Question

我想使用java类更改这些textareas的属性。如您所见，默认情况下禁用textareas。如果用户在数据库中找不到已注册的TIN，我想要启用此功能。这是我的代码：

JSP：

<label style="font-size: 17px;">Registered Name</label><br><br>         
<textarea disabled id="tpName" name="tpName" style="margin-top: -9px; width: 275px; height: 40px;">${name}</textarea>   
<br><br>
<label style="font-size: 17px;">Address</label><br><br>         
<textarea disabled id="tpAddress" name="tpAddress" style="margin-top: -9px; width: 275px; height: 40px;">${address}</textarea>

类：

private String tpTin;
private String tpName;  
private String tpAddress;
private TblTaxPayment tbltaxpayment;

public String getTpTin() {
    return tpTin;
}
public String getTpName() {
    return tpName;
}
public String getTpAddress() {
    return tpAddress;
}
public void setTpTin(String tpTin) {
    this.tpTin = tpTin;
}
public void setTpName(String tpName) {
    this.tpName = tpName;
}
public void setTpAddress(String tpAddress) {
    this.tpAddress = tpAddress;
}

private HttpServletRequest request;

public void setServletRequest(HttpServletRequest request){
    this.request = request;
}
public TblTaxPayment getTblTaxPayment() {
    return tbltaxpayment;
}
public void setTblTaxPayment(TblTaxPayment tbltaxpayment) {
    this.tbltaxpayment = tbltaxpayment;
}

@SuppressWarnings("unused")
public String execute() throws Exception {

    Debugger.border();
    Debugger.startDebug(this.getClass().toString());

    String tax = request.getParameter("tpTin");

    TblTaxPaymentDAO tdao = DAOFactory.getDaoManager(TblTaxPayment.class);
    TblTaxPayment t = null;
    t = tdao.findbyTIN(tax.replace("-", ""));
    tbltaxpayment = (TblTaxPayment) t;

    try{

            Debugger.print("TIN : "+tax);
            if(tax != null) {

                tpTin = tbltaxpayment.getTpTin();                                       
                tpName = tbltaxpayment.getTpName();
                tpAddress = tbltaxpayment.getTpAddress();

                String tin = tpTin;
                String name = tpName;
                String address = tpAddress;

                request.setAttribute("tin", tin);
                request.setAttribute("name", name);
                request.setAttribute("address", address);

                return SUCCESS;
            }else{
                request.setAttribute("name", true);
                request.setAttribute("address", true);              
                return SUCCESS;
            }


    }catch(Exception e){
        e.printStackTrace();
        Debugger.endDebug(this.getClass().toString());
        Debugger.border();
        return ERROR;
    }

}

}

我做了什么。我将该属性设置为true，以便能够在jsp中更改textareas的属性/属性。

Answer 1

如果您的Java类包含确定是否启用了textareas的逻辑，那么您必须首先让您的Java类存储在JSP可以访问的某个位置。您有许多选项：您可以将其设置为请求属性，例如

request.setAttribute("nameRequired", true /* or false */); 
request.setAttribute("addressRequired", true /* or false */);

您可以在Java类中存储标志，并通过getter使它们可用：

boolean nameRequired;
boolean addressRequired;

public String execute () throws Exception {
    ...
    nameRequired = true /* or false */;
    addressRequired = true /* or false */;
    ...
}

public boolean isNameRequired () {
    return nameRequired;
}

public boolean isAddressRequired () {
    return addressRequired;
}

对于上述任何一种情况，您还可以通过让类返回业务状态并让UI决定是否需要名称或地址来进一步将业务逻辑与UI隔离，例如;

request.setAttribute("haveTaxInfo", false /* or true */);

或者其他 - 语义。

在任何情况下，JSP现在都可以访问JSP确定textarea状态所需的信息。然后，在JSP中，您只需根据需要编写disabled属性：

<%

// option 1: if you used request attributes:
boolean nameRequired = Boolean.TRUE.equals(request.getAttribute("nameRequired")); 
boolean addressRequired = Boolean.TRUE.equals(request.getAttribute("addressRequired"));

// option 2: or, if you used class fields:
boolean nameRequired = businessClass.isNameRequired(); 
boolean addressRequired = businessClass.isAddressRequired();

// option 3: or,if you used the business state in a request attribute: 
boolean haveTaxInfo = Boolean.TRUE.equals(request.getAttribute("haveTaxInfo"));
boolean nameRequired = !haveTaxInfo;    // if we don't have the tax info then the name
boolean addressRequired = !haveTaxInfo; // and address are required.

%>

<textarea <%=(nameRequired?"":"disabled")%> id="tpName" name="tpName" style="margin-top: -9px; width: 275px; height: 40px;">${name}</textarea>   
<textarea <%=(addressRequired?"":"disabled")%> id="tpAddress" name="tpAddress" style="margin-top: -9px; width: 275px; height: 40px;">${address}</textarea>

这里带回家的关键是你可以使用<%= ... %> JSP标签来控制你是否写'＃34;禁用＆＃34;到输出。您可以基于某些布尔值在这些标记中使用条件表达式，并且该布尔值必须以某种方式从您的业务类传递到JSP（通过请求属性或getter或其他东西）。

希望有所帮助。

使用java类在jsp中更改textarea的属性

1 个答案: