📄 el-var.xtp
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<document><header> <product>resin</product> <title>EL Variables and Functions</title> <description> <p>Resin configuration can directly access Resin-IoC/WebBeans-configuredbeans and variables using EL expressions in the configuration files.Predefines variables include webApp, host, and resin variables. </p> </description></header><body><localtoc/><!--<s1 name="vars" title="Environment Variables"><p>Each Environment in Resin has an associated set of EL objects andfunctions. The EL Environment is inherited, the objects available in<code>host</code> are also available in <code>web-app</code>.</p><example title="host regexp"><host regexp="www.([^.]+).com"> <root-directory>/opt/www/${host.regexp[1]}</root-directory> <context-param server-id="${server.name}"/> <web-app id="/"> <document-directory>webapps/ROOT</document-directory> </web-app></host></example><deftable title="Environment variables"><tr><th>variable</th><th>attribute</th><th>meaning</th></tr><tr><td>Var</td><td> </td><td>System properties, e.g. ${system["resin.home"]}</td></tr><tr><td>server</td><td> </td><td>Server properties</td></tr><tr><td> </td><td>id</td><td>The server id, as specified in -server id</td></tr><tr><td> </td><td>rootDir</td><td>The server root directory</td></tr><tr><td>host</td><td> </td><td>Virtual host properties</td></tr><tr><td> </td><td>url</td><td>The host's canonical URL</td></tr><tr><td> </td><td>name</td><td>The host name</td></tr><tr><td> </td><td>rootDir</td><td>The host's root directory</td></tr><tr><td> </td><td>warDir</td><td>The host's war directory</td></tr><tr><td> </td><td>warExpandDir</td><td>The host's war expansion directory</td></tr><tr><td> </td><td>regexp</td><td>Regular expression values for host regexp matches</td></tr><tr><td>app</td><td> </td><td>web-app properties</td></tr><tr><td> </td><td>url</td><td>The web-app's canonical URL</td></tr><tr><td> </td><td>name</td><td>The web-app name</td></tr><tr><td> </td><td>contextPath</td><td>The web-app's context path</td></tr><tr><td> </td><td>docDir</td><td>The web-app's document directory</td></tr><tr><td> </td><td>regexp</td><td>Regular expression values for web-app url-regexp matches</td></tr></deftable></s1><s1 name="init" title="Servlet/Filter bean-style initialization" version="2.1.3"><p>EL expressions can be used to configure servlets andfilters. <var>init-param</var> values can use JSP EL expressions, including theability to use system properties.</p><p>Servlets, filters, and resources can be configured like beans with settermethods are called directly (See <a href="doc|ioc-bean.xtp">Bean-styleinit)</a>.</p><p>One example use use for the bean-style servlet initialization is to avoidJNDI lookup inside the servlet code. For example, a servlet that that uses aJDBC DataSource might look like:</p><example title="Servlet using JDBC">package test;...public class TestServlet extends HttpServlet { private DataSource _dataSource; /** * Bean setter is called to configure the servlet * before the init() method. */ public void setDataSource(DataSource dataSource) { _dataSource = dataSource; } ...}</example><p>The servlet is configured as follows:</p><example title="Example configuration"><web-app> <allow-servlet-el/> <servlet servlet-name='test' servlet-class='test.TestServlet'> <init> <data-source>${jndi:lookup("java:comp/env/jdbc/test")}</data-source> </init> </servlet> ...</web-app></example><p>The <code>%lt;data-source%gt;</code> xml tag corresponds to the<code>setDataSource</code> method of the bean. More infomation on thispowerful pattern is in the <a href="doc|ioc-bean.xtp">Bean-style init</a>section of the documentation.</p></s1>--><s1 title="Examples"><s2 title="Servlet/Filter initialization"><p>EL expressions can be used to configure servlets andfilters. <var/init-param/> values can use JSP EL expressions, including theability to use system properties.</p><p>Servlets, filters, and resources can be configured like beans with settermethods are called directly (See <a href="doc|ioc-bean.xtp">Bean-styleinit)</a>.</p><p>One example use for the bean-style servlet initialization is to avoidJNDI lookup inside the servlet code. For example, a servlet that that uses aJDBC DataSource might look like:</p><example title="Servlet using JDBC">package test;...public class TestServlet extends HttpServlet { private DataSource _dataSource; /** * Bean setter is called to configure the servlet * before the init() method. */ public void setDataSource(DataSource dataSource) { _dataSource = dataSource; } ...}</example><p>The servlet is configured as follows:</p><example title="Example configuration"><web-app> <allow-servlet-el/> <servlet servlet-name='test' servlet-class='test.TestServlet'> <init> <data-source>${jndi("java:comp/env/jdbc/test")}</data-source> </init> </servlet> ...</web-app></example><p>The <code><data-source></code> xml tag corresponds to the<code>setDataSource</code> method of the bean. More infomation on thispowerful pattern is in the <a href="ioc-bean.xtp">bean configuration</a>section of the documentation.</p></s2></s1><defun title="Environment variables"><p>Environment variables inherited by the process from the operting system areavailable as variables in el expressions, for example <code>${LANG}</code>.</p></defun><defun title="fmt.sprintf()"><p>Format a string using a sprintf-like format string.