String和StringBuffer作为参数传递（一个小注意事项）

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public static void main(String[] args) {        String s1 = "Hello";        String s2 = "World";        System.out.println(s1 + "-----------" + s2);//Hello-----------World        change(s1, s2);        System.out.println(s1 + "-----------" + s2);//Hello-----------World          StringBuffer sb1 = new StringBuffer("Hello");        StringBuffer sb2 = new StringBuffer("World");        System.out.println(sb1 + "-------------" + sb2);//Hello-----------World        changeBuffer(sb1, sb2);        System.out.println(sb1 + "-------------" + sb2);//Hello-------------WorldWorld    }      private static void changeBuffer(StringBuffer sb1, StringBuffer sb2) {        sb1 = sb2;        sb2 = sb1.append(sb2);    }      private static void change(String s1, String s2) {        s1 = s2;        s2 = s1 + s2;    }

　　注意：StringBuffer直接赋值不会改变实际内容，如果做了操作就会改变