都要用到jbuilder里的一个组件，
你可以去jbuilder目录下拷，
或自己用jdk的组件改一下

no 1:这个程序调用foxmail发送信件

/*这个程序要用到jbuilder的几个类*/

import java.awt.*;
import java.awt.event.*;
import java.applet.*;
import borland.jbcl.layout.*;
import borland.jbcl.control.*;
import java.net.*;

public class emailapplet extends applet{
button button;
textfield textfield;

public emailapplet(){}
public void init(){
try{
jbinit();}
catch(exception e){
e.printstacktrace();}
}//end of init()

public void jbinit()throws exception{
setlayout(new borderlayout());
button=new button("sendmail");
textfield=new textfield();
add("north",textfield);
add("south",button);
}//end of jbinit()

public boolean action(event e,object arg){
if(arg.equals("sendmail")){
try{
/*注意哦,这里是主要代码!!*/
string mailto=textfield.gettext();
url url=new url(mailto);
appletcontext ac=this.getappletcontext();
ac.showdocument(url);}
catch(exception e2){
system.out.println(e2.tostring());}
}//end of if
else{
return super.action(e,arg);}
return true;
}//end of action()

}//end of emailapplet

no 2:这个程序直接发送信件:

import borland.jbcl.layout.*;
import borland.jdbl.*;
import java.awt.*;
import java.applet.applet;
import java.util.stringtokenizer;
import java.net.socket;
import java.io.printstream;
import java.lang.exception;
import java.awt.event.actionevent;

public class mailapplet extends applet{
boolean isstandalone=false;
panelayout panellayout1=new panelayout();
panel panel1=new panel();
label label1=new label();
xylayout xylayout1=new xylayout();
label label2=new label();
textfield textfield1=new textfield();
textfield textfield2=new textfield();
label lable3=new label();
textarea textarea1=new textarea();
button button1=new button();
button button2=new button();
private int smtp_port=25;
frame frame=new frame();
color bgcolor=null;
string send="";
string get="";

public mailapplet(){}

public void init(){
try{
int c1=integer.parseint(getparameter("color1"));
int c2=integer.parseint(getparameter("color2"));
int c3=integer.parseint(getparameter("color3"));
bgcolor=new color(c1,c2,c3);
smtp_port=integer.parseint(getparameter("port"));
send=getparameter("send");
get=getparameter("get");
jbinit();}
catch(exception e){
e.printstacktrace();}
}//end of init()

/*component initialization*/
private void jbinit()throws exception{
this.setsize(new dimension(332,280));
panel1.setbackground(bgcolor);
label1.setalignment(2);
label1.settext("收信人地址:");
label2.setalignment(2);
label2.settext("寄信人地址:");
label3.setalignment(2);
label3.settext("内容:");
button1.setlabel("发 送");
button1.addactionlistener(new mailapplet_button1_actionadapter(this));
button2.setlabel("清 除");
button2.addactionlistener(new mailapplet_button2_actionadapter(this));
panel1.setlayout(xylayout);

this.setlayout(panellayout1);
thsi.add(panel1,new paneconstraints("panel1","panel1",paneconstraints.root,1.0f));

panel1.add(label1,new xyconstraints(10,5,80,20));
panel1.add(label2,new xyconstraints(10,30,80,20));
panel1.add(textfield1,new xyconstraints(95,5,200,20));
panel1.add(textfield2,new xyconstraints(95,30,200,20));
panel1.add(label3,new xyconstraints(10,60,80,20));
panel1.add(textarea1,new xyconstraints(10,80,300,150));
panel1.add(button1,new xyconstraints(50,240,80,25));
panel1.add(button2,new xyconstraints(160,240,80,25));

textfield1.settext(get);
textfield2.settext(send);
}//end of jbinit()

public string getappletinfo(){
return "applet information";}

public string[][] getparameteinfo(){
return null;}

void sendmail(){
string sender=textfield2.gettext();
string geter=textfield1.gettext();
string memo=textarea1.gettext();
stringtokenizer st=new stringtokenizer(sender,"@");
int count=st.counttokens();
if(count!=2){
messagedialog mdlg=new messagedialog(frame,"邮件地址错误","你的发信人地址错误，请确认后重新发送!!",1);
mdlg.show();
textfield2.selectall();
return;}
string sendername=st.nexttoken();
string senderhost=st.nexttoken();
st=new stringtokenizer(geter,"@");
count=st.counttokens();
if(count!=2){
messagedialog mdlg=new messagedialog(frame,"邮件地址错误","你的收信人地址错误，请确认后重新发送!!",1);
mdlg.show();
textfield1.selectall();
return;}
string getername=st.nexttoken();
string geterhost=st.nexttoken();
try{
socket s=new socket(geterhost,smtp_port);
printstream out=new printstream(s.getoutputstream());
out.println("hello:"+senderhost);
/*邮件服务器不认证读者所输smtp是否正确*/
out.println("mail form:"+sendername);
out.println("rcpt to:"+getername);
out.println("data");
out.println(memo);
out.println(". quit");
messagedialog mdlg=new messagedialog(frame,"邮件地址正确","恭喜，您的邮件已经成功发送",1);
mdlg.show();}
catch(exception e){
system.out.println(e.tostring());
messagedialog mdlg=new messagedialog(frame,"邮件发送失败",e.tostring(),1);//"邮件发送出错，请确认合重新发送!",1);
mdlg.show();
return;}
}//end of sendmail()

void button1_actionperformed(actionevent e){
sendmail();
textarea1.settext("");}

void button2_actionperformed(actionevent e){
textfield1.settext("");
textfield2.settext("");
textarea1.settext("");}

}//end of mailapplet

class mailapplet_button1_actionadapter implements java.awt.event.actionlistener{
mailapplet adaptee;
mailapplet_button1_actionadapter(mailapplet adaptee){
this.adaptee=adaptee;}

public void actionperformed(actionevent e){
adaptee.button1_actionperformed(e);}
}//end of this

class mailapplet_button2_actionadapter implements java.awt.event.actionlistener{
mailapplet adaptee;
mailapplet_button2_actionadapter(mailapplet adaptee){
this.adaptee=adaptee;}
public void actionperformed(actionevent e){
adaptee.button2_actionperformed(e);}
}//end of this