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2023-11-16 10:17:34

1.题目：get post请求
根据请求参数返回不同的页面
http://ip:prot/server?opt=a 返回html文件
opt=b 返回图片 opt=c 返回 text

package com.yq.work;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.InputStream;
get请求：
/*
get post请求
根据请求参数返回不同的页面
http://ip:prot/server?opt=a 返回html文件 opt=b 返回图片 opt=c 返回 text
 */
@WebServlet(urlPatterns = "/opt")
public class work1 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String opt = req.getParameter("opt");
        if(opt.equals("a")){
            System.out.println("doGet 处理请求，返回html文件");
            resp.getWriter().append("<html><head><meta charset='UTF-8'></head><body><h3>doGet处理返回结果</h3></body></html>");
        }else if(opt.equals("b")){
            System.out.println("doGet 处理请求，返回图片");
            resp.setContentType("image/jpg");
            //获取图片输入流
            InputStream in = getServletContext().getResourceAsStream("images/猪小屁2.jpg");
            ServletOutputStream out = resp.getOutputStream();
            byte[] data = new byte[4096];
            int len;
            while ((len = in.read(data)) != -1){
                out.write(data,0,len);
            }
            out.close();
            in.close();
        }else if(opt.equals("c")){
            System.out.println("doGet 处理请求，返回text");
            resp.setContentType("text/html");
        }
    }
}

post请求:

package com.yq.work;
/*
post 注册 name phone sex salary job 返回html 提示添加完成消息
 */
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.IOException;

@WebServlet(urlPatterns = "/login2")
public class work12 extends HttpServlet {

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("UTF-8");
        String name = req.getParameter("name");
        String phone = req.getParameter("phone");
        String sex = req.getParameter("sex");
        String salary = req.getParameter("salary");
        String job = req.getParameter("job");
        resp.setContentType("text/html;charset=UTF-8");
        resp.getWriter().append("<html>" +
                "<head>"+"<meta charset='UTF-8'>"+"</head>"+
                "<body>"+"<h3>添加完成</h3><hr>"+
                "<p>"+name+"</p>"+"<p>"+phone+"</p>"+"<p>"+sex+"</p>"+"<p>"+salary+"</p>"+"<p>"+job+"</p>"+
                "</body>"+
                "</html>");
    }
}

html代码：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<h3>get 请求</h3>
<hr>
<form action="opt">
    <p><input type="text" name="opt"></p>
    <p><input type="submit" value="get请求"></p>
</form>
</body>
</html>

运行结果：

2.转发重定向
http://ip:prot/hand?forward=a 转发 html
forward=b进入淘宝网站

package com.yq.work;

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.IOException;

/*
转发 重定向
http://ip:prot/hand?forward=a 转发 html
forward=b进入淘宝网站
 */
@WebServlet(urlPatterns = "/work2")
public class work2 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String option = req.getParameter("option");
        if(option.equals("a")){
            //请求转发
            req.getRequestDispatcher("/work2.html").forward(req,resp);
        }else if(option.equals("b")){
            resp.sendRedirect("https://www.taobao.com");
        }
    }
}

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<h3>验证a或b</h3>
<hr>
<form action="work2" method="get">
    <p><input type="text" name="option"></p>
    <p><input type="submit" value="提交"></p>
</form>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<h3>转发 html</h3>
</body>
</html>

运行结果：

3.配置参数初始化参数 username 获取初始化参数输出

package com.yq.work;

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

/*
配置参数 初始化参数 username 获取初始化参数 输出
 */
@WebServlet(name = "hello",urlPatterns = "/x",loadOnStartup = -1,initParams = {@WebInitParam(name = "username", value = "html")})
public class work3 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("初始化参数 = " + getInitParameter("username"));
    }
}

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<h3>初始化参数</h3>
<hr>
<form action="x">
    <p><input type="submit" value="提交"></p>
</form>
</body>
</html>

运行结果：

4.异常处理出现异常转入提示页面

package com.yq.work;

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.IOException;

/*
异常处理 出现异常 转入提示页面
 */
@WebServlet(urlPatterns = "/exc")
public class work4 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doGet(req, resp);
    }
}

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<h3>异常</h3>
<hr>
<form action="exc" method="post">
    <p><input type="text" name="name"></p>
    <p><input type="submit" value="提交"></p>
</form>
</body>
</html>

运行结果：

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