springmvc java物件轉json，上傳下載（未完）攔截器Interceptor以及原始碼解析（未完待續）
阿新 • • 發佈：2019-06-20
package com.atguigu.my.controller; import java.util.Collection; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.ResponseBody; import com.atguigu.my.bean.Employee; import com.atguigu.my.dao.EmployeeDao; @Controller public class JsonController { @Autowired private EmployeeDao employeeDao; @RequestMapping(value = "/testJson") @ResponseBody public Collection<Employee> getAll() { Collection<Employee> emps = employeeDao.getAll(); ; return emps; } }
只是寫一個<a href = "testJson">測試json</a>
然後再springmvc.xml中開啟註解驅動<mvc:annotation-driven/>
然後需要印如jackson的三個jar包，jackson是阿里巴巴產品，能夠自動將java物件轉為json物件
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:mvc="http://www.springframework.org/schema/mvc" xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd"> <context:component-scan base-package="com.atguigu"></context:component-scan> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/WEB-INF/view/"></property> <property name="suffix" value=".jsp"></property> </bean> <mvc:default-servlet-handler/> <mvc:annotation-driven /> <!-- 處理檔案，將客戶端上傳的File檔案，處理為MultipartFile 注意：檔案解析器的bean中id必須設定為multipartResolver --> <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"> <!-- 設定檔案解析的編碼，注意：一定要和頁面的pageEncoding保持一致 --> <property name="defaultEncoding" value="UTF-8"></property> <!-- 設定最大上傳檔案大小 --> <property name="maxUploadSize" value="88888888"></property> </bean> <mvc:interceptors> <!-- 預設攔截所有請求 --> <bean class="com.atguigu.interceptor.FirstInterceptor"></bean> <bean class="com.atguigu.interceptor.SecondInterceptor"></bean> <!-- 此方式要求攔截器類上必須加註解@Component --> <!-- <ref bean="firstInterceptor"/> --> <!-- 設定自定義攔截方式 --> <!-- <mvc:interceptor> <bean></bean> <mvc:mapping path=""/> <mvc:exclude-mapping path=""/> </mvc:interceptor> --> </mvc:interceptors> </beans>
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5"> <display-name>SpringMVC04</display-name> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> <filter> <filter-name>CharacterEncodingFilter</filter-name> <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class> <init-param> <param-name>encoding</param-name> <param-value>UTF-8</param-value> </init-param> </filter> <filter-mapping> <filter-name>CharacterEncodingFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <!-- The front controller of this Spring Web application, responsible for handling all application requests --> <servlet> <servlet-name>springDispatcherServlet</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:springMVC.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <!-- Map all requests to the DispatcherServlet for handling --> <servlet-mapping> <servlet-name>springDispatcherServlet</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> </web-app>
package com.atguigu.interceptor;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
@Component
public class FirstInterceptor implements HandlerInterceptor {
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
throws Exception {
System.out.println("First:preHandle");
return true;
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
ModelAndView modelAndView) throws Exception {
System.out.println("First:postHandle");
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
throws Exception {
System.out.println("First:afterCompletion");
}
}
package com.atguigu.interceptor;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
@Component
public class SecondInterceptor implements HandlerInterceptor {
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
throws Exception {
System.out.println("Second:preHandle");
return true;
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
ModelAndView modelAndView) throws Exception {
System.out.println("Second:postHandle");
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
throws Exception {
System.out.println("Second:afterCompletion");
}
}
package com.atguigu.test;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
@Controller
public class TestInterceptorController {
/**
* 當有多個攔截器時，
* preHandle：按照攔截器陣列的正向順序執行
* postHandle：按照攔截器陣列的反向順序執行
* afterCompletion：按照攔截器陣列的反向順序執行
*
* 當多個攔截器的preHandle有不同的值時
* 第一個返回false，第二個返回false：只有第一個preHandle會執行
* 第一個返回true，第二個返回false：兩個（全部）攔截器的preHandle都會執行
* 但是（全部）postHandle都不會執行，而afterCompletion只有第一個（返回false的攔截器之前的所有afterCompletion）會執行
* 第一個返回false，第二個返回true:只有第一個的preHandle會執行
*/
@RequestMapping("/testInterceptor")
public String testInterceptor() {
return "success";
}
}