关于Map集合

//错误代码示范
List<Map<String, >> result=new ArrayList<Map<String,  >>();
        Map<String, > map=new HashMap<String,  >();//@1
        List<Role> roleList=new ArrayList<Role>();
        Role r1=new Role();
        r1.setId(1L);
        r1.setRoleName(\"系统管理员\");
        Role r2=new Role();
        r2.setId(2L);
        r2.setRoleName(\"工人\");
        Role r3=new Role();
        r3.setId(3L);
        r3.setRoleName(\"学生\");
        roleList.add(r1);
        roleList.add(r2);
        roleList.add(r3);
        for (Role role:roleList
                ) {
            map.put(\"id\",role.getId());
            map.put(\"roleName\",role.getRoleName());
            result.add(map);
            System.out.println(result);
        }

List<Map<String, >> result=new ArrayList<Map<String,  >>();
        List<Role> roleList=new ArrayList<Role>();
        Role r1=new Role();
        r1.setId(1L);
        r1.setRoleName(\"系统管理员\");
        Role r2=new Role();
        r2.setId(2L);
        r2.setRoleName(\"工人\");
        Role r3=new Role();
        r3.setId(3L);
        r3.setRoleName(\"学生\");
        roleList.add(r1);
        roleList.add(r2);
        roleList.add(r3);
        for (Role role:roleList
                ) {
            Map<String, > map=new HashMap<String,  >();//@2
            map.put(\"id\",role.getId());
            map.put(\"roleName\",role.getRoleName());
            result.add(map);
            System.out.println(result);
        }