What is an open source framework?

I never understood what the framework in java meant. For example, what are the three open source frameworks of java?

In fact, the framework is very simple. You can think of it as a tool or even a plug-in.

The function of the framework is to encapsulate a common and commonly used technology.

Help you do some basic things, so that you don't have to write those complicated things.

Take struts, which you want to learn, as an example: it is written in java in essence, which is no different from our own classes. We can achieve whatever it realizes.

For example, we use request.getParameter () to receive data from the client, but if there are many parameters, we have to write a lot, which is very troublesome. Struts will help us realize it. We don't need to write it. Just write an attribute and you can get the arc. In fact, the essence is still request.getParameter (). .

So never mind what the frame is, just touch it. You use it as a tool, and this is the framework.

Is there a difference between an open source framework and an open source project?

Similarities: they are all open source and all projects.

Difference: the framework is for the convenience of developers, not for developers, such as the libevent network framework. A project refers to a scheme made to realize a certain demand. For example, the scheme of developing libevent is one project, and developing network software using libevent is another project.

What is the Java open source framework?

In fact, the framework is very simple. You can think of it as a tool or even a plug-in.

The function of the framework is to encapsulate a common and commonly used technology.

Help you do some basic things, so that you don't have to write those complicated things.

Take struts, which you want to learn, as an example: it is written in java in essence, which is no different from our own classes. We can achieve whatever it realizes.

For example, we use request.getParameter () to receive data from the client, but if there are many parameters, we have to write a lot, which is very troublesome. Struts will help us realize it, and you don't need to write it, just write an attribute to get it. In fact, the essence is still request.getParameter (). .

So never mind what the frame is, just touch it. You use it as a tool, and this is the framework.

Foreground frame: jQuery

Mvc framework: Struts, spring Mvc

Core framework: Spring

Orm framework: Hibernate, Spring JDBC, myBatis.

What are the advantages and disadvantages of the open source crawler framework?

Should we choose Nutch, Crawler4j, WebMagic, scrapy, WebCollector or others to develop web crawler? According to my experience, let's cut the crap: the reptiles mentioned above can basically be divided into three categories: 1. Nutch, a distributed reptile.

2.JAVA single reptile: Crawler4j, WebMagic, WebCollector.

3. Non-JAVA independent crawler: scrapy

The first category: distributed reptiles

Crawlers use distribution, which mainly solves two problems:

1) group address management

2) Internet speed

Now the more popular distributed crawler is Nutch of Apache. But for most users, Nutch is the worst choice among these reptiles for the following reasons:

1)Nutch is a crawler designed for search engines. Most users need a crawler to capture (extract) accurate data. Nutch runs a set of processes, two thirds of which are designed for search engines. It doesn't make much sense for fine extraction. In other words, extracting data with Nutch will waste a lot of time on unnecessary calculations. And if you try to make Nutch suitable for fine extraction business through secondary development, it basically destroys the framework of Nutch, changes Nutch beyond recognition and has the ability to modify Nutch. It's really better to rewrite a distributed crawler framework yourself.

2)Nutch runs on hadoop, which itself consumes a lot of time. If the number of clustered machines is small, the crawling speed is not as fast as that of a single crawler.

3)Nutch has a plug-in mechanism, which is promoted as a highlight. You can see some open source Nutch plug-ins that provide the function of fine extraction. But anyone who has developed Nutch plug-ins knows how lame the Nutch plug-in system is. Using reflection mechanism to load and call plug-ins makes it extremely difficult to write and debug programs, let alone develop complex fine extraction systems on them. Moreover, Nutch does not provide a corresponding plug-in mount point for fine extraction. Nutch plug-ins only have five or six mount points, and these five or six mount points serve search engines, and do not provide mount points for fine extraction. Most of Nutch's fine extraction plug-ins are mounted on the mount point of "parser", which is actually used to parse links (provide URL for subsequent crawling) and provide some easily extracted webpage information (meta-information and text of webpages) for search engines.

4) Using Nutch for secondary development of crawler, the time required for compiling and debugging of crawler is often more than ten times that of single crawler. Learning Nutch source code is very expensive, let alone making everyone in a team understand Nutch source code. During debugging, there will be various problems (hadoop problem, hbase problem) except the program itself.

5) Many people say that Nutch2 has gora, which can persist data to avro files, hbase, mysql and so on. Many people actually misunderstood. The persistent data mentioned here refers to storing URL information (data needed for URL management) in avro, hbase and mysql. This is not the structured data you want to extract. In fact, for most people, it doesn't matter where the website information exists.

