48-天亮大数据经典大数据笔试题系列之工具类之IO操作

• 工具类意义描述
  • IO操作是最典型、最常用的技术之一，在绝大多数项目开发当中均会有所涉及，故工具之。
• 代码实现

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;

import org.apache.log4j.Logger;

/**
 * I/O操作工具类
 * 
 * @author zel
 * 
 */
public class IOUtil {
	private static Logger logger = Logger.getLogger(IOUtil.class);

	public static String readDirOrFile(String filePath, String fileEncoding) {
		File f = new File(filePath);
		String temp = "";
		if (f.isDirectory()) {
			File[] files = f.listFiles();
			for (File temp_file : files) {
				temp += readDirOrFile(temp_file.getAbsolutePath(), fileEncoding);
			}
			return temp;
		}
		return readFile(filePath, fileEncoding);
	}

	public static ArrayList<String> readDirOrFileToList(String filePath,
			String fileEncoding, ArrayList<String> linkList) {
		File f = new File(filePath);
		if (f.isDirectory()) {
			File[] files = f.listFiles();
			for (File temp_file : files) {
				linkList.add(readFileWithRegexFilter(
						temp_file.getAbsolutePath(), fileEncoding));
			}
			return linkList;
		} else {
			linkList.add(readFileWithRegexFilter(filePath, fileEncoding));
		}
		return linkList;
	}

	/**
	 * fileEncoding若为null,则采用系统默认编码
	 * 
	 * @param filePath
	 * @param fileEncoding
	 * @return
	 */
	public static String readFile(String filePath, String fileEncoding) {
		if (fileEncoding == null) {
			fileEncoding = System.getProperty("file.encoding");
		}
		File file = new File(filePath);
		BufferedReader br = null;

		String line = null;

		StringBuilder sb = new StringBuilder();

		try {
			br = new BufferedReader(new InputStreamReader(new FileInputStream(
					file), fileEncoding));
			while ((line = br.readLine()) != null) {
				sb.append(line + "\n");
			}
			return sb.toString();
		} catch (Exception e) {
			logger.info(e.getLocalizedMessage());
		} finally {
			if (br != null) {
				try {
					br.close();
				} catch (IOException e) {
					logger.info(e.getLocalizedMessage());
					logger.info("关闭IOUtil流时出现错误!");
				}
			}
		}
		return null;
	}

	// 将按行读出的字符串，统一加入到set中，直接去重
	public static Set<String> readFileToSet(String filePath, String fileEncoding) {
		if (fileEncoding == null) {
			fileEncoding = System.getProperty("file.encoding");
		}
		File file = new File(filePath);
		BufferedReader br = null;

		String line = null;

		Set<String> lineSet = new HashSet<String>();

		try {
			br = new BufferedReader(new InputStreamReader(new FileInputStream(
					file), fileEncoding));
			while ((line = br.readLine()) != null) {
				line = line.trim();
				if (StringOperatorUtil.isNotBlank(line) && (!line.startsWith("#"))) {
					lineSet.add(line);
				}
			}
			return lineSet;
		} catch (Exception e) {
			logger.info(e.getLocalizedMessage());
		} finally {
			if (br != null) {
				try {
					br.close();
				} catch (IOException e) {
					logger.info(e.getLocalizedMessage());
					logger.info("关闭IOUtil流时出现错误!");
				}
			}
		}
		return null;
	}

	public static String readFile(String filePath, String fileEncoding,
			long begin_line_number, long end_line_number) {
		if (fileEncoding == null) {
			fileEncoding = System.getProperty("file.encoding");
		}
		File file = new File(filePath);
		BufferedReader br = null;

		String line = null;

		StringBuilder sb = new StringBuilder();

		try {
			br = new BufferedReader(new InputStreamReader(new FileInputStream(
					file), fileEncoding));
			int i = 0;
			// 空读完前边的行
			while (i < begin_line_number && (line = br.readLine()) != null) {
				i++;
			}

			while ((line = br.readLine()) != null
					&& begin_line_number < end_line_number) {
				sb.append(line + "\n");
				begin_line_number++;
			}
			// System.out.println("line---"+line);
			return sb.toString();
		} catch (Exception e) {
			logger.info(e.getLocalizedMessage());
		} finally {
			if (br != null) {
				try {
					br.close();
				} catch (IOException e) {
					logger.info(e.getLocalizedMessage());
					logger.info("关闭IOUtil流时出现错误!");
				}
			}
		}
		return null;
	}

	public static List<String> readFileToList(String filePath,
			String fileEncoding, long begin_line_number, long end_line_number) {
		if (fileEncoding == null) {
			fileEncoding = System.getProperty("file.encoding");
		}
		File file = new File(filePath);
		BufferedReader br = null;

