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学习笔记：使用JSF构建数据库驱动的应用程序

摘要: 学习笔记：使用JSF构建数据库驱动的应用程序

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看了《使用JSF 构建数据库驱动的应用程序》一文后，动手做了练习。这是一个订阅时事通讯的示例 Web 应用程序。订户通过提供他们的电子邮件地址、姓名和首选项进行注册。他们还必须选择一个口令, 以便以后可以更改他们的配置文件。收获不少。

1、

这个没有什么可说的。

2、

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<%@ taglib prefix="c" uri="http://java.sun.com/jstl/core" %>
<%@ taglib prefix="f" uri="http://java.sun.com/jsf/core" %>
<%@ taglib prefix="h" uri="http://java.sun.com/jsf/html" %>

<head>
<h:outputText value="#{labels.login}"/>
<link> rel="stylesheet" type="text/css" href="">
</head>
<body>

</body>

典型的jstl加jsf,看来要好好学习jsp2.0了，赶上不形势啊！
点击链接 Subscribe可进入subscribe.jsp(如图一),填订单页面。
命令按钮的"action"绑定到了视图loginInfo Bean的loginAction()方法， loginAction() 方法会根据登录用户的角色（订户或管理员）返回 profile 或 list（导航法则在faces-config.xml文件中定义），请求转向订户修改配置文件页面 profile.jsp（图二）或订户列表页面 list.jsp（图三）。先看看LoginInfoBean.java源码：

package jsfdb.view;

import jsfdb.model.LoginInfo;

import jsfdb.model.Subscriber;

import jsfdb.model.ModelUtils;

import jsfdb.model.err.LoginException;

import jsfdb.model.err.IncorrectPasswordException;

import jsfdb.model.err.UnknownSubscriberException;

public class LoginInfoBean extends LoginInfo {

    public String loginAction() {

         //初始化一个SubscriberBean对象

        SubscriberBean subscriber= (SubscriberBean) ViewUtils.eval("#{subscriber}");

        //获取管理员的邮件地址，管理员的邮件在web.xml文件中配置

        String adminEmail= (String) ViewUtils.eval("#{initParam.adminEmail}");

        try {

            Subscriber selectedSubscriber

                = ModelUtils.getSubscriberDAO().select(this);//通过数据库验证口令与email

            ModelUtils.copy(selectedSubscriber, subscriber);//订户数据复制进视图bean

            subscriber.setLoggedIn(true);//登录标志设为true

            if (subscriber.getEmail().equals(adminEmail))

                return "list";//如果是超级管理员，转向list.jsp

            else

                return "profile";//如果是订户，转向profile.jsp

        } catch (LoginException x) {

            ViewUtils.addExceptionMessage(x);

            return null;

        } catch (UnknownSubscriberException x) {

            ViewUtils.addExceptionMessage(x);

            return null;

        } catch (IncorrectPasswordException x) {

            ViewUtils.addExceptionMessage(x);

            return null;

        }

    }

}

图一（填订单）

<%@ taglib prefix="c" uri="http://java.sun.com/jstl/core" %>
<%@ taglib prefix="f" uri="http://java.sun.com/jsf/core" %>
<%@ taglib prefix="h" uri="http://java.sun.com/jsf/html" %>

<head>
<h:outputText value="#{labels.subscribe}"/>
<link> rel="stylesheet" type="text/css" href="">
</head>
<body>

size="40" maxlength="80">

</body>

这是SubscriberBean.java源码

package jsfdb.view;

import jsfdb.model.Subscriber;

import jsfdb.model.ModelUtils;

import jsfdb.model.err.ProfileException;

import jsfdb.model.err.SubscribeException;

import jsfdb.model.err.UnsubscribeException;

import javax.faces.component.UIComponent;

import javax.faces.component.EditableValueHolder;

import javax.faces.context.FacesContext;

public class SubscriberBean extends Subscriber {

    public final static String INVALID_EMAIL_ID

        = "jsfdb.view.SubscriberBean.INVALID_EMAIL";

    public final static String SELECT_NEWSLETTER_ID

        = "jsfdb.view.SubscriberBean.SELECT_NEWSLETTER";

    private transient boolean loggedIn = false;

    public boolean isLoggedIn() {

        return loggedIn;

    }

    public void setLoggedIn(boolean loggedIn) {

        this.loggedIn = loggedIn;

    }

    public void emailValidator(FacesContext context, UIComponent comp, Object value) {

