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Request通用方式获取请求参数
○ 请求参数获取方式：§ GET方式：□ String getQueryString()§ POST方式：□ BufferedReader getReader()○ 通用方式：§ Map<String, String[]> getParameterMap()//获取所有参数Map集合§ String[] getParameterValues(Stringname)//根据名称获取参数值（数组）§ String getParameter(Stringname)//根据名称获取参数值（单个值）
/*** Request获取请求数据*/
@WebServlet("/req1")
public class RequestDemo extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {/*** 获取请求行数据*/// □ String getMethod()//获取请求方法String method = req.getMethod();System.out.println(method);//GET//□ String getContextPath()//获取虚拟目录（项目访问路径）/request-demoString path = req.getContextPath();System.out.println(path);//□ StringBuffer getRequestURL()//获取URL（统一资源定位符）：http://localhost:8080/request-demo/req1StringBuffer url = req.getRequestURL();System.out.println(url);//□ String getRequestURI()//获取URI（统一资源标识符）：/request-demo/req1String uri = req.getRequestURI();System.out.println(uri);//□ String getQueryString()//获取请求参数（GET方式）：username=zhangsan&password=123String queryString = req.getQueryString();System.out.println(queryString);/*** 获取请求头数据*///获取请求头：user-agent：浏览器版本信息String reqHeader = req.getHeader("user-agent");System.out.println(reqHeader);}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {/***获取post请求体：请求参数*///获取字符输入流BufferedReader br = req.getReader();//读取数据String line = br.readLine();System.out.println(line);}
}对应的post表单
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>Title</title>
</head>
<body><form action="//localhost:8080/request-demo/req4" method="post"><input type="text" name="username"><input type="password" name="password"><input type="submit"></form>
</body>
</html>
○ 使用通用方式获取参数和，屏蔽了GET和POST的请求方式代码的不同，则代码可以定义为如下格式
@WebServlet("/req3")publicclassRequestDemo2extendsHttpServlet{@OverrideprotectedvoiddoGet(HttpServletRequestreq,HttpServletResponseresp)throwsServletException,IOException{//GET请求逻辑}@OverrideprotectedvoiddoPost(HttpServletRequestreq,HttpServletResponseresp)throwsServletException,IOException{//POST请求逻辑this.doGet(req,resp);}} 执行流程大致同下面相同
创建 Servlet模板
可以使用Servlet模板创建Servlet更高效 ，具体步骤如下：
设置Servlet模板的步骤如下
：
○ Request请求参数中文乱码处理§ 请求参数如果存在中文数据，会乱码§ 解决方案：□ POST：设置输入流的编码® request.setCharacterEncoding("UTF-8");□ GET：□ URL编码：® 将字符串按照编码方式转为二进制® 每个字节转为2个16进制数并在前边加上%
/*** 中文乱码问题的解决方案*/
@WebServlet("/req4")
public class RequestDemo4 extends HttpServlet {protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {/* //1.解决乱码 POST getReader()request.setCharacterEncoding("UTF-8");//设置字符输入流的编码//2.获取usernameString username = request.getParameter("username");System.out.println(username);*///3.GET获取参数的方式底层还是，getQueryString()request.setCharacterEncoding("UTF-8");//设置字符输入流的编码//2.获取usernameString username = request.getParameter("username");System.out.println("乱码：" + username);//乱码原因：tomcat进行URL解码时，默认字符集是ISO-8859-1//3.1先对乱码数据进行编码，转为字节数组//3.2字节数组解码username = new String(username.getBytes("ISO-8859-1"), "utf-8");System.out.println("解决乱码后：" + username);}protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request, response);}
}
对应的post表单
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>Title</title>
</head>
<body><form action="//localhost:8080/request-demo/req4" method="get"><input type="text" name="username"><br><input type="password" name="password"><br><input type="checkbox" name="hobby" value="1">游泳<input type="checkbox" name="hobby" value="2">爬山<br><input type="submit"></form>
</body>
</html>
执行步骤
1.运行tomcat服务器
2.进入链接
3.输入表单文件
4.在输入框中输入任意中文
5.回到idea控制台查看
§ Tomcat8.0之后，已将GET请求乱码问题解决，设置默认的解码方式为UTF-8
