HELP!!!javabean????

JavaBean入门 JSP 资料发布: Wuxuehui 类型: 推荐点击次数: 395 2000-10-31 发布者注册信息一般要求首先，您必须有一个不带有参数的公用构造器。此构造器也应该通过调用各个特性的设置方法来设置特性的缺省值，例如： public Fireworks() { setAutoStart(true); setBackground(Color.black); setSpeed(10); setRadius(40); . . . } 如果 bean 是一个从 java.awt.Component 类继承而来的可视 bean，您就应该为 bean 定义一个缺省的首选大小，例如： public Dimension getPreferredSize() { return (new Dimension(radius*3, radius*3)); } public Dimension getMinimumSize() { return getPreferredSize(); } 特性对于您需要的每个特性，您应该有一个带有匹配公用 getter 和 setter 方法的专用实例变量，例如： private int speed; . . . public int getSpeed() { return speed; } public void setSpeed(int s) { speed = s; } 此 get 和 set 方法必须有与实例变量相同的名称，但是第一个字母要大写并以 get 和 set 开头。由于连接而在任何时候更改它们的特性时，确认 Bean 在运行时行为正确也是很重要的。如果特性的更改影响到 Bean 的可视外观，您应该以此特性设置的方法来调用 repaint();。同样，如果特性的更改影响到 bean 的大小和位置，您需要确认获得验证的事物。我们建议编写您自己的 validateAll 方法，如下所示： private void validateAll() { if (isValid()) { Component self = this; self.invalidate(); Component myParent = self.getParent(); if (myParent != null) { myParent.invalidate(); self = myParent; } self.validate(); } } 然后以此特性设置的方法调用 validateAll();。　 bean 类将无法进行关于调用特性设置方法命令的假设。您应该写 bean 以便可以初始构造它，然后在不引起错误的同时在任何命令中设置其特性。操作对于每个您需要的操作，您应该有一个公用方法，例如： public void start() { if(thread==null) { thread=new Thread(this); thread.start(); } } 您为操作写的方法应该在无须期待用户创建连接或设置很多特性的情况下独立操作。例如，如果您写了一个音频 Bean，您希望通过播放操作处理打开声音的所有步骤、完成您需要的所有设置并播放声音。同样，即使声音未播放，停止操作也应起作用。事件对于您需要的每个事件或事件设置，您应该定义事件和侦听器类。对于此例，查看 FireworksEvent.java 源文件以及 Fireworks.java 文件。此事件类的源应该如同这样： import java.awt.*; import java.util.*; public class FireworksEvent extends EventObject { public static final int EXPLODED = 1; int id = 0; public FireworksEvent(Component source, int id) { super(source); this.id = id; } public int getID() { return id; } } 您应该为此事件设置中的每个事件定义一个公用静态结束事件标识符，例如在此例子中的 EXPLODED。对于侦听器类的源，查看 FireworksListener.java 源文件： import java.util.*; public interface FireworksListener extends EventListener { public abstract void exploded(FireworksEvent e); } 您应该为此事件设置中的每个事件定义一个公用抽象方法，例如在此例子中的 exploded。而且，侦听器类必须扩展 EventListener ，以使 JAR 向导能够找到它。然后，如果由 bean 类播送事件，它必须跟踪侦听事件的对象。要这样做，您需要定义侦听器实例变量以及 addListener 和 removeListener 方法。返回 Fireworks.java 源，例如，您将查看到： private Vector listeners = new Vector(); . . . public void addFireworksListener(FireworksListener f) { listeners.addElement(f); } public void removeFireworksListener(FireworksListener f) { listeners.removeElement(f); } 最后，bean 类需要以正确的次数将事件实际播送到所有的侦听器。要这样做，您需要定义 processEvent 方法并以适当的次数调用它，例如： public void processFireworksEvent(FireworksEvent e) { for (Enumeration enum = listeners.elements(); enum.hasMoreElements(); ) ((FireworksListener)enum.nextElement()).exploded(e); } public void run() { . . . processFireworksEvent(new FireworksEvent(this, FireworksEvent.EXPLODED)); }

