BigInteger学习使用

1.RightsHelper定义

import java.math.BigInteger;

/**
 * 权限计算帮助类
 */
public class RightsHelper {
    /**
     * 利用BigInteger对权限进行2的权的和计算
     * @param rights int型权限编码数组
     * @return 2的权的和
     */
    public static BigInteger sumRights(int[] rights){
        BigInteger num = new BigInteger("0");
        for(int i=0; i<rights.length; i++){
            num = num.setBit(rights[i]);
        }
        return num;
    }
    /**
     * 利用BigInteger对权限进行2的权的和计算
     * @param rights String型权限编码数组
     * @return 2的权的和
     */
    public static BigInteger sumRights(String[] rights){
        BigInteger num = new BigInteger("0");
        for(int i=0; i<rights.length; i++){
            num = num.setBit(Integer.parseInt(rights[i]));
        }
        return num;
    }
    
    /**
     * 测试是否具有指定编码的权限
     * @param sum
     * @param targetRights
     * @return
     */
    public static boolean testRights(BigInteger sum,int targetRights){
        return sum.testBit(targetRights);
    }
    
    /**
     * 测试是否具有指定编码的权限
     * @param sum
     * @param targetRights
     * @return
     */
    public static boolean testRights(String sum,int targetRights){
        if(Tools.isEmpty(sum))
            return false;
        return testRights(new BigInteger(sum),targetRights);
    }
    
    /**
     * 测试是否具有指定编码的权限
     * @param sum
     * @param targetRights
     * @return
     */
    public static boolean testRights(String sum,String targetRights){
        if(Tools.isEmpty(sum))
            return false;
        return testRights(new BigInteger(sum),targetRights);
    }
    
    /**
     * 测试是否具有指定编码的权限
     * @param sum
     * @param targetRights
     * @return
     */
    public static boolean testRights(BigInteger sum,String targetRights){
        return testRights(sum,Integer.parseInt(targetRights));
    }
}

2.BigInteger的使用

String menuIds ="1,2,36,37,39,38,43,20,3,235,6,50";
BigInteger rights = RightsHelper.sumRights(Tools.str2StrArray(menuIds));


     /**根据角色权限处理权限状态(递归处理)
     * @param menuList：传入的总菜单
     * @param roleRights：加密的权限字符串
     * @return
     */
    public List<Menu> readMenu(List<Menu> menuList,String roleRights){
        for(int i=0;i<menuList.size();i++){
            menuList.get(i).setHasMenu(RightsHelper.testRights(roleRights, menuList.get(i).getMENU_ID()));
            this.readMenu(menuList.get(i).getSubMenu(), roleRights);                    //是：继续排查其子菜单
        }
        return menuList;
    }