| public class WhitherStringBuilder { public String implicit(String[] fields) { String result = ""; for(int i = 0; i < fields.length; i++) result += fields[i]; return result; } public String explicit(String[] fields) { StringBuilder result = new StringBuilder(); for(int i = 0; i < fields.length; i++) result.append(fields[i]); return result.toString(); } } |
public class Parcel2 {
class Contents { private int i = 11; public int value() { return i; } } // 一般會在outer class中建立method來產生inner class物件 public Contents contents() { return new Contents(); } public static void main(String[] args) { Parcel2 q = new Parcel2(); // Defining references to inner classes: Parcel2.Contents c = q.contents(); } } |
| public class DotThis { void f() { System.out.println("DotThis.f()"); } public class Inner { public DotThis outer() { return DotThis.this; } } public Inner inner() { return new Inner(); } public static void main(String[] args) { DotThis dt = new DotThis(); DotThis.Inner dti = dt.inner(); dti.outer().f(); } } |
| public class DotNew { public class Inner {} public static void main(String[] args) { DotNew dn = new DotNew(); DotNew.Inner dni = dn.new Inner(); } } |
public class Parcel5 {
public Destination destination(String s) { class PDestination implements Destination {
private String label;
private PDestination(String whereTo) { label = whereTo; } public String readLabel() { return label; } } return new PDestination(s); } public static void main(String[] args) { Parcel5 p = new Parcel5(); Destination d = p.destination("Tasmania"); } } |
| public class Parcel7 { public Contents contents() { return new Contents() { // Insert a class definition private int i = 11; public int value() { return i; } }; // Semicolon required in this case } public static void main(String[] args) { Parcel7 p = new Parcel7(); Contents c = p.contents(); } } |
| class WithInner { class Inner {} } public class InheritInner extends WithInner.Inner { //! InheritInner() {} // Won’t compile InheritInner(WithInner wi) { wi.super(); } public static void main(String[] args) { WithInner wi = new WithInner(); InheritInner ii = new InheritInner(wi); } } |
| abstract void f(); |
class A{
A() {print("new A");}
}
class B extends A{
B() {print("new B");};
}
public class C extends B{
public C() {print("new C");}
public static void main(String[] args){
C instance = new C();
}
}
Output =>
new A
new B
new C
|
| 父類別 public class Super { static String s = "Super====="; static { //類別的初始化 System.out.println("instance super class static"); } { //類別物件的建立 System.out.println("instance super class"); } public Super(){ //建構子 System.out.println("into Super constructor"); } } |
| 子類別 public class Sub extends Super{ static String s1 = "Sub1-----"; static String s2 = "Sub2-----"; static { //類別的初始化 System.out.println("instance sub class static"); } { //類別物件的建立 System.out.println("instance sub class"); } public Sub(){ //建構子 System.out.println("into Sub constructor"); } } |
| Main類別 public class Main { public static void main(String[] arg){ Sub sub = new Sub(); } } |
執行結果
instance super class static
instance sub class static instance super class into Super constructor instance sub class into Sub constructor |
| Main類別 public class Main { public static void main(String[] arg){ System.out.println(Sub.s); System.out.println(Sub.s1); } } |
執行結果
instance super class static
Super=====
//此時Sub類別並不會進行類別的初始化
instance sub class static
Sub1-----
//此時Sub類別才有進行類別的初始化動作
|
| public class Spoon { static int i; static { i = 47; } } |
public class NewVarArgs {
static void printArray(Object... args) { for(Object obj : args) System.out.print(obj + " "); System.out.println(); } public static void main(String[] args) { // Can take individual elements: printArray(47, 3.14F, 11.11); printArray("one", "two", "three"); printArray(new A(), new A(), new A()); // Or an array:
printArray((Object[])new Integer[]{ 1, 2, 3, 4 });
printArray(); // Empty list is OK } } /* Output: (75% match) 47 3.14 11.11 one two three A@1bab50a A@c3c749 A@150bd4d 1 2 3 4 |
{
users: {},
modal: {},
posts: {},
replies: {},
listeners: {}
}
import combineReducers from 'redux' import * as reducers from '../reducers ... const store = createStore(combineReducers(reducers))
<Router history={hashHistory}>
<Route path='/' component={MainContainer}>
<Route path='feed' component={FeedContainer} onEnter={checkAuth} />
<Route path='logout' component={LogoutContainer} />
<IndexRoute component={HomeContainer}/>
</Route>
</Router>
function checkAuth (nextState, replace) {
if (nextState.location.pathname === '/feed') {
if (isAuthed() !== true) {
replace('/')
}
}
}