软件版本myeclispe8.0,自带tomcat6.0.13。
jdbc:mysql-connector-java-5.1.13-bin.jar
第一步:建立工程。
在Myeclipse中file->new->web project。
因为在测试数据源(jsp)时用到了标签库,所以可以在这里选上jsdl支持,当然也可以在工程建好后右键工程文件夹->myeclipse->add JSTL
Libraries…实现同样的功能。
第二步:导入jdbc的jar包。
要直接将mysql-connector-java-3.1.7-bin.jar复制到“工程文件夹/WebRoot/WEB-INF/lib”文件夹下。这时,myeclipse会自动生成一个
Referenced Libraries,不用管。
第三步:建立context.xml文件。
在“工程文件夹/WebRoot/META-INF”下,新建context.xml文件。文件内容如下:
<?xml version="1.0" encoding="UTF-8"?> <Context debug="5" reloadable="true"> <Resource name="jdbc/mysql" auth="Container" type="javax.sql.DataSource" maxActive="100" maxIdle="30" maxWait="10000" username="root" password="" driverClassName="com.mysql.jdbc.Driver" url="jdbc:mysql://localhost:3306/javatest?autoReconnect=true" /> </Context>
解释:
name="jdbc/mysql" //连接名,jndi中使用。具在JSP中用<sql:query var="rs" dataSource="jdbc/mysql">调用,servlet用 DataSource ds
= (DataSource)ctx.lookup("java:comp/env/jdbc/mysql");调用。这里是tomcat的格式,不同的服务器可能有所不同。
auth="Container"
type="javax.sql.DataSource"
maxActive="100"
maxIdle="30"
maxWait="10000"
username="root" //mysql的用户名
password="" //mysql的用户密码,我这里是空
driverClassName="com.mysql.jdbc.Driver" //驱动类名,一般确定
url="jdbc:mysql://localhost:3306/javatest?autoReconnect=true" //javatest是mysql中要使用的数据库名
第四步:修改web.xml文件。
在web.xml文件中添加以下内容: //重要一定添加进去
<resource-ref> <description>DB Connection</description> <res-ref-name>jdbc/mysql</res-ref-name> <res-type>javax.sql.DataSource</res-type> <res-auth>Container</res-auth> </resource-ref>
这部分内容一般是确定的。
OK,现在可以测试数据源是否好了。下面是JSP测试文件:
<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%> <%@ taglib uri="http://java.sun.com/jsp/jstl/sql" prefix="sql" %> <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %> <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <base href="<%=basePath%>"> <title>My JSP 'MyJsp.jsp' starting page</title> <meta http-equiv="pragma" content="no-cache"> <meta http-equiv="cache-control" content="no-cache"> <meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="description" content="This is my page"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> <sql:query var="rs" dataSource="jdbc/mysql"> select id, username, password from user </sql:query> </head> <body> <h2>Results</h2> <c:forEach var="row" items="${rs.rows}"> Foo ${row.username}<br/> Bar ${row.password}<br/> </c:forEach> <br> </body> </html>
当然,如果你用servlet测试数据源也是可以的,下面是一个servlet测试例子:
package fx; import java.io.IOException; import java.io.PrintWriter; import java.sql.Connection; import java.sql.ResultSet; import java.sql.SQLException; import javax.naming.Context; import javax.naming.InitialContext; import javax.naming.NamingException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.sql.DataSource; public class DsTest extends HttpServlet { /** * Constructor of the object. */ public DsTest() { super(); } /** * Destruction of the servlet. <br> */ public void destroy() { super.destroy(); // Just puts "destroy" string in log // Put your code here } /** * The doGet method of the servlet. <br> * * This method is called when a form has its tag value method equals to get. * * @param request the request send by the client to the server * @param response the response send by the server to the client * @throws ServletException if an error occurred * @throws IOException if an error occurred */ public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request,response); } /** * The doPost method of the servlet. <br> * * This method is called when a form has its tag value method equals to post. * * @param request the request send by the client to the server * @param response the response send by the server to the client * @throws ServletException if an error occurred * @throws IOException if an error occurred */ public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html"); PrintWriter out = response.getWriter(); out .println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">"); out.println("<HTML>"); out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>"); out.println(" <BODY>"); out.print(" This is "); out.print(this.getClass()); out.println(", using the POST method"); try { Context ctx = new InitialContext(); DataSource ds = (DataSource)ctx.lookup("java:comp/env/jdbc/mysql"); Connection conn = ds.getConnection(); ResultSet rs=conn.createStatement().executeQuery("select * from user"); rs.next(); out.print(rs.getString(2)); } catch (NamingException e) { e.printStackTrace(out); System.out.println(e.getMessage()); } catch (SQLException e) { e.printStackTrace(out); } out.println("connection pool connected !!haha"); out.println(" </BODY>"); out.println("</HTML>"); out.flush(); out.close(); } /** * Initialization of the servlet. <br> * * @throws ServletException if an error occurs */ public void init() throws ServletException { // Put your code here } }
我的mysql数据库名为javatest,表名为user,有三列"id","username","password"。servlet运行结果将打印出user表中的第一个用户名。
注意:如果你新建servlet,myeclipse会自动帮你在web.xml中生成相应的mapping,而这部分内容可能“插”进
<resource-ref> <description>DB Connection</description> <res-ref-name>jdbc/mysql</res-ref-name> <res-type>javax.sql.DataSource</res-type> <res-auth>Container</res-auth> </resource-ref>
中,造成错误。注意自己手动调整。 //要看一下,因为我的好像没有这段代码
别外,注意myeclipse中的servlet映射为“服务器ip:端口/工程文件名/servlet/servlet名”。
还有就是最好使用外部自己配置的Tomcat,并将mysql-connector-java-5.1.13-bin.jar包放到Tomcat的lib目录下。
最好不要用MyEclipse自带的Tomcat,因为我的MyEclipse提示org.apache.tomcat.dbcp.dbcp.SQLNestedException: Cannot load JDBC driver class 'com.mysql.jdbc.Driver'
即Tomcat出现异常,找不到jdbc驱动包