JAVA，求m*n阶矩阵中的2*2阶矩阵和的最大值

import java.util.Scanner;

/**
 * m*n阶矩阵中的2*2阶矩阵和最大值
 * 
 * @author ForeverLover
 *
 */
public class Matrix {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int m;
		int n;
		String s = scan.nextLine();
		String[] sa = s.split(";");
		m = sa.length;
		String[][] ss = new String[m][];
		for (int i = 0; i < m; i++)
			ss[i] = sa[i].split(" ");
		n = ss[0].length;
		int[][] array = new int[m][n];
		for (int i = 0; i < m; i++) {
			for (int j = 0; j < n; j++) {
				array[i][j] = Integer.parseInt((ss[i][j]));
			}
		}
		int max = 0;
		for (int i = 0; i < m - 1; i++) {
			int sum = 0;
			for (int j = 0; j < n - 1; j++) {
				sum = array[i][j] + array[i][j + 1] + array[i + 1][j]
						+ array[i + 1][j + 1];
				max = sum >= max ? sum : max;
			}
		}
		System.out.println(max);
	}
}