Eitan's Blog

public class HashMap<K,V> extends AbstractMap<K,V>
    implements Map<K,V>, Cloneable, Serializable {

    private static final long serialVersionUID = 362498820763181265L;

    /**
     * The default initial capacity - MUST be a power of two.
     * 默认初始容量 - 必须是2的幂次方
     */
    static final int DEFAULT_INITIAL_CAPACITY = 1 << 4; // aka 16

    /**
     * The maximum capacity, used if a higher value is implicitly specified
     * by either of the constructors with arguments.
     * MUST be a power of two <= 1<<30.
     * 最大容量
     */
    static final int MAXIMUM_CAPACITY = 1 << 30;

    /**
     * The load factor used when none specified in constructor.
     * 默认负载因子
     */
    static final float DEFAULT_LOAD_FACTOR = 0.75f;

    /**
     * The bin count threshold for using a tree rather than list for a
     * bin.  Bins are converted to trees when adding an element to a
     * bin with at least this many nodes. The value must be greater
     * than 2 and should be at least 8 to mesh with assumptions in
     * tree removal about conversion back to plain bins upon
     * shrinkage.
     * 树化的阈值
     */
    static final int TREEIFY_THRESHOLD = 8;

    /**
     * The bin count threshold for untreeifying a (split) bin during a
     * resize operation. Should be less than TREEIFY_THRESHOLD, and at
     * most 6 to mesh with shrinkage detection under removal.
     * 取消树化的阈值
     */
    static final int UNTREEIFY_THRESHOLD = 6;

    /**
     * The smallest table capacity for which bins may be treeified.
     * (Otherwise the table is resized if too many nodes in a bin.)
     * Should be at least 4 * TREEIFY_THRESHOLD to avoid conflicts
     * between resizing and treeification thresholds.
     * 进行树化时表的最小容量，否则将进行resized来减少链表长度
     */
    static final int MIN_TREEIFY_CAPACITY = 64;

public class MyApplicationContext {
    public static void main(String[] args) {
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(MyConfiguration.class);
        MyConfiguration myConfiguration = context.getBean(MyConfiguration.class);
        Cat cat1 = myConfiguration.getCat();
        Cat cat2 = myConfiguration.getCat();
        System.out.println(cat1 == cat2);
    }
}

@Configuration
public class MyConfiguration {
	@Bean
	public Cat getCat(){
		Cat cat = new Cat();
		cat.setName("zs");
		return cat;
	}
}

public class Cat {
    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

public class Calculator {
    public int add(int i, int j) {
        return i + j;
    }

    public int sub(int i, int j) {
        return i - j;
    }

    public int mult(int i, int j) {
        return i * j;
    }

    public int div(int i, int j) {
        return i / j;
    }
}

public class MyCglib implements MethodInterceptor {
    @Override
    public Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {
        System.out.println("调用cglib动态代理");
        return methodProxy.invokeSuper(o, objects);
    }
}

public class CglibTest {
    public static void main(String[] args) {
        // 设置cglib生成的class文件保存路径
        System.setProperty(DebuggingClassWriter.DEBUG_LOCATION_PROPERTY, "E:\\mashibing\\spring");
        Enhancer enhancer = new Enhancer();
        enhancer.setSuperclass(Calculator.class);
        enhancer.setCallback(new MyCglib());
        Calculator myCalculator = (Calculator) enhancer.create();
        myCalculator.add(1, 1);
        System.out.println(myCalculator.getClass());
    }
}