Java数据类型转换

 

1       字符串to整型

String num = "111";

int Integer.parseInt(num);      //确保num只有数字字符

1.1    byte and string

publicclass TestMain {

 

    publicstatic String byte2string(byte[] input){

       String returnString = new String(input);

      

       return returnString;

    }

   

    publicstaticbyte[] string2byte(String input){

       byte [] output = input.getBytes();

      

       return output;

    }

   

    /**

     *byte2string时,如果byte定义过大,则会有'/0'字符显示问题,'/0'显示是一个"口口口口口口"

     *@paramargs

     */

    publicstaticvoid process0的问题(){

       String source = "AABB中国CC";

       String dest = null;

       byte[] bt1 = source.getBytes();

       byte[] bt2 = newbyte[32];

      

       //显示是一个"口口口口口口"

       for(int i = 0; i < bt1.length; i ++){

           bt2[i] = bt1[i];

       }

       dest = new String(bt2);

       System.out.println("bt2 = " + dest);

      

       //显示没有"口口口口口口"

       byte[] bt3 = newbyte[bt1.length];

       for(int i = 0; i < bt1.length; i ++){

           bt3[i] = bt1[i];

       }

       dest = new String(bt3);

       System.out.println("bt3 = " + dest);

    }

    publicstaticvoid main(String args[]){

       String test = "AABB中国CC";

      

       //byte反映了字符真实的长度,byte[].length=10

       byte [] ret = TestMain.string2byte(test);

       System.out.println("byte = " + ret + ",/tbyte[].length = " + ret.length);

       //string反映了字符的个数,一个汉字算一个字符,string.length()=8

       String str = TestMain.byte2string(ret);

       System.out.println("string = " + str + ",/tstring.length() = " + str.length());

      

       //byte2string的显示问题

       TestMain.process0的问题();

      

    }

}