篇七：SpringMVC之RequestBody使用

一、作用

　　@requestBody注解常用来处理content-type不是默认的application/x-www-form-urlcoded编码的内容，比如说：application/json或者是application/xml等。一般情况下来说常用其来处理application/json类型。

　　通过@requestBody可以将请求体中的JSON字符串绑定到相应的bean上，当然，也可以将其分别绑定到对应的字符串上。

 

二、使用

　　1、导入jar依赖

        <dependency>
            <groupId>org.codehaus.jackson</groupId>
            <artifactId>jackson-core-asl</artifactId>
            <version>1.9.13</version>
        </dependency>
        <dependency>
            <groupId>org.codehaus.jackson</groupId>
            <artifactId>jackson-mapper-asl</artifactId>
            <version>1.9.13</version>
        </dependency>   
                <dependency>
            <groupId>org.codehaus.jackson</groupId>
            <artifactId>jackson-mapper-lgpl</artifactId>
            <version>1.9.6</version>
        </dependency>     

　　2、applicationContext.xml 配置

    <!-- json转化器 -->
    <bean
        class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
        <property name="messageConverters">
            <list>
                <ref bean="mappingJacksonHttpMessageConverter" />
            </list>
        </property>
    </bean>

    <bean id="mappingJacksonHttpMessageConverter"
        class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter">
        <property name="supportedMediaTypes">
            <list>
                <value>application/json;charset=UTF-8</value>
            </list>
        </property>
    </bean>

　　3、Controller使用

    @ResponseBody
    @RequestMapping(value="insertChannel",method=RequestMethod.POST)
    public String insertUserChannelList(@RequestBody ChannelRequest channelReq){
        ResponseData data = new ResponseData();
        channelHandler.insertUserChannelList(channelReq.getUserId(), channelReq.getChannelList());
        return JSONObject.toJSONString(data);
    }

 

三、HttpServetRequest读取body只能一次的问题

　　1、添加filter配置

    <filter>
        <filter-name>requestFilter</filter-name>
        <filter-class>com.*.*.filter.HttpServletRequestWrapperFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>requestFilter</filter-name>
        <url-pattern>/mobile/news/auth/*</url-pattern>
    </filter-mapping>

 

　　2、body缓存

package com.*.*.wrapper;

import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.*;

/**
 * 缓存requset body 避免在拦截器中读取一次后出错
 */
public class BodyReaderHttpServletRequestWrapper extends HttpServletRequestWrapper {
    private final String body;

    public BodyReaderHttpServletRequestWrapper(HttpServletRequest request) throws IOException {
        super(request);
        StringBuilder stringBuilder = new StringBuilder();
        BufferedReader bufferedReader = null;
        try {
            InputStream inputStream = request.getInputStream();
            if (inputStream != null) {
                bufferedReader = new BufferedReader(new InputStreamReader(inputStream,"UTF-8"));
                char[] charBuffer = new char[1024];
                int bytesRead = -1;
                while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
                    stringBuilder.append(charBuffer, 0, bytesRead);
                }
            } else {
                stringBuilder.append("");
            }
        } catch (IOException ex) {
            throw ex;
        } finally {
            if (bufferedReader != null) {
                try {
                    bufferedReader.close();
                } catch (IOException ex) {
                    throw ex;
                }
            }
        }
        body = stringBuilder.toString();
    }

    @Override
    public ServletInputStream getInputStream() throws IOException {
        final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(body.getBytes("UTF-8"));
        ServletInputStream servletInputStream = new ServletInputStream() {
            @Override
            public boolean isFinished() {
                return false;
            }

            @Override
            public boolean isReady() {
                return false;
            }

            @Override
            public void setReadListener(ReadListener readListener) {

            }

            public int read() throws IOException {
                return byteArrayInputStream.read();
            }
        };
        return servletInputStream;
    }

    @Override
    public BufferedReader getReader() throws IOException {
        return new BufferedReader(new InputStreamReader(this.getInputStream()));
    }

    public String getBody() {
        return this.body;
    }

}