学步园

上一篇， 设计完成了数据库，接下来开始做Servlet啦， 这里主要是用到的技术就是JDBC和JSON的封装返回。

先看JDBC工具类：

package com.ktvtop.util;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;

/**
 * 访问数据工具类
 * @author David kun
 */
public class JDBCUtil {
	/**
	 * 数据库连接路径，账户与密码，并设置编码
	 */
	public final static String URL = "jdbc:mysql://193.168.1.108:3306/test?useUnicode=true&characterEncoding=GBK";
	public final static String userName = "liaokun";
	public final static String password = "123456";

	/**
	 * 连接数据库
	 * 
	 * @return Connection
	 * @throws Exception
	 */
	public static Connection getConnection() throws Exception {
		Class.forName("com.mysql.jdbc.Driver");
		Connection conn = DriverManager.getConnection(URL, userName, password);
		return conn;
	}

	/**
	 * 得到一个PreparedStatement
	 * 
	 * @param conn
	 *            数据库连接
	 * @param sql
	 *            sql语句
	 * @return PreparedStatement
	 * @throws Exception
	 * 
	 */
	public static PreparedStatement getPs(Connection conn, String sql)
			throws Exception {
		PreparedStatement ps = conn.prepareStatement(sql);
		return ps;

	}

	/**
	 * 创建Statement
	 * 
	 * @param conn
	 *            数据库连接
	 * @return Statement
	 * @throws Exception
	 */
	public static Statement getSt(Connection conn) throws Exception {
		Statement st = conn.createStatement();
		return st;

	}

	/**
	 * 返回一个Statement
	 * 
	 * @param st
	 *            Statement
	 * @param sql
	 *            sql数据
	 * @return ResultSet
	 * @throws Exception
	 */
	public static ResultSet getRs(Statement st, String sql) throws Exception {
		ResultSet rs = st.executeQuery(sql);
		return rs;
	}

	/**
	 * 关闭所有资源
	 * 
	 * @param conn
	 *            数据库连接
	 * @param st
	 *            Statement
	 * @param rs
	 *            ResultSet
	 * @throws Exception
	 */
	public static void close(Connection conn, Statement st, ResultSet rs)
			throws Exception {
		if (rs != null) {
			rs.close();
		}
		if (st != null) {
			st.close();
		}
		if (conn != null) {
			conn.close();
		}
	}

	/**
	 * 关闭所有资源
	 * 
	 * @param conn
	 *            数据库连接
	 * @param st
	 *            Statement
	 * @throws Exception
	 */
	public static void close(Connection conn, Statement st) throws Exception {
		if (st != null) {
			st.close();
		}

		if (conn != null) {
			conn.close();
		}
	}

	
}

这里是关键啦：注意看doPost这个方法中是怎么做的。

package com.ktvtop.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.PreparedStatement;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.ktvtop.util.JDBCUtil;

public class RegisterServlet extends HttpServlet {

	
	public RegisterServlet() {
		super();
	}

	
	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		
	}

	
	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 {
		request.setCharacterEncoding("utf-8");
		String type=request.getParameter("type");
		String name=request.getParameter("name");
		String passwd=request.getParameter("passwd");
		String mail=request.getParameter("mail");
		System.out.println(type);
		System.out.println(name);
		System.out.println(passwd);
		System.out.println(mail);
		if(type.equals("register"))
		{
			response.setContentType("application/json");
			PrintWriter out = response.getWriter();
			try {
			Connection	conn = JDBCUtil.getConnection();
			String sql = " insert into user(name,passwd,mail)"+"values(?,?,?)";
			PreparedStatement ps=JDBCUtil.getPs(conn, sql);
			ps.setString(1, name);
			ps.setString(2, passwd);
			ps.setString(3, mail);
			if (ps.executeUpdate()!=0) {
				System.out.println("insert success!");
				out.write("1");
				out.flush();
				out.close();
			}else
			{
				System.out.println("insert success!");
				out.write("0");
				out.flush();
				out.close();
			}
			JDBCUtil.close(conn, ps);
			} catch (Exception e) {
				// TODO: handle exception
				out.write("2");
				out.flush();
				out.close();
			}
		}
	}



}

这里就完成了servlet的设计，这里是一个注册的servlet。请注意看。

等到一个serlvet的地址为：

"http://193.168.1.122:8080/JsonDemo/servlet/RegisterServlet   地址根据自己服务器IP来决定