Java文件上传案例

素颜马尾好姑娘i 2022-06-02 03:05 244阅读 0赞

1、编写upload.jsp,文件上传表单

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>上传文件</title>
    <script type="text/javascript" src="js/jquery.min.js"></script>
    <script type="text/javascript"> //点击新增文件按钮，添加一个上传文件的按钮 function addFile(){ //var $file = $(".files:first").clone(); var str = '<div class="files"><input type="file" name="mf"><a href="javascript:;" onclick="delFile(this)">删除</a></div>'; $(":submit").before(str); }; //删除 function delFile(obj){ $(obj).parent().remove(); }; </script>
    </head>
    <body>
        <form action="upload.do" method="post" enctype="multipart/form-data">
        请选择上传图片：<a href="javascript:addFile();">新增文件</a><br/>
            <div class="files"><input type="file" name="mf"></div>
            <input type="submit" value="上传">
        </form>
    </body>
    </html>

2、编写文件上传的Servlet，导入jar包

/** 文件上传 */
    public class UploadServlet extends HttpServlet{ 
    
        public void service(HttpServletRequest request,HttpServletResponse response) throws IOException{
            // 获取请求提交过来的文件信息 
            /** 获取请求提交的文件信息,使用(commons-fileupload.jar) * commons-fileupload.jar是Apache旗下的工具包(是一款上传文件的解析器),我们使用它解析request的信息 * 它可以将字节从request里面提取出来,并且封装成对象 */
            // 构建一个imageDao
            ImageDao imageDao = new JdbcImageDao();
            //参数设置
            DiskFileItemFactory factory = new DiskFileItemFactory();
            // 利用factory设置临时文件保存目录,上传大小控制
            ServletFileUpload fileUpload = new ServletFileUpload(factory);
    
            try {
                //解析request里的文件信息,返回一个List集合
                List<FileItem> list = fileUpload.parseRequest(request);
                for(FileItem item : list){
                    System.out.println("文件名称:"+item.getName());
                    System.out.println("文件大小"+item.getSize());
                    System.out.println("文件类型"+item.getContentType());
                    System.out.println("上传的元素名"+item.getFieldName());
                    // 将文件保存到目标位置 F盘下
                    // 使用UUID生成唯一性存储型图片名,防止图片之间相互覆盖
                    UUID uuid = UUID.randomUUID();
                    String destName = uuid.toString().replaceAll("-", "");
                    //获取图片的扩展名
                    int index = item.getName().lastIndexOf(".");
                    String type = item.getName().substring(index);
                    //将图片上传到tomcat/webapps/项目的images目录
                    //获取物理路径 
                    String realPath = request.getServletContext().getRealPath("images");
                    File pathFile = new File(realPath);
                    if(!pathFile.exists()){
                        pathFile.mkdirs(); //目录不存在,则创建目录
                    }
                    File destFile = new File(realPath+"\\"+destName+type);
                    System.out.println(destFile.getPath());
                    item.write(destFile);
                    //将文件信息写入数据库
                    Image image = new Image();
                    image.setName(item.getName());
                    image.setSize(item.getSize());
                    image.setPic(destName+type); //存储的文件名
                    // 获取当前上传时间
                    image.setTime(new Timestamp(System.currentTimeMillis()));
                    //插入数据库
                    imageDao.save(image);
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    
    }

编写Web.xml的配置文件

<servlet>
        <servlet-name>uploadServlet</servlet-name>
        <servlet-class>
            com.up.servlet.UploadServlet
        </servlet-class>
      </servlet>
    
      <servlet-mapping>
        <servlet-name>uploadServlet</servlet-name>
        <url-pattern>/upload.do</url-pattern>
      </servlet-mapping>

建表存入图片数据

create table t_image( p_id number primary key, p_name varchar2(100), /* 图片原名称 */ p_size number, /* 图片大小 */ p_pic varchar2(100), /* 图片存储名称 */ p_time timestamp(6) /* 上传时间 */ );
    drop sequence image_seq;
    create sequence image_seq;

创建图片信息的实体类

public class Image implements Serializable{ 
        private Integer id;
        private String name;
        private Long size;
        private String pic;
        private Timestamp time;
        public Integer getId() {
            return id;
        }
        public void setId(Integer id) {
            this.id = id;
        }
        public String getName() {
            return name;
        }
        public void setName(String name) {
            this.name = name;
        }
        public Long getSize() {
            return size;
        }
        public void setSize(Long size) {
            this.size = size;
        }
        public String getPic() {
            return pic;
        }
        public void setPic(String pic) {
            this.pic = pic;
        }
        public Timestamp getTime() {
            return time;
        }
        public void setTime(Timestamp time) {
            this.time = time;
        }
    
