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Created by Fang on April 16, 2012 13:32:10
Last update: April 16, 2012 13:32:10
There are two steps to create a custom function for JSP:
Declare the function in the TLD:
<?xml version="1.0" encoding="UTF-8" ?>
<taglib...
Implement the function (must be static):
package com.example;
public class UrlTransl...
To use the function:
<%@ taglib uri="http://www.example.com/jsp/tags" p...
Created by Dr. Xi on March 13, 2012 08:46:57
Last update: March 13, 2012 08:46:57
This trick sets HTML base to the root context path of the current webapp:
The short version:
<!DOCTYPE html>
<%@ taglib uri="http://java.sun...
The long version:
<!DOCTYPE html>
<%@ taglib uri="http://java.sun...
Created by Fang on January 31, 2012 15:40:34
Last update: January 31, 2012 15:41:28
This is a simple Hello World application with Spring 3 MVC. Like the default Apache HTTPd welcome page, it displays " It works! " when successfully deployed. The sole purpose is to show the minimum elements needed to setup Spring 3 MVC.
I use Maven since it's so much easier than downloading the dependencies manually.
Directory layout:
./src
./src/main
./src/main/webapp
./src/...
pom.xml :
<?xml version="1.0" encoding="UTF-8"?>
<project...
WEB-INF/web.xml :
<?xml version="1.0" encoding="UTF-8"?>
<web-app...
WEB-INF/applicationContext.xml (empty, but needed):
<?xml version="1.0" encoding="UTF-8"?>
<beans x...
WEB-INF/spring-servlet.xml :
<?xml version="1.0" encoding="UTF-8"?>
<beans x...
WEB-INF/jsp/home.jsp :
<!DOCTYPE html>
<html>
<head>
<title>H...
Build with:
mvn clean package
The resulting webapp is target/springmvc.war .
Created by Dr. Xi on June 16, 2011 13:51:53
Last update: June 16, 2011 14:02:10
With an absolute path to a file, this is the way to construct a URL :
URL url = new URL("file:///absolute/path/to/file.e...
What if I want a URL for a file relative to the current working directory?
URL url = new URL("file:///./file.ext"); // this ...
Or, you can use the File class to help you out:
URL url = new URL(String.format("file:///%s/file.e...
Created by alfa on April 06, 2011 13:23:40
Last update: April 06, 2011 13:23:40
A file can be read as URL with the java.net package. You must provide absolute path after the URI scheme name file:// .
package com.demo.io;
import java.io.*;
i...
Created by Fang on August 16, 2010 22:00:05
Last update: August 16, 2010 22:12:25
The tags <sql:update> Executes SQL INSERT , UPDATE , DELETE statements, or SQL DDL statements. Syntax:
<sql:update sql="sqlUpdate" [dataSource="d... or, put the SQL within the element body: <sql:update [dataSource="dataSource"] [v... Attributes: Name Dynamic? Type Description sql true String SQL update statement. dataSource true javax.sql.DataSource or String Data source associated with the database to update. A String value represents a relative path to a JNDI resource or the parameters for the JDBC DriverManager class. var false String Name of the exported scoped variable for the result of the database update. The type of the scoped variable is java.lang.Integer . scope false String Scope of var. Defaults to "page". <sql:transaction> Establishes a transaction context for <sql:query> and <sql:update> subtags. Syntax: <sql:transaction [dataSource="dataSource"] ... where...
Created by Fang on August 16, 2010 21:44:41
Last update: August 16, 2010 22:01:46
The tags <sql:query> Queries a database. Syntax:
<sql:query sql="sqlQuery" var="varName" [scope... or, put the query within the element body: <sql:query var="varName" [scope="{page|req... Attributes: Name Dynamic? Type Description sql true String SQL query statement. dataSource true javax.sql.DataSource or String Data source associated with the database to query. A String value represents a relative path to a JNDI resource or the JDBC parameters for the DriverManager class. maxRows true int The maximum number of rows to be included in the query result. If not specified, or set to -1, no limit on the maximum number of rows is enforced. startRow true int The returned Result object includes the rows starting at the specified index. The first row of the original query result set is at index...
Created by Fang on August 16, 2010 20:42:56
Last update: August 16, 2010 20:47:24
Of course you'll need a datasource to run your SQL statements. It can be set in web.xml , or with the <sql:setDataSource> tag. In web.xml , the declaration is something like this:
<context-param> <param-name>javax.servl... where the parameter value is a relative JNDI path, or parameters for a JDBC connection. In the above example, the real JNDI name for the data source would be: java:comp/env/jdbc/myDataSource . You are out of luck if the JNDI path for the data source does not fall under the java:comp/env/ namespace. In the case of JDBC connection parameters, the expected format is: url[, [driver] [, [user] [,password]]] For example: jdbc:mysql://localhost/,org.gjt.mm.mysql.Driver , where no user name or password is used. <sql:setDataSource> Exports a data source either as a scoped variable or...
Created by Fang on April 02, 2010 21:45:47
Last update: July 17, 2010 02:55:06
This is built upon the simple test application for JSTL , which contained a single servlet and a single JSP page. If I want to use it to test all available JSTL tags, the servlet and JSP page would be too complicated. Instead, I want to group the JSTL tags into separate JSP pages and display each group based on the requested URL. For example, if the URL ends with /CoreBasic , I'll display a page that contains the basic core tags; if the URL ends with /I18N , I'll display a page that contains the internationalization tags (e.g., <fmt:message> ). Furthermore, I want to delegate the handling of each group of tags to separate Java classes. This is the application I'll use for the...
Created by Fang on April 01, 2010 22:24:58
Last update: April 02, 2010 02:49:38
In this note I'll show you how to create and package a JSP custom tag. The purpose of this tag is to display a random splash image for a home page, among a set of images. We should be able to add or delete candidate splash images from the WAR archive without the need to change the JSP. This is the intended use of the tag:
<%@ taglib uri="http://custom.tag.com/demo" prefix... In the above example you provide a set of images named splash*.png (e.g., splash1.png, spalsh2.png, ...), and the tag will pick a random one to display when the JSP is rendered. Let's get started. I'll use Maven for this purpose. Create the standard Maven directory structure ./pom.xml ./src ./src/main ./src/main/jav... pom.xml <project xmlns="http://maven.apache.org/POM/4.0.0"... SplashTag.java package tagdemo; import java.util.ArrayList......
