spring mvc 提升 | 随机漫步的傻瓜

上一篇文章简单介绍了一下springmvc的使用情况，这里对mvc做进一步的改进

1， recourses

上一篇中 home方法直接返回了 "WEB-INF/views/home.jsp";

这里可以看到WEB-INF/views和jsp这些都是很多余只有home是真正可变量

所以我们希望能找到方法可以配置这些即可，不用在多写

spring中有视图处理是该接口 ViewResolver,而默认的生成的处理类是：InternalResourceViewResolver ，仅仅生成了一个JSTLView，而这个Resolver是可以定制的

我们可以这样：

package xyz.sample.baremvc;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
@Configuration
public class AppConfig {
	// Resolve logical view names to .jsp resources in the /WEB-INF/views directory
	@Bean
	ViewResolver viewResolver() {
		InternalResourceViewResolver resolver = new InternalResourceViewResolver();
		resolver.setPrefix("WEB-INF/views/");
		resolver.setSuffix(".jsp");
		return resolver;
	}
}

也可以这样：

<!-- Resolve logical view names to .jsp resources in the /WEB-INF/views directory -->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
	<property name="prefix" value="/WEB-INF/views/" />
	<property name="suffix" value=".jsp" />
</bean>

是不是简单些了，下面再复杂一点

2，方法拦截和参数注入

我们可以指定 action 只可以被 get访问, 也可以直接注入要接收的参数

如下：

package xyz.sample.baremvc;
import java.util.Comparator;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
/**
 * Handles requests for the application home page.
 */
@Controller
public class HomeController {
	@Autowired
	Comparator<String> comparator;
	@RequestMapping(value = "/")
	public String home() {
		System.out.println("HomeController: Passing through...");
		return "home";
	}
	@RequestMapping(value = "/compare", method = RequestMethod.GET)
	public String compare(@RequestParam("input1") String input1,
			@RequestParam("input2") String input2, Model model) {
		int result = comparator.compare(input1, input2);
		String inEnglish = (result < 0) ? "less than" : (result > 0 ? "greater than" : "equal to");
		String output = "According to our Comparator, '" + input1 + "' is " + inEnglish + "'" + input2 + "'";
		model.addAttribute("output", output);
		return "compareResult";
	}
}

WEB-INF/views/compareResult.jsp

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ page session="false" %>
<html>
	<head>
		<title>Result</title>
	</head>
	<body>
		<h1><c:out value="${output}"></c:out></h1>
	</body>
</html>

要注入的service代码

package xyz.sample.baremvc;
import java.util.Comparator;
import org.springframework.stereotype.Component;
@Service
public class CaseInsensitiveComparator implements Comparator<String> {
	public int compare(String s1, String s2) {
		assert s1 != null && s2 != null;
		return String.CASE_INSENSITIVE_ORDER.compare(s1, s2);
	}
}

至此，一个大致的mvc框架是就完工了，基本零配置，比spring+struts简单多了吧