构建Spring Web整个过程的解析

1. 请求过程

2. 搭建Spring MVC

2.1. 配置DispatcherServlet

AbstractAnnotationConfigDispatcherServletInitializer

在Servlet环境下，容器在类路径查找javax.servlet.ServletContainerInitializer接口实现类

Spring中实现名为SpringServletContainerInitializer类并查找WebAplicationInitializer类

AbstractAnnotationConfigDispatcherServletInitializer就是一个WebAplicationInitializer

DispatcherServlet加载包含Web组件的bean，控制器，视图解析器以及处理器映射

ContextLoaderListener 加载应用中驱动应用后端的中间层和数据层组件

import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

public class SpittrWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer{

  //返回带有@Configuration注解的类来配置ContextLoaderListener创建的应用上下文中的bean
	@Override
	protected Class<?>[] getRootConfigClasses() {
		return new Class<?>[] {RootConfig.class};
	}
 
  //返回带有@Configuration注解的类用来定义DispatcherServlet应用上下文中的bean
	@Override
	protected Class<?>[] getServletConfigClasses() {
		return new Class<?>[] {WebConfig.class};
	}

  //映射路径
	@Override
	protected String[] getServletMappings() {

		return new String[]{"/"};
	}
}

WebConfig.class

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
@EnableWebMvc //启用Spring MVC
@ComponentScan(basePackages="com.runnaccpeted.controller")
public class WebConfig extends WebMvcConfigurerAdapter{

	//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;
	}
	
	//静态资源的处理
	@Override
	public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
		configurer.enable();
	}	
}

RootConfig.class

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

配置控制器

解析 /WEB-INF/views/home.jsp

package com.runnaccpeted.controller;

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

@Controller  //=@Component
public class HomeController {
	
	@RequestMapping(value="/",method=RequestMethod.GET)
	public String home(){
		return "home"; //渲染视图名
	}
}

视图 home.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!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=UTF-8">
<title>Insert title here</title>
</head>
<body>
  <h1>Home</h1>
</body>
</html>

测试控制器

import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.view;

import org.junit.Test;

import com.runnaccpeted.controller.HomeController;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;
public class HomeControllerTest {
	
	@Test
	public void test() throws Exception{
		HomeController home = new HomeController();
		MockMvc mockMvc = MockMvcBuilders.standaloneSetup(home).build();
    // 对“/”执行GET请求  预期得到home视图
		mockMvc.perform(get("/")).andExpect(view().name("home"));
	}

}

3. 传递模型数据

model是一个map集合，可以把集合数据传递给视图

import org.springframework.ui.Model;

@RequestMapping(method=RequestMethod.GET)
	public String show(Model model){
		List<User> list=userService.show(Long.MAX_VALUE, 20);
		model.addAttribute("list",list);
		return "list";	
	}

访问数据

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
  
<c:forEach items="${list}" var="user">
 <c:out value="${user.id}"></c:out>
  <c:out value="${user.name}"></c:out>
</c:forEach>

4. 接受请求输入

查询参数

/Users?max=230&count=50

@RequestParam

private static final long MAX=Long.MAX_VALUE;

@RequestMapping(method=RequestMethod.GET)
public String show(
  @RequestParam(value="max",defaultValue="MAX") Long max, 
	@RequestParam(value="count",defaultValue="20") int count, Model model){
		List<User> list=userService.show(Long.MAX_VALUE, 20);
		model.addAttribute("list",list);
		return "list";	
}

路径参数输入

PathVariable

/Users/123

@RequestMapping(value="/{userId}",method=RequestMethod.GET)
public void show(@PathVariable("userId")long userId,Model model){
  model.addAttribute("list",userService.findOne(userId));
  return "selectbyId";
}

表单输入

/Users/register

@RequestMapping("/register",method=RequestMethod.POST)
public void register(User user){
  userService.save(user);
  return "redirect:/Users/"+user.getId();
}

校验表单属性

javax.validation.constraints.*;

导入 validation-api-1.1.0.beta1.jar

注解	描述
@AssertFalse	注解元素必须是Boolean类型，值为false
@AssertTrue	注解元素必须是Boolean类型，值为true
@DecimalMax(“”)	元素为数字，值小于等于给定的BigDecimalString值
@DecimalMin(“”)	元素为数字，值大于等于给定的BigDecimalString值
@Digits	元素为数字，值必须有指定的位数 @Digits(fraction = 0, integer = 0)
@Future	元素值必须是一个将来的日期
@Max	元素为数字，值小于等于给定的值 @Max(value = 0)
@Min	元素为数字，值大于等于给定的值 @Min(value = 0)
@NotNull	元素值不为null
@Null	元素值必须为null
@Past	元素值必须是一个过去的日期
@Pattern	元素值匹配给定的正则表达式 @Pattern(regexp = “”)
@Size	元素值为String，集合，数组，@Size(min=5,max=23)

