Java Advanced programmer face Test __java

Java Advanced programmer face test

1. What do you think is the most important process in the project?

Try to identify progress priorities in the analysis and design phase

2. If you give a team of 4-6 people, how to assign.

Pick a technically competent person as my substitute. Others distribute tasks evenly, perform a comprehensive task assignment every week, and each person receives a week's work

and report progress Daily.

3. A brief description of the software development document?

Requirements analysis, outline design, detailed design, operation manual, test plan

4. How do you think a project is correct?

Is the maximization of corporate interests.

5. You often read those books.

Java programming idea Java Model man-month myth

6.SPRINGMVC working principle?

Client requests are submitted to the Dispacherservlet by the Dispacherservlet controller to query handlermapping to find the controller to process the request

Controller calls the business logic processing, returns the Modelandview

Dispacherservlet Query view resolution, find Modelandview specified view

View is responsible for displaying the results to the client

What is the difference between 7.SPRINGMVC and struts2?

Mechanism: SPRINGMVC's entrance is the SERVLET,STRUTS2 's inlet is the filter

Performance: SPRINGMVC will be faster than STRUTS2. SPRINGMVC is based on the method design, Struts2 is based on the class, each time the request will be an instance of the action, each action will be injected attributes.

Parameter passing: STRUTS2 is the time to accept parameters, you can use attributes to receive parameters, this description can be used to share multiple methods

Interceptor mechanism: STRUTS2 has its own interceptor mechanism, SPRINGMVC uses independent AOP way, STRTUS2 configuration file is larger than SPRINGMVC, SPRINGMVC use concise, SPRINGMVC is more efficient than struts2 development.

8.struts2 working principle.

Client initiates a request to execute a servlet

This request passes through a series of filters, is called by Filterdispatcher, asks Actionmapper to decide whether to call the action

Filterdispatcher the processing of the request to Actionproxy

Actionproxy the desired action class by asking the relevant profile via Configuraction Manager

Actionproxy Create an instance of Actioninvocation

Actioninvocation the interceptor before and after the action is invoked

After the action completes, the corresponding view page is found according to the Struts.xml configuration file

9.Hibernate working principle.

Read and resolve configuration files

Create Sessionfactory

Open session

Create transaction: Transaction

Persistence operation

Commit a transaction

Close session

Close Sessionfactory

10. Why use Spring?

Spring can be well integrated with the major frameworks

Spring manages object creation and destruction factory patterns through the IOC container

When using Hiberna,mybatis, you can use spring's AOP to manage transactions without having to write the code for the committed transaction every time. AOP is actually a dynamic proxy implementation

Declarative transactions and programmatic transactions

11.mybatis advantages and disadvantages.

Advantages: SQL is written in XML to facilitate unified management and optimization

Provides mapping labels that support ORM field relationship mappings for objects and databases

can be optimized for SQL

Disadvantage: Large SQL workload

Mybagtis transplant surname is not good

Cascading not supported

12. What about SSH integration?

Struts (presentation layer) +spring (business layer) +hibernate (persistence layer)

Struts is a framework for the presentation layer that is used primarily to receive requests and distribute requests. Struts actually belong to the VC level in MVC

Hibernate is a persistent layer framework that is primarily responsible for operations with relational databases

Spring is a framework for a business layer, an integrated framework that can be well bonded to presentation and persistence layers.

What is 13.maven?

is a project management, build tool

Role: Help download Jar search dependencies, help download dependent hot deployment, hot compile

14.WEB front-end optimization.

Reduce the number of HTTP requests (merge CSS, JS, picture)

Using the browser's caching mechanism

Using the gzip compressor system: Only for text-class resources effective

Put the CSS file at the beginning of HTML

Put JavaScript files at the end of HTML

Avoid CSS expressions (judging browsers)

Using JavaScript compression

Reduce DNS Lookup

Avoid redirection

Using Ajax

15. Security Testing

Exploit security testing techniques to identify potential vulnerabilities

16. Transaction ISOLATION Level (4 kinds)

Serializable (serialization): A transaction does not see anything else in the execution of an update to the database (the transaction executes without allowing other transactions to execute concurrently, and the transaction can only be executed one after the other, not concurrently)

REPEATABLE READ (REPEATABLE): A transaction can see new inserted records that other transactions have committed during execution, but cannot see updates to existing records by other transactions

Read commited (reading submitted data): A transaction can see new inserted records that other transactions have committed during execution, and can see updates to existing records that have been committed by other transactions.

READ UNCOMMITTED (Reading uncommitted data): A transaction can see updates of newly inserted records that are not submitted by other transactions during execution, and can see that other transactions are not committed to an update of an existing record

17.MYSQL Storage Engine (4 kinds)

MyISAM it does not support transactions, nor does it support foreign keys, especially when access is fast, there is no requirement for transactional integrity or a SELECT, insert-oriented application can basically use this engine to create a table.

Each myisam is stored on disk as 3 files, with the same filename and table name, but the extension is:. frm (storage table definition), YD (MYData, storing data), myi (Myindex, storage index), InnoDB, The InnoDB storage engine provides transaction security with commit, rollback, and crash recovery capabilities. However, compared to the MyISAM storage engine, InnoDB writes less efficiently and consumes more disk space to preserve data and indexes.

1 automatic Growth column 2) FOREIGN KEY constraint

MEMORY

Memory creates a table using content that exists in memory. Each memory table actually corresponds to a disk file, in the format of. frm. Table access of the memory type is very fast because it is in memory and the hash index is used by default, but once the server shuts down, the data in the table is lost, but the table continues to exist.

MERGE

The merge storage engine is a combination of a set of MyISAM tables that must be exactly the same, with no data in the merge table, and queries, updates, deletes for tables of the merge type, which actually operate on the internal MyISAM table.

18. Transactional propagation characteristics

1. Propagation_required: If a transaction exists, the current transaction is supported. Open if there is no transaction

2. Propagation_supports: If there is a transaction, the current transaction is supported. If there is no transaction, the execution of the non-transaction

3. Propagation_mandatory: If a transaction already exists, the current transaction is supported. If there is no active transaction, an exception is thrown.

4. Propagation_requires_new: Always open a new transaction. If a transaction already exists, the transaction that exists is suspended.

5. Propagation_not_supported: Always executes in a non transactional manner and suspends any existing transactions.

6. Propagation_never: Always execute in a non transactional manner, throw an exception if there is an active transaction

7. propagation_nested: If an active transaction exists, it is run in a nested transaction. If there is no active transaction,

20.TCP Protocol (Control Protocol Transmission Control Protocol)

Establish link: three times handshake (1. Dial 2 for each other. Hello, hello, who is the 3 I am Xiao Liu)

Close link: four times wave to ensure reliable

What's 21.shiro?

The Apache Shiro is a powerful and Easy-to-use Java security framework that provides authentication, authorization, encryption, and session management capabilities.

Authentication: Authenticate the user to verify their identity

Authorization: Session Management

22. Project Technology

Front Desk: Customer facing

Front end: CSS Div js jquery

Back end: Springmvc Spring MyBatis

Optimized technology for use:

1. Page static (Freemarker)

2. Caching

2.1 Page Cache (Oscache)