SpringMVC Form Tag Lib Select + Option

For binding data on a jsp page to a form, one of the easiest ways is using spring form tag.

In this article, I will show you how to bind form data by using:

• <form:select>
• <form:option>
• <form:options>

1. Option object

This object contain a pair value of each item in combo box or list box. It composes of item value and item label.

public class Option {

    private String  itemValue;

    private String  itemLabel;
...
}

2. Form Bean

public class User {

    // for a dropdown by using select tag
    private String skill1;

    // for a dropdown by using select, option and options tag
    private String skill2;

    // for multi select list box
    private String[] skills;
....
}

As above code, the attribute skills is used in binding a multi select list box.

3. Form Tags

To generate a dropdown box, we use this syntax:

<form:select 
    path="skill1" 
    items="${lstSkill}" 
    itemValue="itemValue" 
    itemLabel="itemLabel" 
/> 

• path="skill1" means the selected value binds to skill1 attribute
• items="${lstSkill}" means the items displayed in dropdown is stored in lstSkill
• itemValue="itemValue" means the value of each item comes from field itemValue of Option object
• itemLabel="itemLabel" means the label of each item is stored in field itemLabel of Option object

Another way to generate a combo box:

<form:select path="skill2">
    <form:option value="-" label="--Please Select"/>
    <form:options path="skill2" items="${lstSkill}" itemValue="itemValue" itemLabel="itemLabel" />
</form:select>

To generate a multi select list box, we use this syntax:

<form:select 
    path="skills"     
    multiple="true" 
    items="${lstSkill}" 
    itemValue="itemValue" 
    itemLabel="itemLabel" 
/>

• path="skills", here the skills is an array of string
• multiple="true"

4. In Controller

We initialize the item list in GET method

@RequestMapping(value = "/modifyUser", method = RequestMethod.GET)
public ModelAndView modifyUser() {

        /* We use a list of Option instead of Map */
        List<Option> lstSkill = new ArrayList<Option>();
 
        lstSkill.add(new Option("1", "Java"));
        lstSkill.add(new Option("2", "C#"));
        lstSkill.add(new Option("3", "PHP"));
        lstSkill.add(new Option("4", "C++"));
  
        ModelAndView modelView = new ModelAndView("modifyUser");
        modelView.addObject("lstSkill", lstSkill);
        modelView.addObject("user", this.user);
        return modelView;
} 

References:

• http://static.springsource.org/spring/docs/3.1.x/spring-framework-reference/html/view.html#view-jsp-formtaglib

Source code:

• For the demonstration, please download source code from HERE
• My repository on Github