jsp+servlet+二进制图片存取

来源：互联网发布：libjpeg.so.62 ubuntu 编辑：程序博客网时间：2024/05/17 23:44

前段时间做了一个有关图片存取数据库的小项目，虽然本人是个小菜鸟，但在我不断地努力下，嘿嘿，很快做了出来，所然我用的方法是采用二进制存入数据库，然后返回list，在jsp页面显示了出来。
好了，废话不多说了，下面贴代码！~^O^~

一、创建数据库

二、表单提交存入数据库：

JSP页面（上传到相应的servlet）

// ENCTYPE="multipart/form-data"用于表单里有图片上传。 <form action="${pageContext.request.contextPath}/CaptialServlet" method="post" enctype="multipart/form-data"><input hidden="hidden" name="date" type="text" value=<%=date%>></input><input hidden="hidden" name="author" type="text" value=<%=username%>></input><h1>文章发布</h1><label><span>文章标题：</span><input type="text" name="article"/></label><label><span>文章内容:</span><textarea name="content" ></textarea></label><label><span>选择插入图片:</span><input type="file" accept="image/*" name="picture"/>// 输入字段可以接受各种格式的图片</label><label><span> </span><input type="submit" class="button" value="发送" /></label></form>

Servlet（处理表单提交的数据）

public class CaptialServlet extends HttpServlet {    private static final long serialVersionUID = 1L;// 为了在反序列化时,确保类版本的兼容性     private String savePath;     private ServletContext sc;     public void init(ServletConfig config) {            savePath="upload";//得到上传文件的保存目录，将上传的文件存放于服务器项目根目录下（需要自己创建）            sc = config.getServletContext(); // 获取上下文        }    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        doPost(request, response);    }    /**     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)     */    @SuppressWarnings("unchecked")protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        request.setCharacterEncoding("utf-8");        response.setCharacterEncoding("utf-8");        response.setContentType("text/html;charset=utf-8");        PrintWriter out = response.getWriter();        Map<String, String> map=new HashMap<>();// 用于存储表单非二进制流部分        boolean isMultipart = ServletFileUpload.isMultipartContent(request);// 检查输入请求是否为multipart表单数据。        if (isMultipart == true) {   // 如果是二进制流形式的表单            FileItemFactory factory = new DiskFileItemFactory();// 通过它来解析请求。执行解析后，所有的表单项目都保存在一个List中。            ServletFileUpload upload = new ServletFileUpload(factory);            List<FileItem> items = null;            File savedFile=null;            try {                items = upload.parseRequest(request);// 可以上传多个文件            } catch (FileUploadException e) {                // TODO Auto-generated catch block                e.printStackTrace();            }            Iterator<FileItem> itr = items.iterator();            while (itr.hasNext()) {                FileItem item = (FileItem) itr.next();                             if (item.isFormField()) {//检测是否为普通表单 如果是普通表单项目，将其名字与对应的value值放入map中。                    String fieldName = item.getFieldName();                    map.put(fieldName, item.getString("UTF-8"));//获取表单value时确定数据格式，如果不写，有中文的话会乱码                                    } else {   //如果是提交的图片                     File fullFile=new File(item.getName()); //获取提交的文件                     savedFile=new File(sc.getRealPath("/")+savePath,fullFile.getName()); //在项目下新建该文件，                     try {                        item.write(savedFile); //写入文件                                        } catch (Exception e) {                        // TODO Auto-generated catch block                        e.printStackTrace();                    }                                    }            }            out.println("  Map"+map.toString());            out.println("<br/>");            out.println(map.get("article")+" " + map.get("content")+" " + map.get("author")+" " + map.get("date")+" " + null);            FileInputStream str=new FileInputStream(savedFile);//将保存的文件转换为输入流            int length=str.available();//获取输入流的长度；            //下面是我将自己的普通表单内容放到captial对象中             Captial captial=new Captial(0, map.get("article"), map.get("content"), map.get("date"), map.get("author"), null);             UserDao userDao=new UserDao();             boolean flag=userDao.input(captial,str,length);//这步是将captial对象，输入流，和输入流的长度传到 userdao的addUser方法中 用于添加到数据库；             if(flag){                 response.sendRedirect("/businessShow.jsp");             }else{     response.getWriter().print("<script type=\"text/javascript\">alert(\"添加失败,图片限制大小为200*169像素\");location.href(\"/input.jsp\");</script>");             }        } else {            out.print("the enctype must be multipart/form-data");        }     }}

