运行环境: JDK 5.0 + Tomcat 5.5.4 
JDK安装路径: D:\Java\jdk1.5.0_01 Tomcat安装路径:D:\Tomcat 5.5 
设置环境变量(控制面板->系统->高级): java_home=D:\Java\jdk1.5.0_01 path=%JAVA_HOME%\bin classpath=.;D:\Java\jdk1.5.0_01\lib\dt.jar;D:\Java\jdk1.5.0_01\lib\tools.jar;D:\Tomcat 5.5\common\lib\servlet-api.jar;D:\Tomcat 5.5\common\lib\mysql-connector-java-3.1.6-bin.jar; 
 其中D:\Tomcat 5.5\common\lib\servlet-api.jar为Tomcat的servlet API实现,一定要加上,不如无法编译servlet D:\Tomcat 5.5\common\lib\mysql-connector-java-3.1.6-bin.jar;是MySQL的JDBC驱动,connect/J 3.1.6,可到MySQL官方网站下载 
Tomcat5.5虚拟目录设定: D:\Tomcat 5.5\conf\Catalina\localhost下新加一test.xml 内容如下: <Context path="/test" docBase="d:/www" reloadable="true" crossContext="true" debug="0" > </Context> 
d:\www路径将是我们测试网站的根目录,通过http://localhost:8080/test访问该虚拟目录 d:\www下建有目录WEB-INF,下有web.xml设置文件(可参考D:\Tomcat 5.5\webapps\ROOT\WEB-INF\web.xml),classes目录和lib目录 
//连接数据库的Java Bean文件名dbconn.java package NinGoo; import java.sql.*; public class dbconn {  public dbconn() {    }  //declare variable  private Connection conn = null;  ResultSet rs = null;  private String server = "127.0.0.1";  private String port = "3306";  private String db = "test";  private String user = "root";  private String pass = "password";  private String drivername="com.mysql.jdbc.Driver";  private String URL="jdbc:mysql://"+server+":"+port+"/"+db+"?user="+user+"&password="+pass; 
 public Connection getConn(){//get database connection   try{    Class.forName(drivername).newInstance();    conn = DriverManager.getConnection(URL);   }   catch(Exception e){    e.printStackTrace();   }    return this.conn ;  } 
 public ResultSet executeSQL(String str) {   try{    Statement stmt = conn.createStatement();    rs = stmt.executeQuery(str);   }   catch(Exception e){    e.printStackTrace();   }    return this.rs;  }  } 
编译javac welcome.java,将编译后的文件welcome.class放到目录D:\www\WEB-INF\classes\NinGoo\下 
//调用Java Bean的servlet welcome.java import java.io.*; import javax.servlet.*; import javax.servlet.http.*; import java.sql.*; 
 public class welcome extends HttpServlet {  public welcome() {  } 
 public void doGet(HttpServletRequest Req,HttpServletResponse Res) throws ServletException,IOException {   Res.setContentType("text/html"); 
  Connection conn=null;     Statement stmt=null;   ResultSet rs = null; 
  try{    NinGoo.database.dbconn myconn =new  NinGoo.database.dbconn();    conn = myconn.getConn() ;    rs = myconn.executeSQL("select * from test"); //test是MySQL中的一个table    PrintWriter out=Res.getWriter();    out.println("<html><head><title>test</title></head>");    out.println("<body>");    while(rs.next()) {     out.println(rs.getString(1));    }    out.println("successfule!</body></html>");   }   catch(Exception e){   }  } } 编译javac welcome.java,将编译后的文件welcome.class放到目录D:\www\WEB-INF\classes下 然后修改D:\www\WEB-INF\web.xml,加入如下设置    <servlet>         <servlet-name>welcome</servlet-name>         <servlet-class>welcome</servlet-class>     </servlet> 
    <servlet-mapping>         <servlet-name>welcome</servlet-name>         <url-pattern>/welcome</url-pattern>     </servlet-mapping> 
保存后重启Tomcat,然后在浏览器中敲入http://localhost:8080/test/welcome  
 
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