MVC架构模式#

package com.luguosong.controller;

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

/**
 * @author luguosong
 */
@Controller
public class HelloController {
    //请求映射
    @RequestMapping("/hello-mvc")
    public String hello() {
        //返回逻辑视图名称
        return "hello";
    }
}

@Controller
public class HelloController {
    //请求映射
    @RequestMapping("/hello1-1")
    public String hello() {
        //返回逻辑视图名称
        return "hello";
    }

    //多个映射可以指向同一个方法
    @RequestMapping({"/hello2-1", "/hello2-2"})
    public String hello() {
        //返回逻辑视图名称
        return "hello";
    }
}

@Controller
public class HelloController {
    //?表示任意单个字符，比如 hello1 或 helloa 都会访问到该方法
    @RequestMapping("/hello?")
    public String hello() {
        //返回逻辑视图名称
        return "hello";
    }
}

@Controller
public class HelloController {
    @RequestMapping("/login/{username}/{password}")
    public String login(@PathVariable String username,
                        @PathVariable String password) {
        //用户登录
        //...
        return "ok";
    }
}

@Controller
public class HelloController {
    //只会接收Get类型的请求
    @RequestMapping(value = "/hello", method = RequestMethod.GET)
    public String hello() {
        //返回逻辑视图名称
        return "hello";
    }
}

@Controller
public class HelloController {
    //表示请求参数中必须存在username和password，且username必须为张三
    @PostMapping(value = "/hello", params = {"username=张三", "password"})
    public String hello() {
        //返回逻辑视图名称
        return "ok";
    }
}

@Controller
public class HelloController {
    //表示请求头中必须存在token
    @PostMapping(value = "/hello", headers = {"token"})
    public String hello() {
        //返回逻辑视图名称
        return "ok";
    }
}

package com.luguosong.controller;

import jakarta.servlet.http.HttpServletRequest;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

/**
 * @author luguosong
 */
@Controller
@RequestMapping("/form")
public class FormController {

    @GetMapping("/formView")
    public String formView() {
        return "get-parameters/form";
    }

    /*
     * 模拟Servlet接收参数
     * */
    @PostMapping("/servlet")
    public String servletPost(HttpServletRequest request) {
        request.setAttribute("username", request.getParameter("username"));
        return "get-parameters/form";
    }

    /*
     * @RequestParam注解value值为请求参数名
     * required属性表示参数是否必须，默认为true
     * defaultValue属性为默认值
     * */
    @PostMapping("/springMvc")
    public String springMvc(
            @RequestParam(
                    value = "username",
                    required = false,
                    defaultValue = "张三") String username,
            HttpServletRequest request) {
        request.setAttribute("username", username);
        return "get-parameters/form";
    }


    /*
     * 如果请求参数的形参名和方法参数名一样，则@RequestParam注解可以省略
     * */
    @PostMapping("/springMvc2")
    public String springMvc2(
            String username,
            HttpServletRequest request) {
        request.setAttribute("username", username);
        return "get-parameters/form";
    }
}

package com.luguosong.controller;

import com.luguosong.pojo.User;
import jakarta.servlet.http.HttpServletRequest;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;

/**
 * @author luguosong
 */
@Controller
@RequestMapping("/formPojo")
public class FormPojoController {

    @PostMapping("/springMvc")
    public String springMvcPojo(
            User user,
            HttpServletRequest request) {
        request.setAttribute("username", user.getUsername());
        return "get-parameters/form";
    }
}

package com.luguosong.pojo;

/**
 * @author luguosong
 */
public class User {
    private String username;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    @Override
    public String toString() {
        return "User{" +
                "username='" + username + '\'' +
                '}';
    }
}

package com.luguosong.controller;

import jakarta.servlet.http.HttpServletRequest;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;

/**
 * @author luguosong
 */
@Controller
@RequestMapping("/formString")
public class FormStringController {

    @RequestMapping("/springMvc")
    public String springMvc(
            @RequestBody String requestBody,
            HttpServletRequest request
    ) {
        request.setAttribute("username", requestBody);
        return "get-parameters/form";
    }
}

package com.luguosong.controller;

import com.luguosong.pojo.User;
import jakarta.servlet.http.HttpServletRequest;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;

/**
 * @author luguosong
 */
@Controller
@RequestMapping("jsonPojo")
public class JsonPojoController {
    @RequestMapping("springMvc")
    public String springMvc(
            @RequestBody User user) {
        System.out.println(user);
        return "get-parameters/form";
    }
}

package com.luguosong.controller;

import jakarta.servlet.http.HttpServletRequest;
import org.springframework.http.HttpHeaders;
import org.springframework.http.RequestEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

