JBuilder
欢迎页面welcome.jsp
当用户录入正确的密码后,switch.jsp控制JSP页面导向welcome.jsp欢迎页面,在这节里,我们来开发这个welcome.jsp页面。因为welcome.jsp需要使用到一个第三方的标签库,所以在开发welcome.jsp之前需要在JBuilder中作一些配置引入这个标签库。
将第三方标签库配置到JBuilder中
Apache开源组织提供了许多有用标签库,欢迎页面welcome.jsp需要使用一个来源于Apache的datetime标签库,可以用这个标签库在JSP中提供各种时间的显示,下载的地址是:http://apache.justdn.org/jakarta/taglibs/datetime/binaries/jakarta-taglibs-datetime-1.0.1.zip。
标签库一般包括两个文件,其一是类包JAR文件,其二是以.tld为扩展名的标签符描述文件。从下载的压缩文档中解压后,我们将taglibs-datetime.jar和taglibs-datetime.tld文件放到<工程目录>/datetimeTag目录下。
要在工程中使用第三方的标签库,必须事先在JBuilder中配置这个标签库,并在工程中引用它。配置标签库和配置类库相似,也是通过Configure Libraries对话框来完成。JBuilder类库及标签库都列在Configure Libraries对话框中左边的树中,类库显示为 图标,而标签库显示为
图标。下面我们来将datetime标签库配置到JBuilder中。
1.Tools->Configure->Libraries->Configure Libraries对话框。
点击Configure Libraries对话框的左下角的Add...按钮,弹出New Library Wizard对话框,如下图所示:

Stored procedures are precompiled SQL statements in MySQL for improving performance and simplifying complex operations. 1. Improve performance: After the first compilation, subsequent calls do not need to be recompiled. 2. Improve security: Restrict data table access through permission control. 3. Simplify complex operations: combine multiple SQL statements to simplify application layer logic.

The working principle of MySQL query cache is to store the results of SELECT query, and when the same query is executed again, the cached results are directly returned. 1) Query cache improves database reading performance and finds cached results through hash values. 2) Simple configuration, set query_cache_type and query_cache_size in MySQL configuration file. 3) Use the SQL_NO_CACHE keyword to disable the cache of specific queries. 4) In high-frequency update environments, query cache may cause performance bottlenecks and needs to be optimized for use through monitoring and adjustment of parameters.

The reasons why MySQL is widely used in various projects include: 1. High performance and scalability, supporting multiple storage engines; 2. Easy to use and maintain, simple configuration and rich tools; 3. Rich ecosystem, attracting a large number of community and third-party tool support; 4. Cross-platform support, suitable for multiple operating systems.

The steps for upgrading MySQL database include: 1. Backup the database, 2. Stop the current MySQL service, 3. Install the new version of MySQL, 4. Start the new version of MySQL service, 5. Recover the database. Compatibility issues are required during the upgrade process, and advanced tools such as PerconaToolkit can be used for testing and optimization.

MySQL backup policies include logical backup, physical backup, incremental backup, replication-based backup, and cloud backup. 1. Logical backup uses mysqldump to export database structure and data, which is suitable for small databases and version migrations. 2. Physical backups are fast and comprehensive by copying data files, but require database consistency. 3. Incremental backup uses binary logging to record changes, which is suitable for large databases. 4. Replication-based backup reduces the impact on the production system by backing up from the server. 5. Cloud backups such as AmazonRDS provide automation solutions, but costs and control need to be considered. When selecting a policy, database size, downtime tolerance, recovery time, and recovery point goals should be considered.

MySQLclusteringenhancesdatabaserobustnessandscalabilitybydistributingdataacrossmultiplenodes.ItusestheNDBenginefordatareplicationandfaulttolerance,ensuringhighavailability.Setupinvolvesconfiguringmanagement,data,andSQLnodes,withcarefulmonitoringandpe

Optimizing database schema design in MySQL can improve performance through the following steps: 1. Index optimization: Create indexes on common query columns, balancing the overhead of query and inserting updates. 2. Table structure optimization: Reduce data redundancy through normalization or anti-normalization and improve access efficiency. 3. Data type selection: Use appropriate data types, such as INT instead of VARCHAR, to reduce storage space. 4. Partitioning and sub-table: For large data volumes, use partitioning and sub-table to disperse data to improve query and maintenance efficiency.

TooptimizeMySQLperformance,followthesesteps:1)Implementproperindexingtospeedupqueries,2)UseEXPLAINtoanalyzeandoptimizequeryperformance,3)Adjustserverconfigurationsettingslikeinnodb_buffer_pool_sizeandmax_connections,4)Usepartitioningforlargetablestoi


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