SpringMVC(四) -- ViewResolver

一.背景介绍

ViewResolver主要作用是将逻辑视图名称解析为真正的视图对象View，即将视图解析为可以在客户端呈现的HTML页面。

二.源码分析

ViewResolver

视图解析器:将视图名转换成视图对象

public interface ViewResolver {

	@Nullable
	View resolveViewName(String viewName, Locale locale) throws Exception;

}

View

视图对象:

public interface View {

	String RESPONSE_STATUS_ATTRIBUTE = View.class.getName() + ".responseStatus";

	String PATH_VARIABLES = View.class.getName() + ".pathVariables";

	String SELECTED_CONTENT_TYPE = View.class.getName() + ".selectedContentType";

	@Nullable
	default String getContentType() {
		return null;
	}

	void render(@Nullable Map<String, ?> model, HttpServletRequest request, HttpServletResponse response)
			throws Exception;

}

AbstractView

public abstract class AbstractView extends WebApplicationObjectSupport implements View, BeanNameAware {

    @Override
	public void render(@Nullable Map<String, ?> model, HttpServletRequest request,
			HttpServletResponse response) throws Exception {

		if (logger.isDebugEnabled()) {
			logger.debug("View " + formatViewName() +
					", model " + (model != null ? model : Collections.emptyMap()) +
					(this.staticAttributes.isEmpty() ? "" : ", static attributes " + this.staticAttributes));
		}

		Map<String, Object> mergedModel = createMergedOutputModel(model, request, response);
		prepareResponse(request, response);
		renderMergedOutputModel(mergedModel, getRequestToExpose(request), response);
	}

    protected abstract void renderMergedOutputModel(
			Map<String, Object> model, HttpServletRequest request, HttpServletResponse response) throws Exception; 
}