用java编写一个矩阵类,其中封装有一个代表矩阵的二维数组，并提供一个实现两个不同行列矩阵的相加方法。利用随机函数产生两个3行4列的矩阵，验证类实验。

代码如下：

import java.util.Random;

public class Matrix {
    private int[][] matrix;
    private int row;
    private int col;

    public Matrix(int[][] matrix) {
       this.matrix = matrix;
       this.row = matrix.length;
       this.col = matrix[0].length;
    }

    public Matrix add(Matrix other) {
        if (this.row != other.row || this.col != other.col) {
            throw new IllegalArgumentException("Matrices do not have the same size");
        }

        int[][] result = new int[this.row][this.col];

        for (int i = 0; i < this.row; i++) {
            for (int j = 0; j < this.col; j++) {
                result[i][j] = this.matrix[i][j] + other.matrix[i][j];
            }
        }

        return new Matrix(result);
    }

    public static void main(String[] args) {
        Random r = new Random();
        int[][] matrix1 = new int[3][4];
        for (int i = 0; i < matrix1.length; i++) {
            for (int j = 0; j < matrix1[0].length; j++) {
                matrix1[i][j] = r.nextInt(10);
            }
        }

        int[][] matrix2 = new int[3][4];
        for (int i = 0; i < matrix2.length; i++) {
            for (int j = 0; j < matrix2[0].length; j++) {
                matrix2[i][j] = r.nextInt(10);
            }
        }

        Matrix m1 = new Matrix(matrix1);
        Matrix m2 = new Matrix(matrix2);

        Matrix result = m1.add(m2);

        System.out.println("Matrix 1: ");
        printMatrix(m1);
        System.out.println("Matrix 2: ");
        printMatrix(m2);
        System.out.println("Result: ");
        printMatrix(result);
    }

    private static void printMatrix(Matrix matrix) {
        for (int i = 0; i < matrix.row; i++) {
            for (int j = 0; j < matrix.col; j++) {
                System.out.print(matrix.matrix[i][j] + " ");
            }
            System.out.println();
        }
    }
}

运行结果如下：

Matrix 1:
0 7 7 3
3 8 7 2
2 3 7 2
Matrix 2:
7 5 5 7
7 9 9 8
7 1 1 7
Result:
7 12 12 10
10 17 16 10
9 4 8 9