Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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 txyd.util; import java.io.UnsupportedEncodingException; import java.util.Collection; /** * Converts String to and from bytes using the encodings required by the Java specification. These encodings are specified in <a * href="http://java.sun.com/j2se/1.4.2/docs/api/java/nio/charset/Charset.html">Standard charsets</a> * * @author <a href="mailto:ggregory@seagullsw.com">Gary Gregory</a> * @version $Id: StringUtils.java 801391 2009-08-05 19:55:54Z ggregory $ * @see CharEncoding * @see <a href="http://java.sun.com/j2se/1.4.2/docs/api/java/nio/charset/Charset.html">Standard charsets</a> * @since 1.4 */ public class StringUtils extends org.apache.commons.lang3.StringUtils { /** * Encodes the given string into a sequence of bytes using the ISO-8859-1 charset, storing the result into a new * byte array. * * @param string the String to encode * @return encoded bytes * @throws IllegalStateException Thrown when the charset is missing, which should be never according the the Java specification. * @see <a href="http://java.sun.com/j2se/1.4.2/docs/api/java/nio/charset/Charset.html">Standard charsets</a> * @see #getBytesUnchecked(String, String) */ public static byte[] getBytesIso8859_1(String string) { return StringUtils.getBytesUnchecked(string, CharEncoding.ISO_8859_1); } /** * Encodes the given string into a sequence of bytes using the US-ASCII charset, storing the result into a new byte * array. * * @param string the String to encode * @return encoded bytes * @throws IllegalStateException Thrown when the charset is missing, which should be never according the the Java specification. * @see <a href="http://java.sun.com/j2se/1.4.2/docs/api/java/nio/charset/Charset.html">Standard charsets</a> * @see #getBytesUnchecked(String, String) */ public static byte[] getBytesUsAscii(String string) { return StringUtils.getBytesUnchecked(string, CharEncoding.US_ASCII); } /** * Encodes the given string into a sequence of bytes using the UTF-16 charset, storing the result into a new byte * array. * * @param string the String to encode * @return encoded bytes * @throws IllegalStateException Thrown when the charset is missing, which should be never according the the Java specification. * @see <a href="http://java.sun.com/j2se/1.4.2/docs/api/java/nio/charset/Charset.html">Standard charsets</a> * @see #getBytesUnchecked(String, String) */ public static byte[] getBytesUtf16(String string) { return StringUtils.getBytesUnchecked(string, CharEncoding.UTF_16); } /** * Encodes the given string into a sequence of bytes using the UTF-16BE charset, storing the result into a new byte * array. * * @param string the String to encode * @return encoded bytes * @throws IllegalStateException Thrown when the charset is missing, which should be never according the the Java specification. * @see <a href="http://java.sun.com/j2se/1.4.2/docs/api/java/nio/charset/Charset.html">Standard charsets</a> * @see #getBytesUnchecked(String, String) */ public static byte[] getBytesUtf16Be(String string) { return StringUtils.getBytesUnchecked(string, CharEncoding.UTF_16BE); } /** * Encodes the given string into a sequence of bytes using the UTF-16LE charset, storing the result into a new byte * array. * * @param string the String to encode * @return encoded bytes * @throws IllegalStateException Thrown when the charset is missing, which should be never according the the Java specification. * @see <a href="http://java.sun.com/j2se/1.4.2/docs/api/java/nio/charset/Charset.html">Standard charsets</a> * @see #getBytesUnchecked(String, String) */ public static byte[] getBytesUtf16Le(String string) { return StringUtils.getBytesUnchecked(string, CharEncoding.UTF_16LE); } /** * Encodes the given string into a sequence of bytes using the UTF-8 charset, storing the result into a new byte * array. * * @param string the String to encode * @return encoded bytes * @throws IllegalStateException Thrown when the charset is missing, which should be never according the the Java specification. * @see <a href="http://java.sun.com/j2se/1.4.2/docs/api/java/nio/charset/Charset.html">Standard charsets</a> * @see #getBytesUnchecked(String, String) */ public static byte[] getBytesUtf8(String string) { return StringUtils.getBytesUnchecked(string, CharEncoding.UTF_8); } /** * Encodes the given string into a sequence of bytes using the named charset, storing the result into a new byte * array. * <p> * This method catches {@link UnsupportedEncodingException} and rethrows it as {@link IllegalStateException}, which * should never happen for a required charset name. Use this method when the encoding is required to be in the JRE. * </p> * * @param string the String to encode * @param charsetName The name of a required {@link java.nio.charset.Charset} * @return encoded bytes * @throws IllegalStateException Thrown when a {@link UnsupportedEncodingException} is caught, which