演示获取表单提交的信息

package com.javaweb.httprequest;
import java.beans.IntrospectionException;
import java.beans.PropertyDescriptor;
//演示获取表单提交的信息
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Enumeration;
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 org.omg.CosNaming.NamingContextExtPackage.StringNameHelper;


/**
 * Servlet implementation class ServletBiaodanRequest
 */
@WebServlet("/servletBiaodanRequest")
public class ServletBiaodanRequest extends HttpServlet {
private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public ServletBiaodanRequest() {
        super();
        // TODO Auto-generated constructor stub
    }


/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// test1(request);
// test2(request);
// test3(request);
//test4(request);
//test5(request);
//test6(request);
//test7(request);
}


/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);

}
//1：获取单个控件的值
public void test1(HttpServletRequest request) {
String name=request.getParameter("username");//参数是控件的名字
/*当名字username的参数不写的时候，输出结果为空，当username写错时输出的为null*/
System.out.println("姓名："+name);
}
//2：获取单个控件的值eg：获取密码
public void test2(HttpServletRequest request) {
String [] pass=request.getParameterValues("password");
for (String string : pass) {
System.out.println(string );
}
}
//3：获取所有控件的名字和值：
public void test3(HttpServletRequest request) {
//获取所有控件的名字
Enumeration enu= request.getParameterNames();
while (enu.hasMoreElements()) {
String name=enu.nextElement();
//由于名字可能会重复
String []values=request.getParameterValues(name);
for (String value : values) {
System.out.println(name+":"+value);
}
}
}
//4：将表单中的所有值封装到javabean中，采用propertyDesceipt
public void test4(HttpServletRequest request) {

//将页面传递的内容封装到user对象中
User user=new User();
System.out.println("封装前:"+user);
//获取所有控件的名字
Enumeration enu= request.getParameterNames();
while (enu.hasMoreElements()) {
String name=enu.nextElement();
//由于名字可能会重复
String []values=request.getParameterValues(name);
try {
//拿到属于name的属性描述器
PropertyDescriptor pd=new PropertyDescriptor(name, User.class);
//将值注入到属性中，拿到写描述器
Method method=pd.getWriteMethod();
/*为了兼容jdk1.4sun公司开发了invoke方法在执行的时候将参数拆开进行传递，就导致了
* illegalargumentexception异常
* 解决办法1：*/
if (values.length==1) {
method.invoke(user, values);
}else {
//解决办法1：
method.invoke(user, (Object)values);
//解决办法2:
method.invoke(user, new Object[ ] {values});

}
} catch (IntrospectionException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
System.out.println("封装后"+user);
}
// 5.将表单中的所有值封装到Javabean中： 采用第三方的jar进行封装： BeanUtils类
public void test5(HttpServletRequest request) {
// 将页面传递的内容封装到user对象中
User user = new User();
System.out.println("封装前： " + user);
// 获取所有控件的名字
Enumeration enu = request.getParameterNames();
while (enu.hasMoreElements()) {
String name = enu.nextElement();
// 由于名字可能会重复
String[] values = request.getParameterValues(name);


// 采用BeanUtils类封装
try {
BeanUtils.setProperty(user, name, values);
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
System.out.println("封装后： " + user);
}


// 6.将表单中的所有值封装到Javabean中： 采用第三方的jar进行封装： BeanUtils类
public void test6(HttpServletRequest request) {
// 将页面传递的内容封装到user对象中
User user = new User();
System.out.println("封装前： " + user);
// 拿到控件的名字和值的键值对
Map map = request.getParameterMap();


for (Map.Entry entry : map.entrySet()) {
// 拿到控件的名字
String name = entry.getKey();
// 拿到控件的值
String[] values = entry.getValue();


// 封装数据
try {
BeanUtils.setProperty(user, name, values);
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}


System.out.println("封装后： " + user);
}


// 7.终极必杀技
public void test7(HttpServletRequest request) {
// 将页面传递的内容封装到user对象中
User user = new User();
System.out.println("封装前： " + user);

try {
BeanUtils.populate(user, request.getParameterMap()) ;
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("封装后： " + user);
}


}