String类一些常用及容易混淆的操作

public class Demo1 {

public static void main(String[] args) {
// TODO Auto-generated method stub

/*String 对象两种实例方法*/
String str1="hello";
String str2="hello";

String str3="world";
String str4=new String("world");

/*==比较 与equals方法比较字符串*/
System.out.print("1\t");
System.out.println(str1==str2);   		//true
System.out.print("2\t");
System.out.println(str3==str4);   		//false
System.out.print("3\t");
System.out.println(str3.equals(str4));	//true

/*字符串与字符数组转换*/
char s[]=str1.toCharArray();
System.out.print("4\t");
for(char i:s)
System.out.print(i);
System.out.println();

/*去字符串左右空格*/
String str5="  I am a boy  ";
System.out.print("5\t");
System.out.println(str5.trim());

/*按注定字符拆分字符串*/
String str6[]=str5.split(" ");
System.out.print("6\t");
for(String str:str6)
System.out.println(str);

/*字符串引用传递之匿名对象*/
String str7="hello";
System.out.print("7\t");
System.out.println(str7);
fun(str7);
System.out.print("8\t");
System.out.println(str7);

/*字符串引用传递之非匿名对象*/
Demo demo=new Demo();
demo.str="hello";
System.out.print("9\t");
System.out.println(demo.str);
fun(demo);
System.out.print("10\t");
System.out.println(demo.str);
}

public static void fun(String str){
str="你好";
}

public static void fun(Demo demo){
demo.str="你好";
}
}

class Demo{
String str;
}