List＜BigDecimal＞ sydfList = new ArrayList＜＞()； 找到集合中的最大值和最小值

To find the maximum and minimum values in the sydfList which contains BigDecimal objects, you can use Java 8 streams for a concise and efficient solution. Here’s how you can do it:

import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.List;

public class Main {
    public static void main(String[] args) {
        List<BigDecimal> sydfList = new ArrayList<>();
        sydfList.add(new BigDecimal("10.5"));
        sydfList.add(new BigDecimal("8.2"));
        sydfList.add(new BigDecimal("15.7"));
        sydfList.add(new BigDecimal("6.4"));
        
        // Finding the maximum value
        BigDecimal max = sydfList.stream()
                                 .max(BigDecimal::compareTo)
                                 .orElse(BigDecimal.ZERO);
        
        // Finding the minimum value
        BigDecimal min = sydfList.stream()
                                 .min(BigDecimal::compareTo)
                                 .orElse(BigDecimal.ZERO);
        
        System.out.println("Maximum value: " + max);
        System.out.println("Minimum value: " + min);
    }
}

Explanation:

1. Initialization: We initialize sydfList with BigDecimal objects.

2. Finding Maximum Value:

   • We use stream() on sydfList to convert it into a stream of BigDecimal.
   • max() function is applied on the stream to find the maximum value.
   • BigDecimal::compareTo is used as the comparator to determine the ordering of BigDecimal objects.
   • orElse(BigDecimal.ZERO) ensures that if the stream is empty, we default to BigDecimal.ZERO.

3. Finding Minimum Value:

   • Similarly, min() function is used to find the minimum value.
   • Again, BigDecimal::compareTo is used as the comparator.
   • orElse(BigDecimal.ZERO) handles the case where the stream is empty.

4. Output: Finally, we print out the maximum and minimum values found in the list.

This approach leverages Java 8’s Stream API, which provides a functional approach to operate on collections, making the code concise and readable.