SpringMVC 学习笔记(四)

41. 尚硅谷_佟刚_SpringMVC_返回JSON.avi

SpringMVC中使用@ResponseBody注解标注业务方法，将业务方法的返回值做成json输出给页面

导包：

除了一些spring的包之外，还需要jackson-annotations.jar , jackson-core.jar , jackson-databind.jar 这三个包

开启@ResponseBody注解：

在 spring-mvc.xml 中通过<mvc:annotation-driven />开启@ResponseBody注解

使用@ResponseBody标注业务方法

package com.loger.controller;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import com.loger.entity.User;

/**
 * ResponseBody 注解，可以将如下类型的数据做成json：
 * 1）基本数据类型，如 boolean , String , int 等
 * 2) Map 类型数据
 * 3）集合或数组
 * 4）实体对象
 * 5）实体对象集合
 *
 */

@Controller
@RequestMapping("/test")
public class JsonController {

    @RequestMapping("test1.do")
    @ResponseBody
    public boolean test1(){
        return true;
    }

    @RequestMapping("/test2.do")
    @ResponseBody
    public Map<String, Object> test2(){
        Map<String , Object> map = new HashMap<String ,Object>();
        map.put("id", "s20070");
        map.put("name", "郑城斌");
        return map;
    }

    @RequestMapping("/test3.do")
    @ResponseBody
    public List<String> test3(){
        List<String> list = new ArrayList<>();
        list.add("aaa");
        list.add("bbb");
        list.add("ccc");
        return list;
    }

    @RequestMapping("/test4.do")
    @ResponseBody
    public User test4(){
        User user = new User();
        user.setId("s20068");
        user.setName("余清波");
        user.setAge(21);
        return user;
    }

    @RequestMapping("/test5.do")
    @ResponseBody
    public List<User> test5(){
        List<User> list = new ArrayList<>();

        User user1 = new User();
        user1.setId("s200681");
        user1.setName("余清波1");
        user1.setAge(21);
        list.add(user1);

        User user2 = new User();
        user2.setId("s200682");
        user2.setName("余清波2");
        user2.setAge(21);
        list.add(user2);

        User user3 = new User();
        user3.setId("s200683");
        user3.setName("余清波3");
        user3.setAge(21);
        list.add(user3);

        return list;
    }
}

输出结果：

@reponseBoby内部使用了httpMessageconvert对象

42. 尚硅谷_佟刚_SpringMVC_HttpMessageConverter原理.avi

43. 尚硅谷_佟刚_SpringMVC_使用HttpMessageConverter实现文件下载

需求:

点击页面上的超链接,然后下载服务器端的文件:

<a href="testResponseEntity" id="testJson">Test 下载</a>

需要传入3个参数,分别是:请求体、请求头和状态码

handler层具体的代码如下:

 @RequestMapping("/testResponseEntity")
        public ResponseEntity<byte[]> testResponseEntity(HttpSession session) throws IOException {
            byte[] body=null;
            ServletContext sc=session.getServletContext();
            InputStream in=sc.getResourceAsStream("/files/test3");
            body=new byte[in.available()];
            in.read(body);

            HttpHeaders headers=new HttpHeaders();
            headers.add("Content-Disposition","attachment;filename=test3.txt");

            HttpStatus statusCode=HttpStatus.OK;

            ResponseEntity<byte[]> response=new ResponseEntity<byte[]>(body,headers,statusCode);
            return response;
        }
    

整个项目工程的代码如下所示：

44. 尚硅谷_佟刚_SpringMVC_国际化_概述.avi

第一步：

在src目录下建立下面三个文件

message_en_US.properties

message.username=username

message_zh_CN.properties

message.username=\u7528\u6237\u540D

message.properties

message.username=username

上面名字以啥开头message_en_US.properties都是以message开头的，对于的文件内容都以message开头

接下来在spring-mvc中配置

<?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-4.1.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-4.1.xsd">
    <!-- 配置自动扫描包  扫描com.ibigsea.springmvc 包下的类，后期会使用spring进行管理 -->
    <context:component-scan base-package="com.wst.springmvc.handlers"/>
<!-- 配置视图解析器 如返回helloworld
                         为 [/WEB-INF/pages/helloworld.jsp] -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
     <!-- 前缀 -->
        <property name="prefix" value="/WEB-INF/pages/"/>
         <!-- 后缀 -->
        <property name="suffix" value=".jsp"/>
    </bean>

        <!-- 配置国际化资源文件 -->
    <bean id="messageSource"
    class="org.springframework.context.support.ResourceBundleMessageSource">
            <property name="basename" value="message"></property>
    </bean>
    <mvc:annotation-driven></mvc:annotation-driven>
</beans>
上面中

<property name="basename" value="message"></property>  对于的就是文件开头的名字
并且需要配置mvc:annotation-driven></mvc:annotation-driven>
<context:component-scan配置扫描对于的handle文件，因为handle使用@Control自动标签进行扫描
web.xml为

<?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_3_0.xsd"
    version="3.0" >
        <filter>
            <filter-name>HiddenHttpMethodFilter</filter-name>
            <filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>
        </filter>

        <filter-mapping>
            <filter-name>HiddenHttpMethodFilter</filter-name>
            <url-pattern>/*</url-pattern>
        </filter-mapping>
    <servlet>
        <servlet-name>springDispatcherServlet</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!-- 加载spirng配置文件 -->
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:spring-mvc.xml</param-value>
        </init-param>
        <!-- 启动就加载 -->
        <load-on-startup>1</load-on-startup>
    </servlet>

