Shulou(Shulou.com)06/02 Report--

In this issue, the editor will bring you about how to define dialects in Thymeleaf. The article is rich in content and analyzes and narrates it from a professional point of view. I hope you can get something after reading this article.

Thymeleaf Custom dialect to realize Page filtering function

All the th:x attributes currently in use are just a standard, out-of-the-box feature set. If you want to define your own set of attributes (or tags) with the name you want, and use them in thymeleaf to deal with your templates. You can define your own dialect. Now let's use custom dialects to achieve page permission filtering.

Dialect

Thymeleaf itself provides StandardDialect, as well as SpringStandardDialect provided in conjunction with Spring. The default syntax of Thymeleaf, such as th:if, is defined in StandardDialect, where th is the dialect prefix and if is the dialect processor name.

The following is defined in the source code of StandardDialect

Public class StandardDialect extends AbstractProcessorDialect implements IExecutionAttributeDialect, IExpressionObjectDialect {public static final String NAME = "Standard"; public static final String PREFIX = "th"; public static final int PROCESSOR_PRECEDENCE = 1000;...}

The PREFIX = "th" defines that it needs to be called in the form of th:XX when used in the template.

Custom dialect

Dialect is an interface, so you need to create a custom dialect SecurityDialect class, and then specify a specific processor. Instead of implementing the interface directly, you inherit the AbstractProcessorDialect abstract class, specifying the name and the prefix prefix.

Package com.wise.tiger.dialect; / * Custom Thymeleaf dialect: used to handle custom dialects: filter permission operation * / @ Component public class SecurityDialect extends AbstractProcessorDialect {/ / dialect name public static final String DIALECT_NAME = "wise_authority"; / / dialect prefix public static final String PREFIX = "wise" / / dialect processing priority, and standard dialect level public static final int PROCESSOR_PRECEDENCE = 1000; public SecurityDialect () {super (DIALECT_NAME, PREFIX, PROCESSOR_PRECEDENCE);} / / add dialect processor @ Override public Set getProcessors (String dialectPrefix) {final Set processors = new HashSet (); processors.add (new SecurityElementTagProcessor (dialectPrefix)); return processors }}

@ Component means to register the custom dialect with the Spring IoC container, where you need to add a dialect processor.

Custom dialect processor

There are many kinds of dialect processors, all of which are defined in the form of interfaces, using the element processor (IElementProcessor) interface, which is the basic interface for element Element processing. Thymeleaf provides two basic IElementTagProcessor implementations that can be easily implemented by the processor:

Org.thymeleaf.processor.element.AbstractElementTagProcessor, the handler used to match element events by element name (that is, do not view attributes).

Org.thymeleaf.processor.element.AbstractAttributeTagProcessor, a handler for matching element events by element event or attribute (which can also be an element name).

The official recommendation is not to implement this interface directly to implement our own processor, but to inherit the class AbstractAttributeTagProcessor/AbstractElementTagProcessor.

Package com.wise.tiger.dialect / / * import * / / * define dialect processor * add department * determine whether the permission of the currently logged-in employee contains the permission values defined by module and permission * if so, do not deal with it, if not Hide the content of the tag tag * / public class SecurityElementTagProcessor extends AbstractElementTagProcessor {/ / tag name private static final String PRO_NAME = "authority" / / priority private static final int PRECEDENCE = 1000 Public SecurityElementTagProcessor (String dialectPrefix) {super (TemplateMode.HTML, / / this processor will only be applied to HTML mode dialectPrefix, / / dialect prefix wise, equivalent to the th PRO_NAME,// processor name in th:if Equivalent to if true,// in th:if using dialect prefix as signature null,// has no attribute name: false,// attribute name will be matched by tag name without prefix PRECEDENCE) / / dialect priority. Standard dialect defaults to 1000} @ Override protected void doProcess (ITemplateContext context, IProcessableElementTag tag, IElementTagStructureHandler structureHandler) {/ / get the module attribute value of tag String module = tag.getAttributeValue ("module") / / get the permission attribute value of tag String permission = tag.getAttributeValue ("permission"); / / get the request object bound by the current thread HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes ()). GetRequest (); / / once you have got the session, you can get the user information stored in session. Employee emp = (Employee) request.getSession (). GetAttribute ("employee"); / / permission to build tag tags Privilege privilege = new Privilege (module,permission); if (! isPermitted (emp,privilege)) {structureHandler.setAttribute ("style", "display:none") }} / * determine whether the logged in employee has the operation right * @ param emp logged in employee * @ param privilege permission value * @ return * / private boolean isPermitted (Employee emp Privilege privilege) {for (Role role: emp.getRoles ()) {if (role.getPrivileges (). Contains (privilege)) {return true }} return false;}} use a custom dialect. Add the department above is how to customize the dialect in the Thymeleaf shared by the editor. If you happen to have similar doubts, you might as well refer to the above analysis to understand. If you want to know more about it, you are welcome to follow the industry information channel.

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