如何在 TomCat 中为 Android 应用程序创建 mysql 数据库？

Question

谁能指出我学习如何创建 MYSQL 数据库并将其保存在 Tomcat 网络服务器中的方向？该数据库将用于 android 应用程序。 谢谢。

Answer 1

这是一个在 Android 中使用 MySQL 数据库的示例登录应用程序。为了从 Android 设备/模拟器连接到 MySQL 数据库，我将通过 JSON 处理的应用程序向 Servlet 发送 HTTP 请求。所以这里有两个不同的项目。 查询创建 MySQL 数据库

CREATE TABLE `users` (
  `id` int(10) unsigned NOT NULL auto_increment,
  `uname` varchar(45) NOT NULL,
  `password` varchar(45) NOT NULL,
  PRIMARY KEY  (`id`)
);

INSERT INTO `users` (`id`,`uname`,`password`) VALUES
 (1,'admin','123');

注意： 您必须需要将以下两个 jar 放置到项目类路径中。 1.json-simple-1.1.1.jar 2.mysql-connector-java-5.xxx-bin.jar LoginServlet.java

import dbConnection.DBConnectionHandler;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.sql.*;
import java.util.Enumeration;
import org.json.simple.JSONObject;

public class LoginServlet extends HttpServlet {

    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /** 
     * Handles the HTTP <code>GET</code> method.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        //response.setContentType("text/html;charset=UTF-8");
        JSONObject json = new JSONObject();


        //ObjectOutputStream out = new ObjectOutputStream(response.getOutputStream());
        Enumeration paramNames = request.getParameterNames();
        String params[] = new String[2];
        int i = 0;
        while (paramNames.hasMoreElements()) {
            String paramName = (String) paramNames.nextElement();

            //System.out.println(paramName);
            String[] paramValues = request.getParameterValues(paramName);
            params[i] = paramValues[0];

            //System.out.println(params[i]);
            i++;

        }

        String sql = "SELECT uname, password FROM users where uname=? and password=?";
        Connection con = DBConnectionHandler.getConnection();

        try {
            PreparedStatement ps = con.prepareStatement(sql);
            ps.setString(1, params[0]);
            ps.setString(2, params[1]);
            ResultSet rs = ps.executeQuery();
            if (rs.next()) {
                json.put("info", "success");
            } else {
                json.put("info", "fail");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        //System.out.println(json);
        response.setContentType("application/json");
        response.setCharacterEncoding("UTF-8");
        response.getWriter().write(json.toString());
    }

    /** 
     * Handles the HTTP <code>POST</code> method.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }
}

DBConnectionHandler.java

public class DBConnectionHandler {

    Connection con = null;

    public static Connection getConnection() {
        Connection con = null;
        try {
            Class.forName("com.mysql.jdbc.Driver");//Mysql Connection
        } catch (ClassNotFoundException ex) {
            Logger.getLogger(DBConnectionHandler.class.getName()).log(Level.SEVERE, null, ex);
        }
        try {
            con = DriverManager.getConnection("jdbc:mysql://localhost:3306/dbname", "root", "pass");//mysql database

        } catch (SQLException ex) {
            Logger.getLogger(DBConnectionHandler.class.getName()).log(Level.SEVERE, null, ex);
        }
        return con;
    }

}

activity_main.xml

<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:orientation="vertical"
        android:padding="10dip" >
        <!--  View Title Label -->
        <TextView
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_marginBottom="10dip"
            android:text="LOGIN"
            android:textSize="25dip"
            android:textStyle="bold" />
        <!--  User Name Label -->
        <TextView
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="User Name" />
        <!--  User Name TextField -->
        <EditText
            android:id="@+id/txtUser"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content" />

        <!--  Password Label -->
        <TextView
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="15dip"
            android:text="Password" />
        <!--  Password TextField -->
        <EditText
            android:id="@+id/txtPass"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:password="true" />

        <!--  Login Button -->      
        <Button
            android:id="@+id/button1"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="20dip"
            android:text="Login" />
        </LinearLayout>

</ScrollView>

你可以在这里找到完整的教程和源代码http://www.javaknowledge.info/sample-login-app-in-android-using-servlet-and-json-parsing/