Servlet CRUD-Servlet提供编辑功能

修改HeroListServlet新增加一列 edit，里面放上指向 /editHero的超链package servlet;import java.io.IOException;import java.util.List;import javax.servlet.ServletException;import javax.servlet.http.HttpServ

litengbin

424人浏览 · 2018-01-25 00:42:28

litengbin · 2018-01-25 00:42:28 发布

修改HeroListServlet

新增加一列 edit，里面放上指向 /editHero的超链

package servlet;
 
import java.io.IOException;
import java.util.List;
 
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
import bean.Hero;
import dao.HeroDAO;
 
public class HeroListServlet extends HttpServlet {
 
    protected void service(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html; charset=UTF-8");
         
        List<Hero> heros = new HeroDAO().list();
 
        StringBuffer sb = new StringBuffer();
        sb.append("<table align='center' border='1' cellspacing='0'>\r\n");
        sb.append("<tr><td>id</td><td>name</td><td>hp</td><td>damage</td><td>edit</td><td>delete</td></tr>\r\n");
 
        String trFormat = "<tr><td>%d</td><td>%s</td><td>%f</td><td>%d</td><td><a href='editHero?id=%d'>edit</a></td><td><a href='deleteHero?id=%d'>delete</a></td></tr>\r\n";
 
        for (Hero hero : heros) {
            String tr = String.format(trFormat, hero.getId(), hero.getName(), hero.getHp(), hero.getDamage(),hero.getId(),hero.getId());
             
            sb.append(tr);
        }
 
        sb.append("</table>");
 
        response.getWriter().write(sb.toString());
 
    }
}

配置web.xml

在web.xml中把 /editHero路径映射到 HeroEditServlet类上

<?xml version="1.0" encoding="UTF-8"?>
<web-app>
 
    <servlet>
        <servlet-name>HelloServlet</servlet-name>
        <servlet-class>HelloServlet</servlet-class>
        <load-on-startup>10</load-on-startup>
    </servlet>
 
    <servlet-mapping>
        <servlet-name>HelloServlet</servlet-name>
        <url-pattern>/hello</url-pattern>
    </servlet-mapping>
 
    <servlet>
        <servlet-name>LoginServlet</servlet-name>
        <servlet-class>LoginServlet</servlet-class>
    </servlet>
 
    <servlet-mapping>
        <servlet-name>LoginServlet</servlet-name>
        <url-pattern>/login</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>RegisterServlet</servlet-name>
        <servlet-class>RegisterServlet</servlet-class>
    </servlet>
 
    <servlet-mapping>
        <servlet-name>RegisterServlet</servlet-name>
        <url-pattern>/register</url-pattern>
    </servlet-mapping>
 
    <servlet>
        <servlet-name>HeroListServlet</servlet-name>
        <servlet-class>servlet.HeroListServlet</servlet-class>
    </servlet>
 
    <servlet-mapping>
        <servlet-name>HeroListServlet</servlet-name>
        <url-pattern>/listHero</url-pattern>
    </servlet-mapping>
 
    <servlet>
        <servlet-name>HeroAddServlet</servlet-name>
        <servlet-class>servlet.HeroAddServlet</servlet-class>
    </servlet>
 
    <servlet-mapping>
        <servlet-name>HeroAddServlet</servlet-name>
        <url-pattern>/addHero</url-pattern>
    </servlet-mapping>
 
    <servlet>
        <servlet-name>HeroDeleteServlet</servlet-name>
        <servlet-class>servlet.HeroDeleteServlet</servlet-class>
    </servlet>
 
    <servlet-mapping>
        <servlet-name>HeroDeleteServlet</servlet-name>
        <url-pattern>/deleteHero</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>HeroEditServlet</servlet-name>
        <servlet-class>servlet.HeroEditServlet</servlet-class>
    </servlet>
 
    <servlet-mapping>
        <servlet-name>HeroEditServlet</servlet-name>
        <url-pattern>/editHero</url-pattern>
    </servlet-mapping>
 
</web-app>

准备HeroEditServlet

HeroEditServlet 根据浏览器传过来的id获取一个hero对象
然后根据这个hero对象，准备一个类似add.html的页面，不同之处在于每个输入框都是有值的。
最后还会提供一个type="hidden"的input,用于提交id到路径/updateHero

package servlet;
 
import java.io.IOException;
 
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
import bean.Hero;
import dao.HeroDAO;
 
public class HeroEditServlet extends HttpServlet {
 
    protected void service(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
 
        int id = Integer.parseInt(request.getParameter("id"));
 
        Hero hero = new HeroDAO().get(id);
 
        StringBuffer format = new StringBuffer();
        response.setContentType("text/html; charset=UTF-8");
 
        format.append("<!DOCTYPE html>");
 
        format.append("<form action='updateHero' method='post'>");
        format.append("名字 ： <input type='text' name='name' value='%s' > <br>");
        format.append("血量 ： <input type='text' name='hp'  value='%f' > <br>");
        format.append("伤害： <input type='text' name='damage'  value='%d' > <br>");
        format.append("<input type='hidden' name='id' value='%d'>");
        format.append("<input type='submit' value='更新'>");
        format.append("</form>");
 
        String html = String.format(format.toString(), hero.getName(), hero.getHp(), hero.getDamage(), hero.getId());
 
        response.getWriter().write(html);
 
    }
}

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