1. 实现Mybatis拦截器

@Intercepts({
        @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})})
@SuppressWarnings({"unchecked", "rawtypes"})
public class MybatisInterceptor implements Interceptor {

   private final Logger log = LoggerFactory.getLogger(MybatisInterceptor.class);
    @Override
    public Object intercept(Invocation invocation) throws Throwable {
        try {
            // 获取xml中的一个select/update/insert/delete节点，是一条SQL语句
            MappedStatement mappedStatement = (MappedStatement) invocation.getArgs()[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 (invocation.getArgs().length > 1) {
                parameter = invocation.getArgs()[1];
                System.out.println("parameter = " + parameter);
            }
            String sqlId = mappedStatement.getId(); // 获取到节点的id,即sql语句的id
            System.out.println("sqlId = " + sqlId);
            BoundSql boundSql = mappedStatement.getBoundSql(parameter); // BoundSql就是封装myBatis最终产生的sql类
            Configuration configuration = mappedStatement.getConfiguration(); // 获取节点的配置
            String sql = getSql(configuration, boundSql, sqlId); // 获取到最终的sql语句
            System.out.println("sql = " + sql);
        } catch (Exception e) {
            e.printStackTrace();
        }
        // 执行完上面的任务后，不改变原有的sql执行过程
        return invocation.proceed();
    }

    // 封装了一下sql语句，使得结果返回完整xml路径下的sql语句节点id + sql语句
    public static String getSql(Configuration configuration, BoundSql boundSql, String sqlId) {
        String sql = showSql(configuration, boundSql);
        StringBuilder str = new StringBuilder(100);
        str.append(sqlId);
        str.append(":");
        str.append(sql);
        return str.toString();
    }

    // 如果参数是String，则添加单引号， 如果是日期，则转换为时间格式器并加单引号； 对参数是null和不是null的情况作了处理
    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(new Date()) + "'";
        } else {
            if (obj != null) {
                value = obj.toString();
            } else {
                value = "";
            }

        }
        return value;
    }

    // 进行？的替换
    public static String showSql(Configuration configuration, BoundSql boundSql) {
        // 获取参数
        Object parameterObject = boundSql.getParameterObject();
        List<ParameterMapping> parameterMappings = boundSql.getParameterMappings();
        // sql语句中多个空格都用一个空格代替
        String sql = boundSql.getSql().replaceAll("[\\s]+", " ");
        if (CollectionUtils.isNotEmpty(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
            TypeHandlerRegistry typeHandlerRegistry = configuration.getTypeHandlerRegistry();
            // 如果根据parameterObject.getClass(）可以找到对应的类型，则替换
            if (typeHandlerRegistry.hasTypeHandler(parameterObject.getClass())) {
                sql = sql.replaceFirst("\\?",
                        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);
                        sql = sql.replaceFirst("\\?",
                                Matcher.quoteReplacement(getParameterValue(obj)));
                    } else if (boundSql.hasAdditionalParameter(propertyName)) {
                        // 该分支是动态sql
                        Object obj = boundSql.getAdditionalParameter(propertyName);
                        sql = sql.replaceFirst("\\?",
                                Matcher.quoteReplacement(getParameterValue(obj)));
                    } else {
                        // 打印出缺失，提醒该参数缺失并防止错位
                        sql = sql.replaceFirst("\\?", "缺失");
                    }
                }
            }
        }
        return sql;
    }

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

    @Override
    public void setProperties(Properties properties) {

    }

}

2. 添加拦截器

@Configuration
public class mybatisconfig {

    @Bean
    public MybatisInterceptor mybatisInterceptor() {
        return new MybatisInterceptor();
    }
}

标签：obj,String,Object,boundSql,全量,sql,Mybatis,class
来源： https://blog.csdn.net/qq_39361915/article/details/122405545