Recommendation::Main.java

package pA;import java.util.Scanner;import java.util.Arrays;import java.util.Random;import java.math.*;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;public class Main {public static Recommend[] arr;public static Pair[] arrp;public static Scanner input;public static Recommend A;public static int n;public static int num;public static int information;//JDBC的协议、主机名（此处是本地机）、端口号、需要连接的数据库等信息    public static String url = "jdbc:mysql://localhost:3306/recommend";    public static String user = "root";                   //登录用户名    public static String password = "123456";             //登录密码        public static Connection con;    public static Statement stmt;public static void main(String[] args) {setup();loop();}public static void setup() {        try {        Class.forName("com.mysql.jdbc.Driver"); //指定MySQL驱动。            con = DriverManager.getConnection(url, user, password);  //连接MySQL数据库            System.out.println("连接数据库服务器成功。");            stmt = con.createStatement();        } catch (ClassNotFoundException e) {    //捕获没有找到驱动的异常，是forName()方法抛出的。            System.out.println("没有找到MySQL驱动。");        } catch (SQLException e) {              //捕获连接失败的异常，是Connection对象抛出的。            System.out.println("连接数据库服务器失败。");        }                                        String chars = "abcdefghijklmnopqrstuvwxyz";//!!!here        //String sql1 = "INSERT INTO user VALUES(0,1,2,3,4,5,6,7,'Zhangsan')";        String sql1 = "INSERT INTO user VALUES("+        Math.random()+","+        Math.random()+","+        Math.random()+","+        Math.random()+","+        Math.random()+","+        Math.random()+","+        Math.random()+","+        Math.random()+","+        "'"+        "Zhangsan"+//单字母用户        "')";        try {        int cnt1 = stmt.executeUpdate(sql1);//执行UPDATE语句，返回更新的记录数。          if (cnt1 != 0) {          System.out.println("INSERT语句执行成功。");        }        } catch (SQLException e) {              //捕获连接失败的异常，是Connection对象抛出的。            System.out.println("连接数据库服务器失败。");        }                        //again        Random random = new Random();                //System.out.println(chars.charAt((int)(Math.random() * 26)));        for (int i = 0; i < 10; i++) {        String tmp = "INSERT INTO user VALUES("+        Math.random()+","+        Math.random()+","+        Math.random()+","+        Math.random()+","+        Math.random()+","+        Math.random()+","+        Math.random()+","+        Math.random()+","+        "'"+        chars.charAt((int)(Math.random() * 26))+//用户        chars.charAt((int)(Math.random() * 26))+        "')";        try {            int cnt1 = stmt.executeUpdate(tmp);//执行UPDATE语句，返回更新的记录数。              if (cnt1 != 0) {              System.out.println("INSERT语句执行成功。");            }            } catch (SQLException e) {              //捕获连接失败的异常，是Connection对象抛出的。                System.out.println("连接数据库服务器失败。");            }        }                //again1        for (int i = 0; i < 10; i++) {        String tmp = "INSERT INTO feature VALUES("+        Math.random()+","+        Math.random()+","+        Math.random()+","+        Math.random()+","+        Math.random()+","+        Math.random()+","+        Math.random()+","+        Math.random()+","+        "'"+        chars.charAt((int)(Math.random() * 26))+//商品名        chars.charAt((int)(Math.random() * 26))+        "')";        try {            int cnt1 = stmt.executeUpdate(tmp);//执行UPDATE语句，返回更新的记录数。              if (cnt1 != 0) {              System.out.println("INSERT语句执行成功。");            }            } catch (SQLException e) {              //捕获连接失败的异常，是Connection对象抛出的。                System.out.println("连接数据库服务器失败。");            }        }                                System.out.println("Please input the number of features of one vector.");input = new Scanner(System.in);n = input.nextInt();System.out.println("Please input the considering vector.");A = new Recommend(n);System.out.println("Please input the number of comparing vectors.");num = input.nextInt();System.out.println("Please input these vectors.");arr = new Recommend[num];for (int i = 0; i < num; i++) {arr[i] = new Recommend(n);}//Recommend B = new Recommend(n);//double s = A.getSimiliar(B);//System.out.print("The similiar factor is ");//System.out.println(s);arrp = new Pair[num];}public static void loop() {while (true) {catchInfo();//dealWithInfo();}}public static void catchInfo() {System.out.println("Please input the kind of information.");System.out.println("1 for update; 2 for output to screen.");information = input.nextInt();switch (information) {case 1:update();break;case 2:outputToScreen();}}//public static void dealWithInfo() {//}public static void outputToScreen() {System.out.println("Input recommend mode:");System.out.println("0 for all; 1 for part; 2 for this user's preference.");int mode = input.nextInt();if (mode == 0) {for (int i = 0; i < num; i++) {arrp[i] = new Pair(i, A.getSimiliar(arr[i]));}} else if (mode == 1) {System.out.println("Input the part of recommend.");int index = input.nextInt();for (int i = 0; i < num; i++) {arrp[i] = new Pair(i, A.getSimiliarPartOf(arr[i], index));}} else if (mode == 2) {for (int i = 0; i < num; i++) {arrp[i] = new Pair(i, A.getThisUsersPrefer(arr[i]));}}Arrays.sort(arrp, new PairCmp());//System.out.println("The pre " + num + " number of goods and the recommend rates are:");System.out.println("The pre " + num + " number of goods are:");for (int i = 0; i < num; i++) { //输出前num个物品，推荐度依次降低//System.out.println((int)arrp[i].first + " " + arrp[i].second);System.out.println((int)arrp[i].first);}}public static void update() {System.out.println("Please input the way which the customer view or buy.");System.out.println("1 for view; 2 for buy.");int w = input.nextInt();if (w == 1) {A.rate[0] += 1;A.maintainRate();for (int i = 0; i < n; i++) {A.feature[i] = A.rate[i];}} else if (w == 2) {A.rate[0] += 3;A.maintainRate();for (int i = 0; i < n; i++) {A.feature[i] = A.rate[i];}} else {System.out.println("Input wrong.");}}}