		String line = null;

		List<String> list = new ArrayList<String>();

		try {
			br = new BufferedReader(new InputStreamReader(new FileInputStream(
					file), fileEncoding));
			int i = 0;
			// 空读完前边的行
			while (i < begin_line_number && (line = br.readLine()) != null) {
				i++;
			}

			while ((line = br.readLine()) != null
					&& begin_line_number < end_line_number) {
				list.add(line);
				begin_line_number++;
			}
		} catch (Exception e) {
			logger.info(e.getLocalizedMessage());
		} finally {
			if (br != null) {
				try {
					br.close();
				} catch (IOException e) {
					logger.info(e.getLocalizedMessage());
					logger.info("关闭IOUtil流时出现错误!");
				}
			}
		}
		return list;
	}

	public static String readFileWithRegexFilter(String filePath,
			String fileEncoding) {
		if (fileEncoding == null) {
			fileEncoding = System.getProperty("file.encoding");
		}
		File file = new File(filePath);
		BufferedReader br = null;

		String line = null;

		StringBuilder sb = new StringBuilder();

		try {
			br = new BufferedReader(new InputStreamReader(new FileInputStream(
					file), fileEncoding));
			while ((line = br.readLine()) != null) {
				sb.append(line + "\n");
			}
			return sb.toString();
		} catch (Exception e) {
			logger.info(e.getLocalizedMessage());
		} finally {
			if (br != null) {
				try {
					br.close();
				} catch (IOException e) {
					logger.info(e.getLocalizedMessage());
					logger.info("关闭IOUtil流时出现错误!");
				}
			}
		}
		return null;
	}

	/**
	 * 将一个字符串写入到一个文件
	 * 
	 * @param path
	 *            储存的文件路径
	 * @param value
	 *            储存的文件内容
	 * @throws IOException
	 */
	public static void writeFile(String path, String value, String encoding) {
		File f = new File(path);
		FileOutputStream fos = null;

		// 文件路径的父路径是否存在做判断
		FileOperatorUtil.createParentDirFromFile(path);

		try {
			fos = new FileOutputStream(f);
			fos.write(value.getBytes(encoding));
			fos.close();
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if (fos != null) {
				try {
					fos.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
	}

	/**
	 * 以追加的方式向文件中写入
	 * 
	 * @param path
	 * @param value
	 */
	public static void writeFile(String path, String value, boolean isAppend,
			String encoding) {
		File f = new File(path);
		// 排除其父目录不存在的情况
		FileOperatorUtil.createParentDirFromFile(path);
		FileOutputStream fos = null;
		try {
			if (isAppend) {
				fos = new FileOutputStream(f, isAppend);
			} else {
				fos = new FileOutputStream(f);
			}
			fos.write(value.getBytes(encoding));
			fos.close();
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if (fos != null) {
				try {
					fos.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
	}

	public static List<String> tranBatchLineToList(String source) {
		if (source == null || source.isEmpty()) {
			return null;
		}
		List<String> lineList = new LinkedList<String>();
		StringReader sb = new StringReader(source);
		BufferedReader br = new BufferedReader(sb);

		String temp_line = null;
		try {
			while ((temp_line = br.readLine()) != null) {
				lineList.add(temp_line);
			}
			br.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return lineList;
	}

	public static List<String> getLineArrayFromFile(String path, String encoding) {
		String keywordString = readDirOrFile(path, encoding);
		List<String> lineArray = new LinkedList<String>();

		try {
			String temp_line = null;
			StringReader sr = new StringReader(keywordString);
			BufferedReader br = new BufferedReader(sr);
			while ((temp_line = br.readLine()) != null) {
				if (!temp_line.startsWith("#")) {
					lineArray.add(temp_line);
				}
			}
			br.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return lineArray;
	}

	// 得到某个文件的bufferedReader流
	public static BufferedReader getBufferedReader(String filePath,
			String encoding) {
		BufferedReader br = null;
		try {
			FileInputStream fis = new FileInputStream(new File(filePath));
			br = new BufferedReader(new InputStreamReader(fis, encoding));
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		}
		return br;
	}

	public static void closeReader(Reader reader) {
		if (reader != null) {
			try {
				reader.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}

