创建并连接数据库，并修改登录和注册接口

node_modules/mysql2/lib/parsers/parser_cache.js

@@ -0,0 +1,77 @@
+'use strict';
+
+const { createLRU } = require('lru.min');
+
+const parserCache = createLRU({
+  max: 15000,
+});
+
+// the fixed-size options head keeps JSON.stringify (cheap for a flat array,
+// and it normalizes exotic values the same way as before); the per-field part
+// is built by hand with length-prefixed strings, so no delimiter collision is
+// possible and no throwaway nested arrays are allocated per query
+function appendString(key, value) {
+  if (value === undefined || value === null) {
+    return `${key}u/`;
+  }
+  return `${key}${value.length}#${value}/`;
+}
+
+function keyFromFields(type, fields, options, config) {
+  let key = JSON.stringify([
+    type,
+    typeof options.nestTables,
+    options.nestTables,
+    Boolean(options.rowsAsArray),
+    Boolean(options.supportBigNumbers || config.supportBigNumbers),
+    Boolean(options.bigNumberStrings || config.bigNumberStrings),
+    typeof options.typeCast === 'boolean'
+      ? options.typeCast
+      : typeof options.typeCast,
+    options.timezone || config.timezone,
+    Boolean(options.decimalNumbers),
+    options.dateStrings,
+    Boolean(config.jsonStrings),
+  ]);
+
+  for (let i = 0; i < fields.length; ++i) {
+    const field = fields[i];
+    key = appendString(key, field.name);
+    key += `${field.columnType}/${field.length}/`;
+    key = appendString(key, field.schema);
+    key = appendString(key, field.table);
+    key += `${field.flags}/${field.characterSet}/`;
+    key = appendString(key, field.extendedTypeName);
+    key = appendString(key, field.extendedFormat);
+  }
+
+  return key;
+}
+
+function getParser(type, fields, options, config, compiler) {
+  const key = keyFromFields(type, fields, options, config);
+  let parser = parserCache.get(key);
+
+  if (parser) {
+    return parser;
+  }
+
+  parser = compiler(fields, options, config);
+  parserCache.set(key, parser);
+  return parser;
+}
+
+function setMaxCache(max) {
+  parserCache.resize(max);
+}
+
+function clearCache() {
+  parserCache.clear();
+}
+
+module.exports = {
+  getParser: getParser,
+  setMaxCache: setMaxCache,
+  clearCache: clearCache,
+  _keyFromFields: keyFromFields,
+};