Javaweb获取表单数据的多种方式

Javaweb获取表单数据的多种方式

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)

getParameterNames():返回form表单中的所有key值。

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 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：

用户名

密码

性别 男

女

爱好 篮球

足球

游戏

<input type="checkbox" name="hobby" value="media"/>电影

城市

北京

上海

深圳

杭州

二、通过Map的形式获取表单数据

getParameterMap()：http://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 map = request.getParameterMap();

for (Map.Entry 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);

}

}

PropertyDescriptor的使用，点击查看

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

@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 ServletExcephttp://tion, 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);

}

}

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