页面参数自动映射到JavaBean[仿struts 模型驱动]之简易版
开发使用的基础框架中没有涉及到模型驱动这块，也就是说，没有写方法将前台页面请求参数封装映射到对应的JavaBean属性当中，所以使用这个基础框架开发系统起来，页面的参数一个一个request.getParameter(paramName)取出参数值,然后又一大堆bean.setXXX()才能组装成这个JavaBean对象，重复劳动工作十分明显，且造成后台代码繁杂，不够简单明了。所以为此写了一个简易版的servlet模型驱动，将页面参数自动映射到对应的JavaBean之中，免去大量重复性劳动，使代码更加统一而简洁舒适。
这里利用了Apache的一个开源框架包（最近老利用Apache的开源包，Apache强大，无私共享精神值得赞叹）commons-beanutils，专门针对JavaBean处理各种操作的，十分方便。
一、先贴官网：
http://commons.apache.org/beanutils/
下载jar包：
http://apache.etoak.com/commons/beanutils/binaries/commons-beanutils-1.8.3-bin.zip
目前版本：commons-beanutils-1.8.3.jar
二、源代码很简单（部分参考到了struts里的思路）：
RequestUtils类：
三、JavaBean代码：
四、jsp页面上参数域直接写“JavaBean类名.属性名”即可，以下类型经测试都正确，写法如下：
五、源代码摘选（BeanUtilsBean.java）：
六、总结
目前只是简易版参数映射，能做到日常开发一般性处理要求，看了Apache beanutils包相关源代码，处理得挺细致的，功能应该很强大，我只是用到了一点点而已，还没处理二进制的方式提交表单enctype=“multipart/form-data”的情况，等着以后慢慢细致化吧。
这里利用了Apache的一个开源框架包（最近老利用Apache的开源包，Apache强大，无私共享精神值得赞叹）commons-beanutils，专门针对JavaBean处理各种操作的，十分方便。
一、先贴官网：
http://commons.apache.org/beanutils/
下载jar包：
http://apache.etoak.com/commons/beanutils/binaries/commons-beanutils-1.8.3-bin.zip
目前版本：commons-beanutils-1.8.3.jar
二、源代码很简单（部分参考到了struts里的思路）：
RequestUtils类：
package com.basekj.util;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import org.apache.commons.beanutils.BeanUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* request操作类
* @author
* @version 1.0
* 2010-8-23 09:46:15
*
*/
public class RequestUtils {
private static final Log logger = LogFactory.getLog(RequestUtils.class);
/**
* 页面参数自动获取并映射到对应的JavaBean上
* @param request
* @param obj(可配置多个JavaBean,无顺序)
*/
public static void getReqParemetersToJavaBean(HttpServletRequest request,Object[] obj) {
HashMap properties = new HashMap();
try {
Enumeration names = request.getParameterNames();
while (names.hasMoreElements()) {
String name = (String) names.nextElement();
Object parameterValue = null;
parameterValue = request.getParameterValues(name);
properties.put(name, parameterValue);
}
if ((obj == null) || (properties == null)) {
return;
}
Iterator entries = properties.entrySet().iterator();
while (entries.hasNext()) {
Map.Entry entry = (Map.Entry)entries.next();
String[] nature = ((String) entry.getKey()).split("\\.");
String className = "";
String propertyName = "";
if(nature != null && nature.length == 2) {
className = nature[0];
propertyName = nature[1];
} else {
continue;
}
for(Object o:obj) {
// Class newClass = Class.forName("com.hxkj.entity."+className);
// if(newClass.isInstance(o)) {
// BeanUtils.setProperty(o, propertyName, entry.getValue());
// }
String beanName = o.getClass().getSimpleName();
if(beanName.equals(className)) {
BeanUtils.setProperty(o, propertyName, entry.getValue());
}
}
}
} catch (Exception e) {
e.printStackTrace();
logger.error(e.getMessage());
return;
}
}
}
三、JavaBean代码：
package com.basekj.entity;
/**
*
* @author
* @date 2010-08-18
*/
public class ParemetersBean {
private String username;
private String pwd;
private int type;
private String area;
private String[] fruit;
private String city;
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public String[] getFruit() {
return fruit;
}
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 int getType() {
return type;
}
public void setType(int type) {
this.type = type;
}
public String getArea() {
return area;
}
public void setArea(String area) {
this.area = area;
}
public void setFruit(String[] fruit) {
this.fruit = fruit;
}
}
package com.basekj.entity;
/**
*
* @author
* @date 2010-08-18
*/
public class ParemetersBean2 {
private String id;
private String name;
private String city;
private String nested;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public String getNested() {
return nested;
}
public void setNested(String nested) {
this.nested = nested;
}
}
四、jsp页面上参数域直接写“JavaBean类名.属性名”即可，以下类型经测试都正确，写法如下：
