Java简单练习之按倒N顺序写入文件

      一般的String写入文件都是一行一行写入的，也就是横向顺序写入的，简单的练习下纵向按块写入，如下所示：

   

    思路：

    使用2维数据Array[][]，然后赋值，很简单。

 

    下面是代码，代码是写着玩的，不是很严谨，没什么实用价值。

    

import java.io.FileOutputStream;
import java.io.OutputStreamWriter;

public class 文件按列写 {
	// 按指定编码的字节数截取字符串
	public String subStrMethod(String srcStr, int count, String charSet)
			throws Exception {
		if (srcStr == null || srcStr.length() == 0) {
			return null;
		}
		if (charSet == null) {
			charSet = "utf-8";
		}
		if (srcStr.getBytes(charSet).length <= count) {
			return srcStr;
		}
		int num = 0;// 已经截取字符的长度
		int length = 0;// 每个字符的长度
		StringBuffer sb = new StringBuffer();
		char ch[] = srcStr.toCharArray();
		for (int i = 0; i < ch.length; i++) {
			length = String.valueOf(ch[i]).getBytes(charSet).length;
			num += length;
			if (num > count) {
				break;
			}
			sb.append(ch[i]);
		}
		return sb.toString();
	}

	public String generateTestData(int num) {
		StringBuffer sb = new StringBuffer();
		for (int i = 1; i <= num; i++) {
			sb.append("第").append(i).append("行测试数据");
		}
		return sb.toString();
	}

	public void writeContentToFile(String str, String filePath,
			String charsetName) throws Exception {
		if (charsetName == null) {
			charsetName = "utf-8";
		}
		OutputStreamWriter out = new OutputStreamWriter(new FileOutputStream(
				filePath), charsetName);
		out.write(str);
		out.close();
	}

