假期生活第7天

假期生活第7天

今天的重点主要是文件上传

一个是form表单上传

 

 

package demo.web;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.IOException;
import java.util.List;
import java.util.UUID;
@WebServlet("/upload")
public class UploadServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //创建ServletFileUpload对象（核心对象）
        //创建一个FileIteFactory接口的实现类对象
        DiskFileItemFactory factory=new DiskFileItemFactory();
        ServletFileUpload servletFileUpload=new ServletFileUpload(factory);
        try {
            List fileItems = servletFileUpload.parseRequest(req);
            //对解析后的结果进行处理
            for (FileItem fileItem:fileItems){
                //判断当前项是否为一个普通的表单字段
                if(fileItem.isFormField()){
                    String fileName=fileItem.getFieldName();
                    String value=fileItem.getString("utf-8");
                }else {
                    //是文件就创建上传目录
                    String dirPath=this.getServletContext().getRealPath("/headerimgs");
                    File directory = new File(dirPath);
                    if(!directory.exists()){
                        directory.mkdir();
                    }
                    //获取上传的文件名
                    String fileName=fileItem.getName();
                    //以文件的方式保存图片到服务器磁盘
                    String fname= UUID.randomUUID().toString()+
                            fileName.substring(fileName.indexOf("."));
                    String path=this.getServletContext().getRealPath("/headerimgs/"+fname);
                    File file = new File(path);
                    //保存文件
                    fileItem.write(file);
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }


    }
}

上面要注意文件类型，如果报错可以先试试设置格式

还有一个是ajax上传

今天主要用的这个，出现了很多问题。因为我用的普通三层架构，没有用框架。所以在网上找了很久

function upload(obj){
//html代码就不发出来l，没什么特别，id是跟图片一起绑定的，到时候根据id显示图片

        var url=window.location.search
        var id
        if(url.indexOf("?")!=-1){
            id=url.substr(url.indexOf("=")+1)
        }else {
            id=0
        }
//用的formData对象
        var formData = new FormData();
        formData.append('images', $('#previewImg')[0].files[0]);
        formData.append('id',id);
        layer.msg('图片上传中', {icon: 16});
        $.ajax({
            type:"post",
            processdata: false,
            //类型选择false，到时候可根据类型自动变换
            contentType: false,
            cache:false,
            url:"/wygl/upload",
            data:formData,
            success:function(data){
                alert(data)
                if(data.code==1000){

                    console.log(data.image_name);
                    layer.closeAll('loading');
                    layer.msg(data.info,{icon:1,time:1000});
                    $("#pimages").attr('src',data.image_name);
                    $("#avatar").val(data.image_name);
                    $(".imgs").show();
                    return false;
                }else{
                    alert(data.image_name)
                    layer.msg(data.info,{icon:2,time:4000});
                }
            }
        });
    }

 @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        response.setCharacterEncoding("utf-8");
        Part images = request.getPart("images");
        //form-data; name="images"; filename="bi-ad.gif"
        String header = images.getHeader("Content-Disposition");
        // 获取原文件名
        int start = header.lastIndexOf("=")+1;
        String name = header.substring(start).replace(""", "");
        System.out.println(name);
        //是文件就创建上传目录
        String dirPath=this.getServletContext().getRealPath("/wy/img");
        File directory = new File(dirPath);
        if(!directory.exists()) {
            directory.mkdir();
        }
        //生成随机文件名
        String filename = UUID.randomUUID().toString().substring(6) + name;
        String realPath = this.getServletContext().getRealPath("/wy/img/" + filename);


        //写入磁盘
        images.write(realPath);
        int id = Integer.parseInt(request.getParameter("id"));
        System.out.println(id);
        //String path = "img/"+filename;
        String string="{"code":1000,"image_name":""+filename+""}";
        System.out.println(string);
        if(id>0){
            boolean b = service.updatepicture(id, filename);
            if(b){
                response.getWriter().write(string);
            }


        }



    }
}

我现在根据这个可以上传文件，也把文件名传到数据库中了，但是在读取文件时却发生了错误，系统提示找不到路径，那么就是路径信息不对，暂时还不知道应该怎么解决这个问题，今天居然写了7个小时代码，真的很强啊