一、首先是基於XML配置的依賴注入例項

  在本例項中，Spring MVC並非主要講解內容，其檔案正規化不再重複，而有關依賴注入檔案包括：介面類car.java，實現了car介面的Taxi,java和Train.java。在User類中，有一個Car物件屬性。即此Car即為需要注入的物件。然後是配置的檔案，applicationContext.xml，其中包含了Bean的定義。

  下面是各個檔案的內容。

1.user,java

package com.zjn.entity;

import java.io.Serializable;
import java.util.Date;

public class User implements Serializable {
	/**
	 * @author zjn
	 */
	private static final long serialVersionUID = 1L;
	private String name; // name
	private String pwd; // pwd
	private Integer age; // age
	
	private String sex;
	
	private Car car;
	
	//全部實現了set和get方法， 以此完成依賴注入（設值注入）
	public String getSex() {
		return sex;
	}

	public void setSex(String sex) {
		this.sex=sex;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getPwd() {
		return pwd;
	}

	public void setPwd(String pwd) {
		this.pwd = pwd;
	}

	public Integer getAge() {
		return age;
	}

	public void setAge(Integer age) {
		this.age = age;
	}


	public Car getCar() {
		return car;
	}

	public void setCar(Car car) {
		this.car = car;
	}
	
	public void run() {
		String runtype=car.getType();
		System.out.println(runtype);
	}

}
 

2.介面類Car和它的具體類Taxi和Train。

package com.zjn.entity;

public interface Car {
	public String getType();

}

package com.zjn.entity;

public class Taxi implements Car{

	@Override
	public String getType() {
		// TODO Auto-generated method stub
		return "His car is a taxi!";
	}

}

package com.zjn.entity;

public class Train implements Car {

	@Override
	public String getType() {
		// TODO Auto-generated method stub
		return "Wow!He has a train!";
	}

}
 

3.下面是配置檔案applicationContext.xml

<?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-3.0.xsd">

	
	<bean id="taxi" class="com.zjn.entity.Taxi">
	</bean>
	<bean id="train" class="com.zjn.entity.Train">
	</bean>
	
	<bean id="user" class="com.zjn.entity.User">
		<property name="name" value="zfh14"/>
		<property name="pwd" value="19961006"/>
		<property name="age" value="12"/>
		<property name="sex" value="B"/>
		
		<property name="car" ref="train"/>
	</bean>
	
	
</beans>
 

4.然後是呼叫了User物件的UserController，也就是Spring MVC中的Controller。

package com.zjn.controller;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;

import com.zjn.entity.Taxi;
import com.zjn.entity.Train;
import com.zjn.entity.User;
import com.zjn.form.UserForm;

/**
 * 使用者管理
 * 
 * @author zjn
 */
@Controller
public class UserController {
	@RequestMapping("login")
	public String Login(Model model) {
		return "login";
	}

	@RequestMapping("loginTo")
	public String Save(@ModelAttribute("form") UserForm userform, Model model) { // user:檢視層傳給控制層的表單物件；model：控制層返回給檢視層的物件
		System.out.println("the input userform values:"+userform.getName()+","+userform.getSex()+","+userform.getPwd()+","+userform.getAge()+","+userform.getCar());
		ApplicationContext applicationContext = new ClassPathXmlApplicationContext("com/zjn/controller/applicationContext.xml");
		User user = (User) applicationContext.getBean("user");
		user.run();
		System.out.println("the original user values:"+user.getName()+","+user.getSex()+","+user.getPwd()+","+user.getAge()+","+user.getCar());
		
		user.setName(userform.getName());
		user.setAge(userform.getAge());
		user.setSex(userform.getSex());
		user.setPwd(userform.getPwd());
		if(userform.getCar().equals("Taxi")) {
			user.setCar(new Taxi());
		}else if(userform.getCar().equals("Train")) {
			user.setCar(new Train());
		}
		System.out.println("the input user values:"+user.getName()+","+user.getSex()+","+user.getPwd()+","+user.getAge()+","+user.getCar());

		model.addAttribute("user", user);
		return "detail";
	}
}

此處要注意ApplicationContext applicationContext = new ClassPathXmlApplicationContext("com/zjn/controller/applicationContext.xml");這一行中配置檔案的地址。。。不知道為什麼放在WebContent下識別不了。可能是之前寫的地址不對吧。

