java - 代码在本地主机上工作正常但在远程服务器上不工作

Question

我有 android 经验，但不熟悉 hibernate 和 advance java。但我必须解决这个问题。请提出建议。

问题是，下面的代码在我的 tomcat 本地主机服务器上运行良好。但显示远程服务器上的错误。当我登录时，它说“登录无效”，尝试使用相同的 ID 密码登录两次或三次。

public String Login() {
        boolean isValidUser = applicationManager.isValidUser(getUserName(), getUserPassword());

        if (isValidUser == false) {
            if (getLang()!=null && getLang().equals("de")) {
                setLang("de");
                addActionMessage("Ungültige Anmeldung");
            } else {
                setLang("en");
                addActionMessage("Invalid login");
            }
            return ERROR;
        } else { 
            session = ActionContext.getContext().getSession();
            session.put("loggedIn","true");
            session.put("userName", getUserName());
            session.put("userPassword", getUserPassword());

            try {

                HttpSession session1;
                session1 = ServletActionContext.getRequest().getSession();
                session1.setAttribute("lang", getLang());
                session1.setAttribute("loggedIn", "true");
                session1.setAttribute("userName", getUserName());
                session1.setAttribute("userPassword", getUserPassword());
            } catch(Exception e) {
                System.out.println(e);
                e.printStackTrace();
            }
            this.countryList = applicationManager.getCountries();
            return SUCCESS;
        }
    }

HibernateUtil.java :

public class HibernateUtil {

    private static final SessionFactory sessionFactory = buildSessionFactory();

    private static SessionFactory buildSessionFactory(){
        try{
            // create session factory from hibernate.cfg.xml
            return new AnnotationConfiguration().configure().buildSessionFactory();
        }catch(Throwable ex){
            System.err.println("Initial SessionFactory creation failed." + ex);
            throw new ExceptionInInitializerError(ex);
        }
    }

    public static SessionFactory getSessionFactory(){
        return sessionFactory;
    }
}

用户管理器.java :

public class UserManager extends HibernateUtil{

    public ArrayList<User> validateUser(String userName,String userPassword){
        Session session = HibernateUtil.getSessionFactory().getCurrentSession();
        session.beginTransaction();
        ArrayList<User> userList =  new ArrayList<User>();
        try{
            Query query = session.createQuery("from User where userName=:userName and userPassword=:userPassword");
            query.setString("userName", userName);
            query.setString("userPassword", userPassword);
            for(Iterator itr = query.iterate();itr.hasNext();){
                User user = (User) itr.next();
                userList.add(user);
            }
            return userList;
        }catch(HibernateException he){
            he.printStackTrace();
            session.getTransaction().rollback();
        }
        session.getTransaction().commit();
        return userList; 
    }
}

Hiberanate.cfg.xml 看起来像这样:

    <hibernate-configuration>
      <session-factory>
          <property name="connection.driver_class">
              com.mysql.jdbc.Driver
          </property>

          <property name="connection.url">
              jdbc:mysql://xxxxx/xxxxx
          </property>

          <property name="connection.username">samir</property>
          <property name="connection.password">samir</property>
          <property name="c3p0.acquire_increment">1</property> 
          <property name="c3p0.idle_test_period">100</property> <!-- seconds --> 
          <property name="c3p0.max_size">100</property> 
          <property name="c3p0.max_statements">0</property> 
          <property name="c3p0.min_size">10</property> 
          <property name="c3p0.timeout">100</property> <!-- seconds -->               
          <property name="dialect">
              org.hibernate.dialect.MySQLDialect
          </property>
          <property name="current_session_context_class">thread</property>
          <property name="cache.provider_class">
              org.hibernate.cache.NoCacheProvider
          </property>
          <property name="show_sql">true</property>
          <property name="hibernate.use_sql_comments">true</property>

          <property name="hbm2ddl.auto">update</property>


          <mapping class="login.model.User" />

      </session-factory>
    </hibernate-configuration>

日志:

  Hibernate: /* from User where userName=:userName and userPassword=:userPassword */ select user0_.USER_ID as col_0_0_ from users user0_ where user0_.USER_NAME=? and user0_.USER_PASSWORD=?
org.hibernate.exception.JDBCConnectionException: could not execute query using iterate
    at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:97)
    at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
    at org.hibernate.loader.hql.QueryLoader.iterate(QueryLoader.java:450)
    at org.hibernate.hql.ast.QueryTranslatorImpl.iterate(QueryTranslatorImpl.java:403)
    at org.hibernate.engine.query.HQLQueryPlan.performIterate(HQLQueryPlan.java:248)
    at org.hibernate.impl.SessionImpl.iterate(SessionImpl.java:1219)
    at org.hibernate.impl.QueryImpl.iterate(QueryImpl.java:69)
    at application.controller.ApplicationManager.isValidUser(ApplicationManager.java:177)
    at application.view.ApplicationAction.Login(ApplicationAction.java:95)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:440)
    at com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:279)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242)
    at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:163)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:249)
    at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:122)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:148)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:93)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:235)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:89)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:128)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at org.apache.struts2.interceptor.ProfilingActivationInterceptor.intercept(ProfilingActivationInterceptor.java:104)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:267)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:126)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:138)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:148)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:128)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:176)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52)
    at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:468)
    at org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:395)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:567)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454)
    at java.lang.Thread.run(Unknown Source)
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: No operations allowed after connection closed.Connection was implicitly closed due to underlying exception/error:


** BEGIN NESTED EXCEPTION ** 

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException
MESSAGE: Communications link failure

Last packet sent to the server was 47 ms ago.

