File read and write summary

Txt file for read and write operations shown in FIG:

(1) according byte read, read one byte:

File = File new new File ( "C: \\ named text.txt in" );   
        the InputStream in = null ;  
         the try {   
            System.out.println ( "bytes to read the contents of a file, read one byte at:" );  
             // read one byte at   
            in = new new the FileInputStream (File);  
             int tempbyte;  
             the while ((tempbyte = in.read ()) = -1! ) {   
                System.out.println (tempbyte);   
            }   
            in.close () ;   
        } the catch (IOException E) {   
            e.printStackTrace ();   
        }  

（2）按照字节读取，一次读取多个字节：

File file = new File("C:\\text.txt");
InputStream in = null;
try {
System.out.println("以字节为单位读取文件内容，一次读多个字节：");
// 一次读多个字节
byte[] tempbytes = new byte[5];
int byteread = 0;
in = new FileInputStream(file);
// 读入多个字节到字节数组中，byteread为一次读入的字节数
while ((byteread = in.read(tempbytes)) != -1) {
for(int i=0;i<byteread;i++){
if(tempbytes[i]!=0){
System.out.print(tempbytes[i]+" ");
}
}
System.out.println();
}
} catch (Exception e1) {
e1.printStackTrace();
} finally {
if (in != null) {
try {
in.close();
} catch (IOException e1) {
}
}
}

（3）以字符为单位读取文件，一次读取一个字符：

File file = new File("C:\\text.txt");  
        Reader reader = null;  
        try {  
            System.out.println("以字符为单位读取文件内容，一次读一个字节：");  
            // 一次读一个字符  
            reader = new InputStreamReader(new FileInputStream(file));  
            int tempchar;  
            while ((tempchar = reader.read()) != -1) {  
                // 对于windows下，\r\n这两个字符在一起时，表示一个换行。  
                // 但如果这两个字符分开显示时，会换两次行。  
                // 因此，屏蔽掉\r，或者屏蔽\n。否则，将会多出很多空行。  
                if (((char)tempchar) != '\r') {  
                    System.out.print((char)tempchar);  
                }  
            }  
            reader.close();  
        } catch (Exception e) {  
            e.printStackTrace();  
        }  

 

（4）以字符为单位读取文件，一次读取多个字符：

File file = new File("C:\\text.txt");  
        Reader reader = null;  
        try {  
            System.out.println("以字符为单位读取文件内容，一次读多个字节：");  
            // 一次读多个字符  
            char[] tempchars = new char[30];  
            int charread = 0;  
            reader = new InputStreamReader(new FileInputStream(file));  
            // 读入多个字符到字符数组中，charread为一次读取字符数  
            while ((charread = reader.read(tempchars)) != -1) {  
                // 同样屏蔽掉\r不显示  
                if ((charread == tempchars.length)  
                        && (tempchars[tempchars.length - 1] != '\r')) {  
                    System.out.print(tempchars);  
                } else {  
                    for (int i = 0; i < charread; i++) {  
                        if (tempchars[i] == '\r') {  
                            continue;  
                        } else {  
                            System.out.print(tempchars[i]);  
                        }  
                    }  
                }  
            }  
  
        } catch (Exception e1) {  
            e1.printStackTrace();  
        } finally {  
            if (reader != null) {  
                try {  
                    reader.close();  
                } catch (IOException e1) {  
                }  
            }  
        }  

 （5）以行为单位读取文件:

File file = new File("C:\\text.txt");  
        BufferedReader reader = null;  
        try {  
            System.out.println("以行为单位读取文件内容，一次读一整行：");  
            reader = new BufferedReader(new FileReader(file));  
            String tempString = null;  
            int line = 1;  
            // 一次读入一行，直到读入null为文件结束  
            while ((tempString = reader.readLine()) != null) {  
                // 显示行号  
                System.out.println("line " + line + ": " + tempString);  
                line++;  
            }  
            reader.close();  
        } catch (IOException e) {  
            e.printStackTrace();  
        } finally {  
            if (reader != null) {  
                try {  
                    reader.close();  
                } catch (IOException e1) {  
                }  
            }  
        }  

（6）对于一个英语句子，可以用正则表达式：

String[] words = string.split("[^(a-zA-Z)]+");
来将句子转化为英文单词组成的数组。