一、前言

关于apache ant的ant-tools源码包org.apache.tools.ant.util.StringUtils字符串工具类，对字符分行分隔lineSplit、获取Throwable异常堆栈PrintWriter输出为StringWriter字符串、特殊字符过滤处理resolveBackSlash、数组连接拼接join等操作。

二、源码说明

package org.apache.tools.ant.util;@b@@b@import java.io.PrintWriter;@b@import java.io.StringWriter;@b@import java.util.Arrays;@b@import java.util.Collection;@b@import java.util.Vector;@b@import java.util.stream.Collector;@b@import java.util.stream.Collectors; @b@import org.apache.tools.ant.BuildException; @b@@b@public final class StringUtils {@b@@b@    private static final long KILOBYTE = 1024;@b@    private static final long MEGABYTE = KILOBYTE * 1024;@b@    private static final long GIGABYTE = MEGABYTE * 1024;@b@    private static final long TERABYTE = GIGABYTE * 1024;@b@    private static final long PETABYTE = TERABYTE * 1024;@b@@b@     @b@    private StringUtils() {@b@    }@b@@b@  @b@    public static final String LINE_SEP = System.getProperty("line.separator");@b@@b@  @b@    public static Vector<String> lineSplit(String data) {@b@        return split(data, '\n');@b@    }@b@@b@     @b@    public static Vector<String> split(String data, int ch) {@b@        Vector<String> elems = new Vector<String>();@b@        int pos = -1;@b@        int i = 0;@b@        while ((pos = data.indexOf(ch, i)) != -1) {@b@            String elem = data.substring(i, pos);@b@            elems.addElement(elem);@b@            i = pos + 1;@b@        }@b@        elems.addElement(data.substring(i));@b@        return elems;@b@    }@b@@b@   @b@    @Deprecated@b@    public static String replace(String data, String from, String to) {@b@        return data.replace(from, to);@b@    }@b@@b@  @b@    public static String getStackTrace(Throwable t) {@b@        StringWriter sw = new StringWriter();@b@        PrintWriter pw = new PrintWriter(sw, true);@b@        t.printStackTrace(pw); //NOSONAR@b@        pw.flush();@b@        pw.close();@b@        return sw.toString();@b@    }@b@@b@ @b@    public static boolean endsWith(StringBuffer buffer, String suffix) {@b@        if (suffix.length() > buffer.length()) {@b@            return false;@b@        }@b@         @b@        int endIndex = suffix.length() - 1;@b@        int bufferIndex = buffer.length() - 1;@b@        while (endIndex >= 0) {@b@            if (buffer.charAt(bufferIndex) != suffix.charAt(endIndex)) {@b@                return false;@b@            }@b@            bufferIndex--;@b@            endIndex--;@b@        }@b@        return true;@b@    }@b@@b@ @b@    public static String resolveBackSlash(String input) {@b@        StringBuilder b = new StringBuilder();@b@        boolean backSlashSeen = false;@b@        for (int i = 0; i < input.length(); ++i) {@b@            char c = input.charAt(i);@b@            if (!backSlashSeen) {@b@                if (c == '\\') {@b@                    backSlashSeen = true;@b@                } else {@b@                    b.append(c);@b@                }@b@            } else {@b@                switch (c) {@b@                    case '\\':@b@                        b.append((char) '\\');@b@                        break;@b@                    case 'n':@b@                        b.append((char) '\n');@b@                        break;@b@                    case 'r':@b@                        b.append((char) '\r');@b@                        break;@b@                    case 't':@b@                        b.append((char) '\t');@b@                        break;@b@                    case 'f':@b@                        b.append((char) '\f');@b@                        break;@b@                    case 's':@b@                        b.append(" \t\n\r\f");@b@                        break;@b@                    default:@b@                        b.append(c);@b@                }@b@                backSlashSeen = false;@b@            }@b@        }@b@        return b.toString();@b@    }@b@@b@ @b@    public static long parseHumanSizes(String humanSize) throws Exception { //NOSONAR@b@        long factor = 1L;@b@        char s = humanSize.charAt(0);@b@        switch (s) {@b@            case '+':@b@                humanSize = humanSize.substring(1);@b@                break;@b@            case '-':@b@                factor = -1L;@b@                humanSize = humanSize.substring(1);@b@                break;@b@            default:@b@                break;@b@        }@b@        //last character isn't a digit@b@        char c = humanSize.charAt(humanSize.length() - 1);@b@        if (!Character.isDigit(c)) {@b@            int trim = 1;@b@            switch (c) {@b@                case 'K':@b@                    factor *= KILOBYTE;@b@                    break;@b@                case 'M':@b@                    factor *= MEGABYTE;@b@                    break;@b@                case 'G':@b@                    factor *= GIGABYTE;@b@                    break;@b@                case 'T':@b@                    factor *= TERABYTE;@b@                    break;@b@                case 'P':@b@                    factor *= PETABYTE;@b@                    break;@b@                default:@b@                    trim = 0;@b@            }@b@            humanSize = humanSize.substring(0, humanSize.length() - trim);@b@        }@b@        try {@b@            return factor * Long.parseLong(humanSize);@b@        } catch (NumberFormatException e) {@b@            throw new BuildException("Failed to parse \"" + humanSize + "\"", e);@b@        }@b@    }@b@@b@ @b@    public static String removeSuffix(String string, String suffix) {@b@        if (string.endsWith(suffix)) {@b@            return string.substring(0, string.length() - suffix.length());@b@        }@b@        return string;@b@    }@b@@b@ @b@    public static String removePrefix(String string, String prefix) {@b@        if (string.startsWith(prefix)) {@b@            return string.substring(prefix.length());@b@        }@b@        return string;@b@    }@b@@b@   @b@    public static String join(Collection<?> collection, CharSequence separator) {@b@        if (collection == null) {@b@            return "";@b@        }@b@        return collection.stream().map(String::valueOf)@b@            .collect(joining(separator));@b@    }@b@@b@  @b@    public static String join(Object[] array, CharSequence separator) {@b@        if (array == null) {@b@            return "";@b@        }@b@        return join(Arrays.asList(array), separator);@b@    }@b@@b@    private static Collector<CharSequence, ?, String> joining(CharSequence separator) {@b@        return separator == null ? Collectors.joining() : Collectors.joining(separator);@b@    }@b@ @b@    public static String trimToNull(String inputString) {@b@        if (inputString == null) {@b@            return null;@b@        }@b@        String tmpString = inputString.trim();@b@        return tmpString.isEmpty() ? null : tmpString;@b@    }@b@@b@}