        String email = (String) value;

        if (email.indexOf("@") == -1) {

            String compId = comp.getClientId(context);

            ViewUtils.addErrorMessage(context, compId, INVALID_EMAIL_ID);

            ((EditableValueHolder) comp).setValid(false);

        }

    }

    public String subscribeAction() {

        if (countNewsletters() == 0) {

            ViewUtils.addErrorMessage(

                FacesContext.getCurrentInstance(),

                null, SELECT_NEWSLETTER_ID);

            return null;

        }

        try {

            ModelUtils.getSubscriberDAO().insert(this);

            setLoggedIn(true);

            return "subscribed";

        } catch (SubscribeException x) {

            ViewUtils.addExceptionMessage(x);

            return null;

        }

    }

    public String profileAction() {

        if (!loggedIn)

            return "login";

        if (countNewsletters() == 0) {

            ViewUtils.addErrorMessage(

                FacesContext.getCurrentInstance(),

                null, SELECT_NEWSLETTER_ID);

            return null;

        }

        try {

            ModelUtils.getSubscriberDAO().update(this);

            return null;

        } catch (ProfileException x) {

            ViewUtils.addExceptionMessage(x);

            return null;

        }

    }

    public String unsubscribeAction() {

        if (!loggedIn)

            return "login";

        try {

            ModelUtils.getSubscriberDAO().delete(this);

            return "unsubscribed";

        } catch (UnsubscribeException x) {

            ViewUtils.addExceptionMessage(x);

            return null;

        }

    }

    public String cancelAction() {

        if (!loggedIn)

            return "login";

        else

            return "cancel";

    }

    public int getDailyConst() {

        return TYPE_DAILY;

    }

    public int getWeeklyConst() {

        return TYPE_WEEKLY;

    }

    public int getMonthlyConst() {

        return TYPE_MONTHLY;

    }

}

这是修改配置的页面：



图二

再看看list.jsp

图三

<%@ page contentType="text/html; charset=gb2312" %>

<%@ taglib prefix="c" uri="http://java.sun.com/jstl/core" %>
<%@ taglib prefix="sql" uri="http://java.sun.com/jstl/sql" %>
<%@ taglib prefix="f" uri="http://java.sun.com/jsf/core" %>
<%@ taglib prefix="h" uri="http://java.sun.com/jsf/html" %>

SELECT * FROM subscribers ORDER BY subscriberEmail

<head>
<h:outputText value="#{labels.list}"/>
<link> rel="stylesheet" type="text/css" href="">
</head>
<body>

</body>

这个页面用jstl标记访问数据库！

数据适配层和数据访问对象DAO

这个应用通过ModelUtils类访问后端数据源, 提供了 SubscriberDAO 接口的两个实现，一个(JDBCSubscriberDAO.java)基于 JDBC API，另一个(TopLinkSubscriberDAO.java)使用 Oracle TopLink。下面是ModelUtils类的源码:

package jsfdb.model;

import jsfdb.model.dao.SubscriberDAO;

import java.beans.BeanInfo;

import java.beans.Introspector;

import java.beans.PropertyDescriptor;

import java.beans.IntrospectionException;

import java.lang.reflect.Method;

import java.lang.reflect.InvocationTargetException;

import java.util.ResourceBundle;

import java.util.MissingResourceException;

import java.util.logging.Level;

import java.util.logging.Logger;

public class ModelUtils {

    public static final String RESOURCES

        = ModelUtils.class.getPackage().getName() + ".res.ModelResources";

    private static ResourceBundle resources;

    private static SubscriberDAO subscriberDAO;

    public static void log(Throwable x) {

        Logger.global.log(Level.SEVERE, x.getMessage(), x);

    }

    public static synchronized ResourceBundle getResources() {

        if (resources == null)

            try {

                resources = ResourceBundle.getBundle(RESOURCES);

            } catch (MissingResourceException x) {

                log(x);

                throw new InternalError(x.getMessage());

            }

        return resources;

    }

    public static String getResource(String key) {

        return getResources().getString(key);

    }

    public synchronized static SubscriberDAO getSubscriberDAO() {

        if (subscriberDAO == null)

            try {

                Class daoClass = Class.forName(getResource("DAO"));

                subscriberDAO

                    = (SubscriberDAO) daoClass.newInstance();

            } catch (ClassNotFoundException x) {

                log(x);

                throw new InternalError(x.getMessage());