should never happen for a * required charset name. * @see CharEncoding * @see String#getBytes(String) */ public static byte[] getBytesUnchecked(String string, String charsetName) { if (string == null) { return null; } try { return string.getBytes(charsetName); } catch (UnsupportedEncodingException e) { throw StringUtils.newIllegalStateException(charsetName, e); } } private static IllegalStateException newIllegalStateException(String charsetName, UnsupportedEncodingException e) { return new IllegalStateException(charsetName + ": " + e); } /** * Constructs a new <code>String</code> by decoding the specified array of bytes using the given charset. * <p> * This method catches {@link UnsupportedEncodingException} and re-throws it as {@link IllegalStateException}, which * should never happen for a required charset name. Use this method when the encoding is required to be in the JRE. * </p> * * @param bytes The bytes to be decoded into characters * @param charsetName The name of a required {@link java.nio.charset.Charset} * @return A new <code>String</code> decoded from the specified array of bytes using the given charset. * @throws IllegalStateException Thrown when a {@link UnsupportedEncodingException} is caught, which should never happen for a * required charset name. * @see CharEncoding * @see String#String(byte[], String) */ public static String newString(byte[] bytes, String charsetName) { if (bytes == null) { return null; } try { return new String(bytes, charsetName); } catch (UnsupportedEncodingException e) { throw StringUtils.newIllegalStateException(charsetName, e); } } /** * Constructs a new <code>String</code> by decoding the specified array of bytes using the ISO-8859-1 charset. * * @param bytes The bytes to be decoded into characters * @return A new <code>String</code> decoded from the specified array of bytes using the given charset. * @throws IllegalStateException Thrown when a {@link UnsupportedEncodingException} is caught, which should never happen since the * charset is required. */ public static String newStringIso8859_1(byte[] bytes) { return StringUtils.newString(bytes, CharEncoding.ISO_8859_1); } /** * Constructs a new <code>String</code> by decoding the specified array of bytes using the US-ASCII charset. * * @param bytes The bytes to be decoded into characters * @return A new <code>String</code> decoded from the specified array of bytes using the given charset. * @throws IllegalStateException Thrown when a {@link UnsupportedEncodingException} is caught, which should never happen since the * charset is required. */ public static String newStringUsAscii(byte[] bytes) { return StringUtils.newString(bytes, CharEncoding.US_ASCII); } /** * Constructs a new <code>String</code> by decoding the specified array of bytes using the UTF-16 charset. * * @param bytes The bytes to be decoded into characters * @return A new <code>String</code> decoded from the specified array of bytes using the given charset. * @throws IllegalStateException Thrown when a {@link UnsupportedEncodingException} is caught, which should never happen since the * charset is required. */ public static String newStringUtf16(byte[] bytes) { return StringUtils.newString(bytes, CharEncoding.UTF_16); } /** * Constructs a new <code>String</code> by decoding the specified array of bytes using the UTF-16BE charset. * * @param bytes The bytes to be decoded into characters * @return A new <code>String</code> decoded from the specified array of bytes using the given charset. * @throws IllegalStateException Thrown when a {@link UnsupportedEncodingException} is caught, which should never happen since the * charset is required. */ public static String newStringUtf16Be(byte[] bytes) { return StringUtils.newString(bytes, CharEncoding.UTF_16BE); } /** * Constructs a new <code>String</code> by decoding the specified array of bytes using the UTF-16LE charset. * * @param bytes The bytes to be decoded into characters * @return A new <code>String</code> decoded from the specified array of bytes using the given charset. * @throws IllegalStateException Thrown when a {@link UnsupportedEncodingException} is caught, which should never happen since the * charset is required. */ public static String newStringUtf16Le(byte[] bytes) { return StringUtils.newString(bytes, CharEncoding.UTF_16LE); } /** * Constructs a new <code>String</code> by decoding the specified array of bytes using the UTF-8 charset. * * @param bytes The bytes to be decoded into characters * @return A new <code>String</code> decoded from the specified array of bytes using the given charset. * @throws IllegalStateException Thrown when a {@link UnsupportedEncodingException} is caught, which should never happen since the * charset is required. */ public static String newStringUtf8(byte[] bytes) { return StringUtils.newString(bytes, CharEncoding.UTF_8); } /** * ? * * @param parms * @return */ public static boolean isBlankOrEmpty(String parms) { return