在项目中，控制权限保存时，如果多次修改权限，该如何写？

在项目中，控制权限保存时，如果多次修改权限，该如何写？

错误代码：

package cn.itcast.crm.service.impl;

import java.util.List;

import javax.annotation.Resource;

import org.apache.commons.lang.xwork.StringUtils;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Isolation;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;

import cn.itcast.crm.dao.ISysPopedomPrivilegeDao;
import cn.itcast.crm.domain.SysPopedomPrivilege;
import cn.itcast.crm.domain.SysPopedomPrivilegeId;
import cn.itcast.crm.service.ISysPopedomPrivilegeService;

@Transactional(readOnly=true)
@Service(ISysPopedomPrivilegeService.SERVICE_NAME)
public class SysPopedomPrivilegeServiceImpl implements ISysPopedomPrivilegeService {

	@Resource(name=ISysPopedomPrivilegeDao.SERVICE_NAME)
	private ISysPopedomPrivilegeDao sysPopedomPrivilegeDao;
	
	@Transactional(isolation=Isolation.DEFAULT,propagation=Propagation.REQUIRED,readOnly=false)
	public void updatePopedom(String roleId, String[] popedomModules) {
		//保存该权限组对应的所有的权限
		if(StringUtils.isNotBlank(roleId)&&popedomModules!=null&&popedomModules.length>0){
			for(int i=0;i<popedomModules.length;i++){
				if(StringUtils.isNotBlank(popedomModules[i])){
					String[] str=popedomModules[i].split(",");
					SysPopedomPrivilege sysPopedomPrivilege=new SysPopedomPrivilege();
					SysPopedomPrivilegeId id = new SysPopedomPrivilegeId();
					id.setRoleId(roleId);
					id.setPopedomModule(str[0]);
					id.setPopedomPrivilege(str[1]);
					sysPopedomPrivilege.setId(id);
					sysPopedomPrivilegeDao.save(sysPopedomPrivilege);
				}
			}
		}
	}

}<span style="color:#ff0000;">
</span>

错误提示：

正确代码：

package cn.itcast.crm.service.impl;

import java.util.List;

import javax.annotation.Resource;

import org.apache.commons.lang.xwork.StringUtils;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Isolation;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;

import cn.itcast.crm.dao.ISysPopedomPrivilegeDao;
import cn.itcast.crm.domain.SysPopedomPrivilege;
import cn.itcast.crm.domain.SysPopedomPrivilegeId;
import cn.itcast.crm.service.ISysPopedomPrivilegeService;

@Transactional(readOnly=true)
@Service(ISysPopedomPrivilegeService.SERVICE_NAME)
public class SysPopedomPrivilegeServiceImpl implements ISysPopedomPrivilegeService {

	@Resource(name=ISysPopedomPrivilegeDao.SERVICE_NAME)
	private ISysPopedomPrivilegeDao sysPopedomPrivilegeDao;
	
	@Transactional(isolation=Isolation.DEFAULT,propagation=Propagation.REQUIRED,readOnly=false)
	public void updatePopedom(String roleId, String[] popedomModules) {
		//删除该权限组对应的所有权限
		if(StringUtils.isNotBlank(roleId)&&popedomModules!=null&&popedomModules.length>0){
			String whereHql=" and o.id.roleId=?";
			Object[] params={roleId};
			
			List<SysPopedomPrivilege> list=sysPopedomPrivilegeDao.findObjectByConditionWithNoPage(whereHql, params);
			sysPopedomPrivilegeDao.deleteAllObjects(list);
		}
		//保存该权限组对应的所有的权限
		if(StringUtils.isNotBlank(roleId)&&popedomModules!=null&&popedomModules.length>0){
			for(int i=0;i<popedomModules.length;i++){
				if(StringUtils.isNotBlank(popedomModules[i])){
					String[] str=popedomModules[i].split(",");
					SysPopedomPrivilege sysPopedomPrivilege=new SysPopedomPrivilege();
					SysPopedomPrivilegeId id = new SysPopedomPrivilegeId();
					id.setRoleId(roleId);
					id.setPopedomModule(str[0]);
					id.setPopedomPrivilege(str[1]);
					sysPopedomPrivilege.setId(id);
					sysPopedomPrivilegeDao.save(sysPopedomPrivilege);
				}
			}
		}
	}

}

应该先 删除该权限组对应的所有权限，然后再保存该权限组对应的所有的权限。