springMVC第二章数据校验和控制层传参

作者: 韩克 | 来源:发表于2019-07-26 15:54 被阅读0次

springMVC第二章数据校验和控制层传参

知识点一：使用JSR303框架完成数据校验工作

1.导入数据校验所需要的jar包

1.jpg

2.在springMVC-servlet文件中注册所需要的驱动

<?xml version="1.0" encoding="UTF-8"?>
<beans
    xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:p="http://www.springframework.org/schema/p"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xsi:schemaLocation="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
                        http://www.springframework.org/schema/mvc
                        http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">

    <context:component-scan base-package="com.xt.handler"></context:component-scan>

    <!-- 启动校验驱动 -->
    <mvc:annotation-driven/>
    
    <!-- 注入校验bean -->
    <bean class="org.springframework.validation.beanvalidation.LocalValidatorFactoryBean"></bean>

</beans>

3.创建pojo实体类，使用JSR303标准实现数据校验@Pattern@Range...

package com.xt.pojo;

import javax.validation.constraints.Pattern;

import org.hibernate.validator.constraints.Range;

public class Survey {

    private String week;
    @Pattern(regexp="\\w{6,12}",message="姓名必须在6~12位")
    private String name;
    @Range(min=18,max=45,message="年龄必须在18~45之间")
    private int age;
    @Pattern(regexp="\\d{11}",message="电话必须为11位")
    private String tel;
    private String answer1;
    private String answer2;
    private String answer3;
    public Survey() {
        super();
        // TODO Auto-generated aconstructor stub
    }
    public Survey(String week, String name, int age, String tel, String answer1, String answer2, String answer3) {
        super();
        this.week = week;
        this.name = name;
        this.age = age;
        this.tel = tel;
        this.answer1 = answer1;
        this.answer2 = answer2;
        this.answer3 = answer3;
    }
    public String getWeek() {
        return week;
    }
    public void setWeek(String week) {
        this.week = week;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String getTel() {
        return tel;
    }
    public void setTel(String tel) {
        this.tel = tel;
    }
    public String getAnswer1() {
        return answer1;
    }
    public void setAnswer1(String answer1) {
        this.answer1 = answer1;
    }
    public String getAnswer2() {
        return answer2;
    }
    public void setAnswer2(String answer2) {
        this.answer2 = answer2;
    }
    public String getAnswer3() {
        return answer3;
    }
    public void setAnswer3(String answer3) {
        this.answer3 = answer3;
    }
    @Override
    public String toString() {
        return "Survey [week=" + week + ", name=" + name + ", age=" + age + ", tel=" + tel + ", answer1=" + answer1
                + ", answer2=" + answer2 + ", answer3=" + answer3 + "]";
    }
    
    
}

4.在handler中，接受页面请求，进行数据校验。

@Valid:声明该对象需要进行数据校验
@ModelAttribute("survey") 将jsp页面传回来的数据封装到survey中，
由于 @ModelAttribute("survey")前面有@Valid，所以封装好的survey对象也包含了校验后的信息。
BindingResult bindingResult用于收集错误信息，当有错误信息时，hasError()方法为true。

package com.xt.handler;

import javax.validation.Valid;
import javax.websocket.server.PathParam;

import org.springframework.stereotype.Controller;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;

import com.xt.pojo.Survey;

@Controller
@RequestMapping("/survey")
public class SurveyHandler {
    @RequestMapping(value="/{week}/check")
    public String checkMessage(@Valid @ModelAttribute("survey") Survey survey,@PathVariable String week,BindingResult bindingResult) {
        if (bindingResult.hasErrors()) {
            System.out.println("error");
            return "/survey.jsp";
        } else {
            System.out.println("success");
            return "/success.jsp";
        }
    }
}

5.创建survey.jsp,将数据提交到handler中

注册form标签库：<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
从handler中获取封装好的survey对象，该对象中包含了错误信息：form:form modelAttribute="survey"
如果有错误信息将错误信息打印:<span><form:errors path="name"/></span><br/>

