java基础数据类型和处理

import com.alibaba.fastjson.JSONObject;
import com.alibaba.fastjson.JSON;
import java.io.*;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.math.BigDecimal;
import java.text.DecimalFormat;
import java.util.Collections;
import java.util.Comparator;
import java.lang.reflect.Array;
import java.util.*;
import java.util.Map;
import java.text.MessageFormat;
import java.util.Random;

public class JavaBasic {

    //class_variable,for class object.VarName
    static String name = "ss";
    // instance variable,just for instance callable
    private String addr = "south surface";

    //without return result ,static method can be callable by static method and class,
    // but can't be call by method or instance
    public static void printMethod() {
        System.out.println("iammmm");
    }

    void defineArrays() {
        int[] ai = {1, 2, 3, 4};
        Arrays.fill(ai, 5);
        for (int i = 0; i < ai.length; i++) {
            System.out.println(false);
        }
    }

    /**
     * format str : python "{0},{1}".foramt(v1,v2)
     * python str: "%s is ,%s is ".format(v1,v2)
     */
    public String formatStr(String str) {
        String newstr = "my name is {0},age is {1}";
        return (MessageFormat.format(newstr, "1", "22"));
    }

    /**
     * non static can't callable by static method ,just for normal method
     */
    String defineStringMethod() {
        String str = formatStr("sss");
        System.out.println(str);
        return "ss";
    }

    /**
     * create map
     */
    private Map<String, Object> createDict() {
        Map<String, Object> map = new HashMap<String, Object>();
        map.put("key", 1);
        map.put("key2", "v2");
        System.out.println(map);
        return map;
    }

    String defineChar() {
        char[] mychar = {'a', 'b'};
        return new String(mychar);
    }

    //

    /**
     * define array of int,
     * and print Array.toString(arrayObject)
     */
    void getArrayToStr() {
        String[][] str = new String[3][4];
        str[0][0] = new String("Good");
        Object O = str[0][0];
        int[] my = new int[]{1, 2, 3};
        //数组对象转字符串输出
        System.out.println(Arrays.toString(my) + " " + O);
    }

    /**
     * get type of Object
     *
     * @return : type String
     */
    public void type(Object object) {
        String tp = String.valueOf(object.getClass().getName());
        System.out.println(tp.split("\\.").getClass().getName());
        String[] array = tp.split("\\.");
        //数组转列表
        List<String> list = Arrays.asList(array);
        String lastStr = list.get(array.length - 1);
        System.out.println(lastStr);
//       return lastStr;

    }

    /**
     * ArrayList to Array : list1.toArray(array)
     */
    public void createArrayList() {
        List<String> list1 = new ArrayList<String>();
        list1.add("index1");
        list1.add("index2");
        String[] test = list1.getClass().getName().split("\\.");
        // array to arrayList
        List<String> o = Arrays.asList(test);
        String[] array = new String[list1.size()];
        // ArrayList to ARRAY
        String[] aa = list1.toArray(array);
        System.out.println("list1 type is :" + list1.getClass().getName());
        System.out.println(Arrays.toString(aa));

    }

    String[] getArray() {
        String[] m = new String[1];
        return m;
    }

    /**
     * enumerate element and index :
     *
     * @return : ArrayList: [[index,value],[index1,value1]]
     */
    void enumerateList() {
        List<String> list1 = new ArrayList<String>();
        list1.add("index1");
        list1.add("index2");
        List<Object> all = new ArrayList<Object>();
        for (int i = 0; i < list1.size(); i++) {
            List<Object> vec = new ArrayList<Object>();
            vec.add(i);
            vec.add(list1.get(i));
            all.add(vec);
        }
        System.out.println(all);
    }