STACKTRACE:

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

Last packet sent to the server was 47 ms ago.
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
    at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1074)
    at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2873)
    at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2763)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3299)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1837)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1961)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2543)
    at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1737)
    at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1888)
    at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:208)
    at org.hibernate.loader.Loader.getResultSet(Loader.java:1808)
    at org.hibernate.loader.Loader.doQuery(Loader.java:697)
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259)
    at org.hibernate.loader.Loader.doList(Loader.java:2228)
    at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2125)
    at org.hibernate.loader.Loader.list(Loader.java:2120)
    at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:401)
    at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:361)
    at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:196)
    at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1148)
    at org.hibernate.impl.QueryImpl.list(QueryImpl.java:102)
    at application.controller.ApplicationManager.getCountries(ApplicationManager.java:34)
    at application.view.ApplicationAction.execute(ApplicationAction.java:90)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:440)
    at com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:279)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242)
    at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:163)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:249)
    at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:122)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:148)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:93)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:235)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:89)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:128)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at org.apache.struts2.interceptor.ProfilingActivationInterceptor.intercept(ProfilingActivationInterceptor.java:104)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:267)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:126)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:138)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:148)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:128)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:176)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
    at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52)
    at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:468)
    at org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:395)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:567)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.io.EOFException: Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.
    at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:2332)
    at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2774)
    ... 86 more


** END NESTED EXCEPTION **


    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
    at com.mysql.jdbc.Util.getInstance(Util.java:381)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:985)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:957)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:927)
    at com.mysql.jdbc.ConnectionImpl.checkClosed(ConnectionImpl.java:1113)
    at com.mysql.jdbc.ConnectionImpl.prepareStatement(ConnectionImpl.java:4038)
    at com.mysql.jdbc.ConnectionImpl.prepareStatement(ConnectionImpl.java:4004)
    at org.hibernate.jdbc.AbstractBatcher.getPreparedStatement(AbstractBatcher.java:534)
    at org.hibernate.jdbc.AbstractBatcher.getPreparedStatement(AbstractBatcher.java:452)
    at org.hibernate.jdbc.AbstractBatcher.prepareQueryStatement(AbstractBatcher.java:161)
    at org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1573)
    at org.hibernate.loader.hql.QueryLoader.iterate(QueryLoader.java:422)
    ... 71 more
org.hibernate.exception.JDBCConnectionException: could not execute query using iterate

Answer 1

(不是答案，而是一些代码注释。)

1) 用小写字母命名函数，例如:

public String login() { ... }

2) 使用规范的 Java 来检查 boolean 值，例如:

if (!isValidUser) { ... }

3) 使用使规范代码正确“读取”的变量名称，例如:

if (!validUser) { ... }

4) 在进行字符串比较时不再需要空检查，例如:

if ("de".equals(getLang()) { ... }

此外，我不清楚 setLang() 是否只是一个用于使用 getLang() 检索的内容的 setter ；这有点令人困惑，并且在没有进一步了解的情况下使那段代码有点奇怪。

5) 不要将有效的用户代码放在相同的条件中；如果是无效用户，则作为特例处理并返回。然后将有效的用户代码与保护子句区分开来，例如:

if (!validUser) {
    // actionMessage stuff.
    return ERROR;
} 

session = ActionContext.getContext().getSession();
// The rest of valid user code.

6) 对 boolean 值使用 boolean 值，例如:

session.put("loggedIn", true);

7) 对作用域变量使用常量，例如:

session = ActionContext.getContext().getSession();
session.put(SessionKeys.LOGGED_IN, true);

8) 使用SessionAware，它使测试更容易； session 只是一个操作属性:

session.put(SessionKeys.LOGGED_IN, true);

9) 当它是完全不同的东西时，不要命名 session1...在这种情况下，它甚至不是不同的东西，所以你把相同的信息放在两次。

10) 访问 Action 属性时保持一致；不要使用setXxx() 和 this.xxx。大多数情况下，无论如何您都可以使用 xxx。

setCountryList(applicationManager.getCountries()); // Or, my preference in most cases:
countryList = appManager.getCountries();

11) 不要按类型命名变量，除非在需要特别区分的情况下，例如:

countries = appManager.getCountries();

这让我们更易于管理:

public String Login() {
    if (!appManager.isValidUser(username, password)) {
        handleInvalidUser();
        return ERROR;
    } 

    session.put(SessionKeys.LANG,          lang);
    session.put(SessionKeys.LOGGED_IN,     true);
    session.put(SessionKeys.USER_NAME,     username);
    session.put(SessionKeys.USER_PASSWORD, password);

    countries = appManager.getCountries();

    return SUCCESS;
}