可以通过字节流（FileOutputStream）、字符流（OutputStreamWriter）、字符缓冲流（BufferedWriter）读取文本中的数据。

FileOutputStream写入文本

    public void write(){
        String path = "writeTest.txt";
        //File file = new File(path);
        FileOutputStream output = null;
        try {
            // 设置为true的时候，表示在文末追加
            output = new FileOutputStream(path, true);
            output.write("FileOutputStream write something\r\n".getBytes());
            output.write("FileOutputStream 写中文\r\n".getBytes());
            output.close();

        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            if(output != null){
                try {
                    output.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

运行说明：

1）new FileOutputStream(path, true);设置为true的时候，表示在文末追加

2）换行一定要按顺序写\r\n，少一个或者顺序不对，查看文本的时候都不能正确显示换行

3）如果txt文件一开始没有内容，运行程序写入utf-8编码格式的数据，打开文本可以看到写入的中文正常显示，并且文本的编码变更为utf-8
4）如果一开始文本里面有内容，并且文本的编码格式为GBK，运行程序写入utf-8编码格式的数据，打开文本可以看到写入的中文显示乱码

5）没有append方法

OutputStreamWriter写入文本

    public void write2(){
        String path = "writeTest.txt";
        //File file = new File(path);
        FileOutputStream output = null;
        try {
            // 设置为true的时候，表示在文末追加
             output = new FileOutputStream(path, true);
            OutputStreamWriter writer = new OutputStreamWriter(output, "utf-8");
            writer.append("OutputStreamWriter append something\r\n")
                    .append("OutputStreamWriter 写中文\r\n")
                    .append("OutputStreamWriter append something\r\n");
            writer.write("OutputStreamWriter write something\r\n");
            writer.close();

        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            if(output != null){
                try {
                    output.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
    public void write4(){
        String path = "G:\\学习类\\thread\\doc\\writeTest.txt";
        FileWriter writer;
        try {
            writer = new FileWriter(path, true);
            writer.append("FileWriter append something\r\n")
                    .append("FileWriter 写中文\r\n")
                    .append("FileWriter append something\r\n");
            writer.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

运行说明：

1）append返回writher，可以链式编程
2）write没有返回值，只能一句句执行

3）FileWriter简化字符流的写入，new FileWriter(path, true)等同于new OutputStreamWriter(new FileOutputStream(path, true))

BufferedWriter写入文本

    public void write3(){
        String path = "writeTest.txt";
        FileOutputStream output = null;
        OutputStreamWriter oWriter= null;
        try {
            output = new FileOutputStream(path, true);
            oWriter = new OutputStreamWriter(output, "utf-8");
            BufferedWriter writer = new BufferedWriter(oWriter);
            writer.append("BufferedWriter append something\r\n")
                    .append("BufferedWriter 写中文\r\n")
                    .append("BufferedWriter append something\r\n");
            writer.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            if(output != null){
                try {
                    output.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if(oWriter != null){
                try {
                    oWriter.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
    public void write5(){
        String path = "G:\\学习类\\thread\\doc\\writeTest.txt";
        FileWriter fWriter;
        try {
            fWriter = new FileWriter(path, true);
            BufferedWriter writer = new BufferedWriter(fWriter);
            writer.append("BufferedWriter append something\r\n")
                    .append("BufferedWriter 写中文\r\n")
                    .append("BufferedWriter append something\r\n");
            writer.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

运行说明：

比较快