The version of Nutch 2 is not suitable for development at present. The official stable version of Nutch is nutch2.2. 1, but this version is bound with gora-0.3. If you want to use hbase with nutch (most people use nutch2 just to use hbase), you can only use hbase of about 0.90 version, and hadoop version should be reduced to about 0.2 accordingly. And nutch2' s official tutorial is misleading. Nutch2 has two tutorials, Nutch 1.x and Nutch2.x, which are written in official website of Nutch2.x and can support hbase 0.94. But in fact, this Nutch2.x refers to the versions before Nutch2.3 and after Nutch2.2. 1, which are constantly updated by SVN officials. And it's very unstable (it's being revised all the time ......

What does an open source and free rapid application development framework mean?

ThinkAndroid is a free, open source and simple Android development framework released according to Apache2 open source protocol. Its development purpose is to develop Android applications simply and quickly, including Android mvc, simple sqlite orm, ioc module, and module encapsulating Android clitent. It has the function of quickly establishing file cache. Regardless of the format of the cached file, it can be easily cached. Based on the file cache module, the image cache function is realized. When loading pictures in android, the oom and dislocation problems of loading pictures can be easily solved. He also includes a utility class that is often used in mobile phone development, such as log management, configuration file management, android downloader module, network switching detection and so on.

At present, ThinkAndroid mainly has the following modules:

MVC module: separating views from the model.

Ioc module: the ioc module in android, which can bind the UI, read the resources in res, and initialize the object in a completely annotated way.

Database module: orm framework in android, using thread pool to operate sqlite.

Module: encapsulating data requests through the client, supporting asynchronous and synchronous loading.

Cache module: Cache can be well realized through simple configuration and design, and the cache can be configured at will.

Image cache module: imageview does not need to consider the phenomenon of image dislocation when the oom and android containers slide quickly during the image loading process.

Configurator module: used to realize simple pairing configuration. Currently, configuration files can support preferences and properties of access configuration.

Log printing module: it can realize log printing quickly and conveniently, and support the expansion of log printing. At present, writing sdcard to local printing and console printing are supported.

Downloader module: it can simply realize multi-thread download, background download, breakpoint continuation, and control the start, pause and deletion of download.

The network state detection module is used for detecting the network state when the network state changes.

What does PHP open source framework mean?

Open source is open source code, which is free ~

Frame Chuan Lou made it very clear, so I won't say much.

Of course, the frameworks are all written in this language. Spring mvc is written in java, and the c# framework is written in c#

Php must also be written in php.

Can someone explain what Android SDK and open source framework mean? 30 points

Just download Baidu and do more.

Is there any difference between the front-end framework and the php open source framework you often hear?

The PHP open source framework is developed for server scripts, such as CakePHP, CodeIgniter and so on. The front-end framework focuses on browser front-end operations, such as jQuery and extJS. In the overall design of the system, there will be a connection between the two. I hope it helps, thank you!

What are the excellent open source Web application development frameworks?

Jquery, Extjs, prototype, kissy, bootstrap, jQuery UI, easy UI, flex, yui, Dojo, etc. There are frameworks that focus on js and css.

What are the advantages and disadvantages of the open source crawler framework?

No matter what kind of crawler open source framework, there is a significant shortcoming, that is, its functions are limited. I write C++ crawler, so I recommend my own general crawler software.

The pre-sniffer crawler tool I wrote has comprehensive collection range, accurate data, excellent grasping performance, simple visual operation and intelligent automatic collection, which enables enterprises to quickly obtain structured or unstructured data on the Internet with little labor cost.

The software can collect almost all the public data on the Internet, and through the visual operation process, from table building, filtering, collection to storage in one step. It supports regular expression operation and has a powerful object-oriented scripting language system.

The single-machine acquisition capacity can reach 40-80 million, and the daily acquisition capacity exceeds 5 million. The single collection capacity of the server can reach 800 million-160,000, and the daily collection capacity exceeds 20 million. Parallel, can support more than10 billion data links, comparable to Baidu and other search engine systems.

Generally speaking, the characteristics are:

(1) comprehensive acquisition. Basically, enter the URL link and operate it step by step. Configuration scripts are also supported if there are special situations that require special handling to collect.

(2) Humanization. Support dynamic adjustment, automatic timing acquisition and online template update.

(3) High operating efficiency. The operation of the Spider crawler is visual, and what you want to collect can be previewed directly in its crawler software, so that I can directly remove invalid data before collecting data, and the learning cost is very low.

(4) High precision. Data extraction can also be visualized, supporting regular expressions and script configuration to achieve more accurate collection.

(5) strong. Support verification code identification, keyword search, login collection and HTTPS protocol. Don't worry about login and verification code restrictions anymore! !

(6) Strong acquisition performance: the acquisition capacity of a single machine can reach 40-80 million, and the daily acquisition capacity exceeds 5 million. The single collection capacity of the server can reach 800 million-160,000, and the daily collection capacity exceeds 20 million. Parallel, can support more than10 billion data links, comparable to Baidu and other search engine systems.