Javaweb获取表单数据的几种方式
一、通过键值对的形式获取表单数据
- getParameter(String name)：通过key，返回一个value。
- getParameterValues(String name)：通过key返回一个string数组(多个值) 返回个String[]
- getParameterNames():返回form表单中的所有key值。 Enumeration<String> names
下面介绍通过键值对获取form表单数据的数据的方法：
@WebServlet({ "/FormServlet", "/form" })
public class FormServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public FormServlet() {
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/json;charset=utf-8");
PrintWriter out = response.getWriter();
Enumeration<String> paramNames = request.getParameterNames();
while (paramNames.hasMoreElements()) {
String name = paramNames.nextElement();
String[] values = request.getParameterValues(name);
if(values!=null && values.length>0){
StringBuilder builder = new StringBuilder();
for (int i = 0; i < values.length; i++) {
builder.append(values[i]+" ");
}
out.println(name+" : "+builder.toString());
}
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}form表单：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="/TomcatDemo/form" method="post">
用户名<input type="text" name="username"/><br/>
密码 <input type="password" name="password"/><br/>
性别 <input type="radio" name="sex" value="male" checked="checked"/>男
<input type="radio" name="sex" value="female"/>女<br/>
爱好 <input type="checkbox" name="hobby" value="basketball"/>篮球
<input type="checkbox" name="hobby" value="football"/>足球
<input type="checkbox" name="hobby" value="game"/>游戏
<input type="checkbox" name="hobby" value="media"/>电影<br/>
城市 <select name="city">
<option value="bj">北京</option>
<option value="sh">上海</option>
<option value="sz">深圳</option>
<option value="hz">杭州</option>
</select><br/>
<input type="submit" value="注册"/>
<input type="submit" value="登入"/><br/>
</form>
</body>
</html>
二、通过Map的形式获取表单数据
- getParameterMap()：获取form表单的数据，以map的格式封装起来
示例：
@WebServlet({ "/FormServlet", "/form" })
public class FormServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public FormServlet() {
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/json;charset=utf-8");
PrintWriter out = response.getWriter();
User user = new User();
out.println("获取表单数据之前："+user.toString());
Map<String,String[]> map = request.getParameterMap();
for (Map.Entry<String, String[]> m : map.entrySet()) {
String name = m.getKey();
String[] values = m.getValue();
//属性描述器：表示JavaBean类通过存储器导出一个属性
PropertyDescriptor pd=null;
try {
pd = new PropertyDescriptor(name, User.class);
} catch (IntrospectionException e) {
e.printStackTrace();
}
if (values!=null&& pd !=null) {
Method setter = pd.getWriteMethod();
try {
if (values.length==1) {
setter.invoke(user, values[0]);
}else {
setter.invoke(user, (Object)values);
}
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
}
}
out.println("获取表单数据之后："+user.toString());
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}
User类
public class User {
private String username;//属性名称需要和表单数据中的name值保持一致
private String password;
private String sex;
private String[] hobby;
private String city;
...
//set get方法省略
}
三、通过第三方jar包获取封装表单数据
使用第三方jar包：commons-beanutils-1.8.3.jar，下载
@WebServlet({ "/FormServlet", "/form" })
public class FormServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public FormServlet() {
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/json;charset=utf-8");
PrintWriter out = response.getWriter();
User user = new User();
out.println("获取表单数据之前："+user.toString());
try {
//通过第三方jar包处理
BeanUtils.populate(user, request.getParameterMap());
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
out.println("获取表单数据之后："+user.toString());
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}