General verification system

4.3.2. Write a message resource file

The message resources of Commons-Validator include two major parts, the first part is a message including the ValidatorAction object of the parameter placeholder. The second part is the display information of each input form input data, which is used as the information display when the verification fails. In this case, the value includes a display information of an input form:

# ValidatorAction object message

ErrorS.Required = must provide {0} fields!

ERRORS.INT = {0} field must be an integer!

# Nameform Enter the display information of each input data of the form

Nameform.username.displayName = Name

Nameform.DisplayName = age

4.3.3. Write ValidatorAction

We can see the INT and Required ValidatorAction defined by the validator elements in the verification definition rule file, using org.i505.validator.mytypeValidator and org.i505.validator.myvalidator, two classes, which also define the verification method they use. ValidateInt and ValidateRequired and parameter type list of methods. Below is the code of these two classes: package org.i505.validator; import

Org.apache.commons.validator.field;

Import org.apache.commons.validator.GenericTypeValidator;

Import org.apache.commons.validator.validatorutil;

Public class mytypevalidator {

Public Static Integer ValidateInt (Object Bean, Field Field) {

String value = value = validatorutil.getValueAsstring (bean, field.getproperty ());

Integer x = generictypevalidator.formatint (value);

Return X;

}

}

Package Org.i505.validator;

Import org.apache.commons.validator.field;

Import org.apache.commons.validator.GenericvaliDator;

Import org.apache.commons.validator.validatorutil;

Public class myvalidator {

Public Static Boolean ValidateRequired (Object Bean, Field Field) {

String value = value = validatorutil.getValueAsstring (bean, field.getproperty ());

Return! GenericValidator.isblankornull (Value);

}

}

4.3.4. Write Javabean

Commons-Validator is a input verification system for web applications. The FORM definition in the verification rule is for HTML Form forms, but the Common-Validator requires JavaBean when verify internal. The various properties of this JavaBean represent the input control of the HTML Form form. So for the previous verification rules, the JavaBean we implemented needs to define two properties: AGE and Username, the code is as follows:

Public class validatebean extends Object {

String username; string agec;

Public void setusername (String username) {

This. Username = Username;

}

Public string getUsername () {

Return this.username;

}

Public void setage (String age) {

THIS.AGE = AGE;

}

Public string getage () {

Return this.Age;

}

Public string toString () {

Return "{username =" this.username ", agn =" this.age "}"

}

Note that the type of this verification bean is a string type because it only represents the value of the input control of the HTML Form form, and the original user input data can basically expressed by String, if we declare the agge property The type of type is integrated, then we pass a type conversion at the value of the HTML Form form to the BEAN, this earlier than our integer verification, so there may be a risk of generating type conversion errors.

4.3.5. Writing verification main program

Writing verification main programs have the following five steps:

Create and process the ValidatorResources object, which is to initialize this object with the ValidatorResourcesInitializer class using the verification rule definition file. Creating a bean object to be verified To create a Validator object with a FORM defined in the verification rule definition file and telling this object to verify the Bean object. Validate () method running the validator object actually verifies the result of the Bean object print verification

The following is a three-time verification in accordance with the instance code written in the steps described above. The first time the two properties are empty bean objects. The second time is a bean object that is not legal. The third time is BEAN objects with two attributes:

Public static void main (String [] args) throws oews oException, validatorException {

InputStream in = NULL;

Try {

ValidatorResources Resources = New ValidatorResources ();

IN = validateexample.class.getResourceceAsStream ("MyValidator-Example.xml);

ValidatorResourcesInitializer.Initialize (resources, in);

ValidateBean bean = new validatebean ();

Validator Validator = New Validator (Resources, "Nameform");

Validator.AddResource (Validator.Bean_Key, Bean);

ValidatorResults Results = NULL;

Results = validator.validate ();

PrintResults (bean, results, resources);

Bean.setUsername ("Gong Yongsheng");

Bean.setage ("very young");

Results = validator.validate ();

PrintResults (bean, results, resources);

Bean.setage ("28");

Results = validator.validate ();

PrintResults (bean, results, resources);

}

Finally {

IF (in! = NULL) {

In.Close ();

}

}

}

4.3.6. Print verification results

Print verification results may be the most complex part of the verification system, as it involves verifying files and message resource files, involving a lot of objects and their complex relationships. Especially need to be pointed out is the display of the error message text. The following code includes three parts: The first part is to generate a resourcebundle object using the resource file, note that your resource file must be found in ClassLoader; the second part is the actual print verification result; the third part is a function of displaying Chinese messages. The validate () method of the Validator object saves the verification result into the ValidatorResults object returned to it, and it saves the validation result object ValidatorResult, which saves the ValidatorResult of each attribute of the Bean object, first we can get the bean object. Verify the FORM defined by the file to get the corresponding message keys and other information, and through this information from the ValidatorResults object, the ValidatorResult object isvalid function can determine the success of the validation, if the verification is not passed, you can use FORM information Displays the error message text.

