package com.lsm.util;import java.text.CharacterIterator;
import java.text.StringCharacterIterator;
/*** 用于校验一个字符串是否是合法的JSON格式* @author liShuMin**/
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) {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(c) >= 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 jsonStr = "{\"website\":\"oschina.net\"}";String jsonStr = "{"+ " \"ccobjtypeid\": \"1001\","+ " \"fromuser\": \"李四\","+ " \"touser\": \"张三\","+ "  \"desc\": \"描述\","+ "  \"subject\": \"主题\","+ "  \"attach\": \"3245,3456,4345,4553\","+ " \"data\": {"+ "    \"desc\": \"测试对象\","+ "     \"dataid\": \"22\","+ "    \"billno\": \"TEST0001\","+ "    \"datarelation\":["+ " {"+ "  \"dataname\": \"关联对象1\","+ "  \"data\": ["+ "      {"+ "    \"dataid\": \"22\","+ "          \"datalineid\": \"1\","+ "          \"content1\": \"test1\","+ "          \"content2\": \"test2\""+ "      }"+ "  ]"+ " }"+ " ]"+ "  }"+ " }";System.out.println(jsonStr+":"+new JsonValidator().validate(jsonStr));}
}