mybatis攔截器修改sql重新set后不生效？

利用mybatis攔截器做數據權限管理，攔截sql並分析、修改然后重新set。然而有的生效有的不生效。控制台打印的信息表示所有的sql都是修改成功的，那么問題在於重新set的方法。

一開始用的方法是這個：

private void setCurrentSql(Invocation invo, String sql) {
    MappedStatement mappedStatement = getMappedStatement(invo);
    Object[] args = invo.getArgs();
    Object paramObj = args[PARAM_OBJ_INDEX];
    BoundSql boundSql = mappedStatement.getBoundSql(paramObj);
    ReflectUtil.setFieldValue(boundSql, "sql", sql);
}

通過反射去修改boundSql的sql屬性的值，但是有問題。
后來改用這個方法：

private void setCurrentSql(Invocation invo, String sql) {
    BoundSql boundSql = getBoundSql(invo);
    List<ParameterMapping> parameterMappings = boundSql.
            getParameterMappings();
    Object paramObj = boundSql.getParameterObject();
    MappedStatement mappedStatement = getMappedStatement(invo);
    Configuration configuration = mappedStatement.getConfiguration();
    BoundSql newBoundSql = new BoundSql(configuration, sql,
            parameterMappings, paramObj);
    for (ParameterMapping parameterMapping : parameterMappings) {
        String prop = parameterMapping.getProperty();
        if (boundSql.hasAdditionalParameter(prop)) {
            Object param = boundSql.getAdditionalParameter(prop);
            newBoundSql.setAdditionalParameter(prop, param);
        }
    }

    BoundSqlSource newSqlSource = new BoundSqlSource(newBoundSql);
    MappedStatement newMappedStatement = copyFromMappedStatement(
            mappedStatement, newSqlSource);
    Object[] args = invo.getArgs();
    args[MAPPED_STATEMENT_INDEX] = newMappedStatement;
}

問題解決。還有一種方法，看起來更簡潔：

private void setCurrentSql(Invocation invo, String sql) {
    MappedStatement mappedStatement = getMappedStatement(invo);
    Object[] args = invo.getArgs();
    Object paramObj = args[PARAM_OBJ_INDEX];
    BoundSql boundSql = mappedStatement.getBoundSql(paramObj);
    BoundSqlSource boundSqlSource = new BoundSqlSource(boundSql);
    MappedStatement newMappedStatement = copyFromMappedStatement(
            mappedStatement, boundSqlSource);
    MetaObject metaObject = MetaObject.forObject(newMappedStatement,
            new DefaultObjectFactory(), new DefaultObjectWrapperFactory(),
            new DefaultReflectorFactory());
    metaObject.setValue("sqlSource.boundSql.sql", sql);
    args[MAPPED_STATEMENT_INDEX] = newMappedStatement;
}

上面用到的方法getMappedStatement：

private MappedStatement getMappedStatement(Invocation invo) {
    Object[] args = invo.getArgs();
    Object mappedStatement = args[MAPPED_STATEMENT_INDEX];
    return (MappedStatement) mappedStatement;
}

私有內部類BoundSqlSource:

private class BoundSqlSource implements SqlSource {

    private BoundSql boundSql;

    private BoundSqlSource(BoundSql boundSql) {
        this.boundSql = boundSql;
    }

    @Override
    public BoundSql getBoundSql(Object parameterObject) {
        return boundSql;
    }
}

另外還有：

private static final int MAPPED_STATEMENT_INDEX = 0;
private static final int PARAM_OBJ_INDEX = 1;