利用web.xml配置数据库

1.web.xml 配置
  <servlet>
  <!-- 数据库配置 -->
  <init-param>
  <param-name>dbUrl</param-name>
  <param-value>jdbc:mysql://localhost:8080/auth</param-value>
  </init-param>
  <init-param>
  <param-name>driverName</param-name>
  <param-value>com.jdbc.mysql.Driver</param-value>
  </init-param>
  <init-param>
  <param-name>userName</param-name>
  <param-value>root</param-value>
  </init-param>
  <init-param>
  <param-name>passWord</param-name>
  <param-value>123456</param-value>
  </init-param>
  <load-on-startup>1</load-on-startup><!-- 自动启动优先级 -->

  </servlet>

2.初始化

private String dbUrl;private String driverName;private String userName;private String passWord;private Connection conn=null;private PreparedStatement ps=null;private ResultSet rs=null;@Override//初始化public void init(ServletConfig config) throws ServletException {//读取配置文件里面的信息this.dbUrl=config.getInitParameter("dbUrl");this.driverName=config.getInitParameter("driverName");this.userName=config.getInitParameter("userName");this.passWord=config.getInitParameter("passWord");}

3.操作

3.1.查询public String getNickName(String openid) throws SQLException{String nickName="";conn = DriverManager.getConnection(dbUrl,userName,passWord);String sql="select * from user where OPENID=?";ps = conn.prepareStatement(sql);ps.setString(1, openid);rs = ps.executeQuery();while(rs.next()){nickName=rs.getString("NICKNAME");}rs.close();ps.close();conn.close();return nickName;}3.2 更新public int updUser(String openid,String userName,String passWord) throws SQLException{String nickName="";conn = DriverManager.getConnection(dbUrl,userName,passWord);String sql="update user set OPENID=? where USERNAME=? and PASSWORD=?";ps = conn.prepareStatement(sql);ps.setString(1, openid);ps.setString(2, userName);ps.setString(3, passWord);int temp=ps.executeUpdate();rs.close();ps.close();conn.close();return temp;}