java文件上传

1.首先引入jar包

<dependency>
        <groupId>commons-io</groupId>
        <artifactId>commons-io</artifactId>
        <version>2.6</version>
</dependency>

2.前端代码

<input id="img" type="file" onchange="sendChange();"/>

<script>
    function sendChange() {
        fileUpload();
    }

    function fileUpload() {
        var formData = new FormData();
        formData.append('img', $('#img')[0].files[0]);

        if (!validate_img($('#img'))) {
            return;
        }

        $.ajax({
            url: '/upload',
            type: 'POST',
            cache: false,
            data: formData,
            processData: false,
            contentType: false,
            beforeSend: function() {

            },
            success: function(data) {
                alert(data.url);
                if (data.code == 1) {
                    alert('上传成功');
                }
            },
            error: function() {

            }
        });
    }

    //限制上传文件的类型和大小
    function validate_img(ele) {
        // 返回 KB，保留小数点后两位
        var file = ele.val();
        if (!/.(gif|jpg|jpeg|png|GIF|JPG|bmp)$/.test(file)) {
            alert("图片类型必须是.gif,jpeg,jpg,png,bmp中的一种");
            return false;
        } else {
            //返回Byte(B),保留小数点后两位
            if (((ele[0].files[0].size).toFixed(2)) >= (10 * 1024 * 1024)) {
                alert("请上传小于10M的图片");
                return false;
            } else return true;
        }
        return false;
    }
</script>

3.服务端控制器代码

package webapp.controller;

import com.alibaba.fastjson.JSONObject;
import org.apache.commons.io.FileUtils;
import org.springframework.context.annotation.Scope;
import org.springframework.web.bind.annotation.RequestMapping;
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 java.io.File;
import java.io.IOException;
import java.util.UUID;

@Scope("prototype")
@RestController
public class FileController {

    @RequestMapping("upload")
    @ResponseBody
    public JSONObject upload(@RequestParam("img") MultipartFile file) {
        JSONObject out = new JSONObject();

        if (file.isEmpty()) {
            return null;
        }

        String filePath = "/Users/xxx";//文件路径
        File dir = new File(filePath);
        if(! dir.exists()) {
            dir.mkdir();
        }
        String orgName = file.getOriginalFilename();
        String[] split = orgName.split("\.");
        String suffix = split[1];
        String path = filePath + UUID.randomUUID() +"."+suffix;
        File tempFile = null;
        try {
            tempFile =  new File(path);
            FileUtils.copyInputStreamToFile(file.getInputStream(), tempFile);
        } catch (IllegalStateException e) {
            out.put("code",0);
        } catch (IOException e) {
            out.put("code",0);
        }

        out.put("code",1);
        out.put("url",path);
        return out;
    }
}

完事儿～