使用检验注解

import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
public class User {
	private int id;
	
	@NotNull
	@Size(min=5,max=23)
	private String name;
}

验证

import javax.validation.Valid;
import org.springframework.validation.Errors;

 @RequestMapping("/register")
	public String register(@Valid User user,Errors errors){
		if (errors.hasErrors()) {
			return "register";	//返回注册页
		}
		return "show";
	}

5. 渲染Web视图

SpringMVC中定义了名为ViewResolver的接口,resolveViewName方法传入视图名和Locale对象

package org.springframework.web.servlet;
import java.util.Locale;
public abstract interface ViewResolver
{
  public abstract View resolveViewName(String paramString, Locale paramLocale)
    throws Exception;
}

从中的view 接受了request，response对象，结果渲染给response

package org.springframework.web.servlet;

import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public abstract interface View
{
  public abstract void render(Map<String, ?> paramMap, HttpServletRequest paramHttpServletRequest, HttpServletResponse paramHttpServletResponse)
    throws Exception;
}

Spring定义的13种视图解析器

视图解析器	描述
BeanNameViewResolver	视图解析为Spring应用上下文的bean
ContentNegotiatingViewResolver	考虑客户端需要的内容类型来解析视图，委托给另外一个能够产生对应内容类型的视图解析器
InternalResourceViewResolver	解析为内部资源 .jsp
JasperReportViewResolver	解析为JasperReport定义
ResourceBundleViewResolver	资源bundle 属性文件
TitlesViewResolver	解析为Apache Title定义
UrlBasedViewResolver	根据视图的名称解析视图
VelocityLayoutViewResolver	解析为Velocity布局
VelocityViewResolver	解析为Velocity模版
XmlViewResolver	解析为xml特定xml文件中的bean定义
XsltViewResolvet	解析为XSLT转换后的结果

InternalResourceViewResolver

//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;
}

xml配置

<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
  <property name="prefix" value="/WEB-INF/views/"></property>
  <property name="suffix" value=".jsp"></property>
</bean>

5.1. Spring 的jsp标签库

commandName构建模型对象上下文信息

@RequestMapping("/register")
public String show(Model model){
  model.addAttribute(new User());
  return "form";
}

input的value属性值会设置为模型对象中path属性对应的值

<sf:input path=”id”/> == < input name=”id” value=”0” type=”text”/>

<%@taglib uri="http://www.springframework.org/tags/form" prefix="sf" %>
  
 <sf:form method="POST" commandName="user">
  	<sf:input path="id"/>   <!-- < input name="id" value="0" type="text"/> -->
  	<sf:input path="name"/>
  	<sf:password path="password"/>
  </sf:form>

错误展示

path设定对象中的属性

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<sf:errors path="id"/>
==
<span id="user.errors"> </span>

添加样式

*表示所有属性

element 表示错误渲染在div上

<sf:errors path="*" element="div" cssClass="errors"/>

<style>
  div.errors{
    font-color:#f00;
  }
</style>

错误设置在每个属性上

<sf:label path="name" cssErrorClass="error"></sf:label>

<label for="name" class="error"></label>

<style>
  label.error{
    color:red;
  }
</style>

5.2. 错误信息展示

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 @NotNull
@Size(min=5,max=23,message="{name.size}")
private String name;

在根目录下创建 ValidationMessages.properties

1	name.size=Last name must be between {min} and {max} characters long.

6. spring通用标签库

<s:message />

<%@ taglib uri="http://www.springframework.org/tags" prefix="s"%>
  
<!--根据给定的编码获取信息，进行渲染行为 -->  
<s:message code="login.welcome"/>

实现MessageSource接口

import org.springframework.context.MessageSource;
import org.springframework.context.annotation.Bean;
import org.springframework.context.support.ReloadableResourceBundleMessageSource;

  @Bean
	public MessageSource messageSource(){
		ReloadableResourceBundleMessageSource messageSource = new ReloadableResourceBundleMessageSource();
    //服务器文件系统目录下查找信息基于“messages”的文件名 messagesXXX.properties
		messageSource.setBasename("file:///etc/messages"); 
    messageSource.setCacheSeconds(10);
		return messageSource;
	}

messages.properites

1	login.welcome=Welcome!

<s:url />

htmlEscape=”true” 展现 url内容到web页面上

<s:url href="/Users/register" var="register" scope="request" htmlEscape="true">
  <s:param name="id" value="60"></s:param>
  <s:param name="name" value="wt"></s:param>
</s:url>
<a href="${register}"></a>

<s:escapeBody />

<s:escapeBody>
  <h1>
    Hello
  </h1>
</s:escapeBody>

&lt;h1&gt;Hello&lt;/h1&gt;

W.T.的博客

Spring实战-SpringWeb