This article will explain how to use Commons-fileUPload to upload images to the MySQL database and use the Java servlet to display it in your browser.
come out.
Prerequisites:
MYSQL, Tomcat was installed correctly, and Commons-fileUpload-1.0.jar was downloaded.
1, front page
--- Test_UPLOAD.HTM ---
Upload test </ title> <body> <form action = "UPLOAD.JSP" enctype = "multipart / form-data" method = "post"> Your name: <br> <input TYPE = "text" name = "name"> <br> file to process: <input type = "file" name = "userfile"> <br> <input type = "submit"> </ form> </ body> </ html></p>
<p>2. Upload background processing page</p>
<p>--- UPLOAD.JSP ---</p>
<p><% @ Page ContentType = "Text / HTML; Charset = GB2312"%> <% @ Page Import = "Java.io. *"%> <% @ page import = "java.sql. *"%></p>
<p><% @ page import = "java.util. *"%> <% @ page import = "org.apache.commons.fileUpload. *"%> <% @ page import = "com.cf.model.dbmanipulate"% > <% DiskFileUpload upload = new DiskFileUpload (); upload.setSizeThreshold (4096); upload.setRepositoryPath ( "d: / java /"); upload.setSizeMax (10000000); List fileItems = upload.parseRequest (request); Iterator i = fileItems.ITerator (); string name = ((fileItem) i.next ()). getString (); fileItem FI = (fileItem) i.next (); string filename = fi.getname (); // system. Out.println (filename); filename = filename.replace (':', '_'); filename = filename.Replace ('//', '_'); //system.out.println (FileName); / / File savedfile = new file ("D: / java / upload /", filename); //fi.write( //fi.write(); inputStream FIS = fi.getinputStream (); dbmanipulate DM = New dbmanipulate (); long long_size = new Long (FI.GETSIZE ()); int size = long_size.intValue (); preparedStatement PS = DM.DBUPDATE ("IMAGE, DESCRIPTIO n) VALUES (?,?) "); ps.setbinaryStream (1, fis, size); ps.setstring (2, filename); ps.executeUpdate (); string sql =" select id from photo order by id desc limit 1 "; prepaaredStatement PS2 = DM.DBQUERY (SQL); ResultSet RS = ps2.executeQuery (); int index = 0; if (rs.next ()) {index = rs.getint (1);} // ps. Close (); //fis.chose ();%> <% = name%> <a href="javascript:History.go(-1)"> Go on </a> <br> <iframe height = " 600 "width =" 800 "src = photoview? Id = <% = index%></p>
<p>Scrolling = true> 3, servlet displaying the picture</p>
<p>--- blobservlet.java ------</p>
<p>Package com.cf.photo;</p>
<p>Import java.io. *; import java.sql. *; import javax.sql. *; import javax.servlet. *; import javax.servlet.http. *; // import org.apache.commons.logging.log; // Import org.apache.commons.logging.logfactory;</p>
<p>Import com.cf.model. *;</p>
<p>Public class blobservlet extends httpservlet {// private static log log = logfactory.getlog (blobservlet.class);</p>
<p>Protected void doget (httpservletRequest request, httpservletResponse response) throws servletexception, ioException {</p>
<p>ServletOutputStream out = response.getOutputStream (); int id = Integer.parseInt (request.getParameter ( "id")); response.setContentType ( "image / jpeg"); out.write (getBlob (id)); out.flush (); Out.close (); PUBLIC BYTE [] getBlob (int photoid) {string SQL = "SELECT image from photo where id =?"; //Log.info(SQL); blob blob = null; Byte [ ] bytes = null; // String description = ""; PreparedStatement pstmt = null; ResultSet rs = null; DbManipulate mydb = new DbManipulate (); try {pstmt = mydb.DbQuery (sql); pstmt.setInt (1, photoid) Rs = pstmt.executeQuery (); while (rs.next ()) {blob = rs.getblob (1);} BYTES = blob.getbytes (1, (int)));} catch (SQLException E) {} Return Bytes;}}</p>
<p>4. Store the table definition of the image:</p>
<p>Create Database Web_exam;</p>
<p>USE web_exam;</p>
<p>Create Table Photo</p>
<p>ID INT NOT NULL AUTO_INCREMENT Primary Key,</p>
<p>Image Mediumblob NOT NULL,</p>
<p>Description varchar (100) NULL</p>
<p>);</p>
<p>5. Directory structure of the app</p>
<p>% Catalina_Home% / WebApps / Demo</p>
<p>------ Test_UPLOAD.HTM</p>
<p>------ UPLOAD.JSP</p>
<p>------ WEB-INF</p>
<p>| ---- Web.xml</p>
<p>| ----- Build.xml</p>
<p>| ----- LIB</p>
<p>| ------- MySQL-Connector-Java-3.0.16-Ga-bin.jar</p>
<p>| ------- Commons-fileupload-1.0.jar</p>
<p>| ---- SRC | ---- COM</p>
<p>| ----- CF</p>
<p>| ----- Photo</p>
<p>| ----- blobservlet.java</p>
<p>| ----- Model</p>
<p>| ---- DBConnection.java</p>
<p>| ---- DBCONST.JAVA</p>
<p>| ---- DBManipulate.java</p>
<p>6, web.xml file content</p>
