Request -2024/10/16

请求request
在java中获取到前端的数据

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.BufferedReader;
import java.io.IOException;

@WebServlet("/test2")
public class a02Servlet_Test extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //获取请求行
        //获取请求方式
        System.out.println("--------------------------");
        System.out.println("请求方式:" + req.getMethod());
        //获取虚拟目录(项目访问路径)
        System.out.println("获取虚拟目录(项目访问路径):" + req.getContextPath());
        //获取URL(统一资源定位符)
        System.out.println("获取URL(统一资源定位符):" + req.getRequestURL());
        //获取URI(统一资源标识符)
        System.out.println("获取URI(统一资源标识符):" + req.getRequestURI());
        //获取请求参数
        System.out.println("获取请求参数:" + req.getQueryString());

        System.out.println("--------------------------");
        //获取请求头
        System.out.println("user-agent:" + req.getHeader("user-agent"));
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //获取请求体
        //获取字符输入流
        System.out.println("---------------------------");
        BufferedReader reader = req.getReader();
        String s = reader.readLine();
        System.out.println(s);

    }
}

request对象提供的方法:

• 获取所有参数Map集合

Map<String,String[]> getParameterMap()

• 根据名称获取参数值（数组）

String[] getParameterValues(String name)

• 根据名称获取参数值(单个值)

String getParameter(String name)

//请求方式POST,解决request中文乱码
req.setCharacterEncoding("UTF-8");
//请求方式POST,GET通用解决中文乱码方式
username = new String(username.getBytes(StandardCharsets.ISO_8859_1));
请求转发:一种在服务器内部资源跳转方式
req.getRequestDispatcher("资源B路径").forward(req,resp);