[springmvc] Forms

Get a new form

　　Export a JavaBean to the view as the “form bean” or “form backing object”

　　Can pre-populate form using initial bean property values or client query parameters

　　Convenient form tags/macros exist to simplify rendering form fields

1. Invoked on every request

@ModelAttribute
    public void ajaxAttribute(WebRequest request, Model model) {
        model.addAttribute("ajaxRequest", AjaxUtils.isAjaxRequest(request));
    }

2. Invoked initially to create the "form" attribute

    @ModelAttribute("formBean")
    public FormBean createFormBean() {
        return new FormBean();
    }
    
    @RequestMapping(method=RequestMethod.GET)
    public void form() {
    }

Post a form

　　Declare JavaBean argument to trigger binding and validation

　　Declare a BindingResult argument to query binding and validation results

　　Re-render form view if validation errors are present

　　Redirect after successful post by returning target resource URL prefixed with special “redirect:” directive

　　Store any success messages in a flash map cleared after the next request:  Flash map contents are cached temporarily in the session until the next request

completes, then cleared

    @RequestMapping(method=RequestMethod.POST)
    public String processSubmit(@Valid FormBean formBean, BindingResult result, 
                                @ModelAttribute("ajaxRequest") boolean ajaxRequest, 
                                Model model, RedirectAttributes redirectAttrs) {
        if (result.hasErrors()) {
            return null;
        }
        // Typically you would save to a db and clear the "form" attribute from the session 
        // via SessionStatus.setCompleted(). For the demo we leave it in the session.
        String message = "Form submitted successfully.  Bound " + formBean;
        // Success response handling
        if (ajaxRequest) {
            // prepare model for rendering success message in this request
            model.addAttribute("message", message);
            return null;
        } else {
            // store a success message for rendering on the next request after redirect
            // redirect back to the form to render the success message along with newly bound values
            redirectAttrs.addFlashAttribute("message", message);
            return "redirect:/form";            
        }
    }

FormBean.java

import java.math.BigDecimal;
import java.util.Date;
import java.util.Map;

import javax.validation.constraints.Min;
import javax.validation.constraints.Past;

import org.hibernate.validator.constraints.NotEmpty;
import org.springframework.format.annotation.DateTimeFormat;
import org.springframework.format.annotation.NumberFormat;
import org.springframework.format.annotation.DateTimeFormat.ISO;
import org.springframework.format.annotation.NumberFormat.Style;
import org.springframework.samples.mvc.convert.MaskFormat;

public class FormBean {
    
    @NotEmpty
    private String name;
    
    @Min(21)
    private int age;

    @DateTimeFormat(iso=ISO.DATE)
    @Past
    private Date birthDate;

    @MaskFormat("(###) ###-####")
    private String phone;

    @NumberFormat(pattern="$###,###.00")
    private BigDecimal currency;

    @NumberFormat(style=Style.PERCENT)
    private BigDecimal percent;
    
    private InquiryType inquiry;
    
    private String inquiryDetails;
    
    private boolean subscribeNewsletter;
    
    private Map<String, String> additionalInfo;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public Date getBirthDate() {
        return birthDate;
    }

    public void setBirthDate(Date birthDate) {
        this.birthDate = birthDate;
    }

    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }

    public BigDecimal getCurrency() {
        return currency;
    }

    public void setCurrency(BigDecimal currency) {
        this.currency = currency;
    }

    public BigDecimal getPercent() {
        return percent;
    }

    public void setPercent(BigDecimal percent) {
        this.percent = percent;
    }

    public InquiryType getInquiry() {
        return inquiry;
    }

    public void setInquiry(InquiryType inquiry) {
        this.inquiry = inquiry;
    }

    public String getInquiryDetails() {
        return inquiryDetails;
    }

    public void setInquiryDetails(String inquiryDetails) {
        this.inquiryDetails = inquiryDetails;
    }

    public boolean isSubscribeNewsletter() {
        return subscribeNewsletter;
    }

    public void setSubscribeNewsletter(boolean subscribeNewsletter) {
        this.subscribeNewsletter = subscribeNewsletter;
    }

    public Map<String, String> getAdditionalInfo() {
        return additionalInfo;
    }

    public void setAdditionalInfo(Map<String, String> additionalInfo) {
        this.additionalInfo = additionalInfo;
    }

    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append("properties name=");
        if (name != null) {
            sb.append("'").append(name).append("', ");
        } else {
            sb.append(name).append(", ");
        }
        sb.append("age=").append(age).append(", ");
        sb.append("birthDate=").append(birthDate).append(", ");
        sb.append("phone=");
        if (phone != null) {
            sb.append("'").append(phone).append("', ");
        } else {
            sb.append(phone).append(", ");
        }
        sb.append("currency=").append(currency).append(", ");
        sb.append("percent=").append(percent).append(", ");
        sb.append("inquiry=").append(inquiry).append(", ");
        sb.append("inquiryDetails=");
        if (inquiryDetails != null) {
            sb.append("'").append(inquiryDetails).append("', ");
        } else {
            sb.append(inquiryDetails).append(", ");
        }
        sb.append("subscribeNewsletter=").append(subscribeNewsletter).append(", ");
        sb.append("additionalInfo=").append(additionalInfo);
        return sb.toString();
    }
}