package com.alibaba.fastjson2;
class JSONWriterUTF8 {
    protected final long byteVectorQuote;

   JSONWriterUTF8(Context ctx) {
        // " -> 0x22, ' -> 0x27
        this.byteVectorQuote = this.useSingleQuote ? 0x2727_2727_2727_2727L : 0x2222_2222_2222_2222L;
    }

    public void writeStringLatin1(byte[] value) {
        final long vecQuote = this.byteVectorQuote;
        int i = 0;
        final int upperBound = (value.length - i) & ~7;
        // 这里一次检测8个byte是否存在特别字符
        for (; i < upperBound; i += 8) {
            if (containsEscaped(IOUtils.getLongLittleEndian(value, i), vecQuote)) {
                break;
            }
        }
        // ...
    }

    static boolean containsEscaped(long v, long quote) {
        /*
          for (int i = 0; i < 8; ++i) {
            byte c = (byte) data;
            if (c == quote || c == '\\' || c < ' ') {
                return true;
            }
            data >>>= 8;
          }
          return false;
         */
        long x22 = v ^ quote; // " -> 0x22, ' -> 0x27
        long x5c = v ^ 0x5c5c5c5c5c5c5c5cL;

        x22 = (x22 - 0x0101010101010101L) & ~x22;
        x5c = (x5c - 0x0101010101010101L) & ~x5c;

        return ((x22 | x5c | (0x7F7F_7F7F_7F7F_7F7FL - v + 0x1010_1010_1010_1010L) | v) & 0x8080808080808080L) != 0;
    }
}

class JSONReaderASCII {
    static final int ESCAPE_INDEX_NOT_SET = -2;

    protected int nextEscapeIndex = ESCAPE_INDEX_NOT_SET;

    public String readString() {
            int slashIndex = nextEscapeIndex;
            if (slashIndex == ESCAPE_INDEX_NOT_SET || (slashIndex != -1 && slashIndex < offset)) {
                nextEscapeIndex = slashIndex = IOUtils.indexOfChar(bytes, '\\', offset, end);
            }
            if (slashIndex == -1 || slashIndex > index) {
                valueLength = index - offset;
                offset = index;
           // ...
    }
}

package com.alibaba.fastjson2;

class JSONReaderUTF8 {
    public final int readInt32Value() {
       // ...
        while (inRange
                && offset + 1 < end
                && (digit = IOUtils.digit2(bytes, offset)) != -1
        ) {
            // max digits is 19, no need to check inRange (result == MULT_MIN_100 && digit <= (MULT_MIN_100 * 100 - limit))
            if (inRange = (result > INT_32_MULT_MIN_100)) {
                result = result * 100 - digit;
                offset += 2;
            }
        }
    }
}

package com.alibaba.fastjson2.util;
class IOUtils {
    public static int digit2(byte[] bytes, int off) {
        short x = UNSAFE.getShort(bytes, ARRAY_BYTE_BASE_OFFSET + off);
        if (BIG_ENDIAN) {
            x = Short.reverseBytes(x);
        }
        int d;
        if ((((x & 0xF0F0) - 0x3030) | (((d = x & 0x0F0F) + 0x0606) & 0xF0F0)) != 0
        ) {
            return -1;
        }
        return ((d & 0xF) << 3) + ((d & 0xF) << 1)  // (d & 0xF) * 10
                + (d >> 8);
    }
}

import com.alibaba.fastjson2.JSONFactory;

// 手工关闭
JSONFactory.setUseGsonAnnotation(false);

-Dfastjson2.useGsonAnnotation=false

<dependency>
    <groupId>com.alibaba.fastjson2</groupId>
    <artifactId>fastjson2</artifactId>
    <version>2.0.54</version>
</dependency>

<dependency>
    <groupId>com.alibaba.fastjson2</groupId>
    <artifactId>fastjson2</artifactId>
    <version>2.0.54.android5</version>
</dependency>

<dependency>
    <groupId>com.alibaba.fastjson2</groupId>
    <artifactId>fastjson2</artifactId>
    <version>2.0.54.android8</version>
</dependency>

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>2.0.54</version>
</dependency>

<dependency>
    <groupId>com.alibaba.fastjson2</groupId>
    <artifactId>fastjson2-extension-spring5</artifactId>
    <version>2.0.54</version>
</dependency>

<dependency>
    <groupId>com.alibaba.fastjson2</groupId>
    <artifactId>fastjson2-extension-spring6</artifactId>
    <version>2.0.54</version>
</dependency>