java - 如何从 Resultset 构造数组数组

Question

我正在研究 Google 图表 API，并且Google Visualization Candlestick Charts 期望数据是一个数组数组才能正常工作。

例如下面的格式

[
[ "2011-08-01", 136.65, 136.96, 134.15, 136.49 ],
[ "2011-08-02", 135.26, 135.95, 131.50, 131.85 ],
[ "2011-08-05", 132.90, 135.27, 128.30, 135.25 ]
]

这是我从数据库中检索数据的 SQL

String selectsql = "select current_day ,  open_val , high_val , low_val , close_val  from   historical_data where symbol_name = ?";
while(Rset.next())
            {
                String current_day =  SgxRset.getString("current_day");
                String open_val =  SgxRset.getString("open_val");
                String high_val =  SgxRset.getString("high_val");
                String low_val =  SgxRset.getString("low_val");
                String close_val =  SgxRset.getString("close_val");
            }

你能告诉我如何构造数组的数组吗？？

示例程序

import java.util.ArrayList;
import java.util.List;

import org.json.JSONException;

public class TestJSON {

    public static void main(String[] args) throws JSONException {
        Employee emp1 = new Employee();
        emp1.setName("Ravi");
        emp1.setName("20");
        Employee emp2 = new Employee();
        emp2.setName("Kiran");
        emp2.setName("20");
        List<Employee> histList = new ArrayList<Employee>();

         Object[] arrayResultData = histList.toArray();

    }
}


public class Employee {

    String name ;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getAge() {
        return age;
    }
    public void setAge(String age) {
        this.age = age;
    }
    String age ;

}

Answer 1

创建一个类，它将所有这些数据一起保存在一个对象中，就像这样，带有 getter 和 setter:

 public class Data {
            private String current_day;
    private double open_val;
    private double high_val;
    private double low_val;
    private double close_val;

    public Data(String current_day, double open_val, double high_val,
            double low_val, double close_val) {
        this.current_day = current_day;
        this.open_val = open_val;
        this.high_val = high_val;
        this.low_val = low_val;
        this.close_val = close_val;
    }

    public String getCurrent_day() {
        return current_day;
    }

    public void setCurrent_day(String current_day) {
        this.current_day = current_day;
    }

    public double getOpen_val() {
        return open_val;
    }

    public void setOpen_val(double open_val) {
        this.open_val = open_val;
    }

    public double getHigh_val() {
        return high_val;
    }

    public void setHigh_val(double high_val) {
        this.high_val = high_val;
    }

    public double getLow_day() {
        return low_val;
    }

    public void setLow_day(double low_day) {
        this.low_val = low_day;
    }

    public double getClose_day() {
        return close_val;
    }

    public void setClose_day(double close_day) {
        this.close_val = close_day;
    }

    }

现在，将数据存储在您从 SQL 获取的对象数组中。

String selectsql = "select current_day ,  open_val , high_val , low_val ,close_val  from   historical_data where symbol_name = ?";
    List<Data> myList = new ArrayList(Data); 
    while(Rset.next())
                {
                    String current_day =  SgxRset.getString("current_day");
                    String open_val =  SgxRset.getString("open_val");
                    String high_val =  SgxRset.getString("high_val");
                    String low_val =  SgxRset.getString("low_val");
                    String close_val =  SgxRset.getString("close_val");

                    Data data = new Data(current_day,open_val,high_val,low_val,close_val);
                    myList.add(data);
                }

读取数据可以这样写:

 String a = "[ ";
    for (int i = 0; i < myList.size(); i++) {
        String b = "[ \"" + myList.get(i).getCurrent_day() + "\" , "
                + myList.get(i).getOpen_val() + "],";
        if(i==myList.size() -1)
            a += b;
        else
            a += b+",";
    }
    a += " ]";

现在，对我来说输出是:

[ [ "2011-08-01" , 136.65],[ "2011-08-02" , 135.26] ]