很全的JSON数据解析 详细介绍fastJSON与Gson的使用和区别 还有详细demo

/* * Copyright 1999-2101 Alibaba Group. * * 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.alibaba.fastjson.parser; import static com.alibaba.fastjson.parser.JSONToken.COLON; import static com.alibaba.fastjson.parser.JSONToken.COMMA; import static com.alibaba.fastjson.parser.JSONToken.EOF; import static com.alibaba.fastjson.parser.JSONToken.ERROR; import static com.alibaba.fastjson.parser.JSONToken.LBRACE; import static com.alibaba.fastjson.parser.JSONToken.LBRACKET; import static com.alibaba.fastjson.parser.JSONToken.LITERAL_STRING; import static com.alibaba.fastjson.parser.JSONToken.LPAREN; import static com.alibaba.fastjson.parser.JSONToken.RBRACE; import static com.alibaba.fastjson.parser.JSONToken.RBRACKET; import static com.alibaba.fastjson.parser.JSONToken.RPAREN; import java.lang.ref.SoftReference; import java.math.BigDecimal; import java.math.BigInteger; import java.util.ArrayList; import java.util.Calendar; import java.util.Collection; import java.util.HashSet; import java.util.Locale; import java.util.TimeZone; import com.alibaba.fastjson.JSON; import com.alibaba.fastjson.JSONException; import com.alibaba.fastjson.util.Base64; //这个类，为了性能优化做了很多特别处理，一切都是为了性能！！！ /** * @author wenshao<szujobs@hotmail.com> */ public final class JSONScanner implements JSONLexer { public final static byte EOI = 0x1A; private final char[] buf; private int bp; private final int buflen; private int eofPos; /** * The current character. */ private char ch; /** * The token's position, 0-based offset from beginning of text. */ private int pos; /** * A character buffer for literals. */ private char[] sbuf; private int sp; /** * number start position */ private int np; /** * The token, set by nextToken(). */ private int token; private Keywords keywods = Keywords.DEFAULT_KEYWORDS; private final static ThreadLocal<SoftReference<char[]>> sbufRefLocal = new ThreadLocal<SoftReference<char[]>>(); private int features = JSON.DEFAULT_PARSER_FEATURE; private Calendar calendar = null; private boolean resetFlag = false; public int resetCount = 0; public JSONScanner(String input){ this(input, JSON.DEFAULT_PARSER_FEATURE); } public JSONScanner(String input, int features){ this(input.toCharArray(), input.length(), features); } public JSONScanner(char[] input, int inputLength){ this(input, inputLength, JSON.DEFAULT_PARSER_FEATURE); } public JSONScanner(char[] input, int inputLength, int features){ this.features = features; SoftReference<char[]> sbufRef = sbufRefLocal.get(); if (sbufRef != null) { sbuf = sbufRef.get(); sbufRefLocal.set(null); } if (sbuf == null) { sbuf = new char[64]; } eofPos = inputLength; if (inputLength == input.length) { if (input.length > 0 && isWhitespace(input[input.length - 1])) { inputLength--; } else { char[] newInput = new char[inputLength + 1]; System.arraycopy(input, 0, newInput, 0, input.length); input = newInput; } } buf = input; buflen = inputLength; buf[buflen] = EOI; bp = -1; ch = buf[++bp]; } public boolean isResetFlag() { return resetFlag; } public void setResetFlag(boolean resetFlag) { this.resetFlag = resetFlag; } public final int getBufferPosition() { return bp; } public void reset(int mark, char mark_ch, int token) { this.bp = mark; this.ch = mark_ch; this.token = token; resetFlag = true; resetCount++; } public boolean isBlankInput() { for (int i = 0; i < buflen; ++i) { if (!isWhitespace(buf[i])) { return false; } } return true; } public static final boolean isWhitespace(char ch) { // 专门调整了判断顺序 return ch == ' ' || ch == '\n' || ch == '\r' || ch == '\t' || ch == '\f' || ch == '\b'; } /** * Report an error at the current token position using the provided arguments. */ private void lexError(String key, Object... args) { token = ERROR; } /** * Return the current token, set by nextToken(). */ public final int token() { return token; } public final String tokenName() { return JSONToken.name(token); } private static boolean[] whitespaceFlags = new boolean[256]; static { whitespaceFlags[' '] = true; whitespaceFlags['\n'] = true; whitespaceFlags['\r'] = true; whitespaceFlags['\t'] = true; whitespaceFlags['\f'] = true; whitespaceFlags['\b'] = true; } public final void skipWhitespace() { for (;;) { if (whitespaceFlags[ch]) { ch = buf[++bp]; continue; } else { break; } } } public final char getCurrent() { return ch; } public final void nextTokenWithColon() { for (;;) { if (ch == ':') { ch = buf[++bp]; nextToken(); return; } if (ch == ' ' || ch == '\n' || ch == '\r' || ch == '\t' || ch == '\f' || ch == '\b') { ch = buf[++bp]; continue; } throw new JSONException("not match ':' - " + ch); } } public final void nextTokenWithColon(int expect) { for (;;) { if (ch == ':') { ch = buf[++bp]; break; } if (isWhitespace(ch)) { ch = buf[++bp]; continue; } throw new JSONException("not match ':', actual " + ch); } for (;;) { if (expect == JSONToken.LITERAL_INT) { if (ch >= '0' && ch <= '9') { sp = 0; pos = bp; scanNumber(); return; } if (ch == '"') { sp = 0; pos = bp; scanString(); return;