编写一个javabean JSP 资料发布: Wuxuehui 类型: 推荐点击次数: 181 2000-10-31 发布者注册信息首先，一个javabean必须实现可序列化的接口，支持这个接口的对象可以存储和重建它们的状态。如下所示： Public class Simplebean extends Canvas implements Serializable 然后，我们可以为这个javabean定义属性和事件，这样这个javabean就可以具有一定的功能了。如下所示： private Color beanColor = Color.blue; 然后再定义如下两个accessor方法，这两个方法需要定义成public类型： public Color getColor(){ return beanColor; } public void setColor(Color newColor){ beanColor=newColor; repaint(); } 同时，为了使beanColor属性能够与javabean的表现联系起来，需要重载Canvas的paint()方法： public void paint(Graphics g){ g.setColor(beanColor); g.fillRect(0,0,width,height); }

http://61.144.28.245/hjc/web/doc/20010410_3.html
http://61.144.28.245/hjc/web/doc/servlet-jsp/servlet-jsp4.html

Thanks!有没有大点的开发列子，一起算分！！

其实做javabean的水平主要还是取决于你的java的水平下边是我初学jsp时写的第一个bean.....不是你说的哪个大点的东东....也是http://210.52.43.10/zijianyi 里用到的不要笑我：）
package user;
import java.sql.*;public class check{
boolean right=true;
//¼ì²éÊÇ·ñÊý¾ÝÎª¿Õ
public boolean check_blank(String string){
boolean blank=true;
if(string==null||string.trim().compareTo("")==0)
    blank=false;
return blank;
};//¼ì²éÄ³¸ö×Ö·ûÊÇ·ñÎªºÏ·¨×Ö·û
public boolean check_have(String[] words,String temp){
boolean have=true,have_tmp=false;
int i,j;
for(i=0;i<temp.length();i++){
String t=temp.substring(i,i+1);
for(j=0;j<words.length;j++){
have_tmp=false;
if(words[j].equals(t)){
have_tmp=true;
break;}
}
if(!have_tmp){
have=false;
break;
}}
return have;
}//¼ì²é×Ö·û´®Ê±ºòº¬ÓÐÄ³¸ö×Ö·û
public boolean check_str_char(String str,String tag){
boolean have_tag=false;
int i;
for(i=0;i<str.length();i++){
if(str.substring(i,i+1).equals(tag))
have_tag=true;
}
return have_tag;
}//¼ì²éÓÃ»§ÃûÊÇ·ñºÏ·¨
public boolean check_user(String str){
String[]
word={"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p"
    ,"q","r","s","t","u","v","w","x","y","z","A","B","C","D","E","F","G",
        "H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X",
   "y","Z","0","1","2","3","4","5","6","7","8","9","_"};
if(str==null||str.trim().length()<3||str.trim().length()>20)
         {right=false;}
else{
if(!check_have(word,str))
right=false;
}
return right;
}//¼ì²éÃÜÂëÊÇ·ñºÏ·¨
public boolean check_pass(String pass,String repass){
if(pass==null||pass.trim().length()<5||pass.trim().length()>20)
right=false;
else if(!pass.trim().equals(repass))
right=false;
return right;
}
//¼ì²éE-MailÊÇ·ñºÏ·¨
public boolean check_email(String email){
if(!check_str_char(email,"@")||!check_str_char(email,"."))
right=false;
return right;
}//¼ì²âÊÇ·ñÒÑ¾×¢²á
public boolean check_user_have(String user){
int i=0;
