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Java 文本到数字格式IPv4

欢马劈雪

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文本到数字格式IPv4

实例源码：

源代码：

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//来自 N o  w  J a v a . c o m - 时  代  Java

* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

* This code is free software; you can redistribute it and/or modify it

* under the terms of the GNU General Public License version 2 only, as

* published by the Free Software Foundation.  Oracle designates this

* particular file as subject to the "Classpath" exception as provided

* by Oracle in the LICENSE file that accompanied this code.

* This code is distributed in the hope that it will be useful, but WITHOUT

* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

* version 2 for more details (a copy is included in the LICENSE file that

* accompanied this code).

* You should have received a copy of the GNU General Public License version

* 2 along with this work; if not, write to the Free Software Foundation,

* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

* or visit www.oracle.com if you need additional information or have any

* questions.

//package com.nowjava;

public class Main {

public static void main(String[] argv) throws Exception {

String src = "nowjava.com";

System.out.println(java.util.Arrays

.toString(textToNumericFormatV4(src)));

}

private static final int INADDR4SZ = 4;

@SuppressWarnings("fallthrough")

public static byte[] textToNumericFormatV4(String src) {

byte[] res = new byte[INADDR4SZ];

long tmpValue = 0;

int currByte = 0;

boolean newOctet = true;/* 来 自 nowjava.com - 时  代  Java*/

int len = src.length();

if (len == 0 || len > 15) {

return null;

}

* When only one part is given, the value is stored directly in

* the network address without any byte rearrangement.

* When a two part address is supplied, the last part is

* interpreted as a 24-bit quantity and placed in the right

* most three bytes of the network address. This makes the

* two part address format convenient for specifying Class A

* network addresses as net.host.

* When a three part address is specified, the last part is

* interpreted as a 16-bit quantity and placed in the right

* most two bytes of the network address. This makes the

* three part address format convenient for specifying

* Class B net- work addresses as 128.net.host.

* When four parts are specified, each is interpreted as a

* byte of data and assigned, from left to right, to the

* four bytes of an IPv4 address.

* We determine and parse the leading parts, if any, as single

* byte values in one pass directly into the resulting byte[],

* then the remainder is treated as a 8-to-32-bit entity and

* translated into the remaining bytes in the array.

for (int i = 0; i < len; i++) {

char c = src.charAt(i);

if (c == '.') {

if (newOctet || tmpValue < 0 || tmpValue > 0xff

|| currByte == 3) {

return null;

}

res[currByte++] = (byte) (tmpValue & 0xff);

tmpValue = 0;

newOctet = true;

} else {

int digit = Character.digit(c, 10);

if (digit < 0) {
/**代码未完, 请加载全部代码(NowJava.com).**/

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本文系作者在时代Java发表，未经许可，不得转载。如有侵权，请联系nowjava@qq.com删除。

编辑于 2020-03-26 09:23:272020-03-26 09:23:27

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