Spring学习笔记-C5-SpringMVC起步

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Chapter05 SpringMVC起步

5.1 请求在SpringMVC组件之间的流转

这里写图片描述

请求发送
DispatcherServlet查询一个或多个HandlerMapping来确定请求的下一站。
按照HM查询结果，将请求转发到指定的Controller。
Controller返回ModelAndView给DispatcherServlet。
DispatcherServlet使用视图解析器ViewResolver将逻辑试图名匹配为一个特定的视图实现（一般是JSP）。
将Model传出给视图实现，渲染试图。
将渲染结果通过响应对象（Response）传递给客户端。

5.2 使用Java类来搭建SpringMVC

传统配置SpringMVC是用web.xml+Spring配置文件结合的方式。
但是如果你的容器支持Servlet3.0（Tomcat7及以上）

package chapter05;import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;/** * 配置DispatcherServlet * @author NikoBelic * @create 30/12/2016 10:43 */public class SpittrWebInitializer extends AbstractAnnotationConfigDispatcherServletInitializer{    /**     * 指定ContextLoaderListener配置类     * @Author NikoBelic     * @Date 30/12/2016 10:48     */    @Override    protected Class<?>[] getRootConfigClasses()    {        return new Class<?>[]{RootConfig.class};    }    /**     * 指定SpringMVC配置类     * @Author NikoBelic     * @Date 30/12/2016 10:49     */    @Override    protected Class<?>[] getServletConfigClasses()    {        return new Class<?>[]{WebConfig.class};    }    /**     * 将DispatcherServlet映射到 "/"     * @Author     * @Date 30/12/2016 10:44     */    @Override    protected String[] getServletMappings() {        return new String[]{"/"};    }}

/** * 最小但可用的SpringMVC配置 * @author NikoBelic * @create 30/12/2016 10:50 */@Configuration@EnableWebMvc@ComponentScan("chapter05")public class WebConfig extends WebMvcConfigurerAdapter{    @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     * @Author NikoBelic     * @Date 30/12/2016 12:15     */    @Override    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer)    {        configurer.enable();    }}

/** * 最小但可用的SpringMVC配置 * @author NikoBelic * @create 30/12/2016 10:50 */@Configuration@EnableWebMvc@ComponentScan("chapter05")public class WebConfig extends WebMvcConfigurerAdapter{    @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     * @Author NikoBelic     * @Date 30/12/2016 12:15     */    @Override    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer)    {        configurer.enable();    }}

Spring上下文的加载方式有两个，一个是使用SpringMVC的DispatcherServlet去加载（控制器、视图解析器、处理器映射器），另一个是用ContextLoaderListener加载（应用中的其他bean，例如Service、Dao）。
如果上程序所写，我们配置WebConfig类来加载SpringMVC需要的bean。配置RootConfig来加载剩余的bean。

5.2 编写基本的控制器

@Controller其实是包含@Component注解的，二者的功能是相同的，但是为了更加清晰的区分不同的组件，使用@Controller来标识这是一个SpringMVC的组件。
@RequestMapping可以加载类上，也可以加载在方法上，有一下几种情况：
1. 类有注解，方法有注解，那么HTTP访问路径为 http://IP:Port/Project/ControllerMapping/MethodMapping
2. 类无注解，方法有注解 http://IP:Port/Project/MethodMapping
3. 类有注解，方法无注解，那么只允许该Controller中只有一个Method，否则启动报错

我们一般使用方法1

@Controller@RequestMapping("home")public class HomeController{    @RequestMapping(value = "list",method = RequestMethod.GET)    public String home()    {        return "home";    }}

创建一个jsp页面

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %><%@ page contentType="text/html;charset=UTF-8" language="java" %><html><head>    <title>Spittr</title></head><body><h1>Welcome to Spittr</h1><a href="<c:url value="/spittles"/>">Spittles</a><a href="<c:url value="/spitter/register"/>">Spittles</a></body></html>