/**
 * @author luguosong
 */
@Controller
@RequestMapping("requestEntity")
public class RequestEntityController {

    @RequestMapping("/springMvc")
    public String springMvc(RequestEntity<String> requestEntity) {
        /*
         * 获取请求行信息
         * */
        System.out.println("请求方法：" + requestEntity.getMethod());
        System.out.println("请求地址：" + requestEntity.getUrl());

        /*
         * 获取请求头信息
         * */
        HttpHeaders headers = requestEntity.getHeaders();
        System.out.println("请求参数类型：" + headers.getContentType());

        /*
         * 获取请求体信息
         * */
        String entityBody = requestEntity.getBody();
        System.out.println("请求体内容：" + entityBody);
        return "get-parameters/form";
    }
}

package com.luguosong.controller;

import jakarta.servlet.ServletContext;
import jakarta.servlet.http.HttpServletRequest;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.MultipartFile;

import java.io.*;
import java.util.UUID;

/**
 * 文件上传
 *
 * @author luguosong
 */
@Controller
@RequestMapping("/fileUpload")
public class FileUploadController {

    @RequestMapping("/springMvc")
    public String springMvc(
            @RequestParam("fileName") MultipartFile file,
            @RequestParam("username") String username,
            HttpServletRequest request) throws IOException {
        System.out.println("请求参数名：" + file.getName());
        String originalFilename = file.getOriginalFilename();
        System.out.println("文件真实名称：" + originalFilename);

        System.out.println("额外参数：" + username);
        //将文件存储到服务端
        //输入流
        InputStream in = file.getInputStream();
        BufferedInputStream bis = new BufferedInputStream(in);
        //输出流
        ServletContext application = request.getServletContext();//获取ServletContext
        String folderPath = application.getRealPath("/upload");
        File folder = new File(folderPath);
        if (!folder.exists()) {
            folder.mkdirs();
        }
        File saveFile = new File(folder.getAbsolutePath() + "/" + UUID.randomUUID().toString() + originalFilename.substring(originalFilename.lastIndexOf('.')));
        BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(saveFile));
        //开始传输文件
        byte[] bytes = new byte[1024 * 10];
        int readCount = 0;
        while ((readCount = bis.read(bytes)) != -1) {
            bos.write(bytes, 0, readCount);
        }
        bos.flush();
        //释放资源
        bos.close();
        bis.close();

        return "get-parameters/form";
    }
}

package com.luguosong.controller;

import com.luguosong.pojo.User;
import jakarta.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import java.io.IOException;
import java.io.PrintWriter;

/**
 * @author luguosong
 */
@Controller
@RequestMapping("return-string")
public class ResponseStringController {

    /*
     * 模拟servlet返回String字符串
     *
     * 理论上应该返回逻辑视图名称，但此处返回null
     * 通过HttpServletResponse做出响应
     * */
    @RequestMapping("/servlet")
    public String servlet(HttpServletResponse resp) throws IOException {
        resp.setHeader("content-type", "text/html;charset=UTF-8");
        PrintWriter out = resp.getWriter();
        out.println("servlet输出字符串");
        return null;
    }


    /*
     * 模拟springMvc返回String字符串
     *
     * 添加@ResponseBody后，返回的不再是逻辑视图名称
     * 而是直接返回text/html
     * */
    @RequestMapping(value = "/springMvc", produces = "text/html; charset=utf-8")
    @ResponseBody
    public String springMvc() {
        return "Spring MVC输出字符串";
    }
}

package com.luguosong.controller;

import com.luguosong.pojo.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

/**
 * @author luguosong
 */
@Controller
@RequestMapping("return-json-string")
public class ResponseJSONStringController {

    /*
     * 返回json字符串
     * */
    @RequestMapping("user")
    @ResponseBody
    public User getUser() {
        User user = new User();
        user.setUsername("luguosong");
        return user;
    }
}

package com.luguosong.controller;

import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

/**
 * @author luguosong
 */
@Controller
@RequestMapping("/responseEntity")
public class ResponseEntityController {
    @RequestMapping("/springmvc")
    public ResponseEntity<String> springMvc() {
        /*
         * 模拟响应404
         * */
        return ResponseEntity.status(HttpStatus.NOT_FOUND).body(null);
    }
}

package com.luguosong.controller;

import jakarta.servlet.http.HttpServletRequest;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;

/**
 * 文件下载
 *
 * @author luguosong
 */
@Controller
@RequestMapping("/fileDownload")
public class FileDownloadController {

    @RequestMapping("/springMvc")
    public ResponseEntity<byte[]> springMvc(
            HttpServletRequest request
    ) throws IOException {
        File file = new File(request.getServletContext().getRealPath("/upload") + "/demo.jpg");
        //创建响应头对象
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
        headers.setContentDispositionFormData("attachment", file.getName());

