62 lines
1.8 KiB
Java
62 lines
1.8 KiB
Java
/*
|
|
* Copyright 2017 Hippo Seven
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
package com.hippo.util;
|
|
/*
|
|
* Created by Hippo on 2017/9/4.
|
|
*/
|
|
|
|
public class HashCodeUtils {
|
|
|
|
private static final int X = 31;
|
|
|
|
/**
|
|
* <pre>{@code
|
|
* args[0].hashCode()*31^(n-1) + args[1].hashCode()*31^(n-2) + ... + args[n-1].hashCode()
|
|
* }</pre>
|
|
* Returns 0 if {@code args == null}.
|
|
*/
|
|
public static int hashCode(Object... args) {
|
|
if (args == null) {
|
|
return 0;
|
|
}
|
|
int hash = 0;
|
|
for (Object o : args) {
|
|
hash = X * hash + (o != null ? o.hashCode() : 0);
|
|
}
|
|
return hash;
|
|
}
|
|
|
|
/**
|
|
* http://stackoverflow.com/questions/332079
|
|
*
|
|
* @param bytes The bytes to convert.
|
|
* @return A {@link String} converted from the bytes of a hashable key used
|
|
* to store a filename on the disk, to hex digits.
|
|
*/
|
|
public static String bytesToHexString(final byte[] bytes) {
|
|
final StringBuilder builder = new StringBuilder();
|
|
for (final byte b : bytes) {
|
|
final String hex = Integer.toHexString(0xFF & b);
|
|
if (hex.length() == 1) {
|
|
builder.append('0');
|
|
}
|
|
builder.append(hex);
|
|
}
|
|
return builder.toString();
|
|
}
|
|
}
|