A method for loading multiple validator in spring MVC.

The first thing to say is what is called validator:

Validator is a validator that validates data received in the background and verifies the data.

SPRINGMVC Server Authentication is available in two ways, one based on the validator interface and one using the Annotaion JSR-303 standard.

1. Validation using the Annotaion JSR-303 standard

Using this need to import a package that supports the JSR-303 standard, it is recommended to use Hibernate validator This package to see the standard native annotations first:

Limit	Description
@Null	Limit is null only
@NotNull	Limit must be non-null
@AssertFalse	The limit must be false
@AssertTrue	The limit must be true
@DecimalMax (value)	Limit must be a number that is less than the specified value
@DecimalMin (value)	The limit must be a number that is not less than the specified value
@Digits (integer,fraction)	The limit must be a decimal, and the number of digits in the integer part cannot exceed integer, and the number of fractional digits cannot exceed fraction
@Future	The limit must be a future date
@Max (value)	Limit must be a number that is less than the specified value
@Min (value)	The limit must be a number that is not less than the specified value
@Past	The limit must be a past date
@Pattern (value)	The restriction must conform to the specified regular expression
@Size (Max,min)	Limit character length must be between min to Max
@Past	Verify that the annotation's element value (date type) is earlier than the current time
@NotEmpty	Verifies that the element value of the annotation is not null and is not empty (string length is not 0, collection size is not 0)
@NotBlank	Verifies that the element value of the annotation is not null (NOT NULL, the first space is removed after the length is 0), differs from @notempty, @NotBlank is applied only to strings and the whitespace is stripped of the string when compared
@Email	Verify that the element value of the annotation is email, or you can specify a custom email cell with regular expressions and flag

To use it very simply, precede the variable that needs to be validated with the annotation, see the user after use

 1  public  class   user { 2  @NotEmpty (message = "User name cannot be empty" )  3  private   String username;  4  @Size (min=6, max=, message = "Password length does not conform to standard" 5  private   String password;  6  private   String nickname;  7  8   ...  9 } 

Then the controller inside the method on the need to verify the object or data to join the @validated can be.

2. Using the Validator interface

The main thing is to do validator entity class, to implement validator interface:

Studentvalidator.java

 Public classStudentvalidatorImplementsvalidator{ Public BooleanSupports (class<?>clazz) {          returnStudent.class. Equals (Clazz); }         Public voidValidate (Object obj, Errors e) {validationutils.rejectifempty (E,"Name", "Name.empty"); Validationutils.rejectifempty (E,"Gender", "null"); Validationutils.rejectifempty (E,"Age", "null"); Student s=(Student) obj; if(S.getage () < 18) {E.rejectvalue ("Age" and "young"); }Else if(S.getage () > 50){              //e.reject ("Age", "old");         }      }        }  

Teachervalidator.java

 Public classTeachervalidatorImplementsvalidator{ Public BooleanSupports (class<?>clazz) {          returnTeacher.class. Equals (Clazz); }         Public voidValidate (Object obj, Errors e) {validationutils.rejectifempty (E,"Name", "Name.empty"); Validationutils.rejectifempty (E,"Gender", "null"); Validationutils.rejectifempty (E,"Age", "null"); Teacher T=(Teacher) obj; }        }  

Peoplecontorller.java

@Controller Public classUsercontroller {@AutowiredPrivateStudentvalidator Studentvalidator; @AutowiredPrivateTeachervalidator Teachervalidator; @RequestMapping (Value= "/savestudent", method =requestmethod.post) Public voidsavestudent (@Valid @RequestBody Student Student) {...} @RequestMapping (Value= "/saveteacher", method =requestmethod.post) Public voidsavestudent (@Valid @RequestBody Teacher Teacher) {...} @InitBinder Public voidInitbinder (Webdatabinder binder) {//This method loads the validator, determines the object to be validated by the request, and loads the relative validator. This method is loaded according to the request, that is, n times the request is loaded n times the method        if(Studentvalidator.supports (Binder.gettarget (). GetClass ())&&!studentvalidator.getclass (). GetName (). Contains ("Org.springframework") {binder.addvalidators (studentvalidator); }Else{binder.addvalidators (teachervalidator); }    }}

PS: You need to make a judgment to realize the existence of multiple validators.

A method for loading multiple validator in spring MVC.