    /**
     * iter map by foreach ,but it cant change key or value in the iteral :
     */
    List<Object> iterMap() {
        List<Object> out = new ArrayList<Object>();
        Map<String, Object> map = createDict();
        for (String k : map.keySet()) {
            List<Object> in = new ArrayList<Object>();
            String value = String.valueOf(map.get(k));
            in.add(k);
            in.add(value);
            out.add(in);
        }
        System.out.println(out);
        return out;
    }

    /**
     * iter Map by use entrySet() : python dict.items():
     */
    void iterMap2() {
        List<Object> out = new ArrayList<Object>();
        Map<String, Object> map = createDict();
        for (Map.Entry<String, Object> item : map.entrySet()) {
            List<Object> in = new ArrayList<Object>();
            String k = String.valueOf(item.getKey());
            String v = String.valueOf(item.getValue());
            in.add(0, k);
            in.add(1, v);
            out.add(in);
        }
        System.out.println(out);

    }

    /**
     * list remove element :
     */
    void removeList() {
        // == 比对象，equals 比value
        List<Integer> out = new ArrayList<Integer>();
        out.add(1);
        out.add(3);
        out.add(1);
        for (int i = 0; i < out.size(); i++) {
            if (out.get(i).equals(1)) {
                out.remove(i);
            }
        }
        System.out.println(out);

    }

    /**
     * SIMPLE java return ：三目运算:
     */
    int javaSimple() {
        int a, b, c;
        a = 10;
        b = 1;
//       c= ;
        return (a == 1) ? a : b;
    }

    /**
     * calculator timeInterval init type is long :100L:
     *
     * @return : String
     */
    String timercount() throws InterruptedException {
        long date = new Date().getTime();
        Thread.sleep(1000);
        long date_end = new Date().getTime();
        String millions = String.valueOf(date_end - date);
        return millions;
    }

    /**
     * sort ArrayList for same type elements in list
     */
    public static void sortbyCollect() {
        List<Integer> aa = new ArrayList<>();
        List<Integer> bb = new ArrayList<>();
        bb.add(100);
        aa.add(9);
        aa.add(4);
        aa.set(0, 99);
        aa.addAll(bb);
        Collections.sort(aa);
        Collections.reverse(aa);
        System.out.println(aa.toString());
    }

    public Map<String, String> sortMap(Map map) {
        System.out.println(map);
        List<Map.Entry<String, String>> list = new ArrayList<Map.Entry<String, String>>(map.entrySet());
        Collections.sort(list, new Comparator<Map.Entry<String, String>>() {
            public int compare(Map.Entry<String, String> o1, Map.Entry<String, String> o2) {
                return o1.getValue().compareTo(o2.getValue());
            }
        });
        System.out.println(map);
        return map;
    }

    void listWhileHas() {
        ArrayList<String> list = new ArrayList<String>();
        list.add("a");
        list.add("b");
        //用迭代器 遍历
        ListIterator<String> it = list.listIterator();
        while (it.hasNext()) {
            //添加泛型之后 可以省去 强转了行的麻烦
            String next = it.next();
            System.out.println(next);
        }

    }

    /**
     * gen timestamp str for example:
     * 15576676767676
     */
    public static String timestamp() {
        return String.valueOf(System.currentTimeMillis());
    }

    /**
     * random ArrayList of [min,max) or [min,max]
     */
    public static List genRandomlist(int START, int END) {
        // 可以取到边界值上下
        List<Integer> list = new ArrayList<Integer>();
        for (int i = 0; i < END - START + 1; i++) {
            int numeric = new Random().nextInt(END - START + 1) + START;
            list.add(numeric);

        }
        System.out.println(list);
        return list;
    }

    /**
     * random ArrayList of [min,max) or [min,max]
     */
    public static List mathRandom(int min, int max) {
        // max-min 不加1，只可以到[0,10);max-min+1 [1,10]
        List list = new ArrayList();
        for (int i = 0; i < max - min; i++) {
            int num = (int) (Math.random() * (max - min + 1) + min);
            list.add(num);
        }
        System.out.println(list);
        return list;
    }

