byte[] data1="hello world".getBytes();
byte[] data2 = "2000".getBytes();
byte[] data3 = new byte[data1.length+data2.length];
System.arraycopy(data1,0,data3,0,data1.length);
System.out.println(new String(data3));
//1.要拷贝复制的原始数据
//2.原始数据的读取位置(从原始数据哪个位置开始拷贝)
//3.存放要拷贝的原始数据的目的地
//4.开始存放的位置()
//5.要读取的原始数据长度(拷贝多长)
System.arraycopy(data2,0,data3,data1.length,data2.length);
System.out.println(new String(data3));
System.out.println(data2.length);
byte[] head = new byte[data2.length];
//拷贝data3的后4位到head中
System.arraycopy(data3,data3.length-4,head,0,head.length);
System.out.println(new String(head));
输出结果:
hello world
hello world2000
4
2000