编写 Session Bean类 public class Converter Bean implements Session Bean public double dollar ToYen(double dollars Context initCtx Double dollars ToYen null try initCtx new InitialContext(; myEnv=(Context)initCtx lookup(java: comp/env); dollarsToYen Double)my Env. lookup dollarsToYen ); catch(NamingException nek ne printstackTrace o; return dollarsToYen doubleValueo* dollars; public double yen ToEuro(double yen )类似 dollar ToYe的实现 } public Converter Beano合 商业方法实现 public void ejbcreate()仆 从EB环境中查找环境 public void ejbRemoveot 条目 dollarsToYen(美元对日元汇 public void ejbPassivateot 率),根据其值进行币值换算 public void ejbActivateot public void setSession Context(Session Context Cont }编写Session Bean类 public class ConverterBean implements SessionBean{ public double dollarToYen(double dollars){ Context initCtx, myEnv; Double dollarsToYen = null; try{ initCtx = new InitialContext(); myEnv = (Context)initCtx.lookup("java:comp/env"); dollarsToYen = (Double)myEnv.lookup("dollarsToYen"); }catch(NamingException ne){ ne.printStackTrace(); } return dollarsToYen.doubleValue() * dollars; } public double yenToEuro(double yen){ //类似dollarToYen的实现 } public ConverterBean() {} public void ejbCreate() {} public void ejbRemove() {} public void ejbPassivate() {} public void ejbActivate() {} public void setSessionContext(SessionContext Context) {} } 商业方法实现： 从EJB环境中查找环境 条目dollarsToYen（美元对日元汇 率），根据其值进行币值换算