    /**
     * gen (0,1) str
     */
    public static String genfloatZeroandOne() {
        double db = new Random().nextDouble() * 1 + 0;
//        DecimalFormat df = new DecimalFormat("0.00");
//        return df.format(floats);
        float ft = (float) db;
        System.out.println(db);//四舍弃，五入
        return String.format("%.3f", db);
    }

    /**
     * TYPE Transfer
     */
    public static void chageType(String str) {
        float ft = Float.valueOf(str).floatValue();
        byte b = Byte.parseByte(str);
        short t = Short.parseShort(str);
        int i = Integer.parseInt(str);
        long l = Long.parseLong(str);
        Float f = Float.parseFloat(str);
        Double d = Double.parseDouble(str);
        System.out.println(ft);
    }

    public static void genSecureRandom(int start, int end) {

    }

    /**
     * gen uuidString
     */
    public static void genuuid() {
        String uuidstr = UUID.randomUUID().toString().replaceAll("-", "").toLowerCase();
        System.out.println(uuidstr);
    }

    /**
     * time format,default Calender.get() is  int
     * month start by 0
     */
    public static String timeFormat() {
        /**
         Calendar now = Calendar.getInstance();
         String year=String.valueOf(now.get(Calendar.YEAR));
         String month=String.valueOf(now.get(Calendar.MONTH) + 1);
         String day=String.valueOf(now.get(Calendar.DAY_OF_MONTH));
         String hour=String.valueOf(now.get(Calendar.HOUR_OF_DAY));
         String min=String.valueOf(now.get(Calendar.MINUTE));
         String seconds=String.valueOf(now.get(Calendar.SECOND));
         String str="%s-%s-%s %s:%s:%s";
         String curtime= String.format(str,year,month,day,hour,min,seconds);
         */
        Date d = new Date();
        SimpleDateFormat simpeformat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        String curtimestamp = simpeformat.format(d);
        System.out.println(curtimestamp);
        return curtimestamp;
    }

    /**
     * readfile method
     * @return :fileString
     * by FileInputStream
     */
    public static String readfile(String filepath) throws IOException {
        StringBuffer sb = new StringBuffer();
        File file = new File(filepath);
        if (file.exists() && file.isFile()) {
            FileInputStream fip = new FileInputStream(file);
            InputStreamReader reader = new InputStreamReader(fip, "UTF-8");
            while (reader.ready()) {
                /** append char to string buffer*/
                sb.append((char) reader.read());
            }
            /** close reader and fip stream */
            reader.close();
            fip.close();
        }
        System.out.println(sb.toString());
        return sb.toString();
    }

    /**
     * writefile method
     *@return :null
     * @param : by FileOutputStream
     */
    public static void writefile(String pdir,String filename) throws IOException {
        File dir =new File(pdir);
        if(!dir.exists()){
            /** mkdir pdir */
            dir.mkdir();
        }
        File filepath=new File(pdir+filename);
        if(!filepath.exists()){
            /** touch file */
            filepath.createNewFile();
            FileOutputStream fop = new FileOutputStream(filepath);
            OutputStreamWriter writer = new OutputStreamWriter(fop, "UTF-8");
            writer.write("9999dftest花");
            /**close write and fop stream  */
            writer.close();
            fop.close();
        }else{
            System.out.println("file already exist");
            FileOutputStream fop = new FileOutputStream(filepath);
            OutputStreamWriter writer = new OutputStreamWriter(fop, "UTF-8");
            writer.append("我爱singer");
            writer.append("\n9999dftest花");
            /**close write and fop stream  */
            writer.close();
            fop.close();
        }
    }

    /** delete file*/
    public static  void delfile(String filepath){
        File file =new File(filepath);
                if(file.exists()&&file.isFile()){
            file.delete();
            System.out.println("file delete ok ");
        }else{
            System.out.println("file not exist");
        }
    }