    }

编写图片上传和查看的DAO接口

public interface ImageDao {
        public void save(Image image);
        public List<Image> findAll();
    }

编写DAO接口的实现类

public class JdbcImageDao implements ImageDao{ 
        //图片上传
        @Override
        public void save(Image image) {
            String sql  = "insert into t_image "
                + "(p_id,p_name,p_size,p_pic,p_time)"
                + " values (image_seq.nextval,?,?,?,?)";
            try {
                Connection conn = DbUtil.openConnection();
                PreparedStatement pst = conn.prepareStatement(sql);
                pst.setString(1, image.getName());
                pst.setLong(2, image.getSize());
                pst.setString(3, image.getPic());
                pst.setTimestamp(4, image.getTime());
                pst.executeUpdate();//执行
            } catch (SQLException e) {
                e.printStackTrace();
                throw new RuntimeException("数据库访问异常",e);
            }finally{
                DbUtil.closeConnection();
            }
    
        }
        //查看图片
        @Override
        public List<Image> findAll() {
            String sql  = "select * from t_image order by p_time desc";
                try {
                    Connection conn = DbUtil.openConnection();
                    PreparedStatement pst = conn.prepareStatement(sql);
                    ResultSet rs = pst.executeQuery();
                    List<Image> list = new ArrayList<Image>();
                    while(rs.next()){
                        Image image = new Image();
                        image.setId(rs.getInt("p_id"));
                        image.setName(rs.getString("p_name"));
                        image.setSize(rs.getLong("p_size"));
                        image.setPic(rs.getString("p_pic"));
                        image.setTime(rs.getTimestamp("p_time"));
                        list.add(image);
                    }
                    return list;
                } catch (SQLException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                    throw new RuntimeException("数据库访问异常",e);
                }finally{
                    DbUtil.closeConnection();
                }
        }
    }

编写JdbcUtil工具类

public final class DbUtil {
        private static ThreadLocal<Connection> threadLocal 
            = new ThreadLocal<Connection>();
        static{
            try {
                Class.forName("oracle.jdbc.OracleDriver");
            } catch (ClassNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        public static Connection openConnection() throws SQLException{
            //先从threadLocal尝试获取Connection
            Connection conn = threadLocal.get();//利用线程ID
            //如果存在就直接返回，不存在就新建connection并放入threadLocal
            if(conn == null){
                conn = DriverManager.getConnection(
                        "jdbc:oracle:thin:@localhost:1521:XE", 
                        "system", "123456"); 
                threadLocal.set(conn);//线程ID conn对象
    
            }
            return conn;
        }
        public static void closeConnection(){
            Connection conn = threadLocal.get();//利用线程ID
            if(conn != null){
                threadLocal.set(null);
                try {
                    conn.close();
                } catch (SQLException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
        public static void main(String[] args) throws SQLException{
            Connection conn = DbUtil.openConnection();
            System.out.println(conn);
            DbUtil.closeConnection();
        }
    }

**注意：不要忘了修改JdbcUtil的配置信息，主机地址，账户，密码等**  
conn = DriverManager.getConnection(  
“jdbc:oracle:thin:@localhost:1521:XE”,  
“system”, “123456”);

--------------------

编写查看图片的 view.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
    <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>上传文件</title>
    <script type="text/javascript" src="js/jquery.min.js"></script>
    <script type="text/javascript"> </script>
    </head>
    <body>
    
        <table>
            <c:forEach items="${images}" var="image">
                <tr>
                    <td>${image.id}</td>
                    <td>${image.name}</td>
                    <td>${image.size}</td>
                    <td><img width="30px" height="30px" src="images/${image.pic}" /></td>
                    <td>${image.time}</td>
                </tr>
            </c:forEach>
        </table>
    
    </body>
    </html>

编写查看图片的Servlet

public class ViewServlet extends HttpServlet{ 
    
        @Override
        public void service(HttpServletRequest request, HttpServletResponse response) 
                throws ServletException, IOException {
            //调用ImageDao查询
            ImageDao imageDao = new JdbcImageDao();
            List<Image> list = imageDao.findAll();
            //将集合放入request
            request.setAttribute("images",list);
            // 跳转到view.jsp
            request.getRequestDispatcher("view.jsp").forward(request, response);
        }
    
    }

编写查看图片的Web.xml

<servlet>
        <servlet-name>viewServlet</servlet-name>
        <servlet-class>
            com.up.servlet.ViewServlet
        </servlet-class>
      </servlet>
    
      <servlet-mapping>
        <servlet-name>viewServlet</servlet-name>
        <url-pattern>/view.do</url-pattern>
      </servlet-mapping>

[D][]

[D]: http://download.csdn.net/download/xyphf/10183092