1、FileInputStream（）
// 构建字节输入流对象，参数为文件名
FileInputStream fin = new FileInputStream("message");
System.out.println("输入流可读入字节数：" + fin.available());
// 建立byte型数组b,从输入流读取的数据暂时存放在b中
byte b[] = new byte[fin.available()];
// 从输入流读取数据
fin.read(b);
String str5=new String(b);
System.out.println(str5);
// 关闭输入流，对文件的操作，一定要在最后关闭输入输出流
fin.close();
2、RandomAccessFile（）
String str6="";
ArrayList<String> strs=new ArrayList<String>();
RandomAccessFile file=new RandomAccessFile("message","r");
str6 = file.readLine();
while(str6!=null){
strs.add(str6);
str6 = file.readLine();
}
for(int j=0;j<strs.size();j++){
System.out.println(strs.get(j));
}
file.close();
3、File
File file2=new File("message");
if(file2.exists()&&file2.isFile()){
InputStream is=new FileInputStream(file2);
byte[] buf = new byte[is.available()];
System.out.println(is.available());
while(is.read(buf)!=-1){
//每次读取打印
System.out.println(new String(buf));
}
}
4、避免乱码
File file3 = new File("message");
if (file3.exists() && file3.isFile()) {
try {
InputStream is = new FileInputStream(file3);
InputStreamReader reader = new InputStreamReader(is,"utf-8");//
char[] cbuf = new char[is.available()];//字符，字节
StringBuffer sb2=new StringBuffer();//2
while (reader.read(cbuf) != -1) {
sb2.append(cbuf);
}
System.out.println(sb2.toString());
} catch (Exception e) {
}
}
5、BufferedReader
File file = new File("message");
try {
InputStream is = new FileInputStream(file);
if (file.exists() && file.isFile()) {
BufferedReader br = new BufferedReader(
new InputStreamReader(is, "utf-8"));
StringBuffer sb2 = new StringBuffer();
String line = null;
while ((line = br.readLine()) != null) {
sb2.append(line + "\n");
}
br.close();
System.out.println(sb2.toString());
}
} catch (Exception e) {
}