作者:netkiller
public String randomString(String chars, int length) {
Random rand = new Random();
StringBuilder buf = new StringBuilder();
for (int i = 0; i < length; i++) {
buf.append(chars.charAt(rand.nextInt(chars.length())));
}
return buf.toString();
}
public class Test {
public Test() {
// TODO Auto-generated constructor stub
}
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("2010-09-11T20:00:30".replace("T", " "));
}
}
{"status":0,"message":"","bankcode":"ABOC;IBC;CCTB;ICBC"}
转换后
{\"status\":0,\"message\":\"\",\"bankcode\":\"ABOC;IBC;CCTB;ICBC\"}
package test;
public class str {
public static void main(String[] args) {
String jsonString = "{\"status\":0,\"message\":\"\",\"bankcode\":\"ABOC;IBC;CCTB;ICBC\"}";
System.out.println(jsonString);
System.out.println(jsonString.replace("\"", "\\\""));
}
}
例如:
String str = "helloword!!!";
System.out.println(str.substring(1,4));
System.out.println(str.substring(3,5));
System.out.println(str.substring(0,4));
将得到结果为:
ell
lo
hell
public class MainClass {
public static void main(String[] arg) {
long b = 12L;
System.out.println(String.valueOf(b));
}
}
判断元素是否存在
import java.util.ArrayList;
public class arraylist {
public static void main(String[] args) {
// TODO Auto-generated method stub
ArrayList<String> whitelist = new ArrayList<String>();
whitelist.add("Neo");
whitelist.add("Jam");
whitelist.add("Sam");
if (whitelist.contains("Neo")) {
System.out.println("Found!");
}else{
System.out.println("Not Found!");
}
}
}
package cn.netkiller.type;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
public class ArrayListExample {
public static void main(String[] args) {
// TODO Auto-generated method stub
List<String> list = new ArrayList<String>();
list.add("Jack");
list.add("Jet");
list.add("Jack");
list.add("Mike");
list.add("Kitty");
list.add("Tom");
//while 循环
Iterator<String> it = list.iterator();
while (it.hasNext()) {
System.out.println(it.next());
}
for (Iterator<String> it1 = list.iterator(); it1.hasNext();) {
System.out.println(it1.next());
}
// for 循环
for (int i = 0; i < list.size(); i++) {
System.out.println(list.get(i));
}
// for 循环加强版
for (String i : list) {
System.out.println(i);
}
}
}
public static void main(String[] args) {
DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
//get current date time with Date()
Date date = new Date();
System.out.println(dateFormat.format(date));
//get current date time with Calendar()
Calendar cal = Calendar.getInstance();
System.out.println(dateFormat.format(cal.getTime()));
}
package cn.netkiller.java;
public class StringToArray {
public static void main(String[] args) {
// TODO Auto-generated method stub
String str="a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z";
String[] array = null;
array = str.split(",");
for(int i=0; i<array.length; i++){
System.out.println(array[i]);
}
}
}
package cn.netkiller.java;
import java.util.Arrays;
public class ArrayToString {
public static void main(String[] args) {
String[] array = {"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"};
System.out.println(Arrays.toString(array));
System.out.println(Arrays.toString(array).replaceAll(", |\\[|\\]", ""));
}
}
Timestamp转化为String:
SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); //定义格式,不显示毫秒
Timestamp now = new Timestamp(System.currentTimeMillis()); //获取系统当前时间
String str = df.format(now);
String转化为Timestamp:
SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String time = df.format(new Date());
Timestamp ts = Timestamp.valueOf(time);