import java.io.BufferedWriter;import java.io.FileOutputStream;import java.io.FileWriter;import java.io.IOException;import java.io.OutputStreamWriter;import java.io.PrintWriter;import java.io.RandomAccessFile;//如果文件存在，则追加内容；如果文件不存在，则创建文件，追加内容的三种方法public class AppendContentToFile {    @SuppressWarnings("static-access")    public static void main(String[] args) {        AppendContentToFile a = new AppendContentToFile();        a.method1();        a.method2("E:\\dd.txt", "222222222222222");        a.method3("E:\\dd.txt", "33333333333");    }    public void method1() {        FileWriter fw = null;        try {            // 如果文件存在，则追加内容；如果文件不存在，则创建文件            File f = new File("E:\\dd.txt");            fw = new FileWriter(f, true);        } catch (IOException e) {            e.printStackTrace();        }        PrintWriter pw = new PrintWriter(fw);        pw.println("追加内容");        pw.flush();        try {            fw.flush();            pw.close();            fw.close();        } catch (IOException e) {            e.printStackTrace();        }    }    public static void method2(String file, String conent) {        BufferedWriter out = null;        try {            out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file, true)));            out.write(conent + "\r\n");        } catch (Exception e) {            e.printStackTrace();        } finally {            try {                out.close();            } catch (IOException e) {                e.printStackTrace();            }        }    }    public static void method3(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.writeBytes(content + "\r\n");            randomFile.close();        } catch (IOException e) {            e.printStackTrace();        }    }}