使用servlet和Java Bean访问MySQL

　　使用servlet和Java Bean访问mysql

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