	/**
	 * 读取指定文件的若干行，并转化为List集合
	 * 
	 * @param path
	 * @param encoding
	 * @param begin_number
	 * @param line_length
	 * @return
	 */
	public static List<String> getLineArrayFromFile(String path,
			String encoding, long begin_line_number, int line_length,
			boolean isOnlyColumn) {
		long end_line_number = begin_line_number + line_length;
		String keywordString = readFile(path, StaticValue.default_encoding,
				begin_line_number, end_line_number);

		List<String> lineArray = new LinkedList<String>();
		String[] strArray = null;
		try {
			String temp_line = null;
			StringReader sr = new StringReader(keywordString);
			BufferedReader br = new BufferedReader(sr);

			if (isOnlyColumn) {
				while ((temp_line = br.readLine()) != null) {
					if (StringOperatorUtil.isNotBlank(temp_line)) {
						lineArray.add(temp_line);
					}
				}
			} else {
				while ((temp_line = br.readLine()) != null) {
					strArray = temp_line.split(StaticValue.separator_tab);
					if (strArray.length >= 2) {
						lineArray.add(strArray[0]);
					}
				}
			}
			br.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return lineArray;
	}

	/**
	 * 得到指定的文本的指定的行内容
	 * 
	 * @param path
	 * @param encoding
	 * @param begin_line_number
	 * @param line_length
	 * @param isOnlyColumn
	 * @return
	 */
	public static List<String> getLineArrayFromFile(String path,
			String encoding, long begin_line_number, int line_length) {
		long end_line_number = begin_line_number + line_length;

		return readFileToList(path, encoding, begin_line_number,
				end_line_number);
	}

	public static List<String> tranBatchLineToList(String source,
			int begin_line_number, int end_line_number) {
		if (source == null || source.isEmpty()) {
			return null;
		}
		List<String> lineList = new LinkedList<String>();
		StringReader sb = new StringReader(source);
		BufferedReader br = new BufferedReader(sb);

		String temp_line = null;
		try {
			int i = 0;
			// 空读完前边的行
			while (i < begin_line_number && (temp_line = br.readLine()) != null) {
				i++;
			}
			while ((temp_line = br.readLine()) != null
					&& begin_line_number < end_line_number) {
				lineList.add(temp_line);
				begin_line_number++;
			}
			br.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return lineList;
	}

	public static String tranSetToString(Set<String> strSet) {
		if (strSet == null || strSet.isEmpty()) {
			return null;
		}
		StringBuilder sb = new StringBuilder();
		for (String line : strSet) {
			sb.append(line + StaticValue.separator_next_line);
		}
		return sb.toString();
	}

	public static String tranListToString(List list) {
		if (list == null || list.isEmpty()) {
			return null;
		}
		StringBuilder sb = new StringBuilder();
		for (Object line : list) {
			if (line.toString().trim().length() > 0) {
				sb.append(line);
			}
		}
		return sb.toString();
	}

	public static String tranSetToStringWithFixNature(Set<String> strSet) {
		if (strSet == null || strSet.isEmpty()) {
			return null;
		}
		StringBuilder sb = new StringBuilder();
		for (String line : strSet) {
			// sb.append(line +
			// StaticValue.separator_tab+StaticValue.default_nature+StaticValue.separator_tab+StaticValue.default_term_freq+
			// StaticValue.separator_next_line);
		}
		return sb.toString();
	}

	public static void main(String[] args) throws Exception {
		// String source=readFile("resource/library.dic",null);
		// String source = readFile(ReadConfigUtil.getValue("dic.path"), null);
		// String source = readDirOrFile("d://temp", "gbk");
		// System.out.println(source);

		String source_string = IOUtil.readFile("d:\\test\\new_words2.txt",
				"utf-8");
		StringReader sr = new StringReader(source_string);
		BufferedReader br = new BufferedReader(sr);
		String temp = null;
		StringBuilder sb = new StringBuilder();

		HashSet<String> hashSet = new HashSet<String>();

		while ((temp = br.readLine()) != null) {
			if (temp.trim().length() > 1 && temp.trim().length() <= 4) {
				if (!hashSet.contains(temp)) {
					sb.append(temp + "\n");
				} else {
					hashSet.add(temp);
				}
			}
		}
		IOUtil.writeFile("d:\\test\\new_words3.txt", sb.toString(),
				StaticValue.default_encoding);
	}
}

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