private String update(final PluginDTO pluginDTO) {
        Assert.isNull(pluginMapper.nameExistedExclude(pluginDTO.getName(), Collections.singletonList(pluginDTO.getId())), AdminConstants.PLUGIN_NAME_IS_EXIST + pluginDTO.getName());
        if (Objects.nonNull(pluginDTO.getFile())) {
            Assert.isTrue(checkFile(Base64.decode(pluginDTO.getFile())), AdminConstants.THE_PLUGIN_JAR_FILE_IS_NOT_CORRECT_OR_EXCEEDS_16_MB);
        }
        final PluginDO before = pluginMapper.selectById(pluginDTO.getId());
        PluginDO pluginDO = PluginDO.buildPluginDO(pluginDTO);
        if (pluginMapper.updateSelective(pluginDO) > 0) {
            // publish update event.
            pluginEventPublisher.onUpdated(pluginDO, before);
        }
        return ShenyuResultMessage.UPDATE_SUCCESS;
    }
update plugin.<br>

@param pluginDTO plugin
@return success is empty
shenyu-admin/src/main/java/org/apache/shenyu/admin/service/impl/PluginServiceImpl.java