Java/JSTL/Database

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Версия от 18:01, 31 мая 2010; (обсуждение)
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JSTL SQL Query

<%@ taglib uri="http://java.sun.ru/jstl/core" prefix="c" %>
<%@ taglib uri="http://java.sun.ru/jstl/sql" prefix="sql" %>
<sql:setDataSource var="dataSource" driver="org.gjt.mm.mysql.Driver"
url="jdbc:mysql://localhost/forum?user=forumuser"
scope="session" />
<html>
  <head>
    <title>Query Example</title>
  </head>
  <body>
<sql:query var = "users" dataSource="${dataSource}">
select column_uid,column_pwd,column_accesses,column_first,column_last,column_bad,column_posted,column_type from t_users
</sql:query>
<table border=1>
<c:forEach var="row" items="${users.rows}">
<tr>
<td><c:out value="${row.column_uid}"/></td>
<td><c:out value="${row.column_pwd}"/></td>
<td><c:out value="${row.column_accesses}"/></td>
<td><c:out value="${row.column_first}"/></td>
<td><c:out value="${row.column_last}"/></td>
<td><c:out value="${row.column_bad}"/></td>
<td><c:out value="${row.column_posted}"/></td>
<td><c:out value="${row.column_type}"/></td>
</tr>
</c:forEach>
</table>

  </body>
</html>





JSTL SQL Update

<%@ taglib uri="http://java.sun.ru/jstl/core" prefix="c" %>
<%@ taglib uri="http://java.sun.ru/jstl/core-rt" prefix="c-rt" %>
<%@ taglib uri="http://java.sun.ru/jstl/sql" prefix="sql" %>
<sql:setDataSource var="dataSource" driver="org.gjt.mm.mysql.Driver"
url="jdbc:mysql://localhost/forum?user=forumuser"
scope="session" />
<html>
  <head>
    <title>General Query</title>
  </head>
  <body>
  <c:choose>
    <c:when test="${param.cmd!=null}">
      <c:set var="str" value="${param.cmd}" />
    </c:when>
    <c:otherwise>
      <c:set var="str"
      value="select * from tableName" />
    </c:otherwise>
  </c:choose>
  Please enter a query:
  <br />
  <form method="post">
    <textarea name="cmd" cols="40" rows="5">
<c:out value="${str}" />
    </textarea>
    <br />
    <input type="submit" />
  </form>
  <c:if test="${pageContext.request.method=="POST"}">
    <c:catch var="e">
      <sql:query var="users" dataSource="${dataSource}"
      sql="${param.cmd}" />
      <table border="1">
        <c:forEach var="row" items="${users.rows}"
        varStatus="status">
          <jsp:useBean id="status"
          type="javax.servlet.jsp.jstl.core.LoopTagStatus" />
          <c-rt:if test="<%=status.getCount()==1%>">
            <tr>
              <c:forEach var="col" items="${row}">
                <th>
                  <c:out value="${col.key}" />
                </th>
              </c:forEach>
            </tr>
          </c-rt:if>
          <tr>
            <c:forEach var="col" items="${row}">
              <td>
                <c:out value="${col.value}" />
              </td>
            </c:forEach>
          </tr>
        </c:forEach>
      </table>
    </c:catch>
    <c:if test="${e!=null}">
      <h3>Error</h3>
      <c:out value="${e}" />
    </c:if>
  </c:if>
  </body>
</html>





JSTL: Transaction with a JSP

<%@ taglib uri="http://java.sun.ru/jstl/core" prefix="c" %>
<%@ taglib uri="http://java.sun.ru/jstl/sql" prefix="sql" %>
<html>
<HEAD>
      <TITLE>Using a Transaction with a JSP</TITLE>
     </HEAD>
<body bgcolor="white">
          <h2>View table Data</h2>
  
<sql:transaction>  
    
  <sql:update>
  insert into atable values(2, "Joe","Id","Feb-24-1996","F")
  </sql:update>
  
