JSP--beans and Forms processing

JS forms (forms) are a common way to interact on a Web site. JSP makes form processing easier. The standard way to work with a form in a JSP is to define a "bean". This "Bean" is not a full Java bean. You just define a class so that it has an area that corresponds to each area of the form. This class area must have "setters" to match the name of the form area. For example, let's revise the getname.html of the previous tutorial and collect the email address and the age of the user. Specific code changes are as follows:

＜HTML＞

＜BODY＞

＜FORM METHOD=POST ACTION="SaveName.jsp"＞

What's your name? ＜INPUT TYPE=TEXT NAME=username SIZE=20＞＜BR＞

What's your e-mail address? ＜INPUT TYPE=TEXT NAME=email SIZE=20＞＜BR＞

What's your age? ＜INPUT TYPE=TEXT NAME=age SIZE=4＞

＜P＞＜INPUT TYPE=SUBMIT＞

＜/FORM＞

＜/BODY＞

＜/HTML＞

To collect data, we define a Java class that has "username", "email", "age" areas, and we provide "setter" methods "Setusername", "Setemail" and "Setage". This "setter" method is just a way to start with "set" followed by a region name. The first letter of the area name is capitalized. So if the area is "email", its "setter" method is "Setemail". Similarly, the Getter method is similar to a definition, it simply uses "get" instead of "set". and to make setters and getters must be public. For example:

public class UserData {

String username;

String email;

int age;

public void setUsername( String value )

{

username = value;

}

public void setEmail( String value )

{

email = value;

}

public void setAge( int value )

{

age = value;

}

public String getUsername() { return username; }

public String getEmail() { return email; }

public int getAge() { return age; }

}