int[] a=new int []{1,2,3,4,5};
        int[] b=new int []{2,3,4};
        for(int ai=0,bi=0,al=a.length,bl=b.length;ai<al;){
            if(bi==bl||a[ai]<b[bi]){
                System.out.print(a[ai]+",");
                ai++;
            }else if(a[ai]==b[bi]){
                ai++;
                bi++;
            }else{
                bi++;
            }
        }

------解决方案--------------------
jdk1.6里提供了新方法!