spring mvc

目录

pom

Controller

WebConfig

Interceptor

pom

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

Controller

package dr.cqr.controller;

import dr.cqr.config.UserInfo;
import dr.cqr.vo.Search;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.MultipartHttpServletRequest;

import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
import java.util.List;
import java.util.stream.Collectors;

import static java.lang.Thread.sleep;


@RestController
@RequestMapping("/test")
public class Test {
    @GetMapping("/t")
    public String tt () throws InterruptedException {

        sleep(10000);
        System.out.println(UserInfo.get("token"));
        System.out.println(UserInfo.get("name"));

        return "ok";
    }

    // @RequestMapping：
    // 是一个通用注解，可用于处理所有HTTP方法（GET、POST、PUT、DELETE等）。
    // 需要通过method属性显式指定HTTP方法。否则默认处理所有方法。
    // @RequestMapping(value = "/request_mapping_get", method = RequestMethod.GET)
    @RequestMapping(value = "/request_mapping_get", method = {RequestMethod.GET, RequestMethod.POST})
    public String RequestMappingGet () {
        return "request_mapping_get";
    }

    // @PostMapping
    // @GetMapping
    // @PutMapping
    // @DeleteMapping
    // @PatchMapping
    @GetMapping("/get_mapping_get")
    public String GetMappingGet () {
        return "get_mapping_get";
    }

    // 路径变量与参数  路径上不能设置可选
    @GetMapping("/get_mapping_get/{id}/{name}")
    public String GetMappingGetId (@PathVariable Long id,
                                   @PathVariable(value = "name", required = false) String name) {
        System.out.println(id);
        System.out.println(name);

        return "ok";
    }


    // 请求参数处理
    // 使用@RequestParam获取查询参数（如?name=John）
    // 使用@RequestBody和@ResponseBody处理JSON/XML等格式。
    @PostMapping("/search")
    public String Search (@RequestParam String name,
                          @RequestParam(value = "email", required = false, defaultValue = "ff@123") String emails,
                          @RequestParam(value = "sex", required = false, defaultValue = "1") String sex,
                          @RequestHeader(value = "token", required = false, defaultValue = "") String token,
                          Search search  // form-data  x-www-from-urlencode
                          ) {

        System.out.println(name);
        System.out.println(emails);
        System.out.println(sex);
        System.out.println(token);
        System.out.println(search);
        return "ok";
    }


    @PostMapping(value = "/search2", consumes = "application/json")
    public String Search2 (@RequestParam String name,
                          @RequestParam(value = "email", required = false, defaultValue = "ff@123") String emails,
                          @RequestHeader(value = "token", required = false, defaultValue = "") String token,
                          @RequestBody(required = false) Search search  // raw
    ) {

        System.out.println(name);
        System.out.println(emails);
        System.out.println(token);
        System.out.println(search);

        return "ok";
    }

    // 单文件上传 form-data
    @PostMapping("/upload")
    public String handleFileUpload(@RequestParam("file") MultipartFile file) {
        if (file.isEmpty()) {
            return "File is empty";
        }
        try {
            byte[] bytes = file.getBytes();
            // 处理文件字节流，例如保存到磁盘或数据库等


            System.out.println(file.getOriginalFilename());

            System.out.println(new String(bytes));

            return "File uploaded successfully";
        } catch (IOException e) {
            return "Failed to upload file";
        }
    }

    // 多文件上传 form-data
    @PostMapping("/uploadMultiple")
    public String handleMultipleFileUpload(HttpServletRequest request) {
        MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) request;
        List<MultipartFile> files = multipartRequest.getFiles("files"); // 假设表单字段名为files，且可以上传多个文件。注意这里是复数形式。

        if (files == null || files.isEmpty()) {
            return "No files uploaded";
        } else {

            return "Files uploaded successfully: " + files.stream()
                    .map(MultipartFile::getOriginalFilename) // 获取文件名列表，可以根据需要修改此部分代码以处理文件内容等。
                    .collect(Collectors.toList()); // 例如，转换为列表形式返回文件名。
        }
    }

}

WebConfig

package dr.cqr.config;

import dr.cqr.interceptor.LoginInterceptor;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.MediaType;
import org.springframework.web.servlet.config.annotation.ContentNegotiationConfigurer;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
@EnableWebMvc
public class WebConfig implements WebMvcConfigurer {

    @Override
    public void configureContentNegotiation(ContentNegotiationConfigurer configurer) {
        configurer
                .defaultContentType(MediaType.APPLICATION_JSON)
                .mediaType("json", MediaType.APPLICATION_JSON)
                .mediaType("xml", MediaType.APPLICATION_XML)
                .mediaType("csv", MediaType.TEXT_PLAIN);
    }

    // 在Spring配置中注册拦截器
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new LoginInterceptor())
                .addPathPatterns("/**") // 拦截所有请求，也可以指定路径模式如 "/api/**"
                .excludePathPatterns("/api/ignore/**") // 排除某些路径，如忽略"/api/ignore/**"的请求
                .order(0); //执行顺序
    }
}

Interceptor

package dr.cqr.interceptor;


import dr.cqr.config.UserInfo;
import org.springframework.lang.Nullable;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

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

// 拦截器
// preHandle	Controller方法执行前 登录验证、参数预处理  能阻断请求
// postHandle	Controller执行后视图渲染前 统一添加响应头、修改Model数据
// afterCompletion	视图渲染完成后 资源释放、日志记录
public class LoginInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("开始请求");
        String url = request.getRequestURI();//是否是登录请求
        if (url.contains("login")) {
            return true;//进行放行
        } else {//判断是否登录过
            String token = request.getHeader("token");
            System.out.println(token);

            String name = request.getParameter("name");
            UserInfo.set("name", name);

            //response.setContentType("text/html");
            //response.setCharacterEncoding("UTF-8");
            //response.getWriter().println("token不存在");
            //return false;

            return true;
        }
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable ModelAndView modelAndView) throws Exception {
        System.out.println("结束请求1");
    }

     @Override
     public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable Exception ex) throws Exception {
         System.out.println("结束请求2");
     }

}

登录信息UserInfo

package dr.cqr.config;

import java.util.HashMap;
import java.util.Map;

public class UserInfo {

    // ThreadLocal叫做线程变量，意思是ThreadLocal中填充的变量属于当前线程，
    // 该变量对其他线程而言是隔离的，也就是说该变量是当前线程独有的变量。
    // ThreadLocal为变量在每个线程中都创建了一个副本，
    // 那么每个线程可以访问自己内部的副本变量。
    // 当一个线程结束时，它所使用的所有 ThreadLocal 相对的实例副本都可被回收
    private static final ThreadLocal<Map<String, String>> THREAD_LOCAL = new ThreadLocal<>();

    //判断线程map是否为空，为空就添加一个map
    public static Map<String, String> getLocalMap() {
        Map<String, String> map = THREAD_LOCAL.get();
        if (map == null) {
            map = new HashMap<>(10);
            THREAD_LOCAL.set(map);
        }
        return map;
    }
    //把用户信息添加到线程map中
    public static void set(String key, String name) {
        Map<String, String> map = getLocalMap();
        map.put(key, name);
    }
    //获得线程map中的数据
    public static String get(String key) {
        Map<String, String> map = getLocalMap();
        return map.get(key);
    }
}