package zOther;

import java.lang.reflect.Field;

/**

* @description: 描述

* @author: dekai.kong (dekai.kong@luckincoffee.com)

* @date: 2018-11-05 17:26

*/

public class TestJava {

public static void main(String[] args) {

/**

String a = "201810";

// System.out.println(a.substring(4));

System.out.println(a.substring(0,1));

System.out.println(11 / 2);

int ax = 10;

String ks = "#"+StringUtils.join(Arrays.asList("bbbb".split("")),"#")+"#";

System.out.println(ks);

int b = ax;

b = 3;

System.out.println(a+"--"+b);

Integer z = new Integer(1);

Integer x = z;

x = 9;

String xx = "";

System.out.println(x.hashCode());

System.out.println(z.hashCode());

System.out.println(z+"--"+x);

String num = "123456";

Integer index = 0;

System.out.println(parseInt(num,index));

Integer c1 = 0;

System.out.println("c1:"+c1);

System.out.println("index:"+index);

List<Integer> lx = new ArrayList<>();

lx.add(1);

lx.add(2);

lx.add(3);

Integer[] xa = lx.toArray(new Integer[lx.size()]);

System.out.println(lx);

System.out.println("znm3");

StringBuffer sv = new StringBuffer("vvv");//线程安全

StringBuilder ac = new StringBuilder("avc");//线程不安全

sv.reverse();

ac.reverse();

System.out.println(1235%100);

// System.out.println(Integer.parseInt("888888888888"));

char[] b123 = new char[9];

System.out.println(b123);

char[] data={'a','b','c'};

String s=new String(data);

System.out.println(s);

//字符串的list可以直接转成字符串数组

List<String> lxs = new ArrayList<>();

lxs.add("1");

lxs.add("2");

lxs.add("3");

String[] xas = lxs.toArray(new String[lxs.size()]);

System.out.println(xas);

//null == 0时 报空指针

Integer axa = null;

// System.out.println(axa == 0);

*/

/**

//线程

try {

xmain();

// xmain3();

// xmain2();

} catch (Exception e) {

e.printStackTrace();

}

*/

int i = 0;

Ax a = new Ax();

tein(i);

teAx(a);

System.out.println(i);

System.out.println(a.value);

}

public static int parseInt(String num,int index){

int result = 0;

while(index < num.length() && num.charAt(index)<='9' && num.charAt(index)>='0'){

result = result *10 + (num.charAt(index) - '0');

index += 1;

}

Integer x1 = 0;

Field field = null;

try {

field = x1.getClass().getDeclaredField("value");

} catch (NoSuchFieldException e) {

e.printStackTrace();

} catch (SecurityException e) {

e.printStackTrace();

}

field.setAccessible(true);

try {

field.set(x1,index);

} catch (IllegalAccessException e) {

e.printStackTrace();

}

return result;

}

//test

//Test

static int c = 0;

//jvm锁粗话问题 https://blog.csdn.net/ft305977550/article/details/78769573

//经典 可看

public static void xmain() throws InterruptedException {

for (int i = 0; i < 500; i++) {

Thread t = new Thread() {

@Override

public void run() {

for (int j = 0; j < 100; j++) {

c++;

//System.out.println(c); 可能引起锁粗化

}

}

};

t.start();

// t.join();

}

Thread.sleep(10000);

System.out.println(c);

}

public static void xmain3() throws Exception{

Thread a = new Thread() {

@Override

public void run() {

for( int j = 0 ; j < 100000 ; j++ ) c++;

}

};

a.start();

Thread b = new Thread() {

@Override

public void run() {

for( int j = 0 ; j < 100000 ; j++ ) c--;

}

};

b.start();

a.join();

b.join();

System.out.println(c);

}

public static void xmain2() throws InterruptedException {

for (int i = 0; i < 10; i++) {

Thread t = new ThreadX(c);

t.start();

System.out.println(t.getName());

t.join();

}

Thread.sleep(5000);

System.out.println(c);

}

public static void tein (int i){

i = i+1;

}

public static void teAx (Ax a){

a.value = a.value+1;

}

static class Ax{

public int value;

public Ax(){

value = 0;

}

}

}