java写入文件(txt)

FileOutputStream
public class FileOutputStream extends OutputStream
构造方法:
FileOutputStream(File file)
FileOutputStream(File file, boolean append)
FileOutputStream(FileDescriptor fdObj)
FileOutputStream(String name)
FileOutputStream(String name, boolean append)

File file=new File("C:\\Test\\Java\\12.txt");
try {
    //FileOutputStream  fos=new FileOutputStream(file,true);
	FileOutputStream  fos=new FileOutputStream("C:\\Test\\Java\\12.txt",true);//默认是false(覆盖文件中以前的内容)
    //String st="10ssssssssss"+System.getProperty("line.separator");
	byte b[]=new String("\r\n9,四十四,22").getBytes("GBK");
    //byte[] b=st.getBytes("GBK");
	for(int i=0;i<b.length;i++){
		fos.write(b[i]);
	}
	fos.close();
} catch (FileNotFoundException e) {
	// TODO Auto-generated catch block
	e.printStackTrace();
} catch (UnsupportedEncodingException e) {
	// TODO Auto-generated catch block
	e.printStackTrace();
} catch (IOException e) {
	// TODO Auto-generated catch block
	e.printStackTrace();
}

OutputStreamWriter
public class OutputStreamWriter extends Writer
构造方法:
OutputStreamWriter(OutputStream out)
OutputStreamWriter(OutputStream out, Charset cs)
OutputStreamWriter(OutputStream out, CharsetEncoder enc)
OutputStreamWriter(OutputStream out, String charsetName)

try {
	OutputStreamWriter osw=new OutputStreamWriter(new FileOutputStream("C:\\Test\\Java\\12.txt",false),"GBK");
	osw.write("QQQAAAAAAAAAsssssssssssssssssssssssss开始"+System.getProperty("line.separator"));
	osw.write("QQQAAAAAAAAAsssssssssssssssssssssssss结束\r\n");
	osw.close();
} catch (FileNotFoundException e) {
	// TODO Auto-generated catch block
	e.printStackTrace();
} catch (IOException e) {
	// TODO Auto-generated catch block
	e.printStackTrace();
}

FileWriter
public class FileWriter extends OutputStreamWriter
构造方法:
FileWriter(File file)
FileWriter(File file, boolean append)
FileWriter(FileDescriptor fd)
FileWriter(String fileName)
FileWriter(String fileName, boolean append)
存在乱码问题，未解决

try {
	FileWriter fw=new FileWriter("C:\\Test\\Java\\12.txt",true);
	fw.write("\r\n在哪里abc");
	fw.close();
} catch (IOException e) {
	// TODO Auto-generated catch block
	e.printStackTrace();
}

BufferedWriter[推荐使用]
public class BufferedWriter extends Writer
构造方法:
BufferedWriter(Writer out)
BufferedWriter(Writer out, int sz)

try {
	BufferedWriter bw=new BufferedWriter(new OutputStreamWriter(new FileOutputStream("C:\\Test\\Java\\12.txt",true), "GBK"));
    //BufferedWriter bw=new BufferedWriter(new FileWriter("C:\\Test\\Java\\12.txt",true));
	bw.write("\r\n我是中国人oy");
	bw.close();
} catch (UnsupportedEncodingException e) {
	// TODO Auto-generated catch block
	e.printStackTrace();
} catch (FileNotFoundException e) {
	// TODO Auto-generated catch block
	e.printStackTrace();
} catch (IOException e) {
	// TODO Auto-generated catch block
	e.printStackTrace();
}