package NB;/** * 訓練樣本的屬性 javaBean * */public class JavaBean { int age; String income; String student; String credit_rating; String buys_computer; public JavaBean(){ }public JavaBean(int age,String income,String student,String credit_rating,String buys_computer){  this.age=age;  this.income=income;  this.student=student;  this.credit_rating=credit_rating;  this.buys_computer=buys_computer;}public int getAge() {  return age;}public void setAge(int age) {  this.age = age;}public String getIncome() {  return income;}public void setIncome(String income) {  this.income = income;}public String getStudent() {  return student;}public void setStudent(String student) {  this.student = student;}public String getCredit_rating() {  return credit_rating;}public void setCredit_rating(String credit_rating) {  this.credit_rating = credit_rating;}public String getBuys_computer() {  return buys_computer;}public void setBuys_computer(String buys_computer) {  this.buys_computer = buys_computer;}@Overridepublic String toString() {  return "JavaBean [age=" + age + ", income=" + income + ", student="      + student + ", credit_rating=" + credit_rating + ", buys_computer="      + buys_computer + "]";}}

package NB;import java.io.BufferedReader;import java.io.File;import java.io.FileReader;import java.util.ArrayList;public class TestNB {  /**data_length   * 算法的思想   */  public static ArrayList<JavaBean> list = new ArrayList<JavaBean>();;  static int data_length=0;  public static void main(String[] args) {    // 1.讀取數據，放入list容器中    File file = new File("E://test.txt");    txt2String(file);    //數據測試樣本    testData(25,"Medium","Yes","Fair");  }  // 讀取樣本數據  public static void txt2String(File file) {    try {      BufferedReader br = new BufferedReader(new FileReader(file));// 構造一個BufferedReader類來讀取文件      String s = null;      while ((s = br.readLine()) != null) {// 使用readLine方法，一次讀一行        data_length++;        splitt(s);      }      br.close();    } catch (Exception e) {      e.printStackTrace();    }  }  // 存入ArrayList中   public static void splitt(String str){      String strr = str.trim();      String[] abc = strr.split("[//p{Space}]+");      int age=Integer.parseInt(abc[0]);      JavaBean bean=new JavaBean(age, abc[1], abc[2], abc[3], abc[4]);      list.add(bean);    }   // 訓練樣本，測試   public static void testData(int age,String a,String b,String c){     //訓練樣本     int number_yes=0;     int bumber_no=0;     // age情況 個數     int num_age_yes=0;     int num_age_no=0;     // income     int num_income_yes=0;     int num_income_no=0;     // student     int num_student_yes=0;     int num_stdent_no=0;     //credit     int num_credit_yes=0;     int num_credit_no=0;     //遍歷List 獲得數據     for(int i=0;i<list.size();i++){      JavaBean bb=list.get(i);      if(bb.getBuys_computer().equals("Yes")){ //Yes        number_yes++;        if(bb.getIncome().equals(a)){//income          num_income_yes++;        }        if(bb.getStudent().equals(b)){//student          num_student_yes++;        }        if(bb.getCredit_rating().equals(c)){//credit          num_credit_yes++;        }        if(bb.getAge()==age){//age          num_age_yes++;        }      }else {//No        bumber_no++;        if(bb.getIncome().equals(a)){//income          num_income_no++;        }        if(bb.getStudent().equals(b)){//student          num_stdent_no++;        }        if(bb.getCredit_rating().equals(c)){//credit          num_credit_no++;        }        if(bb.getAge()==age){//age          num_age_no++;        }      }     }      System.out.println("購買的歷史個數:"+number_yes);      System.out.println("不買的歷史個數:"+bumber_no);      System.out.println("購買+age:"+num_age_yes);      System.out.println("不買+age:"+num_age_no);      System.out.println("購買+income:"+num_income_yes);      System.out.println("不買+income:"+num_income_no);      System.out.println("購買+stundent:"+num_student_yes);      System.out.println("不買+student:"+num_stdent_no);      System.out.println("購買+credit:"+num_credit_yes);      System.out.println("不買+credit:"+num_credit_no);      //// 概率判斷      double buy_yes=number_yes*1.0/data_length; // 買的概率      double buy_no=bumber_no*1.0/data_length; // 不買的概率      System.out.println("訓練數據中買的概率:"+buy_yes);      System.out.println("訓練數據中不買的概率:"+buy_no);      /// 未知用戶的判斷      double nb_buy_yes=(1.0*num_age_yes/number_yes)*(1.0*num_income_yes/number_yes)*(1.0*num_student_yes/number_yes)*(1.0*num_credit_yes/number_yes)*buy_yes;      double nb_buy_no=(1.0*num_age_no/bumber_no)*(1.0*num_income_no/bumber_no)*(1.0*num_stdent_no/bumber_no)*(1.0*num_credit_no/bumber_no)*buy_no;      System.out.println("新用戶買的概率:"+nb_buy_yes);      System.out.println("新用戶不買的概率:"+nb_buy_no);      if(nb_buy_yes>nb_buy_no){        System.out.println("新用戶買的概率大");      }else {        System.out.println("新用戶不買的概率大");      }   }}