spring之消息转换器的实例代码
- 零下一度原创
- 2017-07-19 16:48:391380浏览
//domain
package com.crazy.goods.tools;/**
* 0755-351512
* @author Administrator
* */public class Phone {private String qno;private String number;public String getQno() {return qno;
}public void setQno(String qno) {this.qno = qno;
}public String getNumber() {return number;
}public void setNumber(String number) {this.number = number;
}
}//消息转换器 要实现一个抽象类AbstractHttpMessageConverter
package com.crazy.goods.tools;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import org.springframework.http.HttpInputMessage;import org.springframework.http.HttpOutputMessage;import org.springframework.http.converter.AbstractHttpMessageConverter;import org.springframework.http.converter.HttpMessageNotReadableException;import org.springframework.http.converter.HttpMessageNotWritableException;public class MyMessageConvertor extends AbstractHttpMessageConverter<Phone> {/** * 将请求头数据转换成Phone */
@Overrideprotected Phone readInternal(Class<? extends Phone> arg0,
HttpInputMessage msg) throws IOException,
HttpMessageNotReadableException {//参数必须使用post提交必须在body中InputStream is=msg.getBody();
BufferedReader br=new BufferedReader(new InputStreamReader(is));
String param=br.readLine();
String phone=param.split("=")[1];
Phone phoneObj=new Phone();
phoneObj.setQno(phone.split("-")[0]);
phoneObj.setNumber(phone.split("-")[1]);return phoneObj;
}/** * 当前的转换器支持转换的类 */@Overrideprotected boolean supports(Class<?> arg0) {if(arg0==Phone.class){return true;
}return false;
}/** * 用于将返回的对象转换成字符串显示在网页 */@Overrideprotected void writeInternal(Phone phone, HttpOutputMessage arg1)throws IOException, HttpMessageNotWritableException {
String p=phone.getQno()+"-"+phone.getNumber();
arg1.getBody().write(p.getBytes("UTF-8"));
}
}//springmvc.xml 要配置bean：消息转换器，只有post提交方式才会被转换器拦截
<?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:tx="http://www.springframework.org/schema/tx"xmlns:aop="http://www.springframework.org/schema/aop"xmlns:mvc="http://www.springframework.org/schema/mvc"xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/context http://www.springframework.org/schema/tx http://www.springframework.org/schema/aop http://www.springframework.org/schema/mvc ">
<!--springmvc只能扫描控制层 -->
<context:component-scan base-package="com.crazy.goods">
<context:exclude-filter type="annotation" expression="org.springframework.stereotype.Service"/>
<context:exclude-filter type="annotation" expression="org.springframework.stereotype.Repository"/>
</context:component-scan>
<!--消息转换器 必须使用post提交 -->
<mvc:annotation-driven>
<mvc:message-converters>
<bean class="com.crazy.goods.tools.MyMessageConvertor">
<property name="supportedMediaTypes">
<list>
<value>text/html;charset=UTF-8</value>
<value>application/x-www-form-urlencoded</value>
</list>
</property>
</bean>
</mvc:message-converters>
</mvc:annotation-driven>
</beans>servlet测试
<br>
package com.crazy.goods.servlet;
<br>
import java.io.IOException;
<br>
import javax.servlet.ServletException;<br>import javax.servlet.annotation.WebServlet;<br>import javax.servlet.http.HttpServlet;<br>import javax.servlet.http.HttpServletRequest;<br>import javax.servlet.http.HttpServletResponse;
<br>
import org.springframework.stereotype.Controller;<br>import org.springframework.web.bind.annotation.PathVariable;<br>import org.springframework.web.bind.annotation.RequestBody;<br>import org.springframework.web.bind.annotation.RequestMapping;<br>import org.springframework.web.bind.annotation.RequestMethod;<br>import org.springframework.web.bind.annotation.ResponseBody;
<br>
import com.crazy.goods.tools.Phone;
<br>
/**<br> * @author Administrator<br> * 创建时间：2017年7月1日下午3:11:27<br> */<br>@Controller<br>public class ReservePageServelt {
<br>
// /**<br>// * forward:转发<br>// * redirect:重定向<br>// * @param req<br>// * @param resp<br>// * @return<br>// * @throws ServletException<br>// * @throws IOException<br>// */<br>// @RequestMapping(value="/add",method={RequestMethod.GET})<br>// public String doGet(HttpServletRequest req, HttpServletResponse resp/*,@PathVariable("testid") String testid*/) throws ServletException, IOException {<br>// req.getRequestDispatcher("/reversegood.jsp").forward(req, resp);<br>// return "/reversegood.jsp";<br>// resp.getWriter().print(testid);<br>// }<br><br><br> //消息转换器思路，<br><br> //原理就是将请求体或者请求头的数据转换为action方法的参数，同时将方法的返回值的内容转换为响应头<br> //当url路径访问过来时，看到使用了@RequestBody注解，这个注解标识这个类要被消息转换器处理，就会springmvcxml文件中读到消息转换器，然后进入supports方法<br> //判断这个类是否被指定的转换器支持，如果支持，就调用readInternal方法，进行切割，然后将值传递到对象中,处理完成为对象之后，就会调用writeInternal转换为响应头<br> @RequestMapping(value="/add")<br> @ResponseBody<br> public Phone messageConvertor( @RequestBody Phone phone,HttpServletResponse response) {<br> System.out.println(phone.getQno()+phone.getNumber());<br> return phone;<br><br> }<br><br>}
<br>
总结：消息转换器的原理就是，自定义将请求体的数据转换为形参（对象），然后将方法的返回值内容转换为响应头
步骤：
当url路径访问过来时，看到使用了@RequestBody注解，这个注解标识这个类要被消息转换器处理，就会springmvcxml文件中读到消息转换器，然后进入supports方法<br>判断这个类是否被指定的转换器支持，如果支持，就调用readInternal方法，进行切割，然后将值传递到对象中.
处理完成为对象之后，就会调用writeInternal转换为响应头
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