Spring笔记

• Spring MVC 设置Response的charset

  @RequestMapping(value = "/login", produces = "text/plain;charset=gb2312")
  @ResponseBody
  public String login(HttpServletRequest req, HttpServletResponse resp) {
          
  }

   
• Spring MVC 超时处理

  //在stackoverflow上看到的一个有趣的案例
  //场景: 用户访问,如果后台处理时间<10s时返回正常结果页面,否则返回超时页面
  
  //AsyncTaskExecutor异步任务处理, 但它的submit()方法是阻塞型的.
  final Future<ModelAndView> future = asyncTaskExecutor.submit(new Callable<ModelAndView>() {
      @Override
      public ModelAndView call() throws Exception {
          //lengthy computations...
          return new ModelAndView("done");
      }
  });
  try {
      return future.get(10, TimeUnit.SECONDS); // 设置超时时间
  } catch (TimeoutException e) { //捕获超时异常进行处理
      return new ModelAndView("timeout");
  }

   
• Spring MVC 获取 Session Attribute

使用范例

@RequestMapping("/data/file/selectFileLog")
public @ResponseBody Pagination selectFileLog(@RequestBody Pagination page, 
			@SessionAttribute("loginUser")LoginUser loginUser){
        //do sth.
}

 实现步骤: 

//1. 创建注解类
@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
public @interface SessionAttribute {
	
	public String value();
	
	public boolean required() default true;
	
}

//2. 实现Resolver
public class SessionAttributeArgumentsResolver implements WebArgumentResolver {
	
	Logger console = Logger.getLogger(SessionAttributeArgumentsResolver.class);

	@Override
	public Object resolveArgument(MethodParameter param, NativeWebRequest request)
			throws Exception {
		Annotation[] annotations = param.getParameterAnnotations();
		for (Annotation annotation : annotations){
			if(SessionAttribute.class.isInstance(annotation)){
				SessionAttribute sa = (SessionAttribute) annotation;
				String attrName = sa.value();
				boolean required = sa.required();
				Object res = request.getAttribute(attrName, RequestAttributes.SCOPE_SESSION);
				if (null == res && required){
					throw new RuntimeException("Attribute:{ " + attrName + " } not exsited in session !");
					
				}
				return res;
			}
		}
		return UNRESOLVED;
	}

}

<!--3. 配置Resolver -->
<mvc:annotation-driven >
        <mvc:argument-resolvers>
            <bean id="sessionAttributeArgumentsResolver" class="com.lhw.util.base.SessionAttributeArgumentsResolver"></bean>
        </mvc:argument-resolvers>
</mvc:annotation-driven>

  

• Spring JDBC 插入并获取新增记录的ID

public static long commonInsert(JdbcTemplate jt, String tableName, String idColumn, Map<String, Object> object){
	SimpleJdbcInsert sji = new SimpleJdbcInsert(jt)
			.withTableName(tableName)
			.usingGeneratedKeyColumns(idColumn);
	return sji.executeAndReturnKey(object).longValue();
}