<div align="center"> 姓名： <input name="ParemetersBean.username" type="text" value=""> </div> <div align="center"> 密码： <input name="ParemetersBean.pwd" type="password" value=""> </div> <div align="center"> 类型： <select name="ParemetersBean.type"> <option value="1"> a </option> <option value="2"> b </option> <option value="3"> c </option> <option value="4"> d </option> </select> </div> <div> <input type="checkbox" name="ParemetersBean.fruit" value="apple"> 苹果 <br> <input type="checkbox" name="ParemetersBean.fruit" value="orange"> 桔子 <br> <input type="checkbox" name="ParemetersBean.fruit" value="mango"> 芒果 <br> </div> <div> <input type="radio" name="ParemetersBean.city" value="hf"> 合肥 <br> <input type="radio" name="ParemetersBean.city" value="nj"> 南京 <br> <input type="radio" name="ParemetersBean.city" value="sh"> 上海 <br> </div> <div align="center"> 文本域： <textarea rows="2" name="ParemetersBean.area"></textarea> </div> <div align="center"> id： <input name="ParemetersBean2.id" type="text" value=""> </div> <div align="center"> name： <input name="ParemetersBean2.name" type="text" value=""> </div> <div> 这个参数没有对应的JavaBean属性，不会做映射处理，也不会影响其他属性 <input name="ParemetersBean2.efdfvfdsf" type="text" value=""> </div> <div> <input type="radio" name="ParemetersBean2.city" value="dj"> 东京 <br> <input type="radio" name="ParemetersBean2.city" value="ny"> 纽约 <br> <input type="radio" name="ParemetersBean2.city" value="bl"> 巴黎 <br> </div>
五、源代码摘选（BeanUtilsBean.java）：
/**
* <p>Set the specified property value, performing type conversions as
* required to conform to the type of the destination property.</p>
*
* <p>If the property is read only then the method returns
* without throwing an exception.</p>
*
* <p>If <code>null</code> is passed into a property expecting a primitive value,
* then this will be converted as if it were a <code>null</code> string.</p>
*
* <p><strong>WARNING</strong> - The logic of this method is customized
* to meet the needs of <code>populate()</code>, and is probably not what
* you want for general property copying with type conversion. For that
* purpose, check out the <code>copyProperty()</code> method instead.</p>
*
* <p><strong>WARNING</strong> - PLEASE do not modify the behavior of this
* method without consulting with the Struts developer community. There
* are some subtleties to its functionality that are not documented in the
* Javadoc description above, yet are vital to the way that Struts utilizes
* this method.</p>
*
* @param bean Bean on which setting is to be performed
* @param name Property name (can be nested/indexed/mapped/combo)
* @param value Value to be set
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception InvocationTargetException if the property accessor method
* throws an exception
*/
public void setProperty(Object bean, String name, Object value)
throws IllegalAccessException, InvocationTargetException {
// Trace logging (if enabled)
if (log.isTraceEnabled()) {
StringBuffer sb = new StringBuffer(" setProperty(");
sb.append(bean);
sb.append(", ");
sb.append(name);
sb.append(", ");
if (value == null) {
sb.append("<NULL>");
} else if (value instanceof String) {
sb.append((String) value);
} else if (value instanceof String[]) {
String[] values = (String[]) value;
sb.append('[');
for (int i = 0; i < values.length; i++) {
if (i > 0) {
sb.append(',');
}
sb.append(values[i]);
}
sb.append(']');
} else {
sb.append(value.toString());
}
sb.append(')');
log.trace(sb.toString());
}
// Resolve any nested expression to get the actual target bean
Object target = bean;
Resolver resolver = getPropertyUtils().getResolver();
while (resolver.hasNested(name)) {
try {
target = getPropertyUtils().getProperty(target, resolver.next(name));
name = resolver.remove(name);
} catch (NoSuchMethodException e) {
