java - 四舍五入并显示值

Question

我有以下代码:

import java.sql.*;
import java.math.*;

public class Testd1 {

    public static void main(String[] args) {

        System.out.println("Sum of the specific column!");

        Connection con = null;
        int m = 1;
        double sum, sum1, sum2;
        int e[];
        e = new int[100];
        int p;

        int decimalPlaces = 5;

        for (int i = 0; i < e.length; i++) {
            e[i] = 0;
        }

        double b2, c2, d2, u2, v2;
        int i, j, k, x, y;
        double mat[][] = new double[10][10];

        try {
            Class.forName("com.mysql.jdbc.Driver");

            con = DriverManager.getConnection(
                "jdbc:mysql://localhost:3306/prathi", "root", "mysql");
            try {
                Statement st = con.createStatement();

                ResultSet res = st.executeQuery(
                    "SELECT  Service_ID,SUM(consumer_feedback) " +
                    "FROM  consumer1 group by Service_ID");
                while (res.next()) {
                    int data = res.getInt(1);
                    System.out.println(data);
                    System.out.println("\n\n");

                    int c1 = res.getInt(2);
                    e[m] = res.getInt(2);
                    if (e[m] < 0) {
                        e[m] = 0;
                    }
                    m++;
                    System.out.print(c1);
                    System.out.println("\t\t");
                }
                sum = e[1] + e[2] + e[3] + e[4] + e[5];
                System.out.println("\n \n The sum is" + sum);
                for (p = 21; p <= 25; p++) {
                    if (e[p] != 0) {
                        e[p] = e[p] / (int) sum;
                        //I have type casted sum to get output
                    }
                    BigDecimal bd1 = new BigDecimal(e[p]);
                    bd1 = bd1.setScale(decimalPlaces,
                        BigDecimal.ROUND_HALF_UP); // setScale is immutable
                    e[p] = bd1.intValue();
                    System.out.println("\n\n The normalized value is" + e[p]);

                    mat[4][p - 21] = e[p];
                }

            } catch (SQLException s) {
                System.out.println("SQL statement is not executed!");
            }
        } catch (Exception e1) {
            e1.printStackTrace();
        }
    }
}

我有一个名为consumer1的表。计算总和后我得到的值如下

mysql> 按 Service_ 从 Consumer1 组中选择 Service_ID,sum(consumer_feedback)身份证号；

Service_ID 总和(consumer_feedback) 31 17 32 0 33 60 34 38 35 | 35 38在我的程序中，我正确地获得了每个 Service_ID 的总和。但是，在标准化之后，即当我计算 17/153=0.111 时，我得到的标准化值是 0。我希望在四舍五入后正确显示标准化值。我的输出如下

C:>javac Testd1.java

C:>java Testd1具体列的总和!31

1732

033

6034

3835

38

总和是153.0

归一化值为0

归一化值为0

归一化值为0

归一化值为0

归一化值为0

但是，标准化后，我想要得到 17/153=0.111。我得到的标准化值为 0。我希望对这些值进行四舍五入。

Answer 1

int e[];

...

e[p] = bd1.intValue();

e 是一个整数数组。您如何期望整数值为 0.111？

将 e 更改为某种可以保存小数的类型。