Private static resourcebundle apps =

ResourceBundle.getBundle (

"Org.i505.validator.myApplicationResources");

Public Static Void PrintResults

ValidateBean Bean,

ValidatorResults RESULTS,

ValidatorResources Resources) {

Boolean Success = True;

Form form = resources.get (locale.getdefault (), "nameform");

System.out.println ("/ N / N Verification:");

System.out.println (bean);

Iterator propertyNames = results.get ();

While (propertyNames.hasnext ()) {

String PropertyName = (String) PropertyNames.next ();

Field Field = (Field) Form.GetfieldMap (). Get (PropertyName);

String prettyfieldname = getGBKMSG (apps.getstring (file.getarg0 (). GetKey ()));

ValidatorResult Result = results.getvalidatorResult (propertyName);

Map actionMap = result.getActionMap ();

Iterator Keys = ActionMap.keyset (). Iterator ();

While (keys.hasnext ()) {

String actname = (string) keys.next ();

ValidatorAction action = Resources.getValidatorAction (actname);

System.out.println (

PropertyName

"[["

ACTNAME

"] ("

(Result.issalid (ACTNAME)? "Verification": "Verification Fail")

")");

IF (! Result.issalid (actname) {

Success = false; string message = getGBKMSG (apps.getstring (action.getmsg ()));

Object [] args = {prettyfieldname};

System.out.println (

"The error message is:"

MessageFormat.Format (Message, Args);

}

}

}

IF (Success) {

System.out.println ("Form Verification");

}

Else {

System.out.println ("Failed Failed";

}

}

Public Static String getGBKMSG (String MSG) {

String GBKSTR = ""

Try {

GBKSTR = New String (Msg.getbytes ("ISO-8859-1"), "GBK");

}

Catch (unsupportedencodingexception e) {

// Todo Auto-Generated Catch Block

E.PrintStackTrace ();

}

Return GBKSTR;

}

The verification results are as follows:

Verification: {username = null, agn = null}

AGE [Required] error message is: Must provide age field!

Username [Required] error message is: Must provide a name field!

Form verification failed

Verification: {username = Gong Yongsheng, AGE = very young}

AGE [Required] (Verification Pass)

AGE [INT] (Verification Failed)

The error message is: the age field must be an integer!

UserName [Required] Factifies Failed

Verification: {username = Gong Yongsheng, AGE = 28}

AGE [Required] (Verification Pass)

AGE [INT] (Verification Pass)

Username [Required] (Verification Pass)

Form verification

5. Internal analysis 5.1.

The ValidatorResults object has a map, with Field's getKey (), this Field's verification result ValidatorResult object is a value.

The ValidatorResult object also has a map, with the name of each validator element of Field (a list of Field Validator Elements in the Depends of the field element), with a value that indicates the success of the verification success or not.

The ValidatorResources object contains a map, represented by a string of local, formset is the value (so formset has a variety of versions), which also contains a map, saving global constants, with a constant name, constant value; Also included with a MAP, with the value of the Validator element, the ValidatorAction object is the value.

The FormSet object contains a map, with the Form's Name property, the Form object is a value; also contains a map, with the Name of the child element constant of the Formset element, the value of the child elements constant value.

The Form object contains a map, which is a value of the Field object corresponding to the field element, and the Field object is a value; there is also an array of Field objects that save the order.

The Field object has a MAP, with the name of var, the VAR object is the value.

The Validator object contains a map, with the names in the MethodParams parameter list of each validator element, the corresponding object is the value, the key and value of this MAP will be used as the parameter of the Methods attribute in the corresponding validator element. Through these MAP, Commons-Validator has paved a class relational table between the various types of the system, see the figure below:

5.2. How to call the validator element of the ValidatorAction verification rule define the ValidatorAction, and the field element references these validatorAction through the Depends property. From the verification main program from the above code sample, you can know that the validator.validate () method is for a FORM element, which will verify the various field of this FORM element, and verify the field is the Depends property that calls the field element. The verification method defined by each validator element.

Validator elements define a verification method using ClassName, Method, and MethodParams, such as the XML fragment below defines a verification method of validation of an integer ValidateIntInt, with two parameters. The type is java.lang.object, Org.apache.commons.validator.field. The verification method ValidateInt will be implemented in the org.i505.validator code.

ClassName = "Org.i505.validator.mytypevalidator"

Method = "ValidateInt"

Methodparams = "java.lang.object, org.apache.commons.validator.field"

Msg = "errors.int" />

So much, now the problem is how the validator.validate () method calls each verification method (such as validateInt)?

We analyze this problem with a sequential diagram and a piece of code.

The above figure is a brief sequential diagram, and the interpretation of this sequence diagram:

1. Add resources to Validator objects (add items to resource MAP)

2. Actual verification

For each field defined by the Form, call the following steps:

#begin

3. Verify a field

Perform the following steps to each ValidatorAction for Field:

#begin

4. Verify a ValidatorAction

5. Merge verification results

#end

#end

The following code explains the fourth step in the above: Verify a validatorAction.