return; // Skip this property setter
}
}
if (log.isTraceEnabled()) {
log.trace(" Target bean = " + target);
log.trace(" Target name = " + name);
}
// Declare local variables we will require
String propName = resolver.getProperty(name); // Simple name of target property
Class type = null; // Java type of target property
int index = resolver.getIndex(name); // Indexed subscript value (if any)
String key = resolver.getKey(name); // Mapped key value (if any)
// Calculate the property type
if (target instanceof DynaBean) {
DynaClass dynaClass = ((DynaBean) target).getDynaClass();
DynaProperty dynaProperty = dynaClass.getDynaProperty(propName);
if (dynaProperty == null) {
return; // Skip this property setter
}
type = dynaProperty.getType();
} else if (target instanceof Map) {
type = Object.class;
} else if (target != null && target.getClass().isArray() && index >= 0) {
type = Array.get(target, index).getClass();
} else {
PropertyDescriptor descriptor = null;
try {
descriptor =
getPropertyUtils().getPropertyDescriptor(target, name);
if (descriptor == null) {
return; // Skip this property setter
}
} catch (NoSuchMethodException e) {
return; // Skip this property setter
}
if (descriptor instanceof MappedPropertyDescriptor) {
if (((MappedPropertyDescriptor) descriptor).getMappedWriteMethod() == null) {
if (log.isDebugEnabled()) {
log.debug("Skipping read-only property");
}
return; // Read-only, skip this property setter
}
type = ((MappedPropertyDescriptor) descriptor).
getMappedPropertyType();
} else if (index >= 0 && descriptor instanceof IndexedPropertyDescriptor) {
if (((IndexedPropertyDescriptor) descriptor).getIndexedWriteMethod() == null) {
if (log.isDebugEnabled()) {
log.debug("Skipping read-only property");
}
return; // Read-only, skip this property setter
}
type = ((IndexedPropertyDescriptor) descriptor).
getIndexedPropertyType();
} else if (key != null) {
if (descriptor.getReadMethod() == null) {
if (log.isDebugEnabled()) {
log.debug("Skipping read-only property");
}
return; // Read-only, skip this property setter
}
type = (value == null) ? Object.class : value.getClass();
} else {
if (descriptor.getWriteMethod() == null) {
if (log.isDebugEnabled()) {
log.debug("Skipping read-only property");
}
return; // Read-only, skip this property setter
}
type = descriptor.getPropertyType();
}
}
// Convert the specified value to the required type
Object newValue = null;
if (type.isArray() && (index < 0)) { // Scalar value into array
if (value == null) {
String[] values = new String[1];
values[0] = null;
newValue = getConvertUtils().convert(values, type);
} else if (value instanceof String) {
newValue = getConvertUtils().convert(value, type);
} else if (value instanceof String[]) {
newValue = getConvertUtils().convert((String[]) value, type);
} else {
newValue = convert(value, type);
}
} else if (type.isArray()) { // Indexed value into array
if (value instanceof String || value == null) {
newValue = getConvertUtils().convert((String) value,
type.getComponentType());
} else if (value instanceof String[]) {
newValue = getConvertUtils().convert(((String[]) value)[0],
type.getComponentType());
} else {
newValue = convert(value, type.getComponentType());
}
} else { // Value into scalar
if (value instanceof String) {
newValue = getConvertUtils().convert((String) value, type);
} else if (value instanceof String[]) {
newValue = getConvertUtils().convert(((String[]) value)[0],
type);
} else {
newValue = convert(value, type);
}
}
// Invoke the setter method
try {
getPropertyUtils().setProperty(target, name, newValue);
} catch (NoSuchMethodException e) {
throw new InvocationTargetException
(e, "Cannot set " + propName);
}
}
六、总结
目前只是简易版参数映射，能做到日常开发一般性处理要求，看了Apache beanutils包相关源代码，处理得挺细致的，功能应该很强大，我只是用到了一点点而已，还没处理二进制的方式提交表单enctype=“multipart/form-data”的情况，等着以后慢慢细致化吧。