springmvc 文件上传和对json的支持_spring 上传文件并传入json-优快云博客

本文链接：https://blog.youkuaiyun.com/weixin_44347229/article/details/103263152

本文介绍如何在SpringMVC中实现文件上传功能，包括添加依赖、配置解析器及编写控制器方法，并演示了JSON数据的响应处理。

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1、文件上传

1.添加文件上传相关依赖

 <commons-fileupload.version>1.3.3</commons-fileupload.version>
 <dependency>
      <groupId>commons-fileupload</groupId>
      <artifactId>commons-fileupload</artifactId>
      <version>${commons-fileupload.version}</version>
    </dependency>

2.写一个文件上传请求方法

package com.lg.ssm.controller;

import org.apache.commons.io.FileUtils;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.multipart.MultipartFile;

import java.io.File;
import java.io.IOException;

/**
 * @author 废废
 * @site
 * @company xxx公司
 * @create 2019-11-25 16:25
 */
@Controller
@RequestMapping("/book")
public class BookController {
    @Autowired
    private BookService bookService;
    @RequestMapping("/upload")
    public String upload(MultipartFile file){
        System.out.println(file.getOriginalFilename());
        System.out.println(file.getContentType());
        try {
            FileUtils.copyInputStreamToFile(file.getInputStream(),new File("D:/image/"+file.getOriginalFilename()));
        } catch (IOException e) {
            e.printStackTrace();
        }
        return  "redirect:/book/list";
    }

}

3.在 spirngmvc-servlet.xml中配置文件上传解析器(CommonsMultipartResolver)

<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <!-- 必须和用户JSP 的pageEncoding属性一致，以便正确解析表单的内容 -->
        <property name="defaultEncoding" value="UTF-8"></property>
        <!-- 文件最大大小(字节) 1024*1024*50=50M-->
        <property name="maxUploadSize" value="52428800"></property>
        <!--resolveLazily属性启用是为了推迟文件解析，以便捕获文件大小异常-->
        <property name="resolveLazily" value="true"/>
    </bean>

5.upload.jsp

<%--
  Created by IntelliJ IDEA.
  User: gg176
  Date: 2019/11/26
  Time: 18:36
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>文件上传</title>
</head>
<body>
<form action="${pageContext.request.contextPath}/book/upload" method="post" enctype="multipart/form-data">
    上传文件：<input type="file" name="file">
    <button type="submit">上传</button>
</form>
</body>
</html>

5.访问上传此图片，需要完成图片的虚拟映射
在这里插入图片描述

2、josn返回处理

在方法上面加入注解：@ResponseBody
@responseBody注解的作用是将controller的方法返回的对象通过适当的转换器转换为指定的格式之后，写入到response对象的body区，通常用来返回JSON数据或者是XML
将查询出来的数据直接返回

package com.lg.ssm.controller;

import com.lg.ssm.model.Book;
import com.lg.ssm.service.BookService;
import com.lg.ssm.utils.PageBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import javax.servlet.http.HttpServletRequest;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * @author 废废
 * @site
 * @company xxx公司
 * @create 2019-11-25 16:25
 */
@Controller
@RequestMapping("/book")
public class BookController {
    @Autowired
    private BookService bookService;


    /*  josn */
    @ResponseBody
    @RequestMapping("/json1")
    public Map json1(Book book,HttpServletRequest request){
        PageBean pageBean = new PageBean();
        pageBean.setRequest(request);
        List<Map> list = this.bookService.listPager(book, pageBean);
        Map map = new HashMap();
        map.put("total",pageBean.getTotal());
        map.put("data",list);
        return map;
    }
    @ResponseBody
    @RequestMapping("/json2")
    public   List<Map> json2(Book book,HttpServletRequest request){
        PageBean pageBean = new PageBean();
        pageBean.setRequest(request);
        List<Map> list = this.bookService.listPager(book, pageBean);
        return list;
    }

    @ResponseBody
    @RequestMapping("/json3")
    public   String json3(Book book,HttpServletRequest request){

        return "springmvc string to josn";
    }

}

结果如图：
在这里插入图片描述