    <sql:query var="resultObj">
    select * from atable
    </sql:query>
</sql:transaction>  
<table>
<c:forEach items="${resultObj.rows}" var="row">
  <c:forEach items="${row}" var="column">
    <tr>
   <td align="right">
     <b><c:out value="${column.key}" /></b>
     </td>
     <td>
       <c:out value="${column.value}" />
     </td></tr>
     </c:forEach>
       </c:forEach>
     </table>
</body>
</html>





Presenting database content using tags

//web.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
  "http://java.sun.ru/dtd/web-app_2_3.dtd">
<web-app>
  <resource-ref>
    <res-ref-name>jdbc/address</res-ref-name>
    <res-type>javax.sql.DataSource</res-type>
    <res-auth>Container</res-auth>
  </resource-ref>
</web-app>


<%@ taglib prefix="sql" uri="http://java.sun.ru/jstl/sql" %>
<%@ taglib prefix="c" uri="http://java.sun.ru/jstl/core" %>
<html>
<head>
<title>Presenting database content using tags</title>
<sql:setDataSource
  dataSource="jdbc/address"
  var="conn"
/>
</head>
<body>
<h1>Address List</h1>
<sql:query dataSource="${conn}" var="addresses">
    SELECT * FROM AddressList
</sql:query>
<table width="90%" border="1">
<tr>
<!-- add the table column headings -->
<c:forEach var="columnName" items="${addresses.columnNames}">
  <th> <c:out value="${columnName}"/> </th>
</c:forEach>
</tr>
<!-- add the table rows from the result set -->
<c:forEach var="row" items="${addresses.rowsByIndex}">
  <tr>
    <c:forEach var="column" items="${row}">
      <td><c:out value="${column}"/></td>
    </c:forEach>
  </tr>
</c:forEach>
</table>
</body>
</html>





SQL Tag Out Examples

<%@ taglib uri="http://java.sun.ru/jstl/core" prefix="c" %>
<%@ taglib uri="http://java.sun.ru/jstl/sql" prefix="sql" %>
<sql:setDataSource var="dataSource" driver="sun.jdbc.odbc.JdbcOdbcDriver" url="jdbc:odbc:forum"/>
<html>
  <head>
    <title>SQL Tag Out Examples</title>
  </head>
  <body>
<sql:query var = "users" dataSource="${dataSource}">
select column_uid,column_pwd,column_accesses,column_first,column_last,column_bad,column_posted,column_type from t_users
</sql:query>
<table border=1>
<c:forEach var="row" items="${users.rows}">
<tr>
<td><c:out value="${row.column_uid}"/></td>
<td><c:out value="${row.column_pwd}"/></td>
<td><c:out value="${row.column_accesses}"/></td>
<td><c:out value="${row.column_first}"/></td>
<td><c:out value="${row.column_last}"/></td>
<td><c:out value="${row.column_bad}"/></td>
<td><c:out value="${row.column_posted}"/></td>
<td><c:out value="${row.column_type}"/></td>
</tr>
</c:forEach>
</table>

  </body>
</html>





Updating a database using the sql:update tag

//web.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
  "http://java.sun.ru/dtd/web-app_2_3.dtd">
<web-app>
  <resource-ref>
    <res-ref-name>jdbc/address</res-ref-name>
    <res-type>javax.sql.DataSource</res-type>
    <res-auth>Container</res-auth>
  </resource-ref>
</web-app>

<%@ taglib prefix="sql" uri="http://java.sun.ru/jstl/sql" %>
<%@ taglib prefix="c" uri="http://java.sun.ru/jstl/core" %>
<html>
<head>
<title>Updating a database using the sql:update tag</title>
<sql:setDataSource
  var="conn"
  dataSource="jdbc/address"
/>
</head>
<body>
<h1>Modify Address List</h1>
<sql:update dataSource="${conn}" var="addresses">
    INSERT INTO AddressList (name, street, city, country, telephone) VALUES (?, ?, ?, ?, ?)
    <sql:param value="${param["name"]}"/>
    <sql:param value="${param["street"]}"/>
    <sql:param value="${param["city"]}"/>
    <sql:param value="${param["country"]}"/>
    <sql:param value="${param["tel"]}"/>
</sql:update>
</body>
</html>


Источник — «http://jexp.ru/index.php?title=Java/JSTL/Database&oldid=6692»