记账本开发记录——第十五天（2020.2.2）

今天简单学习了一下request的使用方法，与昨天的response相对应的，requset为HTTP请求。request请求的运行过程与response大致一致，这里就不再赘述。

首先，request也可以获取请求头，请求头和请求体。每个依次写了一个demo:

package com.ithiema.header;

import java.io.IOException;
import java.util.Enumeration;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class HeaderServlet extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        
        //1、获得指定的头
        String header = request.getHeader("User-Agent");
        System.out.println(header);
        //2、获得所有的头的名称
        Enumeration<String> headerNames = request.getHeaderNames();
        while(headerNames.hasMoreElements()){
            String headerName = headerNames.nextElement();
            String headerValue = request.getHeader(headerName);
            System.out.println(headerName+":"+headerValue);
        }
        
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }
}

package com.ithiema.line;

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

public class LineServlet extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        
        //1、获得请求方式
        String method = request.getMethod();
        System.out.println("method:"+method);
        //2、获得请求的资源相关的内容
        String requestURI = request.getRequestURI();
        StringBuffer requestURL = request.getRequestURL();
        System.out.println("uri:"+requestURI);
        System.out.println("url:"+requestURL);
        //获得web应用的名称
        String contextPath = request.getContextPath();
        System.out.println("web应用："+contextPath);
        //地址后的参数的字符串
        String queryString = request.getQueryString();
        System.out.println(queryString);
        //3、获得客户机的信息---获得访问者IP地址
        String remoteAddr = request.getRemoteAddr();
        System.out.println("IP:"+remoteAddr);
        
        
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }
}

关于请求头，写了一个注册的小demo,代码如下：

package com.ithiema.register;

import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.sql.SQLException;
import java.util.Map;
import java.util.UUID;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.beanutils.BeanUtils;
import org.apache.commons.dbutils.QueryRunner;

import com.ithiema.utils.DataSourceUtils;

public class RegisterServlet extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        //设置request的编码---只适合post方式
        request.setCharacterEncoding("UTF-8");
        
        //get方式乱码解决
        //String username = request.getParameter("username");//乱码
        //先用iso8859-1编码 在使用utf-8解码
        //username = new String(username.getBytes("iso8859-1"),"UTF-8");
        
        
        //1、获取数据
        //String username = request.getParameter("username");
        //System.out.println(username);
        //String password = request.getParameter("password");
        //.....

        //2、将散装的封装到javaBean
        //User user = new User();
        //user.setUsername(username);
        //user.setPassword(password);

        //使用BeanUtils进行自动映射封装
        //BeanUtils工作原理：将map中的数据 根据key与实体的属性的对应关系封装
        //只要key的名字与实体的属性 的名字一样 就自动封装到实体中
        Map<String, String[]> properties = request.getParameterMap();
        User user = new User();
        try {
            BeanUtils.populate(user, properties);
        } catch (IllegalAccessException | InvocationTargetException e) {
            e.printStackTrace();
        }

        //现在这个位置 user对象已经封装好了
        //手动封装uid----uuid---随机不重复的字符串32位--java代码生成后是36位
        user.setUid(UUID.randomUUID().toString());

        //3、将参数传递给一个业务操作方法
        try {
            regist(user);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        
        //4、认为注册成功跳转到登录页面
        response.sendRedirect(request.getContextPath()+"/login.jsp");
        

    }

    //注册的方法
    public void regist(User user) throws SQLException{
        //操作数据库
        QueryRunner runner = new QueryRunner(DataSourceUtils.getDataSource());
        String sql = "insert into user values(?,?,?,?,?,?,?,?,?,?)";
        
        runner.update(sql,user.getUid(),user.getUsername(),user.getPassword(),user.getName(),
                user.getEmail(),null,user.getBirthday(),user.getSex(),null,null);
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }



}

关于注册的业务逻辑和思路，已经很熟练，不再赘述。主要是其中的BeanUtils，这是一个工具类，通过BeanUtils可以很方便的将内容封存到实体中去。

以上是今天学习的内容

今日的问题：在今天的学习中，发现无法按照老师所说的存放到数据库中后是正常的文字，依然是乱码。为了解决这个问题，从网上各种搜寻无果，最后发现自己连数据库也连不上了。在发这篇博客之前我甚至都不能存储数据，说实话是挺气的，等博客发布后再对其进行一下修复试试，明天再看吧