Spring学习-07-spring在web中的使用

spring在web中的使用 在web项目中使用spring

在之前的示例中，我们都使用的是非web进行测试的，即没有部署到tomcat容器里面，在实际开发中，需要创建web项目，此时只需要将spring容器放到ServletContext域中即可。

添加依赖 导入相关spring-web的jar包，这里只需要在项目中添加下面依赖即可：

    
        org.springframework
        spring-webmvc
        5.0.4.RELEASE
    

注册监听器 ContextLoaderListener

这里将spring容器放到ServletContext域中，需要在ServletContext初始化的时候添加进去，此时就需要使用监听器接口ServletContextListener 对 ServletContext 进行监听。在 web.xml 中注册该监听器。

    org.springframework.web.context.ContextLoaderListener
  

通过源码可以看到spring在ContextLoaderListener的initWebApplicationContext方法中创建了容器对象。

指定spring配置文件的位置 需要在web.xml文件中指定spring配置文件所在的位置

    contextConfigLocation
    classpath:applicationContext.xml
  

这里使用注解的方式，所以在配置文件中添加：

创建servlet 不要忘了添加下面依赖：

    
        javax.servlet
        javax.servlet-api
        3.1.0
    
    
        javax.servlet
        jsp-api
        2.0
    

创建一个servlet在servlet中注入UserService，这里使用以前创建的UserService和UserDao：

package com.monkey1024.servlet;

import com.monkey1024.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.context.support.SpringBeanAutowiringSupport;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import java.io.IOException;

@WebServlet("/springtest")
public class SprintServlet extends javax.servlet.http.HttpServlet {
    @Autowired
    private UserService userService;

    /**
     * @param config
     * @throws ServletException
     */
    public void init(ServletConfig config) throws ServletException {
        SpringBeanAutowiringSupport.processInjectionBasedOnServletContext(this,
                config.getServletContext());
    }

    protected void doPost(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws javax.servlet.ServletException, IOException {
        doGet(request, response);
    }

    protected void doGet(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws javax.servlet.ServletException, IOException {
        userService.addUser();
    }
}

 pom.xml

  4.0.0
  com.monkey1024
  02_spring
  0.0.1-SNAPSHOT
  war
  
  	UTF-8
  
  
  		
		    org.springframework
		    spring-context
		    5.0.4.RELEASE
		
		
	        org.springframework
	        spring-webmvc
	        5.0.4.RELEASE
   		
   		
	        javax.servlet
	        javax.servlet-api
	        3.1.0
    	
    	
	        javax.servlet
	        jsp-api
	        2.0
    	
		
			junit
			junit
			3.8.1
			test
		
	
	
		02_spring
		
			
			
				org.apache.maven.plugins
				maven-compiler-plugin
				
					
					1.8
					1.8
					UTF-8
				
			
		
	

web.xml

	
	
		org.springframework.web.context.ContextLoaderListener
	
	
	
		contextConfigLoaction
		classpath:applicationContext.xml
	

applicationContext.xml

SpringServlet.java

package com.monkey1024.servlet;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.context.support.SpringBeanAutowiringSupport;

import com.monkey1024.service.UserService;

@WebServlet("/test ")
public class SpringServlet extends HttpServlet{
	@Autowired
	private UserService userService;
	
	public void init(ServletConfig config) throws ServletException{
		//让servlet支持注入
		SpringBeanAutowiringSupport.processInjectionBasedOnServletContext(this, config.getServletContext());
	}
	protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException{
		userService.addUser();
	}
	protected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException{
		doPost(request,response);
	}

}

UserService.java

package com.monkey1024.service;

public interface UserService {
	void addUser();
}

UserServiceImpl.java

package com.monkey1024.service.impl;

import org.springframework.stereotype.Service;

import com.monkey1024.service.UserService;

@Service("UserService")
public class UserServiceImpl implements UserService{
	public void addUser(){
		System.out.println("用户添加");
	}

}