// add these two objects to the resources Since the Reference

// The current validator action and field

HRESOURCES.PUT (Validator_Action_Key, VA);

HRESOURCES.PUT (Field_Key, Field);

Class C = getClassLoader (). LoadingClass (Va.getClassName ());

List lparams = va.getMethodparamslist ();

INT size = lparams.size ();

INT beanindexpos = -1;

INT FieldIndexpos = -1; class [] paramclass = new class [size];

Object [] Paramvalue = New Object [Size];

For (int x = 0; x

String paramkey = (string) lparams.get (x);

IF (bean_key.equals (paramkey)) {

Beanindexpos = x;

}

IF (Field_Key.Equals (paramkey)) {

FieldIndExpos = x;

}

// there were problems calling getclass on paramvalue []

Paramclass [x] = getClassLoader (). loadingClass (paramkey);

Paramvalue [x] = hResources.get (paramkey);

}

Method M = C.getMethod (Va.getMethod (), paramclass;

// if the method is static we don't need an instance of the class

// to call the method. if it isn't, we do.

IF (! Modifier.ISstatic (M.GETMODIFIERS ())))

Try {

IF (Va.getClassNameInstance () == null) {

Va.setClassNameInstance (C.NewInstance ());

}

}

Catch (Exception EX) {

Log. Error

"COULDN'T LOAD Instance"

"of class"

va.getclassname ()

"."

ex.getMessage ());

}

}

Object result = null;

IF (Field.isIndexed ()) {

Object oindexed =

PropertyUtils.getProperty

HRESOURCES.GET (Bean_Key),

Field.GetIndexedListProperty ());

Object indexedlist [] = new object [0];

OINDEXED InstanceOf Collection {

IndexedList = ((collect) .toarray ();

}

Else IF (OINDEXED.GETCLASS (). isarray ()) {

IndexedList = (Object []) OINDEXED;

}

// set current orthoped object to the parameter arch

Paramvalue [beanindexpos] = indexedlist [POS];

// set Field Clone with the key modified to represent

// the current field

Field Indexedfield = (Field) Field.clone ();

Indexedfield.SetKey

ValidatorUtil.replace

Indexedfield.getKey (),

Field.Token_indexed,

"[" POS "]"); paramvalue [FieldIndexpos] = Indexedfield;

Result = m.invoke (Va.getClassNameInstance (), paramvalue;

Results.add (Field, Va.getName (), IsValid (Result), Result

IF (! isvalid (result)) {

Return False;

}

}

Else {

Result = m.invoke (Va.getClassNameInstance (), paramvalue;

Results.add (Field, Va.getName (), IsValid (Result), Result

IF (! isvalid (result)) {

Return False;

}

}

This code first adds two resources: Field and ValidatorAction, which are currently being verified, then instantiate an object in which the authentication method is located, followed by constructing the parameter list of the verification method according to the key / value of the resource Map and the parameter class list of the verification method. , The authentication method of an object of the verification method is called.

6. Legacy issues We say that Commons-Validator is a universal verification system, it is really a good thing, but if you want to use it in the actual system, you need a certain job, especially when you use its client authentication. Fortunately, the Struts project made a very classic demonstration for us to use these validation systems. I think it is necessary to move these efforts of the Struts project to the Commons-Validator project so that its usability will be greatly improved.

7. Summary as a verified universal framework, some features are not available immediately, it requires developers to package again. Struts reorganizes the client verification mechanism for Commons-Validator, so that this mechanism is immediately available for development Struts programs. With these packaging, the rest of the task is to develop ValidatorAction to meet different verification requirements. In addition, Struts also provides inputs that are verified and a regular expression match, which uses the PERL5 regular expression matching mechanism for Commons-Validator.

When developing a web information system, in addition to verify input, we also need to pay attention to the output of the data. The web interface is HTML code, and this code is interpreted by the browser. If our internal data includes the reserved word of HTML code, a little harm is destroying the browser's explanation of HTML, and it is broken our last interface. It is important to introduce safety hazards, paralyzed information systems. The following code can be used to filter HTML reserves, learn urlencoding, called HTMLENCoding:

Public static string htmlencoding (String value) {

IF (value == null)

Return (NULL);

Char content [] = new char [value.Length ()];

Value.getchars (0, value.Length (), Content, 0);

StringBuffer Result = New StringBuffer (Content.length 50);

For (int i = 0; i

Switch (Content [I]) {

Case '<':

Result.Append ("<");

Break;

Case '>':

Result.Append (">");

Case '&':

Result.Append ("&");

Break;

Case '"":

Result.Append ("" ");

Break;

Case '/' ':

Result.Append ("'");

Break;

Note and default:

Result.Append (Content [i]);

}

}

Return (result.toString ());

}