StringUtils.isBlank(parms) || StringUtils.isEmpty(parms); } /** * ?blank * StringUtils.isBlank(null) = true * StringUtils.isBlank("") = true * StringUtils.isBlank(" ") = true * StringUtils.isBlank("bob") = false * StringUtils.isBlank(" bob ") = false * * @param str * @return */ public static boolean isBlank(String str) { int strLen; if (str == null || (strLen = str.length()) == 0) { return true; } for (int i = 0; i < strLen; i++) { if ((Character.isWhitespace(str.charAt(i)) == false)) { return false; } } return true; } /** * ?empty * StringUtils.isEmpty(null) = true * StringUtils.isEmpty("") = true * StringUtils.isEmpty(" ") = false * StringUtils.isEmpty("bob") = false * StringUtils.isEmpty(" bob ") = false * * @param str * @return */ public static boolean isEmpty(String str) { return str == null || str.length() == 0; } /** * ? * * @param str * @return */ public static String encodeStr(String str) { try { return new String(str.getBytes("ISO-8859-1"), "UTF-8"); } catch (UnsupportedEncodingException e) { e.printStackTrace(); return null; } } // /** // * ? // * @param parms // * @return // */ // public static boolean isInteger(String str) { // Pattern pattern = Pattern.compile("^[-\\+]?[\\d]*$"); // return pattern.matcher(str).matches(); // } /** * ? * * @param str * @return */ public static boolean isInteger(String str) { try { Integer.valueOf(str.trim()); } catch (Throwable throwable) { return false; } return true; } /** * ? * * @param str * @return */ public static boolean isLong(String str) { try { Long.valueOf(str.trim()); } catch (Throwable throwable) { return false; } return true; } /** * Integer * * @param str * @return */ public static Integer getInteger(String str) { Integer result = null; try { result = Integer.valueOf(str.trim()); } catch (Throwable throwable) { } return result; } /** * Long * * @param str * @return */ public static Long getLong(String str) { Long result = null; try { result = Long.valueOf(str.trim()); } catch (Throwable throwable) { } return result; } /** * ? * * @param cs * @param separator * @return */ public static String getStrByCollectionAndSeparator(final Collection<?> cs, final String separator) { if (cs == null || cs.size() == 0) { return ""; } StringBuilder stringBuilder = new StringBuilder(); for (Object item : cs) { stringBuilder.append(item.toString() + separator); } return stringBuilder.substring(0, stringBuilder.lastIndexOf(separator)).toString(); } /** * ? * * @param cs * @param separator * @return */ public static <T> String getStrByArrayAndSeparator(T[] cs, final String separator) { if (cs == null || cs.length == 0) { return ""; } StringBuilder stringBuilder = new StringBuilder(); for (Object item : cs) { stringBuilder.append(item.toString() + separator); } return stringBuilder.substring(0, stringBuilder.lastIndexOf(separator)).toString(); } /** * ??2? * * @param value * @return */ public static int length(String value) { int valueLength = 0; String chinese = "[\u0391-\uFFE5]"; /* ???2?1 */ for (int i = 0; i < value.length(); i++) { /* ? */ String temp = value.substring(i, i + 1); /* ? */ if (temp.matches(chinese)) { /* 2 */ valueLength += 2; } else { /* 1 */ valueLength += 1; } } return valueLength; } /** * null * ?strtrim? * @param str * @return */ public static String nullToEmptyAndTrim(String str) { return str == null ? "" : str.trim(); } /** * ????? * charjavachar16????16??????? * <p> * ??U+0000U+10FFFFU+0000U+FFFFU+10000U+10FFFF * <p> * ????1216??UTF-16 * ??????????U+D800U+DFFF * ??????? * * @param sentence */ public static void printlnChar(String sentence) { // String sentence = "\u03C0\uD835\uDD6B";//? // String sentence = ""; int lengthU = sentence.length(); int lengthP = sentence.codePointCount(0, lengthU); // System.out.println(lengthU); // ?? // System.out.println(lengthP); // ??? if (lengthU != lengthP) {// for (int i = 0; i < lengthU; i++) { int codePoint = sentence.codePointAt(i); if (Character.isSupplementaryCodePoint(codePoint)) { System.out.println(String.valueOf(Character.toChars(codePoint))); i++; } else { System.out.println(sentence.charAt(i)); } } } } /** * * * @param string * @return */ public static String leftTrim(String string) { if (string == null) { return ""; } return string.replaceFirst("^\\s+", ""); } /** * ? * * @param string * @return */ public static String rightTrim(String string) { if (string == null) { return ""; } return string.replaceFirst("\\s+$", ""); } /** * @param string * @return * @Description ? * @author */ public static String toUpperCaseOfFirstChar(String string) { if (string == null || string.trim().equals("")) { return ""; } else { string = string.trim(); String firstChar = string.substring(0, 1).toUpperCase(); string = firstChar + string.substring(1); } return string; } public static void main(String[] args) { System.out.println(5 % 5); System.out.println(isLong("1111111111111111111111")); StringBuilder sb = new StringBuilder("1_2_3_4_5_"); System.out.println(sb.substring(0, sb.lastIndexOf("_"))); } }