使用Tomcat启动服务后，项目会根据SpittrWebInitializer配置的信息加载相关的配置文件。
这里写图片描述

以上构建了一个最简单的一个请求结果展示，那么如果我们需要给前台界面返回一些数据，怎么做？

修改控制器

@Controller@RequestMapping("home")public class HomeController{    @RequestMapping(value = "list",method = RequestMethod.GET)    public String home()    {        return "home";    }    @RequestMapping(value = "spittles",method = RequestMethod.GET)    public ModelAndView getSpittles(ModelAndView mv)    {        List<Spittle> spittleList = createSpittleList(10);        mv.setViewName("spittle");        mv.addObject("spittleList",spittleList);        return mv;    }    /**     * 模拟从数据库获取数据     * @Author NikoBelic     * @Date 31/12/2016 13:15     */    private List<Spittle> createSpittleList(int count)    {        List<Spittle> spittles = new ArrayList<>();        for (int i = 0; i < count; i++)        {            spittles.add(new Spittle(i,"Spittle " + i ,new Date(),null,null));        }        return spittles;    }}

创建JSP页面

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %><%@ page isELIgnored="false" %><%@ page session="false" %><html><head>    <title>Spittr</title></head><body><h1>Spittles</h1><table>    <thead>    <tr>        <td>Id</td>        <td>Message</td>        <td>Time</td>    </tr>    </thead>    <tbody>    <c:forEach items="${spittleList}" var="spittle">        <tr>            <td>${spittle.id}</td>            <td>${spittle.message}</td>            <td>${spittle.time}</td>        </tr>    </c:forEach>    </tbody></table></body></html

这里写图片描述

5.3 接受请求的输入

Controller中的方法接收参数的方式有很多
以分页请求为例。

Controller

@Controller@RequestMapping("home")public class HomeController{    private static List<Spittle> spittleList;    private static final int PAGE_SIZE = 5;    static    {        spittleList = createSpittleList(Math.max(10, new Random().nextInt(100)));        System.out.println("随机生成数据:" + spittleList.size());    }    @RequestMapping(value = "list", method = RequestMethod.GET)    public String home()    {        return "home";    }    /**     * 获取Spittles     *     * @Author NikoBelic     * @Date 31/12/2016 22:22     */    @RequestMapping(value = "spittles/{page}", method = RequestMethod.GET)    public ModelAndView getSpittles(@PathVariable int page, ModelAndView mv)    {        Map<String, Integer> pageInfo = getPageInfo(page, spittleList.size());        List<Spittle> pageSpittleList = spittleList.subList(pageInfo.get("start"), pageInfo.get("end"));        mv.setViewName("spittle");        mv.addObject("spittleList", pageSpittleList);        mv.addObject("totalPage", pageInfo.get("totalPage"));        mv.addObject("page", page);        return mv;    }    /**     * 模拟从数据库获取数据     *     * @Author NikoBelic     * @Date 31/12/2016 13:15     */    private static List<Spittle> createSpittleList(int count)    {        List<Spittle> spittles = new ArrayList<>();        for (int i = 0; i < count; i++)        {            spittles.add(new Spittle(i, "Spittle " + i, new Date(), null, null));c        }        return spittles;    }    /**     * 分页工具     *     * @Author NikoBelic     * @Date 31/12/2016 23:39     */    private Map<String, Integer> getPageInfo(int page, int totalRecord)    {        Map<String, Integer> pageInfo = new HashMap<>();        int start = (page - 1) * PAGE_SIZE; // 当前页起始index        int end;        int totalPage = (int) Math.ceil(totalRecord / (float) PAGE_SIZE);        if (page != totalPage)            end = start + PAGE_SIZE;        else        {            if (totalRecord % PAGE_SIZE != 0)                end = (totalPage - 1) * PAGE_SIZE + totalRecord % PAGE_SIZE;            else                end = start + PAGE_SIZE;        }        pageInfo.put("start", start);        pageInfo.put("end", end);        pageInfo.put("page", page);        pageInfo.put("totalPage", totalPage);        System.out.println("起始:" + start + ",结束:" + end + ",当前页:" + page + ",总页数:" + totalPage + ",总数据:" + totalRecord);        return pageInfo;    }}

