AJAX的跨域问题使用设置响应头和JsonP的方式实现跨域后端数据源编写------AJAX

悠悠 2024-02-18 13:09 26阅读 0赞

> ###  ###
> 
>     import jakarta.servlet.ServletException;
>     import jakarta.servlet.annotation.WebServlet;
>     import jakarta.servlet.http.HttpServlet;
>     import jakarta.servlet.http.HttpServletRequest;
>     import jakarta.servlet.http.HttpServletResponse;
>      
>     import java.io.IOException;
>     import java.io.PrintWriter;
>      
>     @WebServlet("/jsonP1")
>     public class jsonP1 extends HttpServlet
>     {
>         @Override
>         protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
>         {
>     //        jsonP跨域的时候只支持get请求,因为我们写src本质就是一个get请求的传递
>             request.setCharacterEncoding("UTF-8");
>             response.setCharacterEncoding("UTF-8");
>             response.setContentType("text/html;charset=UTF-8");
>             PrintWriter out = response.getWriter();
>             //如果是输出前端代码呢?
>     //        out.println("alert(123);");
>     //        out.println("sayHello();");
>             String fun = request.getParameter("fun");
>     //        out.println(fun + "({\"name\" : \"Jack\"});");
>             out.println(fun + "(5,6);");
>         }
>     }
> 
> import jakarta.servlet.ServletException;  
> import jakarta.servlet.annotation.WebServlet;  
> import jakarta.servlet.http.HttpServlet;  
> import jakarta.servlet.http.HttpServletRequest;  
> import jakarta.servlet.http.HttpServletResponse;  
>   
> import java.io.IOException;  
> import java.io.PrintWriter;  
>   
> @WebServlet("/jsonP1")  
> public class jsonP1 extends HttpServlet  
> \{  
> @Override  
> protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException  
> \{  
> // jsonP跨域的时候只支持get请求,因为我们写src本质就是一个get请求的传递  
> request.setCharacterEncoding("UTF-8");  
> response.setCharacterEncoding("UTF-8");  
> response.setContentType("text/html;charset=UTF-8");  
> PrintWriter out = response.getWriter();  
> //如果是输出前端代码呢?  
> // out.println("alert(123);");  
> // out.println("sayHello();");  
> String fun = request.getParameter("fun");  
> // out.println(fun + "(\{\\"name\\" : \\"Jack\\"\});");  
> out.println(fun + "(5,6);");  
> \}  
> \}

>     import jakarta.servlet.ServletException;
>     import jakarta.servlet.annotation.WebServlet;
>     import jakarta.servlet.http.HttpServlet;
>     import jakarta.servlet.http.HttpServletRequest;
>     import jakarta.servlet.http.HttpServletResponse;
>      
>     import java.io.IOException;
>      
>     @WebServlet("/hello")
>     public class Hello extends HttpServlet
>     {
>         @Override
>         protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
>             //设置响应头
>             response.setHeader("Access-Control-Allow-Origin","http://localhost:8080");
>             //跨域访问的资源允许访问,设置响应头的方式原理是
>             response.getWriter().println("Halla Ajax");
>         }
>     }
> 
> import jakarta.servlet.ServletException;  
> import jakarta.servlet.annotation.WebServlet;  
> import jakarta.servlet.http.HttpServlet;  
> import jakarta.servlet.http.HttpServletRequest;  
> import jakarta.servlet.http.HttpServletResponse;  
>   
> import java.io.IOException;  
>   
> @WebServlet("/hello")  
> public class Hello extends HttpServlet  
> \{  
> @Override  
> protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException \{  
> //设置响应头  
> response.setHeader("Access-Control-Allow-Origin","http://localhost:8080");  
> //跨域访问的资源允许访问,设置响应头的方式原理是  
> response.getWriter().println("Halla Ajax");  
> \}  
> \}