获取MapperedStatement

MappedStatement mappedStatement = (MappedStatement) args[0];

判断sql类型

if (!SqlCommandType.SELECT.equals(mappedStatement.getSqlCommandType())) {
    return invocation.proceed();
}

获取拦截的方法

// 获取执行方法的包名和方法名
String namespace = mappedStatement.getId();
String className = namespace.substring(0, namespace.lastIndexOf("."));
String mapperName = className.substring(className.lastIndexOf(".") + 1, className.length());
String methodName = namespace.substring(namespace.lastIndexOf(".") + 1, namespace.length());

获取参数

Object parameter =  args[1];

获取BoundSql

BoundSql boundSql = mappedStatement.getBoundSql(parameter);
String originalSql = boundSql.getSql();
Object parameterObject = boundSql.getParameterObject();

重置mappedStatement

/**
     * 包装sql后，重置到invocation中
     *
     * @param invocation
     * @param sql
     * @throws SQLException
     */
    private void resetSql2Invocation(Invocation invocation, String sql) throws SQLException {
        final Object[] args = invocation.getArgs();
        MappedStatement statement = (MappedStatement) args[0];
        Object parameterObject = args[1];
        BoundSql boundSql = statement.getBoundSql(parameterObject);
        MappedStatement newStatement = newMappedStatement(statement, new BoundSqlSqlSource(boundSql));
        MetaObject msObject = MetaObject.forObject(newStatement, new DefaultObjectFactory(), new DefaultObjectWrapperFactory(), new DefaultReflectorFactory());
        msObject.setValue("sqlSource.boundSql.sql", sql);
        args[0] = newStatement;
    }
    private MappedStatement newMappedStatement(MappedStatement ms, SqlSource newSqlSource) {
        MappedStatement.Builder builder =
            new MappedStatement.Builder(ms.getConfiguration(), ms.getId(), newSqlSource, 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) {
            StringBuilder keyProperties = new StringBuilder();
            for (String keyProperty : ms.getKeyProperties()) {
                keyProperties.append(keyProperty).append(",");
            }
            keyProperties.delete(keyProperties.length() - 1, keyProperties.length());
            builder.keyProperty(keyProperties.toString());
        }
        builder.timeout(ms.getTimeout());
        builder.parameterMap(ms.getParameterMap());
        builder.resultMaps(ms.getResultMaps());
        builder.resultSetType(ms.getResultSetType());
        builder.cache(ms.getCache());
        builder.flushCacheRequired(ms.isFlushCacheRequired());
        builder.useCache(ms.isUseCache());
        return builder.build();
    }
    // 定义一个内部辅助类，作用是包装sql
    class BoundSqlSqlSource implements SqlSource {
        private BoundSql boundSql;
        public BoundSqlSqlSource(BoundSql boundSql) {
            this.boundSql = boundSql;
        }
        @Override
        public BoundSql getBoundSql(Object parameterObject) {
            return boundSql;
        }
    }