编写代码模拟struts1填充FormBean

使用dom4j解析struts配置文件，利用反射技术从配置文件中读取FormBean，示例代码如下：

1、com.wgy.form.LoginForm类：

public class LoginForm {
    private String name;
    private String password;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    @Override
    public String toString() {
        return "LoginForm [name=" + name + ", password=" + password + "]";
    }
}

2、struts-config.xml文件，位于src下：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts-config PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 1.3//EN"
    "http://jakarta.apache.org/struts/dtds/struts-config_1_3.dtd">

<struts-config>
    <form-beans>
        <form-bean name="loginForm" type="com.wgy.form.LoginForm" />
    </form-beans>
</struts-config>

3、使用dom4j解析上述文件：

public class XmlUtils {
    public static String[] parseXml() throws Exception {
        SAXReader reader = new SAXReader();
        InputStream inStream = XmlUtils.class.getClassLoader()
                .getResourceAsStream("struts-config.xml");
        Document document = reader.read(inStream);
        Element root = document.getRootElement();
        Element formBean = root.element("form-beans").element("form-bean");
        String name = formBean.attributeValue("name");
        String type = formBean.attributeValue("type");
        return new String[] { name, type };
    }
}

4、编写Servlet控制器:

public class ActionServlet extends HttpServlet {

    private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);
    }

    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        try {
            String[] values = XmlUtils.parseXml();
            String formName = values[0];
            String formClassFullName = values[1];
            FormUtils.fillForm(request, formClassFullName, formName);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}

5、将上述servlet配置到web.xml文件中：

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    id="WebApp_ID" version="2.5">
    <display-name>Struts1Test</display-name>
    <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>
    <servlet>
        <servlet-name>ActionServlet</servlet-name>
        <servlet-class>com.wgy.servlet.ActionServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>ActionServlet</servlet-name>
        <url-pattern>*.do</url-pattern>
    </servlet-mapping>
</web-app>

6、编写FormUtils类，利用反射封装FormBean

public class FormUtils {

    @SuppressWarnings("unchecked")
    public static void fillForm(HttpServletRequest request,
            String formClassFullName, String formName) {
        try {
            LoginForm loginForm = (LoginForm) Class.forName(formClassFullName)
                    .newInstance();
            Field[] fields = loginForm.getClass().getDeclaredFields();
            Enumeration<String> parameterNames = request.getParameterNames();
            while (parameterNames.hasMoreElements()) {
                String parameterName = parameterNames.nextElement();
                for (Field field : fields) {
                    String fieldName = field.getName();
                    if (fieldName.equals(parameterName)) {
                        String value = request.getParameter(fieldName);
                        try {
                            BeanUtils.setProperty(loginForm, fieldName, value);
                        } catch (InvocationTargetException e) {
                            e.printStackTrace();
                        }
                    }
                }
            }
            System.out.println(loginForm.toString());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

7、编写测试页面index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>index</title>
</head>
<body>
    <form action="<%=request.getContextPath() %>/login.do" method="post">
        username:<input type="text" name="name" /> <br />
        password:<input type="text" name="password" /> <br />
        <input type="submit" value="登录" />
    </form>
</body>
</html>