[SERVER + mobile client project] servlet Design of Android + servlet + JSON comprehensive case study [2]

In the previous article, the database was designed and Servlet was started. The technology used here is JDBC and JSON encapsulation and return.

First look at the JDBC tool class:

Package COM. ktvtop. util; import Java. SQL. connection; import Java. SQL. drivermanager; import Java. SQL. preparedstatement; import Java. SQL. resultset; import Java. SQL. statement;/*** access data tool class * @ author David Kun */public class jdbcutil {/*** database connection path, account and password, and set the encoding */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 "; /*** connect to the database ** @ 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;}/*** get a preparedstatement ** @ Param conn * database connection * @ Param SQL * SQL statement * @ return preparedstatement * @ throws exception **/public static preparedstatement getps (connection Conn, string SQL) throws exception {preparedstatement PS = Conn. preparestatement (SQL); Return pS ;} /*** create statement ** @ Param conn * database connection * @ Return Statement * @ throws exception */public static statement getst (connection conn) throws exception {statement St = Conn. createstatement (); Return st ;} /*** return a statement ** @ Param st * Statement * @ Param SQL * SQL data * @ return resultset * @ throws exception */public static resultset getrs (statement St, string SQL) throws exception {resultset rs = st.exe cutequery (SQL); Return Rs ;} /*** close all resources ** @ Param conn * database connection * @ Param st * Statement * @ Param RS * resultset * @ throws exception */public static void clos E (connection Conn, statement St, resultset RS) throws exception {If (RS! = NULL) {Rs. Close () ;}if (st! = NULL) {st. Close () ;}if (Conn! = NULL) {Conn. close ();}} /*** close all resources ** @ Param conn * database connection * @ 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 ();}}}

Here is the key: note thatDopostHow is this method implemented.

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 {Connectionconn = 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 exceptionout.write("2");out.flush();out.close();}}}}

The servlet design is completed here. Here is a registered servlet. Please note.

Wait until the address of a Serlvet is:

"Http: // 193.168.1.122: 8080/jsondemo/servlet/registerservlet address depends on the IP address of your server.