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>   
<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title>survey</title>
    </head>
    <body>
        <form:form modelAttribute="survey" action="/springMVCT2/survey/201907/check" method="post">
            <fieldset>
                <legend>读者调查问卷</legend>
                <!-- 基本信息 start -->
                <fieldset>
                    <legend>基本信息</legend>
                    <table>
                        <tr><td>姓名</td>
                        <td><input name="name"><span><form:errors path="name"/></span><br/></td>
                        </tr>
                        <tr><td>年龄</td>
                        <td><input name="age"><span><form:errors path="age"/></span><br/></td>
                        </tr>
                        <tr><td>联系电话</td>
                        <td><input name="tel"><span><form:errors path="tel"/></span><br/></td>
                        </tr>
                    </table>                
                </fieldset>
                <!-- 基本信息 end -->
                <!-- 调查信息 start -->
                <fieldset>
                    <legend>调查信息</legend>
                    <b>您喜欢的本期封面和内容版式设计吗？</b><br/>
                    <textarea rows="3" cols="100" name="answer1"></textarea><br/>
                
                    <b>您喜欢的本期的哪几篇文章？</b><br/>
                    <textarea rows="3" cols="100" name="answer2"></textarea><br/>
                    <b>您不喜欢的本期的哪几篇文章？</b><br/>
                    <textarea rows="3" cols="100" name="answer3"></textarea>
                </fieldset>
                <!-- 调查信息 end -->
                <center><input type="submit" value="提交调查"></center>
            </fieldset>
        </form:form>        
    </body>
</html>

知识点二：使用ModelAndView对象进行控制层传参

ModelAndView mv = new ModelAndView("/survey.jsp");
return mv;
注意：@Valid @ModelAttribute("survey") Survey survey和BindingResult bindingResult之间不能添加其它注解。

package com.xt.handler;

import javax.servlet.http.HttpServletRequest;
import javax.validation.Valid;

import org.springframework.stereotype.Controller;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;

import com.xt.pojo.Survey;

@Controller
@RequestMapping("/survey")
public class SurveyHandler {
    @RequestMapping(value="/{week}/check",method=RequestMethod.POST)
    public ModelAndView checkMessage(HttpServletRequest req, @PathVariable("week") String week,@Valid @ModelAttribute("survey") Survey survey,BindingResult bindingResult) {
        survey.setWeek(week);
        if (bindingResult.hasErrors()) {
            System.out.println("success");
            ModelAndView mv = new ModelAndView("/survey.jsp");
            return mv;
        } else {
            System.out.println("error");
            ModelAndView mv = new ModelAndView("/success.jsp");
            mv.addObject("week",survey.getWeek());
//          mv.addObject("name",survey.getName());
            req.setAttribute("name", survey.getName());
            mv.addObject("age",survey.getAge());
            mv.addObject("tel",survey.getTel());
            mv.addObject("answer1",survey.getAnswer1());
            mv.addObject("answer2",survey.getAnswer2());
            mv.addObject("answer3",survey.getAnswer3());
            System.out.println("success");
            return mv;
        }
    }
}

知识点三：给request，session作用域赋值

方法：直接在public ModelAndView checkMessage(HttpServletRequest req)
参数中添加HttpServletRequest req,HttpSession sessions。

知识点四：利用form标签库从model中读取数据

`
传统方式中，我们生成复选框，下拉选框，都直接在jsp页面编写好html代码，
但是这种方式，不利于代码的可扩展性，比如省份下拉框中，如果新增了其他的省份，
需要修改很多处的代码，给代码的可维护性大大降低。
因此我们一般在程序设计中，一般采用从数据库读出的方式，再结合标签来生成相应的代码。

以生成省份下拉框为例进行演示。
`

编写Province pojo类

package com.xtkj.pojo;

public class Province {

    private int id;
    private String name;
    
