field

问题 Simple question from an absolute n00b. I'm trying to create an edit content screen based on the code given in the Blog Tutorial on the Cake site. Here's my edit function in the controller (it's named Contents): function edit( $id = null ) { $this->Content->id = $id; Debugger::dump( $this->Content->id ); if( empty( $this->data ) ) { $this->data = $this->Content->read(); Debugger::dump( $this->Content ); } else { if( $this->Content->save( $this->data ) ) { $this->Session->setFlash( 'Content has

问题 There are 3 tables: shelf, section and shelf_has_section intermediate table to support n-m relation. The schema build from symfony doctrine:build-schema looks as following. Simply, shelf(id, position) section(id, name) shelf_has_section(shelf_id, section_id, number_of_books) The schema. Shelf: connection: doctrine tableName: shelf columns: id: type: integer(4) fixed: false unsigned: true primary: true autoincrement: true position: type: string(255) primary: false notnull: true autoincrement:

问题 I just started to learn Java, so please bear with me if the answer is somewhat obvious. I did some research but no avail. From what I understand, attributes are not overriden but only field hidden. To determine whether the attribute in the superclass or the subclass is used, Java will check the type of the reference. Then I don't under stand the output here: public class Super { String str = "I'm super!\n"; public String toString() { return str; } } public class Sub extends Super { String str

问题 This question already has answers here : What is the meaning of “static synthetic”? (3 answers) Closed 6 years ago . Can someone explain in an easy to understand way the importance of synthetic fields in Java. I recall reading it in context of non static inner classes where each such inner class instance maintains a reference to the enclosing class. Why are such references/fields called synthetic fields? 回答1: A synthetic field is a compiler-created field that links a local inner class to a

问题 If I specify @AllArgsConstructor using Lombok , it will generate a constructor for setting all the declared (not final, not static) fields. Is it possible to omit some field and this leave generated constructor for all other fields? 回答1: No that is not possible. There is a feature request to create a @SomeArgsConstructor where you can specify a list of involved fields. Full disclosure: I am one of the core Project Lombok developers. 回答2: Alternatively you could use @RequiredArgsConstructor .

问题 I have Field f = this.getClass().getFields()[0]; I need to know if f 's value in this is null or not. There are many methods like getInt() and getDouble() , but I have not found a method like Object getData() or isNull() . Is there such a method? 回答1: field.get(target) returns Object . So you can check if (field.get(this) == null) {..} If the field is primitive, it will get wrapped. int -> Integer , char -> Character , etc. 回答2: You need to get the field from the object then check if it is

问题 I'm pretty new to java, and using netbeans for design a UI. What I am trying to do is... in the form. there are a jComboBox and a JTextField, where user can input the service he is choosing and an observation. So far so good. JComboBox is populated from database entries. The problem is, a user can input N different services at once (there are too much to be a bunch of checkboxes). I was thinking into add a "[+]" button (along with a "[-]" for removal). Thus, users click on [+] and another new

问题 How can I set or get a field in a class whose name is dynamic and stored in a string variable? public class Test { public String a1; public String a2; public Test(String key) { this.key = 'found'; <--- error } } 回答1: You have to use reflection: Use Class.getField() to get a Field reference. If it's not public you'll need to call Class.getDeclaredField() instead Use AccessibleObject.setAccessible to gain access to the field if it's not public Use Field.set() to set the value, or one of the

问题 How can I set or get a field in a class whose name is dynamic and stored in a string variable? public class Test { public String a1; public String a2; public Test(String key) { this.key = 'found'; <--- error } } 回答1: You have to use reflection: Use Class.getField() to get a Field reference. If it's not public you'll need to call Class.getDeclaredField() instead Use AccessibleObject.setAccessible to gain access to the field if it's not public Use Field.set() to set the value, or one of the

问题 So as I click the button, the javascript adds new fields. Currently it adds the new text box to the side.. is there a way to make it add below? I guess as if there were a . Here is the code. Thanks! <html> <head> <script type="text/javascript"> var instance = 1; function newTextBox(element) { instance++; var newInput = document.createElement("INPUT"); newInput.id = "text" + instance; newInput.name = "text" + instance; newInput.type = "text"; //document.body.write("<br>"); document.body