指定行数读取log文件

1、读取log文件第n行数据：

package ocm.axb.cheney.collection;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.List;
public class ReadLog {
		//将文本读取到List中并返回,path - 文件路径,List - 返回读取文件行的集合
		public static List getFileContent(String path) {
			List strList = new ArrayList();
			try {
				File file = new File(path);
				InputStreamReader read = new InputStreamReader(new FileInputStream(
						file), "UTF-8");
				BufferedReader reader = new BufferedReader(read);
				String line;
				while ((line = reader.readLine()) != null) {
					strList.add(line);
				}
			} catch (UnsupportedEncodingException e) {
				e.printStackTrace();
			} catch (FileNotFoundException e) {
				e.printStackTrace();
			} catch (IOException e) {
				e.printStackTrace();
			}
			return strList;
		}

		//获取指定行的值, path - 文件路径,row - 指定行, String - 返回指定行的数据,没有指定行时数据返回空字符串
		public static String listFileByRow(String path, Integer row) {
			List strList = getFileContent(path);
			int size = strList.size();
			if (size >= (row - 1)) {
				return strList.get(row - 1);
			} else {
				return "";
			}
		}
		
		public static void main(String[] args) {
			int startLine = 45;
			System.out.println("第" + startLine + "行："
					+ listFileByRow("E:\\db\\log4j_iws.log", startLine));
		}
}

2、读取log文件第n行到第n+m行数据：

package ocm.axb.cheney.collection;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.List;

public class ReadLog {
	// 将文本读取到List中并返回,path - 文件路径,List - 返回读取文件行的集合
	public static List getFileContent(String path) {
		List strList = new ArrayList();
		try {
			File file = new File(path);
			InputStreamReader read = new InputStreamReader(new FileInputStream(
					file), "UTF-8");
			BufferedReader reader = new BufferedReader(read);
			String line;
			while ((line = reader.readLine()) != null) {
				strList.add(line);
			}
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return strList;
	}

	public static List listFileByRegionRow(String path,
			Integer startLine, Integer endLine) {
		List strList = getFileContent(path);
		// 指定区间的值存到regionList
		List regionList = new ArrayList();
		int size = strList.size();
		// 次方法获取的是第几行到第几行的数据
		if (size >= (endLine - 1)) {
			for (int i = startLine; i <= endLine; i++)
				regionList.add(strList.get(i - 1));
		}
		return regionList;
	}

	public static void main(String[] args) {
		//读取log文件第65行到70行的数据
		int startLine = 65, endLine = 70;
		List regionList = listFileByRegionRow("E:\\db\\log4j_iws.log",
				startLine, endLine);
		if (!regionList.isEmpty()) {
			for (String strLine : regionList) {
				System.out.println("第" + startLine + "行：" + strLine);
				startLine++;
			}
		}

	}
}

3、执行读取log文件最后n行数据：

package ocm.axb.cheney.collection;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.List;

public class ReadLog {
	// 将文本读取到List中并返回,path - 文件路径,List - 返回读取文件行的集合
	public static List getFileContent(String path) {
		List strList = new ArrayList();
		try {
			File file = new File(path);
			InputStreamReader read = new InputStreamReader(new FileInputStream(
					file), "UTF-8");
			BufferedReader reader = new BufferedReader(read);
			String line;
			while ((line = reader.readLine()) != null) {
				strList.add(line);
			}
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return strList;
	}

	public static List listFileByRegionRow(String path, Integer endLine) {
		List strList = getFileContent(path);
		// 指定区间的值存到regionList
		List regionList = new ArrayList();
		int size = strList.size();
		// 此处获取的是log最后多少行数据
		if (size >= endLine) {
			for (int i = size - endLine - 1; i < size; i++) {
				regionList.add(strList.get(i));
			}
		}
		return regionList;
	}

	public static void main(String[] args) {
		// 读取log文件最后5行数据
		int lastLine = 5;
		List regionList = listFileByRegionRow("E:\\db\\log4j_iws.log",
				lastLine);
		if (!regionList.isEmpty()) {
			for (String strLine : regionList) {
				System.out.println(strLine);
			}
		}

	}
}