Servlet的5种方式实现表单提交（注册小功能），后台获取表单数据实例

2019-11-26 12:14:41

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来源：转载

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用servlet实现一个注册的小功能，后台获取数据。

注册页面：

注册页面代码：

<!DOCTYPE html><html><head><meta charset="UTF-8"><title>Insert title here</title></head><body>  <form action="/RequestDemo/RequestDemo3" method="post">    用户名：<input type="text" name="userName"><br/>    密码：<input type="text" name="pwd"><br/>    性别：<input type="radio" name="sex" value="男" checked="checked">男      <input type="radio" name="sex" value="女">女<br/>    爱好：<input type="checkbox" name="hobby" value="足球">足球      <input type="checkbox" name="hobby" value="篮球">篮球      <input type="checkbox" name="hobby" value="排球">排球      <input type="checkbox" name="hobby" value="羽毛球">羽毛球<br/>    所在城市：<select name="city">         <option>---请选择---</option>         <option value="bj">北京</option>         <option value="sh">上海</option>         <option value="sy">沈阳</option>        </select>            <br/>    <input type="submit" value="点击注册">  </form></body></html>

人员实体类：注意：人员实体类要与表单中的name一致，约定要优于编码

package com.chensi.bean;//实体类中的字段要与表单中的字段一致，约定优于编码public class User {  private String userName;  private String pwd;  private String sex;  private String[] hobby;  private String city;  public String getUserName() {    return userName;  }  public void setUserName(String userName) {    this.userName = userName;  }  public String getPwd() {    return pwd;  }  public void setPwd(String pwd) {    this.pwd = pwd;  }  public String getSex() {    return sex;  }  public void setSex(String sex) {    this.sex = sex;  }  public String[] getHobby() {    return hobby;  }  public void setHobby(String[] hobby) {    this.hobby = hobby;  }  public String getCity() {    return city;  }  public void setCity(String city) {    this.city = city;  }  }

接收方法一： Servlet页面(后台接收数据方法一)

package com.chensi;import java.io.IOException;import java.util.Iterator;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;/** * Servlet 获得填写的表单数据 */@WebServlet("/RequestDemo3")public class RequestDemo3 extends HttpServlet {  private static final long serialVersionUID = 1L;      protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {    request.setCharacterEncoding("UTF-8");    //获取传过来的表单数据,根据表单中的name获取所填写的值    String userName = request.getParameter("userName");    String pwd = request.getParameter("pwd");    String sex = request.getParameter("sex");    String[] hobbys = request.getParameterValues("hobby");        System.out.println(userName);    System.out.println(pwd);    System.out.println(sex);    for (int i = 0; hobbys!=null&&i < hobbys.length; i++) {      System.out.println(hobbys[i]+"/t");    }  }  protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {    doGet(request, response);  }}

得到的数据：

接收方法二：

package com.chensi;import java.io.IOException;import java.util.Enumeration;import java.util.Iterator;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;/** * Servlet 获得填写的表单数据 */@WebServlet("/RequestDemo3")public class RequestDemo3 extends HttpServlet {  private static final long serialVersionUID = 1L;      protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {    request.setCharacterEncoding("UTF-8");    //获取传过来的表单数据,根据表单中的name获取所填写的值    Enumeration<String> names = request.getParameterNames();    while (names.hasMoreElements()) {      String strings = (String) names.nextElement();      String[] parameterValues = request.getParameterValues(strings);      for (int i = 0;parameterValues!=null&&i < parameterValues.length; i++) {        System.out.println(strings+":"+parameterValues[i]+"/t");      }    }  }  protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {    doGet(request, response);  }    }

得到的数据：

接收方法三：利用反射赋值给User

package com.chensi;import java.beans.IntrospectionException;import java.beans.PropertyDescriptor;import java.io.IOException;import java.lang.reflect.InvocationTargetException;import java.lang.reflect.Method;import java.util.Enumeration;import java.util.Iterator;import java.util.Map;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 com.chensi.bean.User;/** * Servlet 获得填写的表单数据 */@WebServlet("/RequestDemo3")public class RequestDemo3 extends HttpServlet {  private static final long serialVersionUID = 1L;      protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {    request.setCharacterEncoding("UTF-8");    //获取传过来的表单数据,根据表单中的name获取所填写的值                try {        User u = new User();        System.out.println("数据封装之前: "+u);        //获取到表单数据        Map<String, String[]> map = request.getParameterMap();        for(Map.Entry<String,String[]> m:map.entrySet()){          String name = m.getKey();          String[] value = m.getValue();          //创建一个属性描述器          PropertyDescriptor pd = new PropertyDescriptor(name, User.class);          //得到setter属性          Method setter = pd.getWriteMethod();          if(value.length==1){            setter.invoke(u, value[0]);          }else{            setter.invoke(u, (Object)value);          }        }        System.out.println("封装数据之后: "+u);      } catch (IntrospectionException | IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {        e.printStackTrace();      }          }        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {    doGet(request, response);  }}

得到的结果：

接收方法四：使用apache 的 BeanUtils 工具来进行封装数据（ps：这个Benautils工具，Struts框架就是使用这个来获取表单数据的哦！）

package com.chensi;import java.beans.IntrospectionException;import java.beans.PropertyDescriptor;import java.io.IOException;import java.lang.reflect.InvocationTargetException;import java.lang.reflect.Method;import java.util.Enumeration;import java.util.Iterator;import java.util.Map;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 org.apache.commons.beanutils.BeanUtils;import com.chensi.bean.User;/** * Servlet 获得填写的表单数据 */@WebServlet("/RequestDemo3")public class RequestDemo3 extends HttpServlet {  private static final long serialVersionUID = 1L;      protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {    request.setCharacterEncoding("UTF-8");    //获取传过来的表单数据,根据表单中的name获取所填写的值      //方法四：使用beanUtil来封装User类    User u = new User();    System.out.println("没有使用BeanUtil封装之前： "+u);    try {      BeanUtils.populate(u, request.getParameterMap());      System.out.println("使用BeanUtils封装之后： "+u);    } catch (IllegalAccessException | InvocationTargetException e) {      e.printStackTrace();    }          }        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {    doGet(request, response);  }    }

得到的结果：

接收方法方式五：使用inputStream流来进行接收（一般字符串啥的不用这个方法，一般是文件上传下载时候才会使用这种方法）因为接收到的字符串各种乱码，编码问题解决不好

package com.chensi;import java.beans.IntrospectionException;import java.beans.PropertyDescriptor;import java.io.IOException;import java.lang.reflect.InvocationTargetException;import java.lang.reflect.Method;import java.util.Enumeration;import java.util.Iterator;import java.util.Map;import javax.servlet.ServletException;import javax.servlet.ServletInputStream;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.apache.commons.beanutils.BeanUtils;import com.chensi.bean.User;/** * Servlet 获得填写的表单数据 */@WebServlet("/RequestDemo3")public class RequestDemo3 extends HttpServlet {  private static final long serialVersionUID = 1L;      protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {    request.setCharacterEncoding("UTF-8");    //获取传过来的表单数据,根据表单中的name获取所填写的值    response.setContentType("text/html;charset=UTF-8");    //获取表单数据    ServletInputStream sis = request.getInputStream();    int len = 0;    byte[] b = new byte[1024];    while((len=sis.read(b))!=-1){      System.out.println(new String(b, 0, len, "UTF-8"));    }        sis.close();      }  protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {    doGet(request, response);  }}

得到的结果：（各种乱码。。。。）