Spring学习笔记（五）构建Spring Web应用程序

Spring MVC 实战

最新推荐文章于 2023-06-26 16:25:15 发布

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本文介绍如何使用 Spring MVC 构建一个简单的微博网站，包括配置 DispatcherServlet、启用 Spring MVC、编写控制器处理请求、传递模型数据到视图、处理表单及接受用户输入。

前言

本文所述完整可运行项目程序托管在本人的github:https://github.com/Wuchenwcf/springDemo

本文所述网站发布在本人的服务器：http://www.chongfer.cn/springDemo/

本文所述涉及到Spring依赖注入的基础知识，http://blog.youkuaiyun.com/luchengtao11/article/details/67632383

本文将按照《Spring in action》书本上第五章的部分逐步构建一个简单的微博网站。对于一些知识点只是简要说明，仅作参考。想要更深入地了解，读者们可以阅读原书。

本文所述程序是通过Eclipse建立的标准Maven Web工程，因为用到Spring Mvc,所以需要在Maven pom.xml添加依赖的Spring jar包，如下图所示

一、Spring MVC起步

1.配置DispatcherServlet

package spittr.config;

import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;
public class SpittrWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {


	//
	@Override
	protected Class<?>[] getRootConfigClasses() {
		// TODO Auto-generated method stub
		return new Class<?>[]{RootConfig.class};
	}

	@Override
	protected Class<?>[] getServletConfigClasses() {
		// TODO Auto-generated method stub
		return new Class<?>[] {WebConfig.class};
		
	}

	//将DispatcherServlet映射到了“/”
	@Override
	protected String[] getServletMappings() {
		// TODO Auto-generated method stub
		return new String[]{"/"};
	}
	

}

2.启用Spring MVC

package spittr.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.DefaultServletHandlerConfigurer;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.servlet.view.InternalResourceViewResolver;

@Configuration
//启用Mvc
@EnableWebMvc
//启用组件扫描
@ComponentScan("spittr.web")
public class WebConfig extends WebMvcConfigurerAdapter {
	
	//配置JSP视图解析器
	@Bean
	public ViewResolver viewResolver()
	{
		InternalResourceViewResolver resolver=new InternalResourceViewResolver();
		resolver.setPrefix("/WEB-INF/views/");
		resolver.setSuffix(".jsp");
		resolver.setExposeContextBeansAsAttributes(true);
		return resolver;
	}
	
	//配置静态资源的处理
	@Override
	public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer)
	{
		configurer.enable();
	}

}

3.编写RootConfig

package spittr.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.FilterType;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;

@Configuration
@ComponentScan(basePackages={"spitter"},excludeFilters={@ComponentScan.Filter(type=FilterType.ANNOTATION,value=EnableWebMvc.class)})
public class RootConfig {

}

二、编写基本的控制器

1.最简单的控制器

package spittr.web;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

//声明一个控制器
@Controller
public class HomeController {

	//处理对“/”的GET请求
	@RequestMapping(value="/",method=RequestMethod.GET)
	public String home()
	{
	return "home";
	}
}

2.在WEB-INF/view/下定义一个简单的jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Spittr</title>
</head>
<body>
<h1>Welcome to spittr</h1>
<a href="/spittles"> Spittles</a>|<a href="/spitter/register" > Register</a>
</body>
</html>

到这里，Spring web程序已经能跑起来了,如图所示：

3.传递模型数据到视图中

设计Spittle类

package spittr.Spittle;
import java.util.Date;

import org.apache.commons.lang.builder.EqualsBuilder;
import org.apache.commons.lang.builder.HashCodeBuilder;

public class Spittle {
	private final Long id;
	private final String message;
	private final Date time;
	private Double latitude;
	private Double longitude;
	public Spittle(String message ,Date time,Double longitude,Double latitude)
	{
		this.id=null;
		this.message=message;
		this.time=time;
		this.longitude=longitude;
		this.latitude=latitude;
	}
	
	public long getId()
	{
		return this.id;
	}
	
	public String getMessage()
	{
		return this.message;
	}
	
	public Double getLongitude()
	{
		return this.latitude;
	}
	
	public Double getLatitude()
	{
		return this.latitude;
	}
	
	public boolean equals(Object That)
	{
		//应用此处代码需要comment-lang依赖
		return EqualsBuilder.reflectionEquals(this,That);
	}
	public int hashCode()
	{
		return HashCodeBuilder.reflectionHashCode(this);
	}

}

定义一个数据访问的Repository

package spittr.data;

import java.util.List;

import spittr.Spittle.Spittle;

public interface SpittleRepository {
	List<Spittle> findSpittles(long max,int count);

