jsp简单自定义标签的forEach遍历及转义字符示例

public class ForEachTag2 extends SimpleTagSupport {
private String var;
private Object items;
private Collection collection;
public void setVar(String var){
this.var=var;
}
public void setItems(Object items){
this.items=items;
if(items instanceof Map){
Map map = (Map) items;
collection = map.entrySet();
}
if(items instanceof Collection){//set list
collection =(Collection) items;
}
if(items.getClass().isArray()){
collection = new ArrayList();
int len = Array.getLength(items);
for(int i=0;iObject obj= Array.get(items, i);
collection.add(obj);
}
}
}
@Override
public void doTag() throws JspException, IOException {
Iterator iterator = collection.iterator();
while(iterator.hasNext()){
Object obj = iterator.next();
this.getJspContext().setAttribute(var, obj);
this.getJspBody().invoke(null);
}
}
}

forEach2
com.csdn.items.ForEachTag2
scriptless

var
true


items
true
true

<%
Map map = new HashMap();
map.put("aa","aaaa");
map.put("bb","bbbb");
map.put("cc","cccc");
map.put("dd","dddd");
map.put("ee","eeee");
request.setAttribute("map",map);
%>

${str.key }-----${str.value }


<%
String[] strs ={"aa","bb","cc"} ;
request.setAttribute("strs",strs);
%>

${str}

public void doTag() throws JspException, IOException {
JspFragment jf = this.getJspBody();//获取jsp文件中的内容
StringWriter sw = new StringWriter();//获取一个流对象
jf.invoke(sw);//吧内容放到流对象中
String s =sw.toString();//把jsp内容转成字符串
s= filter(s);//获取进行转义之后的字符
this.getJspContext().getOut().write(s);//写入浏览器
}
public String filter(String message) {//对字符串进行转义的方法
if (message == null)
return (null);
char content[] = new char[message.length()];
message.getChars(0, message.length(), content, 0);
StringBuffer result = new StringBuffer(content.length + 50);
for (int i = 0; i switch (content[i]) {
case '<':
result.append("<");
break;
case '>':
result.append(">");
break;
case '&':
result.append("&");
break;
case '"':
result.append(""");
break;
default:
result.append(content[i]);
}
}
return (result.toString());
}
}

htmlFilter
com.csdn.items.HTMLFilter
scriptless


aaa