            } catch (IllegalAccessException x) {

                log(x);

                throw new InternalError(x.getMessage());

            } catch (InstantiationException x) {

                log(x);

                throw new InternalError(x.getMessage());

            }

        return subscriberDAO;

    }

    public static void copy(Object source, Object dest) {

        try {

            Class sourceClass = source.getClass();

            Class destClass = dest.getClass();

            BeanInfo info = Introspector.getBeanInfo(sourceClass);

            PropertyDescriptor props[]

                = info.getPropertyDescriptors();

            Object noParams[] = new Object[0];

            Object oneParam[] = new Object[1];

            for (int i = 0; i < props.length; i++) {

                Method getter = props[i].getReadMethod();

                if (getter == null)

                    continue;

                Object value = getter.invoke(source, noParams);

                Method setter = props[i].getWriteMethod();

                if (setter != null && sourceClass != destClass)

                    try {

                        setter = destClass.getMethod(

                            setter.getName(),

                            setter.getParameterTypes());

                    } catch (NoSuchMethodException x) {

                        setter = null;

                    }

                if (setter != null) {

                    oneParam[0] = value;

                    setter.invoke(dest, oneParam);

                }

            }

        } catch (IntrospectionException x) {

            log(x);

            throw new InternalError(x.getMessage());

        } catch (IllegalAccessException x) {

            log(x);

            throw new InternalError(x.getMessage());

        } catch (IllegalArgumentException x) {

            log(x);

            throw new InternalError(x.getMessage());

        } catch (SecurityException x) {

            log(x);

            throw new InternalError(x.getMessage());

        } catch (InvocationTargetException x) {

            log(x.getTargetException());

            throw new InternalError(

                x.getTargetException().getMessage());

        }

    }

}

此类的getSubscriberDAO()方法返回 SubscriberDAO 接口的一个实例，该接口定义了在关系数据库中选择、删除、插入、更新 Subscriber 对象的方法。你的应用中具体使用哪一个后端数据源,在 ModelResources资源包有一个 DAO 参数，用于指定要使用的 DAO 实现.

这是ModelResources.properties文件:

DAO=jsfdb.model.dao.JDBCSubscriberDAO

# DAO=jsfdb.model.dao.TopLinkSubscriberDAO
TopLinkSession=JSFDBSession

JavaCompEnv=java:comp/env
DataSource=jdbc/OracleDS

SelectStatement=SELECT \
subscriberPassword, \
subscriberName, \
managerFlag, \
developerFlag, \
administratorFlag, \
subscriptionType \
FROM subscribers \
WHERE subscriberEmail=?

InsertStatement=INSERT INTO subscribers ( \
subscriberEmail, \
subscriberPassword, \
subscriberName, \
managerFlag, \
developerFlag, \
administratorFlag, \
subscriptionType ) \
VALUES (?, ?, ?, ?, ?, ?, ?)

UpdateStatement=UPDATE subscribers SET \
subscriberPassword=?, \
subscriberName=?, \
managerFlag=?, \
developerFlag=?, \
administratorFlag=?, \
subscriptionType=? \
WHERE subscriberEmail=?

DeleteStatement=DELETE FROM subscribers \
WHERE subscriberEmail=?

SubscribeException=Subscription failed. \
Please try another email address.
ProfileException=Couln't update your profile. \
Please contact the Webmaster.
UnsubscribeException=Unsubscription failed. \
Please contact the Webmaster.
LoginException=Login failed. \
Please contact the Webmaster.
UnknownSubscriberException=Unknown subscriber. \
Please subscribe.
IncorrectPasswordException=Incorrect password. \
Please try to login again.

我做这个例子时用了Access数据库

package jsfdb.model.dao;

import jsfdb.model.LoginInfo;

import jsfdb.model.Subscriber;

import jsfdb.model.ModelUtils;

import jsfdb.model.err.IncorrectPasswordException;

import jsfdb.model.err.LoginException;

import jsfdb.model.err.ProfileException;

import jsfdb.model.err.SubscribeException;

import jsfdb.model.err.UnknownSubscriberException;

import jsfdb.model.err.UnsubscribeException;

import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;


public class JDBCSubscriberDAO implements SubscriberDAO {

  //  private DataSource dataSource;

    public JDBCSubscriberDAO() {

          Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");

       

          

    }

    private void close(Connection conn, PreparedStatement ps)

            throws SQLException {

        if (ps != null)

            ps.close();

        if (conn != null)

            conn.close();