}

书本上没有给出这个接口的实现，导致，不能进行前一阶段的测试，这里我写了一个简单的实现累，并在config中添加@bean注解生成Bean

package spittr.data;

import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import spittr.Spittle.Spittle;

public class SpittleRepositoryImp implements SpittleRepository{

	public List<Spittle> findSpittles(long max, int count) {
		// TODO Auto-generated method stub
		List<Spittle> list=new ArrayList<Spittle>();
		for(int i=0;i<count;i++)
			list.add(new Spittle("spittle"+i,new Date()));
		return list;
	}
	

}

然后编写SpittleController类

package spittr.web;

import java.util.List;
import java.util.Map;

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

import spittr.data.SpittleRepository;

@Controller
@RequestMapping("/spittles")
public class SpittleController {

	private SpittleRepository spittleRepository;
	@Autowired
	public SpittleController(SpittleRepository s)
	{
		this.spittleRepository=s;
	}
	
	@RequestMapping(method=RequestMethod.GET)
	public String spittles(Model model)
	{
		model.addAttribute("spittleList",spittleRepository.findSpittles(Long.MAX_VALUE, 20));
		model.addAttribute("s", 12345);
		System.out.println(model.toString());
		return "spittles";
	}
	

}

编写JSP脚本Spittles.jsp

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%@ taglib prefix="s" uri="http://www.springframework.org/tags"%>
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>
<%@ page language="java" contentType="text/html; charset=UTF-8"  
    pageEncoding="UTF-8"%> 
    <%@ page isELIgnored="false" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<c:forEach items="${spittleList}" var="spittle">
    <li id="spittle_<c:out value="spittle.id"/>">
        <div class="spittleMessage">
            <c:out value="${spittle.message}" />
        </div>
        <div>
            <span class="spittleTime"><c:out value="${spittle.time}" /></span>
            <span class="spittleLocation"> (<c:out
                    value="${spittle.latitude}" />, <c:out
                    value="${spittle.longitude}" />)
            </span>
        </div>
    </li>
</c:forEach>

</body>
</html>

此时，整个网站又可以运行了，如下：

三、处理表单，接受用户输入

1.首先编写SpitterController，展现一个表单，允许用户注册该应用

package spittr.web;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@Controller
@RequestMapping("/spitter")
public class SpitterController {
	//处理对“/spitter/register”的请求
	@RequestMapping(value="/register",method=RequestMethod.GET)
	public String showRegistrationForm()
	{
		System.out.println("REgisterForm");
		return "registerForm";
	}
}

2.然后编写registerForm.jsp

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
 <%@ page session="false" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>Spittr</title>
<link rel="stylesheet" type="text/css"
      href="<c:url value="/resources/style.css"/>" >
</head>
<body>

<h1>Register</h1>
<form method="post">
First Name:<input type="text" name="firstName" /><br/>
Last  Name:<input type="text" name="lastName" /><br/>
User  Name:<input type="text" name="userName" /><br/>
Password  :<input type="password" name="password" /><br/>

<input type="submit" value="Register" />
</form>
</body>
</html>

此时，网站又可以完整地运行了，效果如下:

2.处理所提交的表单并注册新用户

创建SpitterController类

package spittr.web;

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

import spittr.Spitter;
import spittr.data.SpitterRepository;

@Controller
@RequestMapping("/spitter")
public class SpitterController {
	
	private SpitterRepository spitterRepository;
	
	//自动注入
	@Autowired
	public SpitterController(SpitterRepository sp)
	{
		this.spitterRepository=sp;
	}
	//处理对“/spitter/register”的请求
	@RequestMapping(value="/register",method=RequestMethod.GET)
	public String showRegistrationForm()
	{
		System.out.println("REgisterForm");
		return "registerForm";
	}
	
	@RequestMapping(value="/register",method=RequestMethod.POST)
	public String processRegistration(Spitter spitter)
	{
		spitterRepository.save(spitter);
		return "redirect:/spitter/"+spitter.getUserName();
	}
	
	@RequestMapping(value="/{username}",method=RequestMethod.GET)
	public String showSpitterProfile(@PathVariable String username,Model model)
	{
		Spitter spitter=spitterRepository.findByUserName(username);
		model.addAttribute(spitter);
		return "profile";
	}
}

2.添加Profile 用来显示用户信息

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
 <%@ page session="false" %>
     <%@ page isELIgnored="false" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Your Profile</title>
</head>
<body>
<h1>Your Profile</h1>
<c:out value="${spitter.userName}"></c:out><br/>
<c:out value="${spitter.firstName}"></c:out>
<c:out value="${spitter.lastName}"></c:out>
</html>

到现在，网站又可以运行了。效果如下：