VB.net 2010 视频教程 VB.net 2010 视频教程 python基础视频教程
SQL Server 2008 视频教程 c#入门经典教程 Visual Basic从门到精通视频教程
当前位置:
首页 > 编程开发 > Java教程 >
  • 4 数据处理及跳转

4 数据处理及跳转

结果跳转方式

ModelAndView

设置 ModelAndView 对象,根据 View 的名称和视图解析器跳转到指定的页面

页面 : {视图解析器前缀} + viewName +{视图解析器后缀}

    <!--视图解析器-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="InternalResourceViewResolver">
        <!--前缀-->
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <!--后缀-->
        <property name="suffix" value=".jsp"/>
    </bean>

对应的Controller类

package com.zzb.controller;

import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.Controller;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ControllerTest1 implements Controller {
    public ModelAndView handleRequest(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception {

        // 创建模型视图
        ModelAndView modelAndView = new ModelAndView();
        // 调用业务层
        String msg = "ControllerTest1";
        modelAndView.addObject("msg", msg);
        // 设置跳转视图
        modelAndView.setViewName("test");

        return modelAndView;
    }
}

ServletAPI

通过设置ServletAPI,不需要视图解析器

1、通过HttpServletResponse进行输出

2、通过HttpServletResponse实现重定向

3、通过HttpServletRequest实现转发

package com.zzb.controller;

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

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@Controller
@RequestMapping("/t3")
public class ControllerTest3 {

    @RequestMapping("/t1")
    public void test1(HttpServletRequest req, HttpServletResponse resp) throws IOException {

        resp.getWriter().println("Hello,Spring BY servlet API");

    }
    @RequestMapping("/t2")
    public void test2(HttpServletRequest req, HttpServletResponse resp) throws IOException {
        // 重定向
        resp.sendRedirect(req.getContextPath() + "/index.jsp");
    }

    @RequestMapping("/t3")
    public void test3(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        // 转发
        req.setAttribute("msg", "/t3/t3");
        req.getRequestDispatcher("/WEB-INF/jsp/test.jsp").forward(req, resp);
    }
}

Spring MVC

通过 Spring MVC 来实现转发和重定向——不需要视图解析器。

注意:测试前先将视图解析器注释掉。

package com.zzb.controller;

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

@Controller
@RequestMapping("/t4")
public class ControllerTest4 {

    @RequestMapping("/t1")
    public String test1(){
        // 转发
        return "/index.jsp";
    }

    @RequestMapping("/t2")
    public String test2(){
        // 显示转发
        return "forward:/index.jsp";
    }

    @RequestMapping("/t3")
    public String test3(){
        // 重定向
        return "redirect:/index.jsp";
    }
}

通过 Spring MVC 来实现转发和重定向——使用视图解析器。

注意:开启视图解析器。

package com.zzb.controller;

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

@Controller
@RequestMapping("/t5")
public class ControllerTest5 {

    @RequestMapping("/t1")
    public String test1(){
        // 转发
        return "test";
    }

    @RequestMapping("/t2")
    public String test2(){
        // 重定向
        return "redirect:/index.jsp";
    }
}

数据处理

处理提交数据

1、提交的域名数据名称和处理方法的参数名一致

package com.zzb.controller;

import com.zzb.pojo.User;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
@RequestMapping("/data")
public class DataController {

    // 域名参数与控制器参数名一致的情况
    @RequestMapping("/t1")
    public String test1(String name, Model model){
        // 1 接收前端参数
        System.out.println(name);

        // 2 将数据返回给前端
        model.addAttribute("msg", name);
        return "test";
    }

}

测试结果:

image-20201215161547471

2、提交的域名数据名称和处理方法的参数名不一致

    // 域名参数与控制器参数名不一致的情况
    @RequestMapping("/t2")
    public String test2(@RequestParam("username") String name, Model model){
        // 1 接受前端参数
        System.out.println(name);
        // 2 将参数传递给前端展示
        model.addAttribute("msg", name);
        return "test";
    }

测试结果:

image-20201215161656888

3、参数是一个对象

package com.zzb.pojo;

public class User {

    private  int id;
    private  String name;
    private int age;

    public User() {
    }

    public User(int id, String name, int age) {
        this.id = id;
        this.name = name;
        this.age = age;
    }

    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 int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}
    // 前端提交的参数是一个对象
    @RequestMapping("/t3")
    public String test3(User user, Model model){
        // 1 接收前端传递的参数
        System.out.println(user.toString());

        // 2 将参数传递给前端页面展示
        model.addAttribute("msg", user.toString());
        return "test";
    }

测试结果:

image-20201215161837158

注意:如果传递参数是对象的话,前端传递的参数名和对象的属性名必须一致,否则为null。

前端展示数据

1、ModelAndView

package com.zzb.controller;

import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.Controller;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ControllerTest1 implements Controller {
    public ModelAndView handleRequest(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception {

