java Txt文件读写操作 重写内容

package com.test.file;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.ArrayList;
import java.util.List;

public class AppendToFile { 

/**
* 随机访问方式
* @param fileName
* @param content
*/
public static void appendMethodA(String fileName, String content) {
try {
// 打开一个随机访问文件流，按读写方式
RandomAccessFile randomFile = new RandomAccessFile(fileName, "rw");
// 文件长度，字节数
long fileLength = randomFile.length();
// 将写文件指针移到文件尾。
randomFile.seek(fileLength);
randomFile.write(System.getProperty("line.separator").getBytes());
randomFile.write(content.getBytes());
randomFile.close();
} catch (IOException e) {
e.printStackTrace();
}
}

/**
* 追加访问方式
* @param fileName
* @param content
*/
public static void appendMethodB(String fileName, String content) {
try {
// 打开一个写文件器，构造函数中的第二个参数true表示以追加形式写文件
FileWriter writer = new FileWriter(fileName, true);
writer.write(System.getProperty("line.separator"));
writer.write(content);
writer.close();
} catch (IOException e) {
e.printStackTrace();
}
}

public static void rewriteMethodA(String fileName, String content) {
try {
List<String> relist = readFile(fileName, content);
for(String s:relist){

String[] ls =s.split("#");
System.out.println(s +"  ---"+ls.length +"ls:"+ls.toString());
}
// writeFile(fileName, relist);
// 打开一个写文件器，构造函数中的第二个参数true表示以追加形式写文件
// FileWriter writer = new FileWriter(fileName);
// writer.write(System.getProperty("line.separator"));
// writer.write(content);
// writer.close();
} catch (IOException e) {
e.printStackTrace();
}
}

private static void writeFile(String filePath, List<String> list)
            throws IOException {
        File file = new File(filePath);
        if (!file.exists()) {
            file.createNewFile();
        }
        FileOutputStream outputStream = new FileOutputStream(file);
        for (String s : list) {
            outputStream.write(s.getBytes());
        }
        outputStream.close();
    }
private static List<String> readFile(String filePath, String str)throws IOException {
        File file = new File(filePath);
        BufferedReader reader = null;
        List<String> list = new ArrayList<String>();
        reader = new BufferedReader(new FileReader(file));
        String text = reader.readLine();
        while (text != null) {
            if (!text.trim().equals(str)) {
                list.add(text + "\r\n");
            }
            text = reader.readLine();
        }
        reader.close();
        return list;
    }
public static void main(String[] args) throws IOException {
String fileName = "D:\\workspace\\t1.txt";

rewriteMethodA(fileName, "AA");
/*String fileName2 = "D:\\workspace\\t2.txt";
String content = "公民";
//按方法A追加文件 
AppendToFile.appendMethodA(fileName2, content);
AppendToFile.appendMethodA(fileName2, "AA");
//显示文件内容 
ReadFromFile.readFileByLines(fileName2);
//按方法B追加文件 
AppendToFile.appendMethodB(fileName, content);
AppendToFile.appendMethodB(fileName, "ZZ");
//显示文件内容 
ReadFromFile.readFileByLines(fileName);*/
}
}




public class ReadFromFile {

public static void readFileByLines(String fileName) throws IOException {
  File a = new File(fileName);
          if(a.exists()){
           FileInputStream fi = new FileInputStream(a);
           InputStreamReader isr = new InputStreamReader(fi, "GBk");
           BufferedReader bfin = new BufferedReader(isr);
           String rLine = "";
           while((rLine = bfin.readLine())!=null){
            System.out.println(rLine);
           }
          }

}


}