恩，這樣，主要的關於依賴注入的部分就全了。

二、基於註解的依賴注入例項，在上面的基於XMl配置的例項基礎上進行修改而成。

  首先，刪除applicationContext.xml。然後，因為初次接觸的原因，模仿了之前找到的一個例子，新增一個UserService.java介面和一個UserServiceImpl.java類。其中，後一個實體類就是針對依賴注入而設計的。

1.UserService,java

package com.zjn.service;

import com.zjn.entity.User;

public interface UserService {
	public User getUser();

}

 UserServiceImpl.java

package com.zjn.service;

import org.springframework.stereotype.Service;

import com.zjn.entity.Train;
import com.zjn.entity.User;

@Service
public class UserServiceImpl implements UserService{
	private User user;

	public UserServiceImpl() {
		user=new User();
		user.setName("zfh");
		user.setAge(22);
		user.setSex("B");
		user.setPwd("123789");
		user.setCar(new Train());
	}
	@Override
	public User getUser() {
		// TODO Auto-generated method stub
		return user;
	}

}

如上，採用構造注入的方式。在下面的UserController類中，控制器每次接受到loginTo請求後，都會去儲存表單的內容，將表單內容儲存在User類中，而這個User類並不是通過new實現的，而是通過UserService的getUser方法來實現的。

而UserService，也並不需要（或者說不能）進行new UserService()

2.UserController.java

package com.zjn.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;

import com.zjn.entity.Taxi;
import com.zjn.entity.Train;
import com.zjn.entity.User;
import com.zjn.form.UserForm;
import com.zjn.service.UserService;

@Controller
public class UserController {
	@Autowired
	UserService userService;
	
	@RequestMapping("login")
	public String Login(Model model) {
		return "login";
	}

	@RequestMapping("loginTo")
	public String Save(@ModelAttribute("form") UserForm userform, Model model) { // user:檢視層傳給控制層的表單物件；model：控制層返回給檢視層的物件
		System.out.println("the input userform values:"+userform.getName()+","+userform.getSex()+","+userform.getPwd()+","+userform.getAge()+","+userform.getCar());
		
		User user = userService.getUser();
		//
		System.out.println("the original user values:"+user.getName()+","+user.getSex()+","+user.getPwd()+","+user.getAge()+","+user.getCar());
		user.run();
		
		user.setName(userform.getName());
		user.setAge(userform.getAge());
		user.setSex(userform.getSex());
		user.setPwd(userform.getPwd());
		if(userform.getCar().equals("Taxi")) {
			user.setCar(new Taxi());
		}else if(userform.getCar().equals("Train")) {
			user.setCar(new Train());
		}
		System.out.println("the input user values:"+user.getName()+","+user.getSex()+","+user.getPwd()+","+user.getAge()+","+user.getCar());
		user.run();
		
		model.addAttribute("user", user);
		return "detail";
	}
}

然後，因為不存在new UserService的情況，所以，這裡的userService是Spring容器自己提供的。故而，需要在配置檔案中掃描UserService和UserServiceImpl所在的包。。我是直接掃描了所有的包。。

恩，貼一下springmvc-servlet.xml的配置檔案吧。

<?xml version="1.0" encoding="UTF-8"?>
<beans:beans xmlns:beans="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
	xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:p="http://www.springframework.org/schema/p"
	xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd ">
	<mvc:annotation-driven />
	<!-- ①：對web包中的所有類進行掃描，以完成Bean建立和自動依賴注入的功能 -->
	<context:component-scan base-package="com.zjn" />

	<!-- 這兩個類用來啟動基於Spring MVC的註解功能，將控制器與方法對映加入到容器中 -->
	<beans:bean
		class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping" />
	<beans:bean
		class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" />

	<!-- 這個類用於Spring MVC檢視解析 -->
	<beans:bean id="viewResolver"
		class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<beans:property name="prefix" value="/WEB-INF/pages/" />
		<beans:property name="suffix" value=".jsp" />
	</beans:bean>
	
</beans:beans>

ok！