[JavaSE实验] JDBC and MySQL 1 JDBC JDBC is an API for the Java programming language that defines how a client may access a database. It provides methods for querying and updating data in a database. JDBC is oriented point of view, the API is as a set of classes in the java.sql package. To use JDBC with a particular database, we need a JDBC driver for that database. 2 About MySQL database MySQL is a leading open source click on the Libraries node and select Add Library option. From the list of options, select MySQL JDBC Driver. 4 Installation and Testing If you don't already have MySQL installed, we must install it

Authrizer：授权器，或者访问控制器，用来决定主体是否有权限进行相应的操作；即控制 着用户能访问应用中的哪些功能； Realm：可以有 1 个或多个 Realm，可以认为是安全实体数据源，即用于获取安全实体的； 可以是 JDBC 实现，也可以是 LDAP 实现，或者内存实现等等；由用户提供；注意：Shiro 跟我学 Shiro——http://jinnianshilongnian.iteye.com/ 8 Memcached 服务器）； SessionDAO：DAO 大家都用过，数据访问对象，用于会话的 CRUD，比如我们想把 Session 保存到数据库，那么可以实现自己的 SessionDAO，通过如 JDBC 写到数据库；比如想把 Session 放到 Memcached 中，可以实现自己的 Memcached SessionDAO；另外 SessionDAO 中可以使用 Cache 进行缓存，以提高性能； username=password,role1,role2 指定用户 名/密码及其角色；role.role1=permission1,permission2 指定角色及权限信息； org.apache.shiro.realm.jdbc.JdbcRealm：通过 sql 查询相应的信息，如“select password from users where username = ?”获取用户密码，“select password

时，源码中会新建上面提到的 PoolHttpConnectionManager，然后调用 oss lient 存取数据时，PoolHttpConnectionManager 会从内部维护的 http 连接池中找到可用连接，进 操作。
这没问题，大多是框架都是这么设计的。
既然 JVM 堆内存中有 160 多万个 PoolHttpConnectionManager 对象，说明肯定是有地方把内次

Access with JDBC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 3.1. Choosing an Approach for JDBC Database Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 3.3. Using the JDBC Core Classes to Control Basic JDBC Processing and Error Handling . . . . . . . . . 70 3.3.1. Using JdbcTemplate . DataSourceTransactionManager / JdbcTransactionManager . . . . . . . . . . . . . . . . . . . . . . . . 92 3.5. JDBC Batch Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

....................................................................... 104 10. Data Access using JDBC ................................................................................................. ........................................................... 105 10.2. Using the JDBC Core classes to control basic JDBC processing and error handling .................................................. .............................................................................. 110 10.4. Modeling JDBC operations as Java objects ......................................................................

Support ...................................................................... 112 11. Data Access using JDBC ................................................................................................. ........................................................... 113 11.2. Using the JDBC Core classes to control basic JDBC processing and error handling .................................................. .............................................................................. 118 11.4. Modeling JDBC operations as Java objects ......................................................................

Support ...................................................................... 123 11. Data Access using JDBC ................................................................................................. ........................................................... 124 11.2. Using the JDBC Core classes to control basic JDBC processing and error handling .................................................. .............................................................................. 129 11.4. Modeling JDBC operations as Java objects ......................................................................

....................................................................... 104 10. Data Access using JDBC ................................................................................................. ........................................................... 105 10.2. Using the JDBC Core classes to control basic JDBC processing and error handling .................................................. .............................................................................. 110 10.4. Modeling JDBC operations as Java objects ......................................................................

Support ...................................................................... 112 11. Data Access using JDBC ................................................................................................. ........................................................... 113 11.2. Using the JDBC Core classes to control basic JDBC processing and error handling .................................................. .............................................................................. 118 11.4. Modeling JDBC operations as Java objects ......................................................................

Support ...................................................................... 112 11. Data Access using JDBC ................................................................................................. ........................................................... 113 11.2. Using the JDBC Core classes to control basic JDBC processing and error handling .................................................. .............................................................................. 118 11.4. Modeling JDBC operations as Java objects ......................................................................