updateservlet.java

基于Oracle JDeveloper 10g IDE的简单用户浏览图书信息

/* UpdateServlet.java */
package mvcBook;
import javax.servlet.ServletException;
import javax.servlet.ServletConfig;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.sql.DataSource;
import javax.naming.*;
import java.sql.Connection;
import java.sql.PreparedStatement;
import javax.sql.rowset.CachedRowSet;
import com.sun.rowset.CachedRowSetImpl;
public class UpdateServlet extends HttpServlet {
    public void init(ServletConfig config) throws ServletException {
        super.init(config);
    }  
    public void doPost(HttpServletRequest req, HttpServletResponse res) throws ServletException {
        doGet(req, res);
    }
    public void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException {
        Connection con = null;
        try {
            req.setCharacterEncoding("GBK");
            // 生成一个新的缓冲存储集
            CachedRowSet rs = new CachedRowSetImpl();
            // 查找数据源并且获得连接
            InitialContext ctx = new InitialContext();
            DataSource ds=(DataSource)ctx.lookup("jdbc/DBConnCoreDS");
            con = ds.getConnection();
            // 为更新图书生成预备好的语句
            PreparedStatement stmt = con.prepareStatement("update book " + 
                                                    "set isbn = ?, " + 
                                                    "title = ?, " + 
                                                    "author = ?, " + 
                                                    "pressname = ? " +
                                                    "where isbn = ?");
            // 把修改过的图书属性设置为SQL输入参数
            stmt.setString(1, req.getParameter("isbn"));
            stmt.setString(2, req.getParameter("title"));
            stmt.setString(3, req.getParameter("author"));
            stmt.setString(4, req.getParameter("pressname"));
            stmt.setString(5, req.getParameter("id"));
            // 进行更新
            stmt.executeUpdate();            
            stmt.close();
            // 设置用于获取图书列表的SQL命令
            rs.setCommand("select * from book");
            // 运行SQL命令
            rs.execute(con);
            // 把行集作为一个请求属性进行存储
            req.setAttribute("rs",rs);
            // 把请求转发到相关URI，这些URI映射到List.jsp页面上以显示新的图书
            getServletContext().getRequestDispatcher("/List.jsp").forward(req, res);
        }
        catch(Exception ex) {
            throw new ServletException(ex);
        }
        finally {
            try {
                if(con != null) {
                    con.close();
                }
            }
            catch(Exception ex) {
                throw new ServletException(ex);
            }
        }
    }
}