st.close(); } if (con != null) { con.close(); } ... Inside the finally block, we close the database resources. We also check if the objects are not equal to null. This is to prevent ENGINE=InnoDB; CREATE TABLE IF NOT EXISTS Books(Id INT PRIMARY KEY AUTO_INCREMENT, AuthorId INT, Title VARCHAR(100), FOREIGN KEY(AuthorId) REFERENCES Authors(Id) ON DELETE CASCADE) ENGINE=InnoDB; INSERT INTO Books(Id, AuthorId, Title) VALUES(1, 1, 'Call of the Wild'); INSERT INTO Books(Id, AuthorId, Title) VALUES(2, 1, 'Martin Eden'); INSERT INTO Books(Id, AuthorId, Title) VALUES(3, 2, 'Old Goriot');

html): <title>Apache Wicket HelloWorldtitle>

html): <title>Apache Wicket HelloWorldtitle>

html): <title>Apache Wicket HelloWorldtitle>

html): <title>Apache Wicket HelloWorldtitle>

Formatter extends Printer, Parser { } Where Formatter extends from the Printer and Parser building-block interfaces: public interface Printer { String print(T fieldValue, Locale locale); } import getValue(Boolean.class); // evaluates to true boolean trueValue = parser.parseExpression("'black' < 'block'").getValue(Boolean.class); Note Greater/less-than comparisons against null follow a simple rule: Expression templates allow a mixing of literal text with one or more evaluation blocks. Each evaluation block is delimited with prefix and suffix characters that you can define, a common choice is to use #{ }

Formatter extends Printer, Parser { } Where Formatter extends from the Printer and Parser building-block interfaces: public interface Printer { String print(T fieldValue, Locale locale); } import getValue(Boolean.class); // evaluates to true boolean trueValue = parser.parseExpression("'black' < 'block'").getValue(Boolean.class); In addition to standard relational operators SpEL supports the instanceof Expression templates allow a mixing of literal text with one or more evaluation blocks. Each evaluation block is delimited with prefix and suffix characters that you can define, a common choice is to use #{ }

9 System.out.println(”index err”); 10 return; 11 } finally { 12 System.out.println(”in finally block!”); 13 } 14 System.out.println(”this is the end”); 15 } 16 } 注意，不论 try 代码块中是否发生了异常事件，finally . . . . 中国海洋大学信息学院计算机系 第 156 页 / 共 306 页 12.2. JAVA 异常处理机制 � 12 � Kessy index err in finally block! 12.2.3 操纵异常对象 发生异常时，系统将自动创建异常类对象，并将作为实参传递给匹配的 catch 语 句块的形参，这样我们就可以在语句块中操纵该异常对象了。主要使用异常类的父类 Throwable 般由程序、数据集合和进程控制块三 部分组成。程序用于描述进程要完成的功能，是控制进程执行的指令集；数据集合是 程序在执行时所需要的数据和工作区；进程控制块 (Program Control Block，简称 PCB)， 包含进程的描述信息和控制信息，是进程存在的唯一标志。 进程具有的特征： 动态性 进程是程序的一次执行过程，是临时的，有生命期的，是动态产生，动态消亡 的； 并发性 任何进程都可以同其他进程一起并发执行；

details, such as the user that launched the application. <title>Startup Failuretitle> If your application fails to start, registered FailureAnalyzers get a chance to provide See AnsiPropertySource for details. ${application.title} The title of your application, as declared in MANIFEST.MF. For example Implementation-Title: MyApp is printed as MyApp. Tip The SpringApplication time (in milliseconds) a connection allocation should block before throwing an exception when the pool is exhausted. Use a negative value to block indefinitely. spring.redis.jedis.pool.min-idle=0 # Target

details, such as the user that launched the application. <title>Startup Failuretitle> If your application fails to start, registered FailureAnalyzers get a chance to provide See AnsiPropertySource for details. ${application.title} The title of your application, as declared in MANIFEST.MF. For example Implementation-Title: MyApp is printed as MyApp. Tip The SpringApplication time (in milliseconds) a connection allocation should block before throwing an exception when the pool is exhausted. Use a negative value to block indefinitely. spring.redis.jedis.pool.min-idle=0 # Target