public class Test {
    public static void main(String args[]){
        TestStringBuffer tsb = new TestStringBuffer();
        String s= new String("abc");
        tsb.setAsb(s);
        System.out.println(tsb.getAsb());
    }
}
class TestStringBuffer{
    
    private StringBuffer sb;
    
    public TestStringBuffer(){
        this.sb = new StringBuffer("数据");
    }
    public String getAsb() {
        return this.sb.toString();
    }
    public void setAsb(String s){
        this.sb.append(s);
    }

------解决方案--------------------
没有这种情况的吧
Java code

public class Test
{
    public static void main(String[] args) throws Exception
    {
        StringBuffer str1 = new StringBuffer("aaa");
        String str2 = "bbb";
        str1.append(str2);
        System.out.println(str1.toString());
    }
}