JSP

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %><%@ page isELIgnored="false" %><%@ page session="false" %><%@ page contentType="text/html;charset=UTF-8" language="java" %><html><head>    <title>Spittr</title></head><body><h1>Spittles</h1><table>    <thead>    <tr>        <td>Id</td>        <td>Message</td>        <td>Time</td>    </tr>    </thead>    <tbody>    <c:forEach items="${spittleList}" var="spittle">        <tr>            <td>${spittle.id}</td>            <td>${spittle.message}</td>            <td>${spittle.time}</td>        </tr>    </c:forEach>    </tbody></table><span><a href="${pageContext.request.contextPath}/home/spittles/1">首页</a></span><span><a href="${pageContext.request.contextPath}/home/spittles/<c:out value='${page-1}'/>"        <c:if test="${page <= 1}">            hidden="hidden"        </c:if>>上一页</a></span><span>当前页:${page}</span><span><a href="${pageContext.request.contextPath}/home/spittles/<c:out value='${page+1}'/>"        <c:if test="${page >= totalPage}">            hidden="hidden"        </c:if>>下一页</a></span><span><a href="${pageContext.request.contextPath}/home/spittles/${totalPage}">尾页</a></span></body></html>

这里写图片描述

5.4 处理表单

我们模拟一个用户注册情景
用户通过浏览器请求得到一个注册页面，通过注册页面完成注册后自动跳转到个人信息页面。
Controller

@Controller@RequestMapping("spitter")public class SpitterController{    @Autowired    private SpitterDao spitterDao;    @RequestMapping(value = "register",method = RequestMethod.GET)    public String showRegisterForm()    {        return "register";    }    @RequestMapping(value ="register",method = RequestMethod.POST)    public String processRegister(Spitter spitter)    {        spitterDao.save(spitter);        return "redirect:/spitter/" + spitter.getUsername();    }    @RequestMapping(value ="{username}" ,method = RequestMethod.GET)    public String showSpitterProfile(@PathVariable String username,Model model)    {        Spitter spitter = spitterDao.findSpitterByUsername(username);        model.addAttribute("spitter",spitter);        return "profile";    }}

注册表单信息

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %><%@ page isELIgnored="false" %><%@ page session="false" %><%@ page contentType="text/html;charset=UTF-8" language="java" %><html><head>    <title>RegisterForm</title></head><body><h1>Register</h1><%--这里Form表单没有设置action,因此他会将请求提交到与展现时相同的URL路径上--%><form method="post">    Username:<input type="text" name="username"/><br/>    Password:<input type="password" name="password"/><br/>    FirstName:<input type="text" name="firstName"/><br/>    LastName:<input type="text" name="lastName"/><br/>    <input type="submit" value="Register"/></form></body></html>

个人信息

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %><%@ page isELIgnored="false" %><%@ page session="false" %><%@ page contentType="text/html;charset=UTF-8" language="java" %><html><head>    <title>Spittr</title></head><body><h1>Your Profile</h1>${spitter.username}<br/>${spitter.firstName} ${spitter.lastName}</body></html>

Model

public class Spitter{    String username;    String firstName;    String lastName;    String password;    public Spitter() {    }    public Spitter(String username, String firstName, String lastName, String password) {        this.username = username;        this.firstName = firstName;        this.lastName = lastName;        this.password = password;    }    public String getUsername() {        return username;    }    public void setUsername(String username) {        this.username = username;    }    public String getFirstName() {        return firstName;    }    public void setFirstName(String firstName) {        this.firstName = firstName;    }    public String getLastName() {        return lastName;    }    public void setLastName(String lastName) {        this.lastName = lastName;    }    public String getPassword() {        return password;    }    public void setPassword(String password) {        this.password = password;    }}

Dao

@Repositorypublic class SpitterDao{    private List<Spitter> spitterList;    public SpitterDao()    {        this.spitterList = new ArrayList<>();        System.out.println(spitterList);    }    public void save(Spitter spitter)    {        spitterList.add(spitter);    }    public Spitter findSpitterByUsername(String username)    {        for (Spitter spitter : spitterList)        {            if (spitter.getUsername().equals(username))                return spitter;        }        return null;    }}

校验表单

注解描述 @AssertFalse 所注解的元素必须是Boolean型，并且值为false @AssertTrue 所注解的元素必须是Boolean型，并且值为true @DecimalMax 必须是数字，且小于指定值 @DecimalMin 必须是数字，且大于指定值 @Digits 必须是数字，并且值必须有指定的位数 @Future 必须是将来的一个日期 @Max 必须是数字，且小于等于指定值 @Min 必须是数字，且大于等于指定值 @NotNull 值不能为null @Null 值必须为null @Past 必须是过去的一个日期 @Pattern 值必须匹配给定的正则表达式 @Size 值必须是String、集合、数组，并且长度必要符合给定的范围

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