public interface UserService {     
 public void addUser(String username, String password);     
    
 public void deleteUser(int id);     
    
 public void updateUser(int id, String username);     
    
 public List queryUser(String username);     
 }   
 

 
 public class UserServiceImpl implements UserService {       
     private DataSource dataSource;       
     public void addUser(String username, String password) {       
         //正确的sql       
         String sql = "insert into aaa (t1,t2,t3) values (seq_food.nextval,'"+username+"','"+password+"')";       
         System.out.println(sql);       
         JdbcTemplate jdbcTemplate = new JdbcTemplate(getDataSource());       
         jdbcTemplate.update(sql);    
     }       
       
     public void deleteUser(int id) {       
       
     }       
       
     public void updateUser(int id, String username) {       
         //错误的sql，测试回滚       
          String sql = "update aa set t2='"+username+"' where t1='"+id+"'";       
         System.out.println(sql);       
         JdbcTemplate jdbcTemplate = new JdbcTemplate(getDataSource());       
         jdbcTemplate.update(sql);       
     }       
       
     public List queryUser(String username) {       
       
         return null;       
     }       
       
     public DataSource getDataSource() {       
         return dataSource;       
     }       
       
     public void setDataSource(DataSource dataSource) {       
         this.dataSource = dataSource;       
     }       
       
 } 
 

public class UserServlet extends HttpServlet {      
     
          
    public void doGet(HttpServletRequest request, HttpServletResponse response)      
            throws ServletException, IOException {      
     
        doPost(request, response);      
    }      
     
          
    public void doPost(HttpServletRequest request, HttpServletResponse response)      
            throws ServletException, IOException {      
        request.setCharacterEncoding("utf-8");      
        response.setContentType("text/html; charset=utf-8");      
        ApplicationContext ctx = WebApplicationContextUtils.getWebApplicationContext(getServletContext());      
        try {      
            UserService userService = (UserService) ctx.getBean("userService");      
            userService.addUser("1", "2");      
            userService.updateUser(10032190, "zf");      
        } catch (DataAccessException e) {      
            e.printStackTrace();      
        }      
              
    }      
     
}