java.sql.Connection Conn;
    java.sql.Statement Stmt;
    java.sql.ResultSet Rst;
try{
    Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");}
catch(java.lang.ClassNotFoundException e){
System.out.print(e);
}
try{
    Conn=DriverManager.getConnection("jdbc:odbc:wangzhan","zijian","zijian");
    Stmt=Conn.createStatement();
Rst=Stmt.executeQuery("select * from user_info where user_name='"+user+"'");
if(Rst.next())i=1;
Rst=Stmt.executeQuery("select * from teacher_info where user_name='"+user+"'");
if(Rst.next())i=1;
    Rst.close();
Stmt.close();
Conn.close();}
catch(SQLException ex){
System.out.print(ex);}
if(i==0)return true;
else return false;
}
//ÅÐ¶ÏÊÇ·ñ¿ÆÄ¿±»´´½¨
public boolean check_sub_have(String sub_name){
int i=0;
java.sql.Connection Conn;
    java.sql.Statement Stmt;
    java.sql.ResultSet Rst;
try{
    Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");}
catch(java.lang.ClassNotFoundException e){
System.out.print(e);
}
try{
    Conn=DriverManager.getConnection("jdbc:odbc:wangzhan","zijian","zijian");
    Stmt=Conn.createStatement();
Rst=Stmt.executeQuery("select * from teach_subject where sub_name='"+sub_name+"'");
if(Rst.next())right=false;
    Rst.close();
Stmt.close();
Conn.close();}
catch(SQLException ex){
System.out.print(ex);}
return right;
}//ÅÐ¶ÏÊÇ·ñÕÂ±»´´½¨
public boolean check_unit_have(String unit_name){
int i=0;
java.sql.Connection Conn;
    java.sql.Statement Stmt;
    java.sql.ResultSet Rst;
try{
    Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");}
catch(java.lang.ClassNotFoundException e){
System.out.print(e);
}
try{
    Conn=DriverManager.getConnection("jdbc:odbc:wangzhan","zijian","zijian");
    Stmt=Conn.createStatement();
Rst=Stmt.executeQuery("select * from teach_unit where unit_name='"+unit_name+"'");
if(Rst.next())right=false;
    Rst.close();
Stmt.close();
Conn.close();}
catch(SQLException ex){
System.out.print(ex);}
return right;
}//ÅÐ¶ÏÊÇ·ñ½Ú±»´´½¨
public boolean check_part_have(String part_name){
int i=0;
java.sql.Connection Conn;
    java.sql.Statement Stmt;
    java.sql.ResultSet Rst;
try{
    Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");}
catch(java.lang.ClassNotFoundException e){
System.out.print(e);
}
try{
    Conn=DriverManager.getConnection("jdbc:odbc:wangzhan","zijian","zijian");
    Stmt=Conn.createStatement();
Rst=Stmt.executeQuery("select * from teach_part where part_name='"+part_name+"'");
if(Rst.next())right=false;
    Rst.close();
Stmt.close();
Conn.close();}
catch(SQLException ex){
System.out.print(ex);}
return right;
}

