update README.md

Author: LuoLiangDSGA

boot-validation/README.md

@@ -189,4 +189,50 @@ public class User {
     @NotNull
     private Action action;
 }
-```
+```
+
+#### 自定义校验
+
+在业务中还会有一些特殊场景, 需要对某些字段增加自定义的校验逻辑, 比如想校验地址是否以`中国`开头, 这时候需要自定义注解, 并且实现`ConstraintValidator`接口自定义校验逻辑
+
+```java
+@Documented
+@Constraint(validatedBy = StartWithValidator.class)
+@Target({METHOD, FIELD})
+@Retention(RUNTIME)
+public @interface StartWithValidation {
+
+    String message() default "不符合要求的初始值";
+
+    String start() default "";
+
+    Class<?>[] groups() default {};
+
+    Class<? extends Payload>[] payload() default {};
+
+}
+
+public class StartWithValidator implements ConstraintValidator<StartWithValidation, String> {
+
+    private String start;
+
+    @Override
+    public void initialize(StartWithValidation constraintAnnotation) {
+        start = constraintAnnotation.start();
+    }
+
+    @Override
+    public boolean isValid(String s, ConstraintValidatorContext constraintValidatorContext) {
+        if (!StringUtils.isEmpty(s)) {
+            return s.startsWith(start);
+        }
+        return false;
+    }
+}
+```
+
+这时候只需要在需要验证的字段上加上我们自定义的`@StartWithValidation`即可
+
+### 总结
+
+本篇文章到此over, 代码

boot-validation/src/main/java/org/boot/config/annotation/StartWithValidation.java

@@ -0,0 +1,35 @@
+package org.boot.config.annotation;
+
+import static java.lang.annotation.ElementType.ANNOTATION_TYPE;
+import static java.lang.annotation.ElementType.CONSTRUCTOR;
+import static java.lang.annotation.ElementType.FIELD;
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.ElementType.PARAMETER;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+import javax.validation.Constraint;
+import javax.validation.Payload;
+import org.boot.config.valid.StartWithValidator;
+
+/**
+ * @author fantasy
+ * @date 2020/7/31
+ */
+@Documented
+@Constraint(validatedBy = StartWithValidator.class)
+@Target({METHOD, FIELD})
+@Retention(RUNTIME)
+public @interface StartWithValidation {
+
+    String message() default "不符合要求的初始值";
+
+    String start() default "";
+
+    Class<?>[] groups() default {};
+
+    Class<? extends Payload>[] payload() default {};
+
+}

boot-validation/src/main/java/org/boot/config/valid/QueryAction.java

@@ -1,7 +1,7 @@
 package org.boot.config.valid;
 
 /**
- * @author luoliang
+ * @author fantasy
  * @date 2020/7/30
  */
 public interface QueryAction {

boot-validation/src/main/java/org/boot/config/valid/StartWithValidator.java

@@ -0,0 +1,28 @@
+package org.boot.config.valid;
+
+import javax.validation.ConstraintValidator;
+import javax.validation.ConstraintValidatorContext;
+import org.boot.config.annotation.StartWithValidation;
+import org.springframework.util.StringUtils;
+
+/**
+ * @author fantasy
+ * @date 2020/7/31
+ */
+public class StartWithValidator implements ConstraintValidator<StartWithValidation, String> {
+
+    private String start;
+
+    @Override
+    public void initialize(StartWithValidation constraintAnnotation) {
+        start = constraintAnnotation.start();
+    }
+
+    @Override
+    public boolean isValid(String s, ConstraintValidatorContext constraintValidatorContext) {
+        if (!StringUtils.isEmpty(s)) {
+            return s.startsWith(start);
+        }
+        return false;
+    }
+}

boot-validation/src/main/java/org/boot/config/valid/UpdateAction.java

@@ -1,7 +1,7 @@
 package org.boot.config.valid;
 
 /**
- * @author luoliang
+ * @author fantasy
  * @date 2020/7/30
  */
 public interface UpdateAction {

boot-validation/src/main/java/org/boot/domain/User.java

@@ -3,6 +3,7 @@
 import javax.validation.constraints.Min;
 import javax.validation.constraints.NotBlank;
 import javax.validation.constraints.NotNull;
+import org.boot.config.annotation.StartWithValidation;
 import org.boot.config.valid.QueryAction;
 import org.boot.config.valid.UpdateAction;
 
@@ -21,6 +22,9 @@ public class User {
     @Min(value = 1, message = "请输入合法年龄", groups = UpdateAction.class)
     private Integer age;
 
+    @StartWithValidation(start = "中国", groups = UpdateAction.class)
+    private String address;
+
     public Long getId() {
         return id;
     }
@@ -45,12 +49,21 @@ public void setAge(Integer age) {
         this.age = age;
     }
 
+    public String getAddress() {
+        return address;
+    }
+
+    public void setAddress(String address) {
+        this.address = address;
+    }
+
     @Override
     public String toString() {
         return "User{" +
                 "id=" + id +
                 ", name='" + name + '\'' +
                 ", age=" + age +
+                ", address='" + address + '\'' +
                 '}';
     }
 }