annotations

问题 I am trying to do some Java annotation magic. I must say I am still catching up on annotation tricks and that certain things are still not quite clear to me. So... I have some annotated classes, methods and fields. I have a method, which uses reflection to run some checks on the classes and inject some values into a class. This all works fine. However, I am now facing a case where I need an instance (so to say) of an annotation. So... annotations aren't like regular interfaces and you can't

问题 I've been playing around with Java Annotation Processors, with great results. Now I would like to do the following, which as far as I can see is not possible. I have several Classes that implement the Builder Pattern. Say for instance new FooBuilder().doSomething("A").doSomethingElse("B").execute(); It is vital that the "chain" of method calls is terminated using an execute() method. Otherwise, the builder will basically do nothing. So I wanted to use JAP to verify the presence of an execute(

问题 How can I tell a class to include only NON_EMPTY and NON_NULL values only, Using @JsonInclude(Include.NON_NULL) @JsonInclude(Include.NON_EMPTY) public class foo{ String a; } is throwing error of duplicate annotation. 回答1: "Null is always considered empty" - Jackson's site So the NON_EMPTY rule covers both cases.. 来源： https://stackoverflow.com/questions/23631511/jackson-jsoninclude-how-to-add-multiple-jsoninclude-annotation-type

问题 How can I tell a class to include only NON_EMPTY and NON_NULL values only, Using @JsonInclude(Include.NON_NULL) @JsonInclude(Include.NON_EMPTY) public class foo{ String a; } is throwing error of duplicate annotation. 回答1: "Null is always considered empty" - Jackson's site So the NON_EMPTY rule covers both cases.. 来源： https://stackoverflow.com/questions/23631511/jackson-jsoninclude-how-to-add-multiple-jsoninclude-annotation-type

问题 I have a teacher table, where it contains one primary key TEACHER_UNIQUE_ID,and other one autoIncrement key with Index TEACHER_ID. Now i have to map autoIncrement key to other table i.e SUBJECT . I have used below code, but this always sets TEACHER_ID as null in subject class. i want it to insert Subject table with actual autoIncremented TEACHER_ID. public class Teacher { @Id @Column(name = "TEACHER_UNIQUE_ID") private String teacherUniqueId; @GeneratedValue(strategy = GenerationType.AUTO)

问题 I'm trying to create a Spring Boot 2.1 application. I have created the following rest controller ... @RestController @RequestMapping("/api/users") public class UserController { ... @PutMapping("/{id}") @PreAuthorize("authentication.principal.id == #id") public ResponseEntity<User> update(@RequestBody User user, @PathVariable UUID id) { final User updatedUser = userService.update(id, user); if (updatedUser == null) { return ResponseEntity.notFound().build(); } else { return ResponseEntity.ok

问题 I'm trying to create a Spring Boot 2.1 application. I have created the following rest controller ... @RestController @RequestMapping("/api/users") public class UserController { ... @PutMapping("/{id}") @PreAuthorize("authentication.principal.id == #id") public ResponseEntity<User> update(@RequestBody User user, @PathVariable UUID id) { final User updatedUser = userService.update(id, user); if (updatedUser == null) { return ResponseEntity.notFound().build(); } else { return ResponseEntity.ok

问题 I'm trying to create a Spring Boot 2.1 application. I have created the following rest controller ... @RestController @RequestMapping("/api/users") public class UserController { ... @PutMapping("/{id}") @PreAuthorize("authentication.principal.id == #id") public ResponseEntity<User> update(@RequestBody User user, @PathVariable UUID id) { final User updatedUser = userService.update(id, user); if (updatedUser == null) { return ResponseEntity.notFound().build(); } else { return ResponseEntity.ok

问题 say, i have one Kotlin class with annotations: @Entity @Table(name="user") data class User (val id:Long, val name:String) How can i get the value of name attribute from @Table annotation? fun <T> tableName(c: KClass<T>):String { // i can get the @Table annotation like this: val t = c.annotations.find { it.annotationClass == Table::class } // but how can i get the value of "name" attribute from t? } 回答1: You can simply: val table = c.annotations.find { it is Table } as? Table println(table?

问题 I am using Jackson parser for parsing for Java object to JSON . I am forcefully adding JSON keys for some java objects, using the following code. @JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.WRAPPER_OBJECT) @JsonSubTypes({ @JsonSubTypes.Type(value = A.class, name = "a"), @JsonSubTypes.Type(value = F.class, name = "f") }) I am having same set classes in Python also. I would like to do the same thing in python. But not sure about what are the alternatives for this Jackson