mysql打印SQL语句

场景：在业务中，系统有时候mysql语句更新和变动，控制台看不到SQL语句信息，这时候需要把数据库交互的SQL语句打印在控制台；

处理此方法之一方案：

增加一个sql语句拦截器，拦截打印SQL语句变更信息；

此代码可以直接复用，新增一个拦截类；

package cn.com.fero.frame.base.interceptor;

import java.text.DateFormat;
import java.util.Date;
import java.util.List;
import java.util.Locale;
import java.util.Properties;
import java.util.regex.Matcher;

import org.apache.ibatis.cache.CacheKey;
import org.apache.ibatis.executor.Executor;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.ParameterMapping;
import org.apache.ibatis.plugin.*;
import org.apache.ibatis.reflection.MetaObject;
import org.apache.ibatis.session.Configuration;
import org.apache.ibatis.session.ResultHandler;
import org.apache.ibatis.session.RowBounds;
import org.apache.ibatis.type.TypeHandlerRegistry;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.CollectionUtils;

@Intercepts(value = {
        @Signature(type = Executor.class, method = "update", args = {MappedStatement.class, Object.class}),
        @Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class, CacheKey.class, BoundSql.class}),
        @Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class})})
public class SqlStatementInterceptor implements Interceptor {

    private Logger logger = LoggerFactory.getLogger(this.getClass());

    @Override
    public Object intercept(Invocation invocation) throws Throwable {
        Object returnValue;
        long start = System.currentTimeMillis();
        // 执行 SQL语句
        returnValue = invocation.proceed();
        long end = System.currentTimeMillis();
        // 耗时
        long time = end - start;
        try {
            final Object[] args = invocation.getArgs();
            MappedStatement ms = (MappedStatement) args[0];
            Object parameter = null;
            //获取参数，if语句成立，表示sql语句有参数，参数格式是map形式
            if (args.length > 1) {
                parameter = invocation.getArgs()[1];
            }
            // 获取到节点的 id,即 sql语句的 id
            String sqlId = ms.getId();
            // BoundSql就是封装 MyBatis最终产生的 sql类
            BoundSql boundSql = ms.getBoundSql(parameter);
            // 获取节点的配置
            Configuration configuration = ms.getConfiguration();
            // 获取到最终的 sql语句
            printSql(configuration, boundSql, sqlId, time);
        } catch (Exception e) {
            logger.error("sql拦截异常:{} ", e.getMessage());
        }
        return returnValue;
    }

    private void printSql(Configuration configuration, BoundSql boundSql, String sqlId, long time) {
        String sql = showSql(configuration, boundSql);
        logger.info("【SQL语句Id】>>>> {}", sqlId);
        logger.info("【SQL语句耗时】>>>> {} ms", time);
        logger.info("【SQL语句】>>>> {}", sql);
    }

    private static String getParameterValue(Object obj) {
        String value = null;
        if (obj instanceof String) {
            value = "'" + obj.toString() + "'";
        } else if (obj instanceof Date) {
            DateFormat formatter = DateFormat.getDateTimeInstance(DateFormat.DEFAULT, DateFormat.DEFAULT, Locale.CHINA);
            value = "'" + formatter.format(obj) + "'";
        } else {
            if (obj != null) {
                value = obj.toString();
            } else {
                value = "";
            }
        }
        return value;
    }

    private static String showSql(Configuration configuration, BoundSql boundSql) {
        // 获取参数
        Object parameterObject = boundSql.getParameterObject();
        List<ParameterMapping> parameterMappings = boundSql.getParameterMappings();
        String questionMark = "?";
        // sql语句中多个空格都用一个空格代替
        StringBuilder result = repaceWhiteSapce(boundSql.getSql());
        if (!CollectionUtils.isEmpty(parameterMappings) && parameterObject != null) {
            // 获取类型处理器注册器，类型处理器的功能是进行java类型和数据库类型的转换　　　　　　
            // 如果根据 parameterObject.getClass(）可以找到对应的类型，则替换
            TypeHandlerRegistry typeHandlerRegistry = configuration.getTypeHandlerRegistry();
            if (typeHandlerRegistry.hasTypeHandler(parameterObject.getClass())) {
                int index = result.indexOf(questionMark);
                if (index > -1){
                    result.replace(index, index + 1, Matcher.quoteReplacement(getParameterValue(parameterObject)));
                }
            } else {
                // MetaObject主要是封装了 originalObject对象，提供了 get和 set的方法用于获取和设置 originalObject的属性值
                // 主要支持对 JavaBean、Collection、Map三种类型对象的操作
                MetaObject metaObject = configuration.newMetaObject(parameterObject);
                for (ParameterMapping parameterMapping : parameterMappings) {
                    String propertyName = parameterMapping.getProperty();
                    if (metaObject.hasGetter(propertyName)) {
                        Object obj = metaObject.getValue(propertyName);
                        int index = result.indexOf(questionMark);
                        if (index > -1){
                            result.replace(index, index + 1, Matcher.quoteReplacement(getParameterValue(obj)));
                        }
                    } else if (boundSql.hasAdditionalParameter(propertyName)) {
                        Object obj = boundSql.getAdditionalParameter(propertyName);
                        // 该分支是动态 sql
                        int index = result.indexOf(questionMark);
                        if (index > -1){
                            result.replace(index, index + 1, Matcher.quoteReplacement(getParameterValue(obj)));
                        }
                    } else {
                        int index = result.indexOf(questionMark);
                        if (index > -1){
                            result.replace(index, index + 1, "缺失");
                        }
                    }
                }
            }
        }
        return result.toString();
    }

    public static StringBuilder repaceWhiteSapce(String original) {
        StringBuilder sb = new StringBuilder();
        //标记是否是前一个空格,空格不继续append
        boolean isFirstSpace = false;
        //        original = original.trim();//如果考虑开头和结尾有空格的情形
        char c;
        for (int i = 0; i < original.length(); i++) {
            c = original.charAt(i);
            if (c == '\n'){
                continue;
            }
            //遇到空格字符时,先判断是不是第一个空格字符
            if (c == ' ' || c == '\t') {
                if (!isFirstSpace) {
                    sb.append(c);
                    isFirstSpace = true;
                }
            } else {//遇到非空格字符时
                sb.append(c);
                isFirstSpace = false;
            }
        }
        return sb;
    }

    @Override
    public Object plugin(Object arg0) {
        return Plugin.wrap(arg0, this);
    }

    @Override
    public void setProperties(Properties properties) {
        // do nothing
    }

}

在配置类中注入SQL打印拦截器；（MybatisPlusInterceptorConfig.java）

    /**
     * 配置 sql打印拦截器
     * @return
     */
    @Bean
    public SqlStatementInterceptor sqlStatementInterceptor() {
        return new SqlStatementInterceptor();
    }

以上配置完成，即可打印变动的SQL信息在控制台显示；