<p><? XML Version = "1.0"?> <! doctype web-app public "- // sun microsystems, Inc.//dtd web application 2.3 // en" http://java.sun.com/j2ee/dtds /WEB-APP_2_3.DTD "></p>
<p><web-app></p>
<p><servlet> <servlet-name> photoview </ servlet-name> <servlet-class> com.cf.photo.blobservlet </ servlet-class> </ servlet> <servlet-mapping> <servlet-name> PhotoView </ servlet-name> <url-pattern> /photoView / * </ url-pattern> </ servlet-maping></p>
<p><Welcome-file-list> <welcome-file> default.jsp </ welcome-file> <welcome-file> index.jsp </ welcome-file> <welcome-file> test.jsp </ welcome-file> <Welcome-File> < / Welcome-file-list></p>
<p></ web-app></p>
<p>7, Ant's buildfile content</p>
<p>------ Build.xml ------</p>
<p><Project name = "buildweb" default = "build" basedir = "."> <proteTY name = "src" location = "src" /> <protety name = "lib" location = "lib" /> <printright name = "build" location = "classes" /> <target name = "build"> <mkdir dir = "$ {build =" $ {src} "destdir =" $ {build} "> < INCLUDE NAME = "** / *. java" /> </ javac> </ target> <target name = "create-jars" depends = "build"> <jar destfile = "$ {lib} /myexam.jar" Basedir = "$ {build}" /> </ target> <target name = "clean" depends = "create-jars"> <delete dir = "$ {build}" /> </ target> </ project></p>
<p>8, dbconst.java</p>
<p>Package com.cf.model;</p>
<p>public interface DbConst {public final static String JDBC_DRIVER = "com.mysql.jdbc.Driver"; public final static String JDBC_URL = "jdbc: mysql: // localhost: 3306 / web_exam?" "useUnicode = true & characterEncoding = GB2312"; public Final static string JDBC_USER = "root"; public final static string jdbc_pass = "chenfu";} 9, dbconnection.java</p>
<p>Package com.cf.model; import java.sql. *; public class dbconnection implements dbconst {</p>
<p>private String jdbcDriver = JDBC_DRIVER; private String databaseURL = JDBC_URL; private String dbUsername = JDBC_USER; private String dbPassword = JDBC_PASS; private Connection con = null; public String getJdbcDriver () {return this.jdbcDriver;} public void setJdbcDriver (String d) { this.jdbcDriver = d;} public String getDatabaseURL () {return this.databaseURL;} public void setDatabaseURL (String url) {this.databaseURL = url;} public String getDbUsername () {return this.dbUsername;} public void setDbUsername ( String u) {this.dbUsername = u;} public String getDbPassword () {return this.dbPassword;} public void setDbPassword (String p) {this.dbPassword = p;}! public boolean isConnected () {return (con = null } Public void disconnected () {if (con! = Null) {Try {con.close ();} catch (sqlexception ignore) {} finally {con = NULL;}}} public void setcon (connection c) { THIS.CON = C;} public connection getcon () THROWS SQLEXCEPTION {IF (iSconnected ()) throw new sqlexception ("alreadyady connected "); if (jdbcDriver == null) throw new SQLException (" No jdbcDriver property "); if (databaseURL == null) throw new SQLException (" No jdbcURL property "); try {Class.forName (jdbcDriver); / /log.info(jdbcDriver);} catch (ClassNotFoundException e) {throw new SQLException (jdbcDriver "class could not loaded");} con = DriverManager.getConnection (databaseURL, dbUsername, dbPassword); return con;}}</p>
<p>10, dbmanipulate.java</p>
<p>Package com.cf.model; import java.sql. *; public class dbmanipulate {private connection con = null; private preparedState pstmt = null;</p>
<p>public PreparedStatement DbQuery (String sql) throws SQLException {DbConnection newcon = new DbConnection (); con = newcon.getCon (); pstmt = con.prepareStatement (sql, ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY); //log.info(sql ); return pstmt;} public PreparedStatement DbUpdate (String sql) throws SQLException {DbConnection newcon = new DbConnection (); con = newcon.getCon (); pstmt = con.prepareStatement (sql); return pstmt;} public void dbClose () {If (pStmt! = Null;}}} 11, go to the web-inferry of the web application, execute Ant in the command line to compile the source file, then open the Tomcat server,</p>
<p>Open the address in the browser: http: // localhost: 8080 / demo / test_upload.htm, try to go upload a JPG picture, see if it is not possible.</p>
<p>12. Welcome everyone to make valuable comments, please contact me:</p>
<p>Email: cf0124@163.com</p>
<p>MSN: CF_ASP_MASTER@yahoo.com.cn</p></div><div class="text-center mt-3 text-grey">
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