java - 当我运行 java servlet 查看 JSON 结果时——它弹出文件下载而不是 http ://localhost:8080/

Question

gif of file download pop up

如何在浏览器中测试 JSON 字符串，而无需执行下载 json 文件的步骤，因为当我运行 servlet 时会弹出“文件下载”对话框，然后在浏览器中查看下载的 json 文件。

下面是 postman 的屏幕截图 - postman 返回 404

postman on localhost 8080

下面是映射的web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">

  <!-- General Description of the web application -->  

  <display-name>webData</display-name>
  <description>data managed in web data table grid</description>  

     <!-- For directory request -->

  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>

     <!-- Define servlets -->

  <servlet>
    <servlet-name>Faces Servlet</servlet-name>
    <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
  </servlet>

  <servlet>
    <servlet-name>queryreturn</servlet-name>
    <servlet-class>com.queryData.Return.QueryReturn</servlet-class>  
  </servlet>

     <!-- Note: All <servlet> elements MUST be grouped together and
         placed IN FRONT of the <servlet-mapping> elements -->  

   <!-- Define servlet's URL mapping -->    

  <servlet-mapping>
    <servlet-name>Faces Servlet</servlet-name>
    <url-pattern>/faces/*</url-pattern>
  </servlet-mapping>

  <servlet-mapping>
    <servlet-name>queryreturn</servlet-name>
    <url-pattern>/queryreturn</url-pattern>
  </servlet-mapping>

  <context-param>
    <description>State saving method: 'client' or 'server' (=default). See JSF Specification 2.5.2</description>
    <param-name>javax.faces.STATE_SAVING_METHOD</param-name>
    <param-value>client</param-value>
  </context-param>

  <context-param>
    <param-name>javax.servlet.jsp.jstl.fmt.localizationContext</param-name>
    <param-value>resources.application</param-value>
  </context-param>

  <listener>
    <listener-class>com.sun.faces.config.ConfigureListener</listener-class>
  </listener>

</web-app>

下面是成功生成JSON字符串但不会在浏览器中运行的bean

package com.queryData.Return;
//Import required java libraries
import java.io.*;
import java.util.List;
import javax.servlet.*;
import javax.servlet.http.*;
import org.json.JSONObject;
import com.queryData.main.Main;
// Extend HttpServlet class
public class QueryReturn extends HttpServlet 
{
    private static final long serialVersionUID = 1L;
    public void init() throws ServletException
      {
          // Do required initialization
      }
      public void doGet(HttpServletRequest request,
                      HttpServletResponse response)
                throws ServletException, IOException
      {
          Main m = new Main();
          List<JSONObject> jObj = m.getJsonObject();
          StringBuilder sb = new StringBuilder();
          for(int i =0 ; i < jObj.size(); i++) 
          {
             sb.append(jObj.get(i).toString());
          }         
          String responseStr = "{\"data\":[" + sb + "]}";

          // Set response content type
          response.setContentType("application/json");
          // Actual logic goes here.
          PrintWriter out = response.getWriter();
          out.println(responseStr);

      }
      public void destroy()
      {
          // do nothing.
      }
}

Answer 1

找到了!解决方案分为两部分，首先，您删除

response.setContentType("application/json;charset=UTF-8");

来自 servlet，它运行完美并显示在 Eclipse 中。其次，URL 不正确，我找到了这篇令人难以置信的文章 - 必读 - 新加坡南洋理工大学

article regarding the absolute URL for this servlet INCLUDES the Project name

就是这样(1) 去掉setContentType和(2) 使用带有项目名称的绝对URL

http://localhost:8080/webData/queryreturn