使用Spring MVC +JDBC 实现输出Json数据和视图两种形式 最后面有源码

从web.xml开始配置：

声明定义两个Servlet分别是输出视图和json

<!-- 声明一个Servlet 并进行配置 -->
	<servlet>
		<servlet-name>rest</servlet-name>
		<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
		<init-param>
			<param-name>contextConfigLocation</param-name>
			<param-value>/WEB-INF/rest-servlet.xml</param-value>
		</init-param>
		<!-- 标记容器是否在启动的时候就加载这个servlet 当是一个负数时或者没有指定时，则指示容器在该servlet被选择时才加载。正数的值越小，启动该servlet的优先级越高。 -->
		<load-on-startup>1</load-on-startup>
	</servlet>
	<servlet-mapping>
		<servlet-name>rest</servlet-name>
		<url-pattern>/rest/*</url-pattern>
	</servlet-mapping>
	<!-- 声明一个Servlet END -->
	<!-- 声明一个Servlet 并进行配置 -->
	<servlet>
		<servlet-name>json</servlet-name>
		<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
		<init-param>
			<param-name>contextConfigLocation</param-name>
			<param-value>/WEB-INF/json-servlet.xml</param-value>
		</init-param>
	</servlet>
	<servlet-mapping>
		<servlet-name>json</servlet-name>
		<url-pattern>/json/*</url-pattern>
	</servlet-mapping>
	<!-- 声明一个Servlet END -->

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans-3.0.xsd


http://www.springframework.org/schema/context


http://www.springframework.org/schema/context/spring-context-3.0.xsd


http://www.springframework.org/schema/mvc


http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">

	<!-- 搜索Controller路径 -->
	<context:component-scan base-package="com.znn.rest.controller">
		<!-- 忽略这个包 -->
		<!-- <context:exclude-filter type="assignable" expression="com..."/> -->
	</context:component-scan>
	<!-- 简写形式 会自动注册DefaultAnnotationHandlerMapping与AnnotationMethodHandlerAdapter两个bean,是spring
		MVC为@Controllers分发请求所必须的。 -->
	<mvc:annotation-driven />
	<!-- 视图解析器 -->
	<bean
		class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<property name="prefix" value=http://www.mamicode.com/"/WEB-INF/jsp/" />>
在包com.znn.rest.controller下创建一个Controller：UserController.java
用注解@Controller进行声明这是一个Controller，Spring会自动扫描到
package com.znn.rest.controller;

import java.lang.reflect.Method;
import java.util.List;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestHeader;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;

import com.znn.dao.UserDao;
import com.znn.vo.User;
/**
 * RestFul 返回视图
 *
 * @author RANDY.ZHANG
 * 2014-5-7
 */
@Controller
public class UserController {
	ApplicationContext applicationContext = new ClassPathXmlApplicationContext("beans.xml");
	UserDao dao = (UserDao) applicationContext.getBean("userDao");

	@RequestMapping("/hi")
	public String helloWorld(Model model) {
		model.addAttribute("msg", "Hello HelloWorld");
		return "hello";
//		return "redirect:hello.jsp";
	}
	@RequestMapping("/user/{id:\\d+}")
	public String getUser(Model model,@PathVariable("id") int userid) {
		User user;
		user = dao.queryAUser(userid);
		if (user == null) {
			model.addAttribute("tip", "<font color='red'>用户不存在！</font>");
		}else {
			model.addAttribute("tip", user.toString());
		}
		return "user";
	}
	@RequestMapping(value = http://www.mamicode.com/"/user/*",method=RequestMethod.GET)>

使用InternalResourceViewResolver进行视图适配，方法返回的字符串会自动添加上前后缀，另外还支持redirect:和forward：两种特殊配置，只是注意下要路径。
关于MVC的注解以及RequestMapping的配置用法到:http://docs.spring.io/spring-framework/docs/current/spring-framework-reference/html/mvc.html#mvc-introduction，里面讲的挺详细。
第二种输出JSON：
从Spring 3.1开始支持@ResponseBody来直接将数据返回到HTTP响应体重，不在需要ModalView或者其他进行渲染。Spring提供了一些HttpMessageConverter来对数据进行转换，比如StringHttpMessageConverter，FormHttpMessageConverter，MappingJackson2HttpMessageConverter ，其他见这里，这里用到了StringHttpMessageConverter用来进行编码转换，MappingJackson2HttpMessageConverter 用来将数据转为Json形式。
json-servlet.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans-3.0.xsd


http://www.springframework.org/schema/context


http://www.springframework.org/schema/context/spring-context-3.0.xsd


http://www.springframework.org/schema/mvc


http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">

	<!-- 搜索Controller路径 -->
	<context:component-scan base-package="<strong>com.znn.json.controller</strong>">
		<!-- 忽略这个包 -->
		<!-- <context:exclude-filter type="assignable" expression="com..."/> -->
	</context:component-scan>

	<!-- Spring 3.1之后开始用这两个 -->
	<bean
		class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping" />
	<bean
		class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
		<property name="messageConverters">
			<list>
				<bean
					class="org.springframework.http.converter.StringHttpMessageConverter">
					<property name="supportedMediaTypes">
						<list>
							<value>text/html; charset=UTF-8</value>
						</list>
					</property>
				</bean>
				<bean
					class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
					<property name="supportedMediaTypes">
						<list>
							<value>text/html; charset=UTF-8</value>
						</list>
					</property>
				</bean>
			</list>
		</property>
	</bean>
</beans>

从3.1开始推荐使用RequestMappingHandlerMapping和RequestMappingHandlerAdapter来代替DefaultAnnotationHandlerMapping和AnnotationMethodHandlerAdapter。不过不换也木事。。。。
在com.znn.json.controller下新建一个Controller
UserJson.java
package com.znn.json.controller;

import java.util.List;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

import com.znn.dao.UserDao;
import com.znn.vo.User;
/**
 * 返回@ResponseBody需要配置HttpMessageConverters
 *
 * @author RANDY.ZHANG
 * 2014-5-7
 */
@Controller
public class UserJson {
	ApplicationContext applicationContext = new ClassPathXmlApplicationContext("beans.xml");
	UserDao dao = (UserDao) applicationContext.getBean("userDao");

	@RequestMapping("/hi")
	public @ResponseBody String helloWorld(Model model) {
//		model.addAttribute("msg", "Hello HelloWorld");
		return "hello world";
//		return "redirect:hello.jsp";
	}

	@RequestMapping("/user/{id:\\d+}")
	public @ResponseBody User getUser(Model model,@PathVariable int id) {
		User user;
		user = dao.queryAUser(id);
		if (user == null) {
			model.addAttribute("tip", "<font color='red'>用户不存在！</font>");
		}else {
			model.addAttribute("tip", user.toString());
		}
		return user;
	}
	@RequestMapping(value = http://www.mamicode.com/{"/user/*","/user"},method=RequestMethod.GET)//,produces="application/json" 406>
木有啥好说的….
跟JDBC连接的及DAO层代码和http://www.erdian.net/?p=141是一样的，不再写。
源码：https://github.com/qduningning/SpringAll