表单 – 为什么要显式地将process =“@ this”添加到p：commandB

process.xhtml

<h:form id="form1">
    <h:inputText value="#{ProcessBean.id}" id="id"/><br/>
    <h:panelGroup id="panel_1">
        <h:inputText value="#{ProcessBean.name}" id="name"/><br/>
    </h:panelGroup>
    <h:panelGroup id="panel_2">
        <h:inputText value="#{ProcessBean.address}"/>
        <br/>
        <p:commandButton process="@form" value="Btm1" id="button1" action="#{ProcessBean.show}"/><!-- Default -->
        <p:commandButton process="@this" value="Btm2" id="button2" action="#{ProcessBean.show}"/>
        <p:commandButton process="@this form1:panel_1" value="Btm3" id="button3" action="#{ProcessBean.show}"/>
    </h:panelGroup>
</h:form>

ProcessBean.java

@ManagedBean(name = "ProcessBean")
public class ProcessBean {
    private String id;
    private String name;
    private String address;
    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getAddress() {
        return address;
    }
    public void setAddress(String address) {
        this.address = address;
    }

    public void show() {
        System.out.println(id);
        System.out.println(name);
        System.out.println(address);
    }
}

让我们的用户输入输入框

001     -> id
Jone    -> name
London  -> address

单击button1,将完成整个表单的所有JSF组件(例如：id,name,address).输出将是：

001
Jone
London

单击button2,该过程将是其自身(例如：button2).没有id,名称,地址的进程.输出将是：

null
null
null

单击button3,所有JSF组件(例如：name)整个panel_1和button3将被处理.输出将是：

null
Jone
null

不调用你的动作方法？调用之前可能存在验证或转换失败.