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
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]+" ");
}
}
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]+" ");
}
}
}
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 。。。。）
