DBUtility.SQLDbHelper”的类型初始值设定项引发异常。”

System.TypeInitializationException:““DBUtility.SQLDbHelper”的类型初始值设定项引发异常。”

public bool chkAdminLoign(string UserName, string UserPwd)
        {
            string strSql = "select count(*) from Administrator where UserName=@UserName and UserPwd=@UserPwd and IsLook=0";
            SqlParameter[] parameters = {
                new SqlParameter("@UserName",System.Data.SqlDbType.NVarChar,50),
                new SqlParameter("@UserPwd", System.Data.SqlDbType.NVarChar,50)};
            parameters[0].Value = UserName;
            parameters[1].Value = UserPwd;
            return SQLDbHelper.Exists(strSql, parameters);
        }

求大神指点！！！！

看一下exist里的方法是怎么样的

1、创建mapper xml文件：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">


SELECT user_id, uuid
FROM xxxx.user_events
WHERE dt = #{dt, jdbcType=INTEGER}
AND user_id = #{userId}

AND project = #{project}



2、获取xml中的sql：

@Autowired
private SqlSessionFactory sqlSessionFactory;

String sql = SqlHelper.getNamespaceSql(sqlSessionFactory, "xxxxMapper.userBaseInfo", params);
log.info("userBaseInfo inVo = {}, querySql = {}", inVo, sql);
3、SqlHelper工具类：

import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.ParameterMapping;
import org.apache.ibatis.mapping.ParameterMode;
import org.apache.ibatis.reflection.MetaObject;
import org.apache.ibatis.session.Configuration;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.type.JdbcType;
import org.apache.ibatis.type.TypeHandlerRegistry;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

import static org.apache.ibatis.type.JdbcType.VARCHAR;

/**

• Mybatis - 获取Mybatis查询sql工具
  */
  public class SqlHelper {

  /**

  • 通过命名空间方式获取sql
  • @param sqlSessionFactory
  • @param namespace
  • @param params
  • @return */ public static String getNamespaceSql(SqlSessionFactory sqlSessionFactory, String namespace, Object params) { params = wrapCollection(params); Configuration configuration = sqlSessionFactory.getConfiguration(); MappedStatement mappedStatement = configuration.getMappedStatement(namespace); TypeHandlerRegistry typeHandlerRegistry = mappedStatement.getConfiguration().getTypeHandlerRegistry(); BoundSql boundSql = mappedStatement.getBoundSql(params); List parameterMappings = boundSql.getParameterMappings(); StringBuilder sqlStringBuilder = new StringBuilder(boundSql.getSql().replaceAll("\n", "")); if (params != null && parameterMappings != null && parameterMappings.size() > 0) { for (ParameterMapping parameterMapping : parameterMappings) { if (parameterMapping.getMode() != ParameterMode.OUT) { Object value; String propertyName = parameterMapping.getProperty(); if (boundSql.hasAdditionalParameter(propertyName)) { value = boundSql.getAdditionalParameter(propertyName); } else if (typeHandlerRegistry.hasTypeHandler(params.getClass())) { value = params; } else { MetaObject metaObject = configuration.newMetaObject(params); value = metaObject.getValue(propertyName); } JdbcType jdbcType = parameterMapping.getJdbcType(); if (jdbcType == null) { jdbcType = VARCHAR; } replaceParameter(sqlStringBuilder, value, jdbcType); } } } return sqlStringBuilder.toString(); }

  /**

  • 根据类型替换参数
  • 仅作为数字和字符串两种类型进行处理，需要特殊处理的可以继续完善这里 *
  • @param sqlStringBuilder
  • @param value
  • @param jdbcType

  • @return
    */
    private static void replaceParameter(StringBuilder sqlStringBuilder, Object value, JdbcType jdbcType) {
    if (value == null) {
    return;
    }

    String strValue = String.valueOf(value);
    switch (jdbcType) {
    //数字
    case BIT:
    break;
    case TINYINT:
    break;
    case SMALLINT:
    break;
    case INTEGER:
    break;
    case BIGINT:
    break;
    case FLOAT:
    break;
    case REAL:
    break;
    case DOUBLE:
    break;
    case NUMERIC:
    break;
    case DECIMAL:
    break;
    //其他，包含字符串和其他特殊类型，加单引号
    default:
    strValue = "'" + strValue + "'";
    }
    int index = sqlStringBuilder.indexOf("?");
    sqlStringBuilder.replace(index, index+1, strValue);
    }

  /**

  • 简单包装参数 *
  • @param object
  • @return */ private static Object wrapCollection(final Object object) { if (object instanceof List) { Map map = new HashMap<>(); map.put("list", object); return map; } else if (object != null && object.getClass().isArray()) { Map map = new HashMap<>(); map.put("array", object); return map; } return object; } }