Node.js Buffer模块功能及常用方法实例分析

var buf = Buffer.alloc(10);

var buf = Buffer.alloc(10,0xff);//可以为十六进制的数据

buf = Buffer.allocUnsafe(10);
buf.fill(0);

buf = Buffer.allocUnsafeSlow(10);

buf = Buffer.from("HelloWorld!");//from(array)
console.log(buf);
buf = Buffer.from([123,22,24,36]);
console.log(buf);
//重建一个buffer，把原来Buffer的数据拷贝给新的buffer
buf2 = Buffer.from(buf);
console.log(buf2);
//buf[index] index取值范围[0,len-1]
console.log(buf[0],buf[1]);

//以大尾的形式存放,4个字节的整数
buf.writeInt32BE(65535,0);
console.log(buf);
//以小尾的方式写入
buf.writeInt32LE(65535,0);
console.log(buf);

var value = buf.readInt32LE(0);
console.log(value);
buf.writeFloatLE(3.16,0);
console.log(buf.readFloatLE(0));

//读取长度
var len = Buffer.byteLength("HelloWorld");
console.log(len);
buf = Buffer.alloc(4*4);
buf.writeInt32LE(65535,0);
buf.writeInt32LE(65535,4);
buf.writeInt32LE(65535,8);
buf.writeInt32LE(65535,12);
console.log(buf);
buf.swap32();
console.log(buf);
//用高位的方式读取
console.log(buf.readInt32BE(0));
console.log(buf.readInt32BE(4));
console.log(buf.readInt32BE(8));
console.log(buf.readInt32BE(12));
for (var i of buf.values()) {
  console.log(i);
}

//以二进制方式转为字符串
console.log(buf.toString('hex'));
console.log(buf.toJSON());
buf.fill('A');
console.log(buf);
console.log(buf.toString('utf8'));