	/**
	 * 优先写第一块
	 * 
	 * @param srcStr
	 *            原字符串
	 * @param charsetName
	 *            目的字符串编码
	 * @param perLineTotalLen
	 *            一行总的长度
	 * @param splitNum
	 *            一行切割块的数量
	 * @param spaceNum
	 *            切割块直接空格的数量
	 * @param colSplitLen
	 *            满多少列输出分割标识
	 * @param splitStr
	 *            分割标识
	 * @throws Exception
	 */
	public String getStrBySplitNum(String srcStr, String charsetName,
			int perLineTotalLen, int splitNum, int spaceNum, int colSplitLen,
			String splitStr) throws Exception {
		String lineSplit = System.getProperty("line.separator");
		if (splitNum <= 0) {
			splitNum = 1;
		}
		if (charsetName == null) {
			charsetName = "utf-8";
		}
		if (srcStr == null || srcStr.length() == 0) {
			return null;
		}
		// 块分割字符串,默认为空行
		if (splitStr == null) {
			splitStr = System.getProperty("line.separator");
		}
		// 每行的字节数大小，默认72
		if (perLineTotalLen <= 0) {
			perLineTotalLen = 72;
		}
		// 块之间的空格，默认4个空格
		if (spaceNum < 0) {
			spaceNum = 4;
		}
		// 每块的列数
		if (colSplitLen < 0) {
			colSplitLen = perLineTotalLen;
		}
		String blockSplitStr = new String();
		for (int i = 0; i < spaceNum; i++) {
			blockSplitStr = blockSplitStr + " ";
		}
		blockSplitStr = new String(blockSplitStr);
		boolean isLastBlock = false;
		// 优先考虑第一块
		String firstBlockStr = new String();
		int perBlockLen = 0;// 每块平均长度
		int firstBlobkLen = 0;// 第一块的长度
		int lastBlockLen = 0;
		String tmpStr = new String();
		int tmpSplitNum = splitNum;
		int tmpColSplitLen = colSplitLen;
		StringBuffer resultStr = new StringBuffer(5120);
		// 行 列
		String[][] resultArray = new String[tmpColSplitLen][tmpSplitNum];
		String tmpValue = null;
		while (srcStr != null && srcStr.length() > 0) {
			firstBlockStr = new String();
			isLastBlock = false;
			perBlockLen = (perLineTotalLen - lastBlockLen - (splitNum - 1)
					* spaceNum)
					/ splitNum;// 每块平均长度
			firstBlobkLen = perBlockLen
					+ (perLineTotalLen - lastBlockLen - (splitNum - 1)
							* spaceNum) % splitNum;// 第一块的长度
			lastBlockLen = lastBlockLen + firstBlobkLen;
			if (srcStr.getBytes(charsetName).length < firstBlobkLen
					* colSplitLen) {
				firstBlockStr = new String(srcStr);
				colSplitLen = (srcStr.getBytes(charsetName).length
						+ firstBlobkLen - 1)
						/ firstBlobkLen;
				isLastBlock = true;
				srcStr = new String();
			} else {
				firstBlockStr = subStrMethod(srcStr, firstBlobkLen
						* colSplitLen, charsetName);
				srcStr = new String(srcStr.substring(firstBlockStr.length()));
			}
			tmpStr = null;
			for (int i = 0; i < colSplitLen; i++) {
				tmpStr = subStrMethod(firstBlockStr, firstBlobkLen, charsetName);
				if (isLastBlock || splitNum == 1) {
					resultArray[i][tmpSplitNum - splitNum] = new String(tmpStr
							+ lineSplit);
				} else {
					resultArray[i][tmpSplitNum - splitNum] = new String(tmpStr
							+ blockSplitStr);
				}
				firstBlockStr = new String(firstBlockStr.substring(tmpStr
						.length()));
			}
			// 可能遇到双字节字符导致实际长度比计算的长度短,需要查看数组是否还能存放数据
			srcStr = new String(firstBlockStr + srcStr);
			tmpStr = null;
			if (srcStr.getBytes(charsetName).length <= (tmpColSplitLen - colSplitLen)
					* firstBlobkLen) {
				for (int k = colSplitLen; k < tmpColSplitLen; k++) {
					tmpStr = subStrMethod(srcStr, firstBlobkLen, charsetName);
					if (tmpStr == null) {
						break;
					}
					if (isLastBlock || splitNum == 1) {
						resultArray[k][tmpSplitNum - splitNum] = new String(
								tmpStr + lineSplit);
					} else {
						resultArray[k][tmpSplitNum - splitNum] = new String(
								tmpStr + blockSplitStr);
					}
					if (srcStr == null || srcStr.length() == 0) {
						srcStr = new String();
						break;
					}
					srcStr = new String(srcStr.substring(tmpStr.length()));
				}
			}
			splitNum = splitNum - 1;
			if (splitNum == 0 && srcStr.length() > 0) {
				splitNum = tmpSplitNum;
				tmpValue = null;
				lastBlockLen = 0;
				for (int i = 0; i < resultArray.length; i++) {
					for (int j = 0; j < resultArray[i].length; j++) {
						tmpValue = resultArray[i][j];
						if (tmpValue != null && tmpValue.length() > 0) {
							resultStr.append(resultArray[i][j]);
						}
					}
				}
				resultStr.append(splitStr).append(lineSplit);
				resultArray = new String[tmpColSplitLen][tmpSplitNum];
			}
		}
		tmpValue = null;
		// 修正数组的值
		for (int i = 0; i < resultArray.length; i++) {
			for (int j = 0; j < resultArray[i].length; j++) {
				tmpValue = resultArray[i][j];
				if (tmpValue != null && tmpValue.length() > 0
						&& (i + 1 < tmpColSplitLen) && (j >= 1)
						&& (resultArray[i + 1][j] == null)) {
					for (int k = i + 1; k < resultArray.length; k++) {
						resultArray[k][j - 1] = new String(
								resultArray[k][j - 1] + lineSplit);
					}
					break;
				}
			}
		}
		tmpValue = null;
		// 得到数组的值
		for (int i = 0; i < resultArray.length; i++) {
			for (int j = 0; j < resultArray[i].length; j++) {
				tmpValue = resultArray[i][j];
				if (tmpValue != null && tmpValue.length() > 0) {
					resultStr.append(resultArray[i][j]);
				}
			}
		}
		resultStr.append(splitStr);
		return resultStr.toString();
	}

	public static void main(String[] args) throws Exception {
		文件按列写 t = new 文件按列写();
		String testStr = t.generateTestData(63);
		String splitStr = "-------------------------------我是分隔符------------------------------";
		//90 每行90字节
		//4 分割4列
		//5 列之间5个空格
		//14 每列14个字节
		String content = t.getStrBySplitNum(testStr, "utf-8", 90, 4, 5, 14,
				splitStr);
		t.writeContentToFile(content, "f:/saveFile/temp/result.txt", "utf-8");
	}
}

  

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