要制作一个下面这样的CMS标签，可以实现 多个自定义参数，带参数名和参数值

#articlelist(channelid=10,pagenumber=1,pagesize=10)

<li> <a href="#(article.getArticleUrl())">#(article.title)</a></li>

#end

---------------------------------------------------

第一步，修改一下jfinal源码 (最新版本不用修改,波总改过了)

package com.jfinal.template.expr.ast;

import java.util.List;

import java.util.Map;

import com.jfinal.template.TemplateException;

import com.jfinal.template.stat.Location;

import com.jfinal.template.stat.ParseException;

import com.jfinal.template.stat.Scope;

/**

 * Assign

 * 

 * 支持三种赋值，其中第二种如果括号中是 ID 或 STR 则演变为第三种是对 map 赋值：

 * 1：ID = expr

 * 2：ID [ expr ] = expr

 *   如果 expr 为 int 或 long 型，则是对 array 赋值

 *   如果 expr 为 ID、STR 型，则是对 map 进行赋值

 *   否则抛异常出来

 * 3：ID [ ID ] = expr 或者 ID [ STR ] = expr

 * 4：支持无限连：id = array[ i = 0 ] = array[1] = 123

 */

public class Assign extends Expr {

private String id;

private Expr index; // index 用于支持 ID [ expr ] = expr 这种形式

private Expr right;

/**

* 数组赋值表达式

*/

public Assign(String id, Expr index, Expr right, Location location) {

if (index == null) {

throw new ParseException("The index expression of array assignment can not be null", location);

}

if (right == null) {

throw new ParseException("The expression on the right side of an assignment expression can not be null", location);

}

this.id = id;

this.index = index;

this.right = right;

this.location = location;

}

/**

* 普通赋值表达式

*/

public Assign(String id, Expr right, Location location) {

if (right == null) {

throw new ParseException("The expression on the right side of an assignment expression can not be null", location);

}

this.id = id;

this.index = null;

this.right = right;

this.location = location;

}

/**

* 获取 assign 表达式左侧标识符 id

* 在自定义指令中得到 id 值，可以得知该赋值表达式是针对哪个变量在操作，有助于扩展

* 需求来源：http://www.jfinal.com/share/379

*/

public String getId() {

return id;

}

public Expr getIndex() {

return index;

}

public Expr getRight() {

return right;

}

/**

* 赋值语句有返回值，可以用于表达式计算

*/

public Object eval(Scope scope) {

if (index == null) {

return assignVariable(scope);

} else {

return assignElement(scope);

}

}

Object assignVariable(Scope scope) {

Object rightValue = right.eval(scope);

if (scope.getCtrl().isWisdomAssignment()) {

scope.set(id, rightValue);

} else if (scope.getCtrl().isLocalAssignment()) {

scope.setLocal(id, rightValue);

} else {

scope.setGlobal(id, rightValue);

}

return rightValue;

}

/**

* 数组或 Map 赋值

*/

@SuppressWarnings({"unchecked", "rawtypes"})

Object assignElement(Scope scope) {

Object target = scope.get(id);

if (target == null) {

throw new TemplateException("The assigned targets \"" + id + "\" can not be null", location);

}

Object idx = index.eval(scope);

if (idx == null) {

throw new TemplateException("The index of list/array and the key of map can not be null", location);

}

Object value;

if (target instanceof Map) {

value = right.eval(scope);

((Map)target).put(idx, value);

return value;

}

if ( !(idx instanceof Integer) ) {

throw new TemplateException("The index of list/array can only be integer", location);

}

if (target instanceof List) {

value = right.eval(scope);

((List)target).set((Integer)idx, value);

return value;

}

if (target.getClass().isArray()) {

value = right.eval(scope);

java.lang.reflect.Array.set(target, (Integer)idx, value);

return value;

}

throw new TemplateException("Only the list array and map is supported by index assignment", location);

}

}

-----------------------------------------------------------------

第二步

public class ArticleListDirective extends Directive {

Expr[] exprArray=null;

@Override

public void setExprList(ExprList exprList) {

// TODO Auto-generated method stub

super.setExprList(exprList);

this.exprArray = exprList.getExprArray();

}

@Override

public void exec(Env env, Scope scope, Writer writer) {

Kv kv=Kv.create();//存放各个参数

for (int i=0;i<exprArray.length;i++)

{  //循环参数列表，并把参数放到 Kv 里面

Assign obj= (Assign)exprArray[i];

//System.out.println(obj.id+"   "+obj.right.eval(scope));

kv.set(obj.getId().toLowerCase(), obj.eval(scope));

}

//  获取到的参数名和参数值 ，都在KV里面，该干啥干啥吧，这里省略了

Page<Article> page = Article.dao.paginateByCache(xxxxxxxxxx);//根据上面得到的参数，自行组合SQL查询 

List list=page.getList();

for (int i=0;i<list.size();i++)

{

   scope.set("article",list.get(i));

       stat.exec(env, scope, writer);//执行自定义标签中包围的 html

}

}

@Override

public boolean hasEnd() {

return true;

}

}

----------------------------------------------------------------

第三步

 @Override

    public void configEngine(Engine me) {

            me.setBaseTemplatePath(PathKit.getWebRootPath());

            me.addDirective("articlelist", new ArticleListDirective());

}

-----------------------------------------------------------------------

结束