        //下载文件
        ResponseEntity<byte[]> entity = new ResponseEntity<>(Files.readAllBytes(file.toPath()), headers, HttpStatus.OK);
        return entity;
    }
}

package com.luguosong.controller.header_info;

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

/**
 * @author luguosong
 */
@Controller
@RequestMapping("/header-info")
public class HeaderInfoController {

    @PostMapping("/springMvc")
    public String springMvc(@RequestHeader(value = "content-type", required = false) String contentType) {
        System.out.println(contentType);
        return "header-info/form";
    }
}

package com.luguosong.controller.header_info;

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

/**
 * @author luguosong
 */
@Controller
@RequestMapping("/cookie")
public class CookieController {

    /*
     * ❗cookie需要在父路径相同的情况才能保存下来
     * 因此通过该地址访问视图
     * */
    @GetMapping("/view")
    public String view() {
        return "header-info/form";
    }

    @RequestMapping("/springMvc")
    public String springMvc(@CookieValue("username") String username) {
        System.out.println(username);
        return "header-info/form";
    }
}

package com.luguosong.controller;

import jakarta.servlet.http.HttpServletRequest;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;

import java.util.Map;

/**
 * @author luguosong
 */
@Controller
@RequestMapping("/request-scope")
public class RequestScopeController {

    /**
     * 模拟Servlet存储Request域
     */
    @RequestMapping("/servlet")
    public String servletTest(HttpServletRequest request) {
        request.setAttribute("requestScope", "通过HttpServletRequest设置请求域");
        return "request-scope";
    }

    /*
     * Model对象存储request域
     * */
    @RequestMapping("/model")
    public String modelTest(Model model) {
        model.addAttribute("requestScope", "通过Model对象设置请求域");
        return "request-scope";
    }

    /*
     * Map集合存储request域
     * */
    @RequestMapping("/map")
    public String mapTest(Map<String, Object> map) {
        map.put("requestScope", "通过Map对象设置请求域");
        return "request-scope";
    }

    /*
     * ModelMap对象存储request域
     * */
    @RequestMapping("/modelMap")
    public String modelMapTest(ModelMap modelMap) {
        modelMap.addAttribute("requestScope", "通过ModelMap对象设置请求域");
        return "request-scope";
    }

    /*
     * ⭐ModelAndView对象存储request域
     * */
    @RequestMapping("/modelAndView")
    public ModelAndView modelAndViewTest() {
        ModelAndView modelAndView = new ModelAndView();
        modelAndView.addObject("requestScope", "通过ModelAndView对象设置请求域");
        modelAndView.setViewName("request-scope");
        return modelAndView;
    }


}

package com.luguosong.controller;

import jakarta.servlet.http.HttpServletRequest;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.SessionAttributes;
import org.springframework.web.servlet.ModelAndView;

/**
 * @author luguosong
 */
@Controller
@RequestMapping("/session-scope")
@SessionAttributes({"sessionScope"})
public class SessionScopeController {

    /*
    * 通过Servlet方式设置session
    * */
    @RequestMapping("/servlet")
    public String servletTest(HttpServletRequest request) {
        request.getSession().setAttribute("sessionScope", "通过Servlet原生方式设置session域");
        System.out.println(request.getSession().getAttribute("sessionScope"));
        return "session-scope";
    }

    /*
    * 通过@SessionAttributes注解设置session
    * */
    @RequestMapping("/modelAndView")
    public ModelAndView modelAndViewTest() {
        ModelAndView modelAndView = new ModelAndView();
        modelAndView.addObject("sessionScope", "通过@SessionAttributes注解方式设置session域");
        modelAndView.setViewName("session-scope");
        return modelAndView;
    }
}

package com.luguosong.controller;

import jakarta.servlet.http.HttpServletRequest;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

/**
 * @author luguosong
 */
@Controller
@RequestMapping("/application-scope")
public class ApplicationScopeController {

    @RequestMapping("/servlet")
    public String servletTst(HttpServletRequest request) {
        request.getServletContext().setAttribute("applicationScope", "通过Servlet方式设置application域");
        return "application-scope";
    }
}

package com.luguosong.controller;

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

/**
 * @author luguosong
 */
@Controller
public class TestController {

    /*
    * 转发
    * */
    @RequestMapping("forward")
    public String forwardTest() {
        return "forward:/test";
    }

    /*
    * 重定向
    * */
    @RequestMapping("redirect")
    public String redirectTest() {
        return "redirect:/test";
    }

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

@Configuration
@EnableWebMvc
public class WebConfig implements WebMvcConfigurer {

    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }
}