springBoot中Contoller的注解用法（文件上传、下载、路径参数等）

    以下是springBoot中Contoller层的各种情况注解使用。

    @RestController

    @RequestMapping

    @PostMapping

    @RequestBody

    @ResponseBody

    @PathParam

    @RequestParam

package com.cheng2839.controller;

import org.apache.commons.lang.CharEncoding;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.websocket.server.PathParam;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Arrays;

/**
 * @RestController 表示是一个Controller，以json方式输出
 * @RequestMapping 表示路径前缀
 */
@RestController
@RequestMapping("/root")
public class MyTestController {

    /**
     * 普通的使用包装对象作为入参，使用@RequestBody
     * @PostMapping 表示Post请求
     *
     * @param testVo
     * @return
     */
    @PostMapping(value = "/test1", produces = "application/json")
    public String test1(@RequestBody TestVo testVo) {
        try {
            return "success";
        } catch (Exception e) {
            return "error";
        }
    }

    /**
     * @ResponseBody 表示响应以json对象输出，和@Controller同时使用，由于此类是用@RestController修饰，所以可以省略@ResponseBody了
     * @RequestMapping 可以指定请求字符集、请求方式等
     * @PathVariable 表示path后的/带的路径参数
     * @param id
     * @return
     */
    //@ResponseBody
    @RequestMapping(path = "/test2/{id}", method = RequestMethod.POST, produces = "application/json")
    public String test2(@PathVariable(name = "id") String id) {
        return id;
    }

    /**
     * @PathParam 表示请求地址后？中带的参数值
     * @param token
     * @return
     */
    @RequestMapping(path = "/test3", method = RequestMethod.GET, produces = "application/json")
    public String test3(@PathParam(value = "token") String token) {
        return token;
    }

    /**
     * 适用于下载文件时用
     * @param request
     * @param response
     * @return
     * @throws IOException
     */
    @RequestMapping(path = "/test4", method = RequestMethod.GET, produces = "application/json")
    public String test4(HttpServletRequest request, HttpServletResponse response) throws IOException {
        String token = request.getHeader("token");  //获取header内容
        boolean type = (Boolean) request.getSession().getAttribute("type"); //获取session中值
        Cookie[] cookies = request.getCookies();  //获取cookie内容

        //输出数据
        String stringData = new String("token="+token+";cookies="+ Arrays.toString(cookies));
        byte[] bytes = stringData.getBytes(CharEncoding.UTF_8);

        //以流的方式输出（下载）
        if (type) {
            OutputStream os = response.getOutputStream();
            os.write(bytes);
            os.flush();
            os.close();
        } else {
            //以文字的方式输出
            PrintWriter writer = response.getWriter();
            writer.print(stringData); //响应值
        }
        return "success";
    }


    /**
     * 适用于上传文件时用(在form-data中放入文件，名称为file)
     * @RequestParam 表示通过form表单提交的参数对象
     * @return
     * @throws IOException
     */
    @RequestMapping(path = "/test5", method = RequestMethod.GET, produces = "application/x-www-form-urlencoded")
    public String test5(@RequestParam(value = "file", required = false) MultipartFile multipartFile) throws IOException{
        InputStream inputStream = multipartFile.getInputStream();
        File cloudFile = new File("/mnt/cheng2839/files/"+System.currentTimeMillis()+multipartFile.getOriginalFilename());
        FileOutputStream fileOutputStream = new FileOutputStream(cloudFile);
        byte[] buf = new byte[1024];
        int len = -1;
        while ((len=inputStream.read(buf))>0) {
            fileOutputStream.write(buf, 0, len);
        }
        fileOutputStream.flush();
        fileOutputStream.close();
        inputStream.close();
        return "success";
    }


    class TestVo {
        private String name;
        private String account;
        // getter and setter functions
    }

}