A, Spring face questions
1, Spring What role in ssm in?
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Spring: lightweight frameworks
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Role: Bean plant Bean used to manage the life cycle and integrated framework.
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Two core: 1, IOC / DI (Inversion of Control / Dependency injection): The dao dependency injection into the service layer, service action to the inversion layer layer, Spring top container is BeanFactory. 2, AOP: Aspect Oriented Programming
2, Spring of affairs?
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Programmatic transaction management: programmatic transaction management, great flexibility, difficult to maintain.
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Declarative transaction management: service code and transaction management can be separated, with annotations and xml configured to manage transactions.
3, the role of IOC in the project?
Role: Ioc resolution of dependencies between objects, all the dependencies Bean through configuration files or annotations associate, reducing the degree of coupling.
4, Spring configuration file contents?
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Open annotation-driven transactions
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Transaction Manager
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Open comments, and configure the scan package
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Configuration database
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SQL session factory configuration, alias, mapping file
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Instead of writing class that implements layer Dao
5, notes in Spring?
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Registration: @Controller @Service @Component
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Injection: @Autowired @Resource
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Request Address: @RequestMapping
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Return specific data types and not Jump: @ResponseBody
6, Spring DI of three ways?
Constructor injection: initializing constructor
<constructor-arg index = "0" type = "java.lang.String" value = "宝马" ></constructor-arg>
Method setter injection: initializing method setter
<property name = "id" value = "1111" ></property>
Interface injection
7, Spring mainly used what model?
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Factory mode: Each method created by Bean
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Singleton pattern: The default for each Bean scopes are single cases
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Proxy mode: Aop achieved through a proxy mode on the
8, IOC, AOP implementation principle?
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IOC: generating a reflection by the object injection
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AOP: Dynamic Proxy
Two, SpringMvc face questions
1, SpringMvc controller is not a singleton, and if so, what is the problem, how to solve?
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Question: singleton, thread-safe in a multithreaded access problems
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Solution: Do not use sync, you can not write field controller inside
2, notes SpringMvc the controller?
@Controller: This comment indicates that the class role-playing controller
3, @ RequestMapping comment on the role of class with?
Action: used to map a URL to a particular class or a method of treatment
4, the front desk multiple parameters, which is an object, the object quickly get?
Method: Direct declare this object in a method, SpringMvc will automatically assign attributes to this object inside
5, SpringMvc the return value of a function?
String，ModelAndView，List，Set 等
General String, Ajax request, returns a List collection
6, SpringMvc forwarding and redirection?
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Forwarding: return: "hello"
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Redirect: return: "redirect: hello.jsp"
7, call each other between SpringMvc and Ajax?
JackSon frame by which the object is directly converted into java json js identifiable objects, the following steps:
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Join JackSon.jar
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Json configuration mapping in the configuration file
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Back Object, list the like directly inside the receiving method Ajax foregoing method requires annotate @ResponseBody
8, SpringMvc work flow chart?
9, Struts2 and SpringMvc difference?
Different entrance:
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Struts2: filter filters
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SpringMvc: a front controller Servlet i.e.
Development of different ways:
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Struts2: development class, attribute parameters passed based on the class, only to cases of
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SpringMvc: Based Method Development (a method corresponding to a url), request parameters passed to the method parameter, a single embodiment may also be cases of (singleton recommended)
Request different ways:
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Struts2：值栈村塾请求和响应的数据，通过OGNL存取数据
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SpringMvc：通过参数解析器将request请求内容解析，给方法形参赋值，将数据和视图封装成ModelAndView对象，最后又将ModelAndView中的模型数据通过request域传输到页面，jsp视图解析器默认使用的是jstl。
三、Mybatis面试题
1、Ibatis和Mybatis？
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Ibatis：2010年，apache的Ibatis框架停止更新，并移交给了google团队，同时更名为MyBatis。从2010年后Ibatis在没更新过，彻底变成了一个孤儿框架。一个没人维护的框架注定被mybatis拍在沙滩上。
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Mybatis：Ibatis的升级版本。
2、什么是Mybatis的接口绑定，有什么好处？
Mybatis实现了DAO接口与xml映射文件的绑定，自动为我们生成接口的具体实现，使用起来变得更加省事和方便。
3、什么情况用注解，什么情况用xml绑定？
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注解使用情况：Sql语句简单时
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xml绑定使用情况：xml绑定 (@RequestMap用来绑定xml文件)
4、Mybatis在核心处理类叫什么?
SqlSession
5、查询表名和返回实体Bean对象不一致，如何处理？
映射键值对即可
<result column = "title" property = "title" javaType = "java.lang.String" />
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column：数据库中表的列名
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property：实体Bean中的属性名
6、Mybatis的好处？
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把Sql语句从Java中独立出来。
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封装了底层的JDBC，API的调用，并且能够将结果集自动转换成JavaBean对象，简化了Java数据库编程的重复工作。
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自己编写Sql语句，更加的灵活。
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入参无需用对象封装（或者map封装）,使用@Param注解
7、Mybatis配置一对多？
<collection property = "topicComment" column = "id" ofType = "com.tmf.bbs.pojo.Comment" select = "selectComment" />
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property：属性名
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column：共同列
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ofType：集合中元素的类型
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select：要连接的查询
8、Mybatis配置一对一？
<association property = "topicType" select = "selectType" column = "topics_type_id" javaType = "com.tmf.bbs.pojo.Type" />
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property：属性名
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select：要连接的查询
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column：共同列
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javaType：集合中元素的类型
9 、${} 和 #{}的区别？
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${}：简单字符串替换，把${}直接替换成变量的值，不做任何转换，这种是取值以后再去编译SQL语句。
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#{}：预编译处理，sql中的#{}替换成？，补全预编译语句，有效的防止Sql语句注入，这种取值是编译好SQL语句再取值。
总结：一般用#{}来进行列的代替
10、获取上一次自动生成的主键值？
select last _insert_id()
11、Mybatis如何分页，分页原理？
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RowBounds对象分页
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在Sql内直接书写，带有物理分页
12、Mybatis工作原理？
原理：
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通过SqlSessionFactoryBuilder从mybatis-config.xml配置文件中构建出SqlSessionFactory。
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SqlSessionFactory开启一个SqlSession，通过SqlSession实例获得Mapper对象并且运行Mapper映射的Sql语句。
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完成数据库的CRUD操作和事务提交，关闭SqlSession。
最后
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