java 的输入/输出

字符的写入与读取

// 文件读操作
String readname = "E:/study/io/readname.txt"; // 指定绝对路径    

try {
    FileReader reader = new FileReader(readname);
    BufferedReader br = new BufferedReader(reader);
    String line;
    while((line = br.readLine()) != null) {
        System.out.println("---------------------");
        System.out.println(line);
        System.out.println("+++++++++++++++++++++");
    }
    br.close();
}catch(FileNotFoundException e) {
    e.printStackTrace();
}catch(IOException e) {
    e.printStackTrace();
}catch(Exception e) {
    e.printStackTrace();
}

// 文件写操作
String writeFileName = "writeFileName.txt"; // 在项目工程目录生成

try{
    File writeName = new File(writeFileName);
    writeName.createNewFile();
    FileWriter write = new FileWriter(writeName);
    BufferedWriter out = new BufferedWriter(write);
    out.write("好的\r\n");
    out.write("\r\n");
    out.write("test\r\n");
    out.write("");
    out.write("end");
    out.flush();
}catch(IOException e) {
    e.printStackTrace();
}

字节的写入与读取

// 字节写入
File f = new File("E:/study/io/outputStream.txt");
try {
    FileOutputStream out = new FileOutputStream(f);
    String[] str = {"Hello,it is\r\n","你好\r\n","是的\r\n"};
    for(String s:str) {
        byte[] b = s.getBytes();
        out.write(b);
    }
    out.close();
}catch(IOException e) {
    e.printStackTrace();
}catch(Exception e) {
    e.printStackTrace();
}

// 字节输出
File f = new File("E:/study/io/readname.txt");
try {
    FileInputStream in = new FileInputStream(f);
    byte[] b = new byte[102400000];
    int temp = 0;
    int len = 0;
    while((temp = in.read()) != -1) {
        b[len] = (byte) temp;
        len++;
    }
    in.close();
    System.out.println(new String(b,0,len));
}catch(FileNotFoundException e) {
    e.printStackTrace();
}catch(IOException e) {
    e.printStackTrace();
}