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Province() {
        super();
        // TODO Auto-generated constructor stub
    }
    public Province(int id, String name) {
        super();
        this.id = id;
        this.name = name;
    }
    @Override
    public String toString() {
        return "Province [id=" + id + ", name=" + name + "]";
    }
}

编写service层，将查询到的provinces返回给controler层

package com.xtkj.service;

import java.util.ArrayList;
import java.util.List;
import org.springframework.stereotype.Service;
import com.xtkj.pojo.Province;

@Service("userService")相当于<bean id="userService" class="...."></bean>
@Service("userService")引号里面的内容<bean里面的id="userService">
@Service("userService")
public class UserService {

    public List<Province> getProvince(){
        
        List<Province> list = new ArrayList<Province>();
        
        list.add(new Province(1, "湖北"));
        list.add(new Province(2, "湖南"));
        list.add(new Province(3, "广西"));
        list.add(new Province(4, "广东"));
    
        return list;
    }
    
}

@Service("userService")就类似于@Controller

在将service注入到handler中

有两种方法：
1.@Autowired 自动注入，需要@Service("userService")与private UserService userService;对象名一致
2.@Resource(name="userService")//获取指定id的bean,通过service名称注入

package com.xtkj.handler;

import java.util.List;

import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;
import javax.validation.Valid;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;

import com.xtkj.pojo.Province;
import com.xtkj.pojo.User;
import com.xtkj.service.UserService;

@Controller
@RequestMapping("/")
public class UserHandler {
    
    @Autowired
    //@Resource(name="userService")//获取指定id的bean
    private UserService userService ;

    @RequestMapping("/regist")
    public String regist(@Valid @ModelAttribute("user") User user,BindingResult br){
        
        if(br.hasErrors()){
            return "/regist.jsp";
        }else{
            System.out.println("account="+user.getAccount());
            
            return "/welcome.jsp";
        }
        
    }
    
    @RequestMapping("/goRegist")
    public String goRegist(HttpServletRequest req){
        
        System.out.println("userService="+userService);
        List<Province> province = userService.getProvince();
        
        req.setAttribute("provinces", province);
        req.setAttribute("user", new User());
        
        return "/regist.jsp";
    }
    
}

注意：由于进入注册页面就需要有省份下拉框的信息，所以，在进入regist.jsp之前首先应该
调用查询方法，然后再请求转发给jsp页面。这样jsp页面才能获取Province数据，由此，就有了
public String goRegist(HttpServletRequest req){...}方法。

编写jsp页面，使用`<form:>`

省份:<form:select path="province">
                <form:options items="${provinces }" itemLabel="name" itemValue="id"/>
            </form:select><br/>
        <input type="submit" value="注册"/>
    </form:form>

完整代码如下：

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'regist.jsp' starting page</title>
    
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->

    <style type="text/css">
        span{
            color:red;
        }
    </style>


  </head>
  
  <body>
    <form:form modelAttribute="user" action="regist.form">
        账号:<input type="text" name="account" value="${user.account }"/><span><form:errors path="account"/></span><br/>
        密码:<input type="password" name="password" value="${user.password }"/><span><form:errors path="password"/></span><br/>
        头像:<img src="img/wa.png"/><br/>
        省份:<form:select path="province">
                <form:options items="${provinces }" itemLabel="name" itemValue="id"/>
            </form:select><br/>
        <input type="submit" value="注册"/>
    </form:form>
  </body>
</html>

知识点五：在SpringMVC中访问静态资源

由于在web.xml中DispatcherServlet的url-pattern为'/'拦截一切资源访问，所以jsp页面请求访问静态资源也会被拦截。解决办法有以下两种：
方法一：修改<url-pattern>

<!-- springMVC核心 -->
  <servlet>
    <servlet-name>springMVC</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
  </servlet>
  
  <servlet-mapping>
    <servlet-name>springMVC</servlet-name>
<!-- <url-pattern>/</url-pattern> -->
    <url-pattern>*.form</url-pattern>
  </servlet-mapping>

springMVC第二章数据校验和控制层传参