    /**
     * delete dir
     * @return:null
     * @warning: clear all dirs and files under path and strart del path
     */
    public static void deleteDir(String path) {
        /** list pathdir under it's file and dir*/
        File dir = new File(path);
        if (dir.exists()) {
            File[] tmp = dir.listFiles();
            for (int i = 0; i < tmp.length; i++) {
                if (tmp[i].isDirectory()) {
                    deleteDir(path + "/" + tmp[i].getName());
                } else {
                    tmp[i].delete();
                }
            }
            /** clear all dirs and files under path and strart del path */
            dir.delete();
        }
    }

    public static String bufferReadeFile(String filepath){
        StringBuffer sb=new StringBuffer();
        try{
            FileReader reader=new FileReader(filepath);
            BufferedReader br =new BufferedReader(reader);
            String line;
            while((line=br.readLine())!=null){
                sb.append(line);
            }

        }catch (IOException e){
            e.printStackTrace();
        }
        /**test output*/
        System.out.println(sb.toString());
        return sb.toString();
    }

    public  static void  bufferWriteFile(String filepath){
        try{
            File filename=new File(filepath);
            /** create newfile if doesn't exist,else pass */
            if(!filename.exists()) {
                filename.createNewFile();
            }
            try{
                FileWriter writer=new FileWriter(filename);
                BufferedWriter bw= new BufferedWriter(writer);
                /** write content  to buffer*/
                bw.write(" Java is really awkward");
                /** flush content from buffer to file */
                bw.flush();
            }catch (IOException f){
                f.printStackTrace();
            }
        }catch (IOException e){
            e.printStackTrace();
        }
    }

    /** Read jsonfile return jsonString   */
    public static  String readJsonFile(String jsonpath){
        StringBuffer sb=new StringBuffer();
        try {
            FileReader reader = new FileReader(new File(jsonpath));
            BufferedReader br=new BufferedReader(reader);
            String line =null;
            while((line=br.readLine())!=null){
                sb.append(line);
                }
        }catch (IOException e){
            e.printStackTrace();
        }
     return sb.toString();

    }
    /** get jsonobject attribute by alibaba fastjson .JsonObject*/
    public static JSONObject jsonToJava(String jsonpath){
        /** get json string from json file*/
        String jsonString=readJsonFile(jsonpath);
        /** jsonString to jsonobject*/
        JSONObject object = JSONObject
                .parseObject(jsonString);
        /**
         * value = object.get("key")
        System.out.println(object.toString());
        String str=object.getString("string");
        Boolean bool=object.getBoolean("boolean");
        List<Object> list=JSONObject.parseArray(object.getJSONArray("list").toString(),Object.class);
        System.out.println(list);
         */
        return object;
    }

    /** fastjson use:
     * 1.fastjson  List转JSONArray
     * List<T> list = new ArrayList<T>();
     * JSONArray array= JSONArray.parseArray(JSON.toJSONString(list))；
     *
     *
     * 2.fastjson  JSONArray转List
     * JSONArray array = new JSONArray();
     * List<EventColAttr> list = JSONObject.parseArray(array.toJSONString(), EventColAttr.class);
     *
     *
     * 3.fastjson  字符串转List
     * String str = "";
     * List<T> list = JSONObject.parseArray(str,T.class);
     * @param jsonStr
     * @return
     */

    /**  denpendended by fastjson.JSON */
    public static Map jsonStrToMap(String jsonStr){
//        Map<String,Object> map = JSON.parseObject(jsonStr,Map.class);
        Map<String,Object> map = (Map)JSON.parse(jsonStr);
        System.out.println(map);
        return map;
    }
    /** 帕布里克，斯泰迪克沃伊得们，让世界从这里感受痛楚吧...*/
    public static void main(String[] args) throws InterruptedException {
            String path = System.getProperty("user.dir") + "/src/testdir/";
            String filename = "test.json";
          jsonStrToMap(readJsonFile(path+filename));

    }
}