自定义HttpMessageConverter

Author: xiaolyuh123

src/main/java/com/chenfeng/xiaolyuh/config/MvcConfig.java

@@ -1,9 +1,12 @@
 package com.chenfeng.xiaolyuh.config;
 
+import java.util.List;
+
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.ComponentScan;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.http.converter.HttpMessageConverter;
 import org.springframework.web.multipart.MultipartResolver;
 import org.springframework.web.multipart.commons.CommonsMultipartResolver;
 import org.springframework.web.servlet.config.annotation.EnableWebMvc;
@@ -16,6 +19,7 @@
 import org.springframework.web.servlet.view.JstlView;
 
 import com.chenfeng.xiaolyuh.interceptor.DemoInterceptor;
+import com.chenfeng.xiaolyuh.message.converter.MyHttpMessageConverter;
 
 /**
  * MVC 配置类。这里我们配置了一个jsp的ViewResolver，用来映射路径和实际页面的位置，
@@ -72,6 +76,31 @@ public void addViewControllers(ViewControllerRegistry registry) {
 		// 无任何业务逻辑只是简单的业务逻辑可以这样子写，代码更简洁，管理集中
 		registry.addViewController("index2").setViewName("index");
 		registry.addViewController("forUpload").setViewName("upload");
+		registry.addViewController("converter").setViewName("converter");
+		
+	}
+	
+	@Bean
+	public MyHttpMessageConverter converter() {
+		return new MyHttpMessageConverter();
+	}
+	
+	/**
+	 * 覆盖掉Spring MVC默认注册的多个HttpMessageConverter
+	 */
+	@Override
+	public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
+		
+		super.configureMessageConverters(converters);
+	}
+	
+	/**
+	 * 仅添加一个自定义的HttpMessageConverter，不覆盖默认的HttpMessageConverter
+	 */
+	@Override
+	public void extendMessageConverters(List<HttpMessageConverter<?>> converters) {
+		// 添加一个自定义的消息转换
+		converters.add(converter());
 	}
 
 	@Override

src/main/java/com/chenfeng/xiaolyuh/controller/ConverterController.java

@@ -0,0 +1,21 @@
+package com.chenfeng.xiaolyuh.controller;
+
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.ResponseBody;
+
+import com.chenfeng.xiaolyuh.entity.DemoObj;
+
+
+@Controller // 声明是一个控制器，并且返回时不需要@ResponseBody
+public class ConverterController {
+	
+	@RequestMapping(value = "/convert", produces = { "application/x-wisely" })// 自定义的媒体类型
+	@ResponseBody
+    public DemoObj convert(@RequestBody DemoObj demoObj) {
+		
+        return demoObj;
+    }
+
+}

src/main/java/com/chenfeng/xiaolyuh/message/converter/MyHttpMessageConverter.java

@@ -0,0 +1,61 @@
+package com.chenfeng.xiaolyuh.message.converter;
+
+import java.io.IOException;
+import java.nio.charset.Charset;
+
+import org.springframework.http.HttpInputMessage;
+import org.springframework.http.HttpOutputMessage;
+import org.springframework.http.MediaType;
+import org.springframework.http.converter.AbstractHttpMessageConverter;
+import org.springframework.http.converter.HttpMessageNotReadableException;
+import org.springframework.http.converter.HttpMessageNotWritableException;
+import org.springframework.util.StreamUtils;
+
+import com.chenfeng.xiaolyuh.entity.DemoObj;
+
+/**
+ * 继承AbstractHttpMessageConverter类来实现自定义的HttpMessageConverter（消息转换器）
+ */
+public class MyHttpMessageConverter extends AbstractHttpMessageConverter<DemoObj> {
+
+	/**
+	 * 
+	 * @Description 建立我们自定义的媒体类型"application/x-wisely"
+	 */
+	public MyHttpMessageConverter() {
+		super(new MediaType("application", "x-wisely", Charset.forName("UTF-8")));
+	}
+	
+	/**
+	 * 表明HttpMessageConverter（消息转换器）只处理DemoObj类
+	 */
+	@Override
+	protected boolean supports(Class<?> clazz) {
+		// 判断clazz类是不是DemoObj类或者是DemoObj的子类
+		return DemoObj.class.isAssignableFrom(clazz);
+	}
+
+	/**
+	 * 重写readInternal方法，处理请求数据。代码表明我们处理有“-”隔开的数据，并转成DemoObj对象
+	 */
+	@Override
+	protected DemoObj readInternal(Class<? extends DemoObj> clazz, HttpInputMessage inputMessage)
+			throws IOException, HttpMessageNotReadableException {
+		
+		String temp = StreamUtils.copyToString(inputMessage.getBody(), Charset.forName("UTF-8"));
+		String[] tempArr = temp.split("-");
+		return new DemoObj(Long.parseLong(tempArr[0]), tempArr[1]);
+	}
+
+	/**
+	 * 重写writeInternal方法，处理数据如何输出到response。此处，我么在原样输出前面加上“HELLO”
+	 */
+	@Override
+	protected void writeInternal(DemoObj t, HttpOutputMessage outputMessage)
+			throws IOException, HttpMessageNotWritableException {
+		
+		String out = "HELLO:" + t.getId() + "-" + t.getName();
+		outputMessage.getBody().write(out.getBytes());
+	}
+
+}

src/main/resources/views/converter.jsp

@@ -0,0 +1,27 @@
+<%@ page language="java" contentType="text/html; charset=UTF-8"
+    pageEncoding="UTF-8"%>
+<!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>HttpMessageConverter Demo</title>
+</head>
+<body>
+    <div id="resp"></div><input type="button" onclick="req();" value="请求"/>
+<script src="assets/js/jquery.js" type="text/javascript"></script>
+<script>
+    function req(){
+        $.ajax({
+            url: "convert",
+            data: "1-wangyunfei", //数据格式和自定义的消息转换器一致
+            type:"POST",
+            contentType:"application/x-wisely", //媒体类型和消息转换器的一致
+            success: function(data){
+                $("#resp").html(data);
+            }
+        });
+    }
+
+</script>
+</body>
+</html>