最近项目中遇到JSON格式验证的问题,由于请求接口中可能存在新旧版本兼容问题,老版本的客户端,情况就不说了,糟透了,各种格式都有,看起来像JSON,但是……呵呵。
所以需要做兼容,就得把之前不规范的东西规范一下,并且验证其正确性;工具类如下:
/** * Project Name:v3a-b2c * File Name:JsonValidator.java * Package Name:com.v3a.util * Date:2014年10月26日下午1:59:59 * Copyright (c) 2014, [email protected] All Rights Reserved. * */ package com.v3a.util; import java.text.CharacterIterator; import java.text.StringCharacterIterator; import java.util.List; import java.util.regex.Pattern; import org.apache.commons.lang.StringUtils; import com.google.common.collect.Lists; /** * ClassName:JsonValidator <br/> * Function: 用于校验一个字符串是否是合法的JSON格式. <br/> * Date: 2014年10月26日 下午1:59:59 <br/> * 用法: new JsonValidator().validate(“JOSN字符串”) * @author 勋辉 * @version * @since JDK 1.7 * @see */ public class JsonValidator { private CharacterIterator it; private char c; private int col; public JsonValidator() { } /** * 验证一个字符串是否是合法的JSON串 * @param input 要验证的字符串 * @return true-合法 ,false-非法 */ public boolean validate(String input) { input = input.trim(); boolean ret = valid(input); return ret; } private boolean valid(String input) { /** * 兼容不规范的JSON格式(使用单引号的方式),将单引号替换为双引号 */ input =formartJson(input); if ("".equals(input)) return true; boolean ret = true; it = new StringCharacterIterator(input); c = it.first(); col = 1; if (!value()) { ret = error("value", 1); } else { skipWhiteSpace(); if (c != CharacterIterator.DONE) { ret = error("end", col); } } return ret; } private boolean value() { return literal("true") || literal("false") || literal("null") || string() || number() || object() || array(); } private boolean literal(String text) { CharacterIterator ci = new StringCharacterIterator(text); char t = ci.first(); if (c != t) return false; int start = col; boolean ret = true; for (t = ci.next(); t != CharacterIterator.DONE; t = ci.next()) { if (t != nextCharacter()) { ret = false; break; } } nextCharacter(); if (!ret) error("literal " + text, start); return ret; } private boolean array() { return aggregate(‘[‘, ‘]‘, false); } private boolean object() { return aggregate(‘{‘, ‘}‘, true); } private boolean aggregate(char entryCharacter, char exitCharacter, boolean prefix) { if (c != entryCharacter) return false; nextCharacter(); skipWhiteSpace(); if (c == exitCharacter) { nextCharacter(); return true; } for (;;) { if (prefix) { int start = col; if (!string()) return error("string", start); skipWhiteSpace(); if (c != ‘:‘) return error("colon", col); nextCharacter(); skipWhiteSpace(); } if (value()) { skipWhiteSpace(); if (c == ‘,‘) { nextCharacter(); } else if (c == exitCharacter) { break; } else { return error("comma or " + exitCharacter, col); } } else { return error("value", col); } skipWhiteSpace(); } nextCharacter(); return true; } private boolean number() { if (!Character.isDigit(c) && c != ‘-‘) return false; int start = col; if (c == ‘-‘) nextCharacter(); if (c == ‘0‘) { nextCharacter(); } else if (Character.isDigit(c)) { while (Character.isDigit(c)) nextCharacter(); } else { return error("number", start); } if (c == ‘.‘) { nextCharacter(); if (Character.isDigit(c)) { while (Character.isDigit(c)) nextCharacter(); } else { return error("number", start); } } if (c == ‘e‘ || c == ‘E‘) { nextCharacter(); if (c == ‘+‘ || c == ‘-‘) { nextCharacter(); } if (Character.isDigit(c)) { while (Character.isDigit(c)) nextCharacter(); } else { return error("number", start); } } return true; } private boolean string() { if (c != ‘"‘) return false; int start = col; boolean escaped = false; for (nextCharacter(); c != CharacterIterator.DONE; nextCharacter()) { if (!escaped && c == ‘\\‘) { escaped = true; } else if (escaped) { if (!escape()) { return false; } escaped = false; } else if (c == ‘"‘) { nextCharacter(); return true; } } return error("quoted string", start); } private boolean escape() { int start = col - 1; if (" \\\"/bfnrtu".indexOf(c) < 0) { return error("escape sequence \\\",\\\\,\\/,\\b,\\f,\\n,\\r,\\t or \\uxxxx ", start); } if (c == ‘u‘) { if (!ishex(nextCharacter()) || !ishex(nextCharacter()) || !ishex(nextCharacter()) || !ishex(nextCharacter())) { return error("unicode escape sequence \\uxxxx ", start); } } return true; } private boolean ishex(char d) { return "0123456789abcdefABCDEF".indexOf(d) >= 0; } private char nextCharacter() { c = it.next(); ++col; return c; } private void skipWhiteSpace() { while (Character.isWhitespace(c)) { nextCharacter(); } } private boolean error(String type, int col) { System.out.printf("type: %s, col: %s%s", type, col, System.getProperty("line.separator")); return false; } public static void main(String[] args) { String json ="{firstName : Brett, ‘lastName‘:‘McLaughlin‘, ‘email‘: ‘aaaa‘}"; boolean valid = new JsonValidator().valid(json); System.out.println(valid); } public static String formartJson(String json) { String replaceAll = json.trim().replaceAll("‘", "\"").replace(" ", ""); char[] charArray = replaceAll.toCharArray(); String regEx = "^[A-Za-z]+$"; Pattern pat = Pattern.compile(regEx); List<Integer> list = Lists.newLinkedList(); StringBuilder builder = new StringBuilder(replaceAll); for (int i = 0; i < charArray.length-1; i++) { if (i < charArray.length) { String current = String.valueOf(charArray[i]).trim(); if(StringUtils.isEmpty(current.trim())){ builder.deleteCharAt(i); continue; }else{ boolean flagcurrent = pat.matcher(current).find(); String last = String.valueOf(charArray[i + 1]).trim(); boolean flaglast = pat.matcher(last).find(); /* * 如果当前是标点,则是false,如果是字母则是true,下一个(last)是字母的,则继续,如果是标点则检查是不是双引号, * 不是则记下标志位 */ if (flagcurrent) { if (!flaglast) { if (!check(last)) list.add(i+1); } }else{ /* * 如果当前不是标点,则检查下一个(last)是不是字符串,如果是,则看当前标点是不是双引号,不是,则记录位置 * 如果当前不是字符串并且last是字符串的情况下,检查当前是不是引号 * */ if(!flagcurrent&&flaglast){ if(!check(current)) { list.add(i+1); } } } } } } //StringBuilder builder = new StringBuilder(replaceAll); for (int i = 0; i < list.size(); i++) { builder.insert(list.get(i)+i, "\""); } return builder.toString(); } /** * 检查字符是不是JSON中的标准标点 * check * @author 勋辉 * @param checkString * @return * @since JDK 1.7 */ public static boolean check(String checkString) { boolean flag = true; switch (checkString) { case "{": flag = false; break; case "}": flag = false; break; case "[": flag = false; break; case ",": flag = false; break; case ":": flag = false; break; case "\"": flag = true; break; } return flag; } }
时间: 2024-10-07 17:24:05