//ÅÐ¶ÏÊÇ·ñÎÊÌâ±»´´½¨
public boolean check_que_have(String que_name){
int i=0;
java.sql.Connection Conn;
    java.sql.Statement Stmt;
    java.sql.ResultSet Rst;
try{
    Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");}
catch(java.lang.ClassNotFoundException e){
System.out.print(e);
}
try{
    Conn=DriverManager.getConnection("jdbc:odbc:wangzhan","zijian","zijian");
    Stmt=Conn.createStatement();
Rst=Stmt.executeQuery("select * from teach_question where que_name='"+que_name+"'");
if(Rst.next())right=false;
    Rst.close();
Stmt.close();
Conn.close();}
catch(SQLException ex){
System.out.print(ex);}
return right;
}
//ÅÐ¶ÏÊÇ·ñbbsÂÛµã±»´´½¨
public boolean check_topic_have(String topic_name){
int i=0;
java.sql.Connection Conn;
    java.sql.Statement Stmt;
    java.sql.ResultSet Rst;
try{
    Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");}
catch(java.lang.ClassNotFoundException e){
System.out.print(e);
}
try{
    Conn=DriverManager.getConnection("jdbc:odbc:wangzhan","zijian","zijian");
    Stmt=Conn.createStatement();
Rst=Stmt.executeQuery("select * from bbs_topic where topic_name='"+topic_name+"'");
if(Rst.next())right=false;
    Rst.close();
Stmt.close();
Conn.close();}
catch(SQLException ex){
System.out.print(ex);}
return right;
} //ÅÐ¶ÏÊÇ·ñbbsÂÛµã±»ÊÕ²Ø
public boolean check_favlist_have(String user_name,int topic_id){
int i=0;
java.sql.Connection Conn;
    java.sql.Statement Stmt;
    java.sql.ResultSet Rst;
try{
    Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");}
catch(java.lang.ClassNotFoundException e){
System.out.print(e);
}
try{
    Conn=DriverManager.getConnection("jdbc:odbc:wangzhan","zijian","zijian");
    Stmt=Conn.createStatement();
Rst=Stmt.executeQuery("select * from bbs_favlist where fav_owner_name='"+user_name+"' and fav_topic_id='"+topic_id+"'");
if(Rst.next())right=false;
    Rst.close();
Stmt.close();
Conn.close();}
catch(SQLException ex){
System.out.print(ex);}
return right;
} //ÅÐ¶ÏÊÇ·ñbbsÂÛµã±»ÊÕ²Ø
public boolean check_quefav_have(String user_name,int que_id){
int i=0;
java.sql.Connection Conn;
    java.sql.Statement Stmt;
    java.sql.ResultSet Rst;
try{
    Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");}
catch(java.lang.ClassNotFoundException e){
System.out.print(e);
}
try{
    Conn=DriverManager.getConnection("jdbc:odbc:wangzhan","zijian","zijian");
    Stmt=Conn.createStatement();
Rst=Stmt.executeQuery("select * from teach_favlist where fav_owner_name='"+user_name+"' and fav_que_id='"+que_id+"'");
if(Rst.next())right=false;
    Rst.close();
Stmt.close();
Conn.close();}
catch(SQLException ex){
System.out.print(ex);}
return right;
}
//ÓÃÖ¸¶¨µÄ×Ö·ûÌæ»»×Ö·û´®ÖÐÄ³¸ö×Ö·û
public String replace(String con,String tag,String rep){
int j=0;
int i=0;
int k=0;
String RETU="";
String temp=con;
int tagc=tag.length();
while(i<con.length()){
if(con.substring(i).startsWith(tag)){
temp=con.substring(j,i)+rep;
RETU+=temp;
i+=tagc;
j=i;
}
else{i+=1;
}
}
RETU+=con.substring(j);
return RETU;
}//½ûÓÃHTML´úÂë±àÂë
public String html(String s){
String re;
re=replace(s,"<","<");
    re=replace(re,">",">");
    re=replace(re,"\n","<br>");
    re=replace(re," "," ");
    re=replace(re,"'","&#39");
    return re;
}//Ð£ÓÑÂ¼¡ªÑ§Ð£Ãû³ÆÊÇ·ñÒÑ¾´æÔÚ
public boolean check_school_have(String school_name){
int i=0;
java.sql.Connection Conn;
    java.sql.Statement Stmt;
    java.sql.ResultSet Rst;
try{
    Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");}
catch(java.lang.ClassNotFoundException e){
System.out.print(e);
}
try{
    Conn=DriverManager.getConnection("jdbc:odbc:wangzhan","zijian","zijian");
    Stmt=Conn.createStatement();
Rst=Stmt.executeQuery("select * from alumnus_school where school_name='"+school_name+"'");
if(Rst.next())right=false;
    Rst.close();
Stmt.close();
Conn.close();}
catch(SQLException ex){
System.out.print(ex);}
return right;
} //Ð£ÓÑÂ¼¡ª°à¼¶Ãû³ÆÊÇ·ñÒÑ¾´æÔÚ
public boolean check_class_have(String class_name){
int i=0;
java.sql.Connection Conn;
    java.sql.Statement Stmt;
    java.sql.ResultSet Rst;
try{
    Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");}
catch(java.lang.ClassNotFoundException e){
System.out.print(e);
}
try{
    Conn=DriverManager.getConnection("jdbc:odbc:wangzhan","zijian","zijian");
    Stmt=Conn.createStatement();
Rst=Stmt.executeQuery("select * from alumnus_class where class_name='"+class_name+"'");
if(Rst.next())right=false;
    Rst.close();
Stmt.close();
Conn.close();}
catch(SQLException ex){
System.out.print(ex);}
return right;
}
}

调试易

HELP!!!javabean????

解决方案 »