibaba.wlq.service.ProductService" autowire="default">
    
	</bean>
    
	<bean id="product" class="com.alibaba.wlq.bean.Product">
    
        <!--获取属性文件中的属性-->
    
		<property name="name" value="${p.name}"></property>
    
		<prope1rty name="num" value="${p.num}"></property>
    
	</bean>