[BUG] 解析MySQL8.x的json类型字段时，_utf8mb4被统一成_utf8了

[lizongbo]

Database Type

MySQL

Database Version

8.0.24

Druid Version

1.2.22

JDK Version

OpenJDK 8

Error SQL

CREATE TABLE `account_info` (
                    `id` varchar(32) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL COMMENT '主键id',
                    `account_num` varchar(64) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL COMMENT '账户编号',
                    `open_acct_agreement_info` json DEFAULT (_utf8mb4'{}') COMMENT '协议信息',
                    `ext_info` json DEFAULT (_utf8mb4'{}') COMMENT '扩展信息',
                    `last_push_time` datetime DEFAULT NULL COMMENT '账户推送时间',
                    `create_time` datetime NOT NULL COMMENT '创建时间',
                    `update_time` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '最后更新时间',
                    PRIMARY KEY (`id`) USING BTREE,
                    UNIQUE KEY `idx_account_num` (`account_num`) USING BTREE
                    + ") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin ROW_FORMAT=COMPACT COMMENT='账户信息表';

Testcase Code

 @Test
    public void test_parse_create() {
        for (DbType dbType : new DbType[]{DbType.mysql}) {
            for (String sql : new String[]{
                "CREATE TABLE `account_info` (\n"
                    + "  `id` varchar(32) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL COMMENT '主键id',\n"
                    + "  `account_num` varchar(64) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL COMMENT '账户编号',\n"
                    + "  `open_acct_agreement_info` json DEFAULT (_utf8mb4'{}') COMMENT '协议信息',\n"
                    + "  `ext_info` json DEFAULT (_utf8mb4'{}') COMMENT '扩展信息',\n"
                    + "  `last_push_time` datetime DEFAULT NULL COMMENT '账户推送时间',\n"
                    + "  `create_time` datetime NOT NULL COMMENT '创建时间',\n"
                    + "  `update_time` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '最后更新时间',\n"
                    + "  PRIMARY KEY (`id`) USING BTREE,\n"
                    + "  UNIQUE KEY `idx_account_num` (`account_num`) USING BTREE\n"
                    + ") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin ROW_FORMAT=COMPACT COMMENT='账户信息表';",

            }) {
                SQLStatementParser parser = SQLParserUtils.createSQLStatementParser(sql, dbType);
                List<SQLStatement> statementList = parser.parseStatementList();
                System.out.println(statementList);
                //assertEquals(1, statementList.size());
                SQLParseAssertUtil.assertParseSql(sql, dbType);
            }
        }
    }

Stacktrace Info

No response

Error Info

json DEFAULT (_utf8mb4'{}')
解析之后生成的sql语句里，变成了

json DEFAULT _utf8mb4' {}'

需要保留原始的编码信息和括号。