如何配置mybatisplus不区分大小写

MybatisPlus 默认是区分大小写的，如果要实现不区分大小写的查询，可以在 MybatisPlus 的配置文件中添加一个全局拦截器，使用拦截器拦截 SQL，将 SQL 中的表名和列名转换为小写，然后再执行 SQL。

具体实现步骤如下：

1. 创建一个拦截器类，实现 MybatisPlus 的拦截器接口 Interceptor，重写其 intercept 方法，如下所示：

public class CaseInsensitiveInterceptor implements Interceptor {
    @Override
    public Object intercept(Invocation invocation) throws Throwable {
        MappedStatement statement = (MappedStatement) invocation.getArgs()[0];
        Object parameter = invocation.getArgs()[1];
        BoundSql boundSql = statement.getBoundSql(parameter);
        String sql = boundSql.getSql().toLowerCase();
        sql = sql.replaceAll("\\bfrom\\b", "FROM");
        sql = sql.replaceAll("\\bselect\\b", "SELECT");
        sql = sql.replaceAll("\\bwhere\\b", "WHERE");
        sql = sql.replaceAll("\\band\\b", "AND");
        sql = sql.replaceAll("\\bor\\b", "OR");
        sql = sql.replaceAll("\\bgroup by\\b", "GROUP BY");
        sql = sql.replaceAll("\\bhaving\\b", "HAVING");
        sql = sql.replaceAll("\\border by\\b", "ORDER BY");
        boundSql = new BoundSql(statement.getConfiguration(), sql,
                boundSql.getParameterMappings(), boundSql.getParameterObject());
        MappedStatement newStatement = copyFromMappedStatement(statement, boundSql);
        invocation.getArgs()[0] = newStatement;
        return invocation.proceed();
    }

    private MappedStatement copyFromMappedStatement(MappedStatement ms, BoundSql boundSql) {
        MappedStatement.Builder builder = new MappedStatement.Builder(ms.getConfiguration(),
                ms.getId(), boundSql, ms.getSqlCommandType());
        builder.resource(ms.getResource());
        builder.fetchSize(ms.getFetchSize());
        builder.statementType(ms.getStatementType());
        builder.keyGenerator(ms.getKeyGenerator());
        if (ms.getKeyProperties() != null && ms.getKeyProperties().length > 0) {
            builder.keyProperty(ms.getKeyProperties()[0]);
        }
        builder.timeout(ms.getTimeout());
        builder.parameterMap(ms.getParameterMap());
        builder.resultMaps(ms.getResultMaps());
        builder.cache(ms.getCache());
        builder.useCache(ms.isUseCache());
        return builder.build();
    }
}

2. 在 MybatisPlus 的配置文件中添加该拦截器，如下所示：

mybatis-plus:
  configuration:
    # 添加拦截器
    interceptors:
      - com.example.demo.CaseInsensitiveInterceptor

通过以上步骤，就可以实现 MybatisPlus 不区分大小写的查询了。