如何使用Spring Boot 2（Spring 5 Tomcat 9）将JSP渲染捕获到String中？

Question

我已经实现了吞咽ttpServletResponse示例，该示例可以在各种在线示例中找到。在过去我使用Spring 4和Tomcat 7时，它对我很有效，但现在我已经迁移到使用Spring Boot 2（使用Spring 5和嵌入式Tomcat 9）捕获JSP呈现似乎不再有效。有人知道如何让SnowinghttpServletResponse示例与Spring Boot 2（Spring 5 Tomcat 9）web应用程序一起工作吗？

使用Spring 4 Tomcat 7的代码示例：

• https://technologicaloddity.com/2011/10/04/render-and-capture-the-output-of-a-jsp-as-a-string/
• https://www.javatips.net/api/CaptureJSP-master/src/main/java/com/technologicaloddity/capturejsp/util/SwallowingJspRenderer.java

Answer 1

我也面临着类似的问题。升级到Spring 5和Tomcat 8.5后，我的内部jsp呈现方法停止工作。事实证明，我没有在模拟请求中定义请求方法（如GET）。这可能是过去的违约？没有花太多时间调查。。。

不管怎样，代码是这样的：

服务：

@Service
public class JspService implements ServletContextAware {

    private InternalResourceViewResolver viewResolver;

    @Autowired
    public void setViewResolver(InternalResourceViewResolver viewResolver) {
        this.viewResolver = viewResolver;
    }

    private ServletContext context;

    @Override
    public void setServletContext(ServletContext servletContext) {
        this.context = servletContext;
    }

    public String renderJspView(String viewName, ModelMap modelMap) throws Exception {

        RequestDispatcher requestDispatcher = context.getRequestDispatcher("/WEB-INF/jsp/" + viewName + ".jsp");
        View view = viewResolver.resolveViewName(viewName, Locale.US);

        MockHttpServletResponse mockResp = new MockHttpServletResponse();
        HttpServletRequest mockRequest = new MockHttpServletRequest();
        JspRequestWrapper requestWrapper = new JspRequestWrapper(mockRequest, requestDispatcher);
        mockResp.flushBuffer(); // important! forces servlet include

        view.render(modelMap, requestWrapper, mockResp);

        return mockResp.getContentAsString();
    }
}

请求包装器

public class JspRequestWrapper extends HttpServletRequestWrapper {

    private final RequestDispatcher requestDispatcher;

    public JspRequestWrapper(HttpServletRequest request, RequestDispatcher requestDispatcher) throws IOException {
        super(request);
        this.requestDispatcher = requestDispatcher;
    }


    @Override
    public RequestDispatcher getRequestDispatcher(String path) {
        return requestDispatcher;
    }

    // Hardcode contextPath and URI so links work
    @Override
    public String getContextPath() {
        return "https://foo.bar.com/<webapp name>";
    }

    @Override
    public String getRequestURI() {
        return "foo.bar.com";
    }

    // Define request method!
    @Override
    public String getMethod() {
        return "GET";
    }
}