        // 创建模型视图
        ModelAndView modelAndView = new ModelAndView();
        // 调用业务层
        String msg = "ControllerTest1";
        modelAndView.addObject("msg", msg);
        // 设置跳转视图
        modelAndView.setViewName("test");

        return modelAndView;
    }
}

2、ModelMap

    @RequestMapping("/t1")
    public String test1(String name, ModelMap modelMap){
        // 1 接收前端参数
        System.out.println(name);

        // 2 将数据返回给前端
        modelMap.addAttribute("msg", name);
        return "test";
    }

3、Model

    @RequestMapping("/t1")
    public String test1(String name, Model model){
        // 1 接收前端参数
        System.out.println(name);

        // 2 将数据返回给前端
        model.addAttribute("msg", name);
        return "test";
    }

3种方法对比:

  • Model 只有寥寥几个方法只适合用于储存数据,简化了新手对于Model对象的操作和理解;

  • ModelMap 继承了 LinkedMap ,除了实现了自身的一些方法,同样的继承 LinkedMap 的方法和特性;

  • ModelAndView 可以在储存数据的同时,可以进行设置返回的逻辑视图,进行控制展示层的跳转。

乱码问题

1、在index.jsp页面写一个表单

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
  <head>
    <title>$Title$</title>
  </head>
  <body>
  <form action=${pageContext.request.contextPath}/data/t1 method="post">
    <input type="text" name="name">
    <input type="submit">
  </form>
  </body>
</html>

2、后端处理程序

@Controller
@RequestMapping("/data")
public class DataController {

    // 域名参数与控制器参数名一致的情况
    @RequestMapping("/t1")
    public String test1(String name, Model model){
        // 1 接收前端参数
        System.out.println(name);

        // 2 将数据返回给前端
        model.addAttribute("msg", name);
        return "test";
    }
}

3、输入中文 哈哈哈 测试

image-20201215163654829

乱码问题通过过滤器解决,Spring MVC 提供了一个过滤器,需要在web.xml中配置!

    <filter>
        <filter-name>encoding</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>utf-8</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>encoding</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

image-20201215164057192

自定义过滤器:

package com.zzb.filter;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.Map;

/**
* 解决get和post请求 全部乱码的过滤器
*/
public class GenericEncodingFilter implements Filter {

   @Override
   public void destroy() {
  }

   @Override
   public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
       //处理response的字符编码
       HttpServletResponse myResponse=(HttpServletResponse) response;
       myResponse.setContentType("text/html;charset=UTF-8");

       // 转型为与协议相关对象
       HttpServletRequest httpServletRequest = (HttpServletRequest) request;
       // 对request包装增强
       HttpServletRequest myrequest = new MyRequest(httpServletRequest);
       chain.doFilter(myrequest, response);
  }

   @Override
   public void init(FilterConfig filterConfig) throws ServletException {
  }

}

//自定义request对象,HttpServletRequest的包装类
class MyRequest extends HttpServletRequestWrapper {

   private HttpServletRequest request;
   //是否编码的标记
   private boolean hasEncode;
   //定义一个可以传入HttpServletRequest对象的构造函数,以便对其进行装饰
   public MyRequest(HttpServletRequest request) {
       super(request);// super必须写
       this.request = request;
  }

   // 对需要增强方法 进行覆盖
   @Override
   public Map getParameterMap() {
       // 先获得请求方式
       String method = request.getMethod();
       if (method.equalsIgnoreCase("post")) {
           // post请求
           try {
               // 处理post乱码
               request.setCharacterEncoding("utf-8");
               return request.getParameterMap();
          } catch (UnsupportedEncodingException e) {
               e.printStackTrace();
          }
      } else if (method.equalsIgnoreCase("get")) {
           // get请求
           Map<String, String[]> parameterMap = request.getParameterMap();
           if (!hasEncode) { // 确保get手动编码逻辑只运行一次
               for (String parameterName : parameterMap.keySet()) {
                   String[] values = parameterMap.get(parameterName);
                   if (values != null) {
                       for (int i = 0; i < values.length; i++) {
                           try {
                               // 处理get乱码
                               values[i] = new String(values[i]
                                      .getBytes("ISO-8859-1"), "utf-8");
                          } catch (UnsupportedEncodingException e) {
                               e.printStackTrace();
                          }
                      }
                  }
              }
               hasEncode = true;
          }
           return parameterMap;
      }
       return super.getParameterMap();
  }

   //取一个值
   @Override
   public String getParameter(String name) {
       Map<String, String[]> parameterMap = getParameterMap();
       String[] values = parameterMap.get(name);
       if (values == null) {
           return null;
      }
       return values[0]; // 取回参数的第一个值
  }

   //取所有值
   @Override
   public String[] getParameterValues(String name) {
       Map<String, String[]> parameterMap = getParameterMap();
       String[] values = parameterMap.get(name);
       return values;
  }
}

然后在web.xml中配置这个过滤器即可!

来源:https://www.cnblogs.com/zzbstudy/p/14139570.html


相关教程