java 二维数组存储 java将二维数组保存在文件

目录

• 1.将二维数组存入txt文件的步骤
• 2.读取txt文件转换为二维数组
• 3.测试用例

1.将二维数组存入txt文件的步骤

public static void saveArray(int[][] array){
		//1.创建字符输出流
		FileWriter writeFile = null;
		try {
			//2.数据想写入的路径及文件
			File file = new File("Array.txt");
			//3.如果该文件不存在，就创建
			if(!file.exists()) {
				file.createNewFile();
			}
			//4.给字节输出流赋予实例
			writeFile = new FileWriter(file);
			//5.通过循环将数组写入txt文件中
			for(int i = 0; i < array.length; i++) {
				//6.数据前n - 1列尾部加入","
				for(int j = 0; j < array[0].length - 1; j++) {
					writeFile.write(array[i][j] + ",");
				}
				//7.数组最后一列后面不加","
				writeFile.write(array[i][array[0].length - 1] + "");
				//8.加上换行符
				writeFile.write("\n");
			}
			//9.把writeFile里的数据全部刷新一次，全部写入文件中
			writeFile.flush();
		} catch (Exception e) {//10.异常捕获
			e.printStackTrace();
		} finally {	
			try {
				//11.如果writeFile不为空，就将其关闭
				if(writeFile != null)
					writeFile.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}

2.读取txt文件转换为二维数组

public static int[][] readArray() {
		//1.声明一个字符输入流
		FileReader reader = null;
		//2.声明一个字符输入缓冲流
		BufferedReader readerBuf = null;
		//3.声明一个二维数组
		int[][] array = null;
		try {
			//4.指定reader的读取路径
			reader = new FileReader("Array.txt");
			//5.通过BufferedReader包装字符输入流
			readerBuf = new BufferedReader(reader);
			//6.创建一个集合，用来存放读取的文件的数据
			List<String> strList = new ArrayList<>();
			//7.用来存放一行的数据
			String lineStr;
			//8.逐行读取txt文件中的内容
			while((lineStr = readerBuf.readLine()) != null) {
				//9.把读取的行添加到list中
				strList.add(lineStr);
			}
			//10.获取文件有多少行
			int lineNum = strList.size();
			//11.获取数组有多少列
			String s =  strList.get(0);
			int columnNum = s.split("\\,").length;
			//12.根据文件行数创建对应的数组
			array = new int[strList.size()][columnNum];
			//13.记录输出当前行
			int count = 0;
			//14.循环遍历集合，将集合中的数据放入数组中
			for(String str : strList) {
				//15.将读取的str按照","分割，用字符串数组来接收
				String[] strs = str.split("\\,");
				for(int i = 0; i < columnNum; i++) {
					array[count][i] = Integer.valueOf(strs[i]);
				}
				//16.将行数 + 1
				count++;
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			//17.关闭字符输入流
			try {
				if(reader != null)
					reader.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
			//18.关闭字符输入缓冲流
			try {
				if(readerBuf != null)
					readerBuf.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		//19.返回稀疏数组
		return array;
	}

3.测试用例

把下面这段代码和上面两段代码都复制到一个class文件中，保存运行一下，就能看到运行结果啦~~

public static void main(String args[]) {
		
		int[][] arr = new int[5][5];
		for(int i = 0; i < arr.length; i++) {
			for(int j = 0; j < arr.length; j++) {
				System.out.print(arr[i][j] + " ");
			}
			System.out.println();
		}
		saveArray(arr);
		
		System.out.println();
		
		int[][] arr1 = readArray();
		
		for(int i = 0; i < arr1.length; i++) {
			for(int j = 0; j < arr1.length; j++) {
				System.out.print(arr1[i][j] + " ");
			}
			System.out.println();
		}
	}