自定义视图以及代码分析

最新推荐文章于 2025-08-15 17:42:04 发布

转载最新推荐文章于 2025-08-15 17:42:04 发布 · 150 阅读

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原文链接：https://my.oschina.net/u/3049601/blog/1512307

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#java #python

2019独角兽企业重金招聘Python工程师标准>>>

SpringMVC提供View接口方式实现自定义视图，先看两种写法

一、使用ModelAndView

这种方式简单易懂，就是SpringMVC是在DispatcherServlet.render方法中调用了MyView.render

package jv.springmvc.requestmapping;

import java.util.Map;

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

import org.springframework.stereotype.Component;
import org.springframework.web.servlet.View;

@Component
public class MyView implements View{


	@Override
	public String getContentType() {
		// TODO Auto-generated method stub
		return "text/html";
	}

	@Override
	public void render(Map<String, ?> model, HttpServletRequest request,
			HttpServletResponse response) throws Exception {
		response.getOutputStream().println("Test SpringMVC user-defined View");
	}
}

	@RequestMapping("testMyView")
	public ModelAndView testMyView(){
		System.out.println("testMyView ,return ModelAndView");
		ModelAndView mv = new ModelAndView(new MyView());
		return mv;
	}

二、使用String

	@RequestMapping("testMyView1")
	public String testMyView1(){
		System.out.println("testMyView ,return String \"myView\"");
		return "myView";
	}

这种方式可能有的同学会觉得好神奇，居然返回一个字符串就能找到对应的视图，说白了就是通过@component注解将MyView在Spring容器中注册了一个实例，而SpringMVC在使用的时候直接拿来用

	protected View resolveViewName(String viewName, Map<String, Object> model, Locale locale,
			HttpServletRequest request) throws Exception {

		for (ViewResolver viewResolver : this.viewResolvers) {
			View view = viewResolver.resolveViewName(viewName, locale);
			if (view != null) {
				return view;
			}
		}
		return null;
	}

	public View resolveViewName(String viewName, Locale locale) throws BeansException {
		ApplicationContext context = getApplicationContext();
		if (!context.containsBean(viewName)) {
			// Allow for ViewResolver chaining.
			return null;
		}
		return context.getBean(viewName, View.class);
	}

因为在SpringMVC配置文件中设置了BeanNameViewResolver为优先级最高的视图解析器，所以在循环viewResolvers时就拿到了BeanNameViewResolver，从而得到MyView的实例

转载于:https://my.oschina.net/u/3049601/blog/1512307