UserDao（Dao层操作）

public class UserDao {    User user = null;    private String SQL ="";         // 查询出发布文章的相关信息，便于展示在jsp页面    public List<Captial> show(){    SQL = "select * from captial";        Connection connection = null;        PreparedStatement pstmt = null;        Captial captial;        List<Captial> list = new ArrayList<Captial>();// 获取数据库字段集        try {            connection = DBDao.getConnection();pstmt = (PreparedStatement) connection.prepareStatement(SQL);            ResultSet rs = (ResultSet) pstmt.executeQuery();//得到数据库的查询结果,一个数据集            while(rs.next()){            captial = new Captial();             captial.setId(rs.getInt("id"));            captial.setArticle(rs.getString("article"));            captial.setContent(rs.getString("content"));            captial.setDate(rs.getString("date"));            captial.setAuthor(rs.getString("author"));            list.add(captial);            }} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();} return list;    }    // 根据id查询图片    public ResultSet show(int id){      SQL = "select picture from captial where id = ?";          Connection connection = null;          PreparedStatement pstmt = null;          try {              connection = DBDao.getConnection();pstmt = (PreparedStatement)     connection.prepareStatement(SQL);pstmt.setInt(1, id);            ResultSet rs = (ResultSet) pstmt.executeQuery();//得到数据库的查询结果,一个数据集            return rs;} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}     return null;    }    // 提交表单数据    public boolean input(Captial captial,FileInputStream file,int length){    boolean flag=true;    String SQL = "insert into captial(article,content,date,author,picture) values(?,?,?,?,?)";    Connection connection = null;        PreparedStatement pstmt = null;        try {            connection = DBDao.getConnection();            pstmt = (PreparedStatement)connection.prepareStatement(SQL);            //这里的意思将用户名和密码填到SQL语句的问号处            pstmt.setString(1, captial.getArticle());            pstmt.setString(2, captial.getContent());            pstmt.setString(3, captial.getDate());            pstmt.setString(4, captial.getAuthor());            pstmt.setBinaryStream(5, file,length);            flag = pstmt.execute();            connection.close();            pstmt.close();            return flag;        } catch (Exception e) {            // TODO: handle exception            e.printStackTrace();            return !flag;        }finally{            DBDao.closeConnection(connection);        }    }}

JDBC连接

public class DBDao {private static String USER = "root";private static String PASSWORD = "root";private static String DB_URL = "jdbc:mysql://localhost:3306/university";    private static String DB_DRIVER = "com.mysql.jdbc.Driver";    private static Connection connection = null;    public static Connection getConnection(){        try {            Class.forName(DB_DRIVER);            connection = DriverManager.getConnection(DB_URL, USER, PASSWORD);        } catch (Exception e) {            System.out.println("数据库连接异常");            e.printStackTrace();        }        return connection;    }    public  static void closeConnection(Connection connection){                    if(connection != null){                        try {                            connection.close(); // 关闭数据库连接                        } catch (SQLException e) {                            e.printStackTrace();                        }                    }                } }

这样，提交的表单就传进数据库了

三、取出数据库数据，并显示在jsp上

Dao层操作为上面的show()和show(id)方法

Servlet（将二进制图片显示出来）

public class BusinessShowPicture extends HttpServlet {       protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doPost(request, response);}protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// TODO Auto-generated method stubint id = Integer.parseInt(request.getParameter("id"));UserDao userDao = new UserDao();ResultSet rs = userDao.show(id);InputStream in = null;OutputStream out = response.getOutputStream();try {while(rs.next()){Blob blob = rs.getBlob("picture");in = blob.getBinaryStream();byte[] blobBuffer = new byte[1024*4];int length = 0;while((length=in.read(blobBuffer))!= -1){out.write(blobBuffer,0,length);}in.close();}} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}}}

jsp显示

<%UserDao userDao = new UserDao();List<Captial> list = userDao.show();for(Captial captial:list){%><div class="" style="min-height:169px !important"><!-- img --><div class="img left"><img src="${pageContext.request.contextPath}/BusinessShowPicture?id=<%=captial.getId() %>" alt="" title=""/></div><div class="block right"><p class="date"><%=captial.getDate()%></p><p class="title"><%=captial.getArticle() %></p><p class="content"><%=captial.getContent() %></p></div></div><%} %>

这样，就完成了！

偶，对了，还有在web.xml配置相应servlet，以及commons-fileupload-1.2.1.jar、commons-io-1.4.jar和mysql-connector-java-5.1.25-bin.jar导入

-----真正完成了！o(*≧▽≦)ツ

下面是完成图啦

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