spring依赖注入（dependency injection）

spring依赖注入包括两个方面：

      依赖：指bean对象创建依赖于容器。bean对象的依赖资源

      注入：bean对象的依赖资源由容器来设置和装配

Spring的注入有两类：

1、构造器的注入：使用constructor-arg

2、setter注入

要求被注入的属性，必须有set方法，set方法生成的方法名，由set+属性（首字母大写），如果属性是boolean类型，没有get方法，是is方法。

a、常量注入

b、bean的注入

Address.java

public class Address {
	private String address;

	public void setAddress(String address) {
		this.address = address;
	}

	public String getAddress() {
		return address;
	}
}

Student.java

public class Student {
	private String name;
	private Address addr;
	public void setName(String name) {
		this.name = name;
	}
	public void setAddr(Address addr) {
		this.addr = addr;
	}
	public void show(){
		System.out.println("name:"+name+" addr="+addr.getAddress());
	}
}

3、数组注入

beans.xml配置

      


	
	
	
            
		傲慢与偏见
		仲夏夜之梦
		悲惨世界
	    
	

Student.java

public class Student {
	private String name;
	private Address addr;
	private String[] books;
	public void setName(String name) {
		this.name = name;
	}
	public void setAddr(Address addr) {
		this.addr = addr;
	}
	public void setBooks(String[] books) {
		this.books = books;
	}
	public void show(){
		System.out.println("name:"+name+" addr:"+addr.getAddress());
		System.out.println("books=");
		for(int i=0;i

4、list注入

beans.xml配置

      


      
      
      
	   
		 傲慢与偏见
		 仲夏夜之梦
		 悲惨世界
	   
	
	
	   
		 羽毛球
		 乒乓球
		 排球
	   
     

Student.java

public class Student {
	private String name;
	private Address addr;
	private String[] books;
	private List hobbies;
	public void setName(String name) {
		this.name = name;
	}
	public void setAddr(Address addr) {
		this.addr = addr;
	}
	public void setBooks(String[] books) {
		this.books = books;
	}
	public void setHobbies(List hobbies) {
		this.hobbies = hobbies;
	}
	public void show(){
		System.out.println("name:"+name+" addr:"+addr.getAddress());
		System.out.println("books=");
		for(int i=0;ibeans.xml配置添加
 
  
 
  

	
 
  
 Student.java 
  
 
  
public class Student {
	private String name;
	private Address addr;
	private String[] books;
	private List hobbies;
	private Map cards;
	public void setName(String name) {
		this.name = name;
	}
	public void setAddr(Address addr) {
		this.addr = addr;
	}
	public void setBooks(String[] books) {
		this.books = books;
	}
	public void setHobbies(List hobbies) {
		this.hobbies = hobbies;
	}
	public void setCards(Map cards) {
		this.cards = cards;
	}
	public void show(){
		System.out.println("name:"+name+" addr:"+addr.getAddress());
		System.out.println("books=");
		for(int i=0;i
 
  

   
	开心消消乐
	宾果消消消
   
Student.java 
  
 
  
public class Student {
	private String name;
	private Address addr;
	private String[] books;
	private List hobbies;
	private Map cards;
	private Set games;
	public void setName(String name) {
		this.name = name;
	}
	public void setAddr(Address addr) {
		this.addr = addr;
	}
	public void setBooks(String[] books) {
		this.books = books;
	}
	public void setHobbies(List hobbies) {
		this.hobbies = hobbies;
	}
	public void setGames(Set games) {
		this.games = games;
	}
	public void setCards(Map cards) {
		this.cards = cards;
	}
	
	public void show(){
		System.out.println("name:"+name+" addr:"+addr.getAddress());
		System.out.println("books=");
		for(int i=0;i
 
  
 
  
 Student.java添加属性 
  
 
  
private String wife;
 
  
 8、properties注入 
  
 
  

	
		20171050
		男
		大一
	
Student.java添加变量 
  
 
  
private Properties info;
 
  
Test测试类
 
  
 
  
public class Test {
	public static void main(String[] args) {
		ApplicationContext context=new ClassPathXmlApplicationContext("beans.xml");
		Student stu=(Student) context.getBean("student");
		stu.show();
	}
}
测试所有代码运行结果，如图： 
  


 9、p命名空间注入 
  
需要在beans.xml配置头文件中加入
 
  
 
  
xmlns:p="http://www.springframework.org/schema/p"
 
  

 beans.xml配置文件中添加 
  
 
  

	
 
  
 新建User.java 
  
 
  
public class User {
	private String name;
	private int age;
	public void setName(String name) {
		this.name = name;
	}
	public void setAge(int age) {
		this.age = age;
	}
	@Override
	public String toString() {
		return "User[name="+name+",age="+age+"]";
	}

}
测试类改为 
  
 
  
public class Test {
	public static void main(String[] args) {
		ApplicationContext context=new ClassPathXmlApplicationContext("beans.xml");
		User u=(User) context.getBean("user");
		System.out.println(u);
      }
}
 
  
 测试结果： 
  
 
  
User[name=小红,age=12]