</p><def>fmt.sprintf(format[,arg1, arg2 ... argN])</def><deftable-parameters><tr> <td>format</td> <td>the format string (see below)</td> <td>required</td></tr><tr> <td>arg1..argN</td> <td>the values used for the conversions in the format string</td> <td>n/a</td></tr></deftable-parameters><p><code/sprintf/> accepts a series of arguments, applies to each a format specifier from `format', and returns the formatted data as a string.`format' is a string containing two types of objects: ordinarycharacters (other than `%'), which are copied unchanged to the output, andconversion specifications, each of which is introduced by `%'. (To include`%' in the output, use `%%' in the format string). </p><p>A conversion specification has the following form:</p><def>%[FLAGS][WIDTH][.PREC][TYPE]</def><p>TYPE is required, the rest are optional.</p><p>The following TYPE's are supported:</p><deftable><tr> <td>%%</td> <td>a percent sign</td></tr><tr> <td>%c</td> <td>a character with the given number</td></tr><tr> <td>%s</td> <td>a string, a null string becomes "#null"</td></tr><tr> <td>%z</td> <td>a string, a null string becomes the empty string ""</td></tr><tr> <td>%d</td> <td>a signed integer, in decimal</td></tr><tr> <td>%o</td> <td>an integer, in octal</td></tr><tr> <td>%u</td> <td>an integer, in decimal</td></tr><tr> <td>%x</td> <td>an integer, in hexadecimal</td></tr><tr> <td>%X</td> <td>an integer, in hexadecimal using upper-case letters</td></tr><tr> <td>%e</td> <td>a floating-point number, in scientific notation</td></tr><tr> <td>%E</td> <td>a floating-point number, like %e with an upper-case "E"</td></tr><tr> <td>%f</td> <td>a floating-point number, in fixed decimal notation</td></tr><tr> <td>%g</td> <td>a floating-point number, in %e or %f notation</td></tr><tr> <td>%G</td> <td>a floating-point number, like %g with an upper-case "E"</td></tr><tr> <td>%p</td> <td>a pointer (outputs a value like the default of toString())</td></tr></deftable><p>Intepret the word `integer' to mean the java type long. Since java does not support unsigned integers, all integers are treated the same.</p><p>The following optional FLAGS are supported:</p><deftable><tr> <td>0</td> <td>If the TYPE character is an integer leading zeroes are used to pad the field width instead of spaces (following any indication of sign or base).</td></tr><tr> <td>+</td> <td>Include a `+' with positive numbers.</td></tr><tr> <td>(a space)</td> <td>use a space placeholder for the `+' that would result from a positive number</td></tr><tr> <td>-</td> <td>The result of is left justified, and the right is padded with blanks until the result is `WIDTH' in length. If you do not use this flag, the result is right justified, and padded on the left.</td></tr><tr> <td>#</td> <td>an alternate display is used, for `x' and `X' a non-zero result will have an "0x" prefix; for floating point numbers the result will always contain a decimal point.</td></tr><tr> <td>j</td> <td>escape a string suitable for a Java string, or a CSV file. The following escapes are applied: " becomes \", newline becomes \n, return becomes \r, \ becomes \\.</td></tr><tr> <td>v</td> <td>escape a string suitable for CSV files, the same as `j' with an additional <code>"</code> placed at the beginning and ending of the string</td></tr><tr> <td>m</td> <td>escape a string suitable for a XML file. The following escapes are applied: < becomes &lt;, > becomes &gt; & becomes &amp; ' becomes &#039, " becomes &034;</td></tr></deftable><p>The optional WIDTH argument specifies a minium width for the field.Spaces are used unless the `0' FLAG was used to indicate 0 padding.</p><p>The optional PREC argument is introduced with a `.', and gives the maximum number of characters to print; or the minimumnumber of digits to print for integer and hex values; or the maximum number of significant digits for `g' and `G'; or the number of digits to print after the decimal point for floating points.</p></defun> <!-- sprintf --><defun title="fmt.timestamp()"><p>Format a timestamp string.</p><example>fmt.timestamp(format[,date])</example><deftable-parameters><tr> <td>format</td> <td>the format string (see below)</td> <td>required</td></tr><tr> <td>date</td> <td>an object with <a href="javadoc|java.util.Date|"/> or <a href="javadoc|java.util.Calendar|"/> or <a href="javadoc|com.caucho.util.QDate|"/></td> <td>the current date and time</td></tr></deftable-parameters><example>msg="The current date and time is ${fmt.timestamp('%Y/%m/%d %H:%M:%S.%s')}"msg="time=${fmt.timestamp('[%Y/%m/%d %H:%M:%S.%s]')}"</example><p><code>format</code> contains regular characters, which are just copied tothe output string, and percent codes which are substituted with time and datevalues.</p><deftable><tr> <th>Code</th> <th>Meaning</th></tr><tr> <td>%a</td> <td>day of week (short)</td></tr><tr> <td>%A</td> <td>day of week (verbose)</td></tr><tr> <td>%b</td> <td>day of month (short)</td></tr><tr> <td>%B</td> <td>day of month (verbose)</td></tr><tr> <td>%c</td> <td>Java locale date</td></tr><tr> <td>%d</td> <td>day of month (two-digit)</td></tr><tr> <td>%H</td> <td>24-hour (two-digit)</td></tr><tr> <td>%I</td> <td>12-hour (two-digit)</td></tr><tr> <td>%j</td> <td>day of year (three-digit)</td></tr><tr> <td>%m</td> <td>month (two-digit)</td></tr><tr> <td>%M</td> <td>minutes</td></tr><tr> <td>%p</td> <td>am/pm</td></tr>⌨️ 快捷键说明
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