    <!-- 拦截所有请求 -->
    <servlet-mapping>
        <servlet-name>springDispatcherServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
      <!-- 避免中文乱码 -->
  <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>
        <init-param>
            <param-name>forceEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>characterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
</web-app>

接下来在jsp页面就可以使用国际化资源文件了
使用标签

<fmt:message key="message.username"></fmt:message>

需要在jsp页面中引入springmc的标签

  <%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>

hello.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<fmt:message key="message.username"></fmt:message>
    <br><br>

</body>
</html>

index.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">

    <title>My JSP 'index.jsp' starting page</title>
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->
  </head>

  <body>
    This is my JSP page0000. <br>
    <a href="abc">测试</a>
  </body>
</html>

除了在jsp页面可以得到对于的

message.username"值之外，我们也可以在handler控制层中获得message.username"对应的值，对于的handle层的代码为

package com.wst.springmvc.handlers;

import java.util.Locale;
import java.util.ResourceBundle;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.support.ResourceBundleMessageSource;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class HelloHandler {

    @Autowired
    ResourceBundleMessageSource reBundleMessageSource;

    @RequestMapping(value="/abc")
    public String testLocal(Locale local ){
        String message = reBundleMessageSource.getMessage("message.username", null,local);
        System.out.println(message);
        return "hello";
    }
}
index.jsp

我们运行看下效果

在英文浏览器下啊

在中文浏览器下

整个代码的下载路径为：

https://pan.baidu.com/s/1D_AbtPvPhO6APS3IkhKjvg

46. 尚硅谷_佟刚_SpringMVC_国际化_通过超链接切换Locale.avi

在上一节的课程中，我们是通过切换浏览器的语言来得到国际话的显示，现在我们想到达下面的这种效果

通过超链接的形式来实现语言的切换，点击中文的时候显示中文，点击英文的时候显示英文，如何实现了，具体可以参考博客

https://blog.csdn.net/hj7jay/article/details/51383248

相当的经典

我们来看整个项目的目录结构如下所示

首先在src目录下建立下面三个文件

message_en_US.properties

message.username=username

message_zh_CN.properties

message.username=\u7528\u6237\u540D

message.properties

message.username=username

这里需要注意的是

message.username中的第一个值必须和message.properties名字是一一对应的二者都是message

接下来在spring-mvc.xml中配置国际化资源文件

<?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-4.1.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-4.1.xsd">
    <!-- 配置自动扫描包  扫描com.ibigsea.springmvc 包下的类，后期会使用spring进行管理 -->
    <context:component-scan base-package="com.ibigsea.springmvc"/>
<!-- 配置视图解析器 如返回helloworld
                         为 [/WEB-INF/pages/helloworld.jsp] -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
     <!-- 前缀 -->
        <property name="prefix" value="/WEB-INF/pages/"/>
         <!-- 后缀 -->
        <property name="suffix" value=".jsp"/>
    </bean>

    <!--将自定义的转换器加入到框架中-->
       <bean id="conversionService" class="org.springframework.format.support.FormattingConversionServiceFactoryBean">
              <property name="converters">
                     <set>
                            <bean class="com.ibigsea.springmvc.handler.EmployeeConverts"/>
                     </set>
              </property>
       </bean>

         <!-- 视图相关配置 -->
    <bean
        class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/pages/" />  <!-- 视图前缀 -->
        <property name="suffix" value=".jsp" />  <!-- 视图后缀 -->
    </bean>
    <!-- 存储区域设置信息 -->
    <bean id="localeResolver"
        class="org.springframework.web.servlet.i18n.SessionLocaleResolver" />
    <!-- 国际化资源文件 -->
    <bean id="messageSource"
        class="org.springframework.context.support.ResourceBundleMessageSource">
        <property name="basename" value="message" />
    </bean>

    <mvc:interceptors>
        <bean id="localeChangeInterceptor"
            class="org.springframework.web.servlet.i18n.LocaleChangeInterceptor">
            <property name="paramName" value="lang" />
        </bean>
    </mvc:interceptors>
    <!-- 配置运行可以访问静态资源文化 -->
    <mvc:default-servlet-handler/>
    <mvc:annotation-driven conversion-service="conversionService"></mvc:annotation-driven>

</beans>
配置三个参数InternalResourceViewResolver 、ResourceBundleMessageSource、LocaleChangeInterceptor和<mvc:annotation-driven
接下来是handle控制层代码

package com.ibigsea.springmvc.handler;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class GuojihuaHandler {

    @RequestMapping("/testGuojihua")
    public String testGuojihua(){
        return "sucess";
    }
}

我们要在sucess.jsp中得到国际化的值

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
 <%@taglib uri="http://www.springframework.org/tags/form" prefix="form" %>
 <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%@taglib prefix="spring" uri="http://www.springframework.org/tags" %>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">

    <title>My JSP 'index.jsp' starting page</title>
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->
  </head>

  <body>
  sucess.jsp页面
  <spring:message code="message.username" />
  Locale: ${pageContext.response.locale }

  </body>
</html>

这里使用了spring标签，需要添加
<%@taglib prefix="spring" uri="http://www.springframework.org/tags" %>

在index.jsp中访问

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">

    <title>My JSP 'index.jsp' starting page</title>
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->
  </head>

  <body>
    <a href="testGuojihua?lang=zh_CN">中文</a> <br>
    <a href="testGuojihua?lang=en_US">英文</a> <br>

  </body>
</html>

我们来看下运行的效果
点击中文的时候显示

点击英文的时候显示

整个代码的下载目录是

https://pan.baidu.com/s/1Whpg447aY79Mz9YiDM1f1w