Spring MVC学习随笔-Ajax集成（JSON格式返回数据）、拦截器（MyInterceptor - ToB企服应用市场:ToB评测及商务社交产业平台

<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.9.8</version>
</dependency>

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@Controller
@RequestMapping("json")
public class JsonController {
/**
* 使用阿里fastjson转换json
*/
@RequestMapping("showAll")
public @ResponseBody List<User> findAll() {
//1.收集数据
//2.调用业务
List<User> users = new ArrayList<>();
users.add(new User(UUID.randomUUID().toString(), "小红", 23, new Date()));
users.add(new User(UUID.randomUUID().toString(), "小名", 29, new Date()));
users.add(new User(UUID.randomUUID().toString(), "小撒", 25, new Date()));
return users;
}
@RequestMapping("findAll")
public void findAll(HttpServletResponse response) throws IOException {
//1.收集数据
//2.调用业务
List<User> users = new ArrayList<>();
users.add(new User(UUID.randomUUID().toString(), "小陈", 23, new Date()));
users.add(new User(UUID.randomUUID().toString(), "小名", 29, new Date()));
users.add(new User(UUID.randomUUID().toString(), "小撒", 25, new Date()));
// fastjson
String s = JSONObject.toJSONStringWithDateFormat(users, "yyyy-MM-dd");
response.setContentType("application/json;charset=UTF-8");
response.getWriter().println(s);
}
}

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@JsonFormat(pattern = "yyyy-MM-dd")
private Date bir;

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public class MyInterceptor implements HandlerInterceptor {
@Override
//**参数1：当前请求对象参数2：当前请求响应对象参数3：当前请求的控制器对应的方法对象**
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
System.out.println("handler = " + ((HandlerMethod)handler).getMethod().getName() );
System.out.println("MyInterceptor.preHandle");
//强制用户登录
Object user = request.getSession().getAttribute("user");
// if (user == null) {
// // 重定向到登录页面
// response.sendRedirect(request.getContextPath() + "/login.jsp");
// return false;
// }
return HandlerInterceptor.super.preHandle(request, response, handler);
}
@Override
// 参数1、2、3同上 **参数4：当前控制器方法的返回值**
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
System.out.println("modelAndView = " + modelAndView);
System.out.println("MyInterceptor.postHandle");
HandlerInterceptor.super.postHandle(request, response, handler, modelAndView);
}
@Override
// 参数1、2、3同上 **参数4：请求过程中出现异常时的异常对象**
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
System.out.println("MyInterceptor.afterCompletion");
if (ex != null) {
System.out.println("ex.getMessage() = " + ex.getMessage());
}
HandlerInterceptor.super.afterCompletion(request, response, handler, ex);
}
}

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<bean id="myInterceptor" />
<mvc:interceptors>
<mvc:interceptor>
<mvc:mapping path="/json/test"/>
<mvc:exclude-mapping path="/json/showAll"/>
<ref bean="myInterceptor"/>
</mvc:interceptor>
</mvc:interceptors>

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@RequestMapping("test")
public String test() {
System.out.println("JsonController.test");
// throw new RuntimeException();
return "index";
}

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public class GlobalExceptionResolver implements HandlerExceptionResolver {
/**
* 用来处理发生异常时的方法
*
* @param request 当前请求对象
* @param response 当前请求对应的响应对象
* @param handler 当前请求的方法对象
* @param ex 当前出现异常时的异常对象
* @return 出现异常时展示视图和数据
*/
@Override
public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {
System.out.println("进入全局异常处理器，获取的异常信息为：" + ex.getMessage());
ModelAndView modelAndView = new ModelAndView();
// 基于不同业务异常跳转到不同页面
modelAndView.setViewName("redirect:/error.jsp"); // return "error" -> error.jsp
// modelAndView中的model默认放到request作用域，如果使用redirect跳转，model中数据会自动拼接到跳转url
modelAndView.addObject("msg", ex.getMessage());
return modelAndView;
}
}

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[/code]
[*]基于不同业务异常跳转不同页面
[code]// 基于不同业务异常跳转到不同页面
if (ex instanceof NotFoundException) {
modelAndView.setViewName("notFound");
} else if (ex instanceof GeneralException) {
modelAndView.setViewName("generalException");
}

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