    }

    public Subscriber select(LoginInfo loginInfo)

            throws LoginException,

            UnknownSubscriberException,

            IncorrectPasswordException {

        Connection conn = DriverManager.getConnection("jdbc:odbc:jsfdb");

        PreparedStatement ps = null;

        try {

            conn = dataSource.getConnection();

            ps = conn.prepareStatement(

                ModelUtils.getResource("SelectStatement"));

            ps.setString(1, loginInfo.getEmail());

            ResultSet rs = ps.executeQuery();

            if (!rs.next())

                throw new UnknownSubscriberException();

            String password = rs.getString(1);

            if (!loginInfo.getPassword().equals(password))

                throw new IncorrectPasswordException();

            Subscriber subscriber = new Subscriber();

            subscriber.setEmail(loginInfo.getEmail());

            subscriber.setPassword(loginInfo.getPassword());

            subscriber.setName(rs.getString(2));

            subscriber.setManager(rs.getBoolean(3));

            subscriber.setDeveloper(rs.getBoolean(4));

            subscriber.setAdministrator(rs.getBoolean(5));

            subscriber.setSubscriptionType(rs.getInt(6));

            return subscriber;

        } catch (SQLException x) {

            ModelUtils.log(x);

            throw new LoginException();

        } finally {

            try {

                close(conn, ps);

            } catch (SQLException x) {

                ModelUtils.log(x);

                throw new LoginException();

            }

        }

    }

    public void insert(Subscriber subscriber)

            throws SubscribeException {

        Connection conn = DriverManager.getConnection("jdbc:odbc:jsfdb");

        PreparedStatement ps = null;

        try {

            conn = dataSource.getConnection();

            ps = conn.prepareStatement(

                ModelUtils.getResource("InsertStatement"));

            ps.setString(1, subscriber.getEmail());

            ps.setString(2, subscriber.getPassword());

            ps.setString(3, subscriber.getName());

            ps.setBoolean(4, subscriber.isManager());

            ps.setBoolean(5, subscriber.isDeveloper());

            ps.setBoolean(6, subscriber.isAdministrator());

            ps.setInt(7, subscriber.getSubscriptionType());

            int rowCount = ps.executeUpdate();

            if (rowCount != 1)

                throw new SubscribeException();

        } catch (SQLException x) {

            ModelUtils.log(x);

            throw new SubscribeException();

        } finally {

            try {

                close(conn, ps);

            } catch (SQLException x) {

                ModelUtils.log(x);

                throw new SubscribeException();

            }

        }

    }

    public void update(Subscriber subscriber)

            throws ProfileException {

        Connection conn = DriverManager.getConnection("jdbc:odbc:jsfdb");

        PreparedStatement ps = null;

        try {

            conn = dataSource.getConnection();

            ps = conn.prepareStatement(

                ModelUtils.getResource("UpdateStatement"));

            ps.setString(1, subscriber.getPassword());

            ps.setString(2, subscriber.getName());

            ps.setBoolean(3, subscriber.isManager());

            ps.setBoolean(4, subscriber.isDeveloper());

            ps.setBoolean(5, subscriber.isAdministrator());

            ps.setInt(6, subscriber.getSubscriptionType());

            ps.setString(7, subscriber.getEmail());

            int rowCount = ps.executeUpdate();

            if (rowCount != 1)

                throw new ProfileException();

        } catch (SQLException x) {

            ModelUtils.log(x);

            throw new ProfileException();

        } finally {

            try {

                close(conn, ps);

            } catch (SQLException x) {

                ModelUtils.log(x);

                throw new ProfileException();

            }

        }

    }

    public void delete(Subscriber subscriber)

            throws UnsubscribeException {

        Connection conn = DriverManager.getConnection("jdbc:odbc:jsfdb");

        PreparedStatement ps = null;

        try {

            conn = dataSource.getConnection();

            ps = conn.prepareStatement(

                ModelUtils.getResource("DeleteStatement"));

            ps.setString(1, subscriber.getEmail());

            int rowCount = ps.executeUpdate();

            if (rowCount != 1)

                throw new UnsubscribeException();

        } catch (SQLException x) {

            ModelUtils.log(x);

            throw new UnsubscribeException();

        } finally {

            try {

                close(conn, ps);

            } catch (SQLException x) {

                ModelUtils.log(x);

                throw new UnsubscribeException();

            }

        }

    }

}

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