前端ajax,后端springBoot

1.准备：

• 1.导入相关的依赖的依赖:

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

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>

        <dependency>
            <groupId>org.mongodb</groupId>
            <artifactId>mongodb-driver</artifactId>
        </dependency>

        <dependency>
            <groupId>org.mongodb</groupId>
            <artifactId>mongodb-driver-core</artifactId>
        </dependency>

        <dependency>
            <groupId>org.mongodb</groupId>
            <artifactId>bson</artifactId>
        </dependency>

        <!-- 引入poi，解析workbook视图 -->
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi</artifactId>
            <version>3.16</version>
        </dependency>
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml</artifactId>
            <version>3.14</version>
        </dependency>
        <!-- 处理excel和上面功能是一样的-->
        <dependency>
            <groupId>net.sourceforge.jexcelapi</groupId>
            <artifactId>jxl</artifactId>
            <version>2.6.10</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

2.设置接收的最大容量：
在application.properties文件中：

## 设置接收文件的大小
spring.servlet.multipart.max-file-size=10MB
spring.servlet.multipart.max-request-size=20MB

2.前端代码：

<form action="/excleimport" method="POST" enctype="multipart/form-data">
    <input type="file" id="file1" name="fileContent">
</form>
<button id='btn'> 提交</button>

这个是选择文件的file,注意这个input标签必须要在form表单中，而且form的enctype必须为multipart/form-data

<script src="/js/jquery-3.4.1.min.js"></script>
<script>
$("#btn").click(function() {
        var formData = new FormData();
        formData.append("excelFile", $("#file1")[0].files[0]);
        $.ajax({
            url: "/excleimport",
            data: formData,
            type: "post",
            processData: false,
            contentType: false,
            success: function(data) {
               alert(data.result);
            },
            error: function() {
                alert("失败")
            }
        });
    })
</script>

这个是js脚本内容,注意的是 processData，contentType这两个属性必须为false；
至此前端内容就结束了，可以直接copy了改就可以了
接下来再看看后端代码，我会贴出excel解析的部分，有需要的可以作为参考：

controller层

 /**
     * Excel表格插入数据到MongoDB
     * @param excelFile
     * @param response
     * @return
     * @throws IOException
     */
   @ResponseBody
    @RequestMapping(value = "/excleimport", method = RequestMethod.POST)
    public Map<String, Object> excleimport(@RequestParam MultipartFile excelFile,
                                           HttpServletResponse response) throws IOException {
        response.setHeader("Access-Control-Allow-Origin", "*");
        Map<String, Object> map = new HashMap<String, Object>();
        String name = excelFile.getOriginalFilename();
        if (!name.endsWith(".xls") && !name.endsWith(".xlsx")) {
            System.out.println("文件不是excel类型");
            map.put("result", "文件类型错误");
        } else {
            map.put("result",ExcelToMongo.getDataFromExcel(excelFile.getInputStream()));
        }
        return map;
    }

到此所有的文件传值与接收就结束了，下面在附上ExcelToMongo.getDataFromExcel方法,也就是解析excel的方法：

package com.pmj.sign.util;

import com.mongodb.MongoClient;
import com.mongodb.MongoClientURI;
import com.mongodb.MongoCredential;
import com.mongodb.ServerAddress;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.bson.Document;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

public class ExcelToMongo {


    public static String getDataFromExcel(InputStream inputStream) {

          Integer PORT = 27017;                    //端口号
          String IP = "localhost";                 //Ip
          String DATABASE = "java";            //数据库名称
          String USERNAME = "pmj";            //用户名
          String PASSWORD = "123456";            //密码
          String COLLECTION = "sign";              //文档名称

        try {

            // 根据输入流导入Excel产生Workbook对象
            Workbook workbook = null;
            try {
                workbook = new HSSFWorkbook(inputStream);
            } catch (IOException e) {
                e.printStackTrace();
            }
            // IP，端口
            ServerAddress serverAddress = new ServerAddress(IP, PORT);
            List<ServerAddress> address = new ArrayList<ServerAddress>();
            address.add(serverAddress);



            // 用户名，数据库，密码
            MongoCredential credential = MongoCredential.createCredential(USERNAME, DATABASE, PASSWORD.toCharArray());
            List<MongoCredential> credentials = new ArrayList<MongoCredential>();
            credentials.add(credential);
            // 通过验证获取连接
            MongoClient mongoClient = new MongoClient(address, credentials);
            // 连接到数据库
            MongoDatabase mongoDatabase = mongoClient.getDatabase(DATABASE);
            // 连接文档
            MongoCollection<Document> collection = mongoDatabase.getCollection(COLLECTION);
            System.out.println("连接成功");
            List<Document> documents = new ArrayList<Document>();
            List<String> fieldList = new ArrayList<String>();
            // 获取Excel文档中第一个表单
            Sheet sheet = workbook.getSheetAt(0);
            Row row0 = sheet.getRow(0);
            for (Cell cell : row0) {
                fieldList.add(cell.toString());
            }
            int rows = sheet.getLastRowNum() + 1;
            int cells = fieldList.size();
            for (int i = 1; i < rows; i++) {
                Row row = sheet.getRow(i);
                Document document = new Document();
                for (int j = 0; j < cells; j++) {
                    Cell cell = row.getCell(j);
                    document.append(fieldList.get(j), cell.toString());
                }
                documents.add(document);
            }
            collection.insertMany(documents);
            System.out.println("插入成功");
            return "插入成功";
        } catch (Exception e) {
            System.err.println(e.getClass().getName() + ": " + e.getMessage());
            return "插入失败";
        }
    }


}