一直以来，有个目标是：使用Beetl的时候，如果web root 里有模板文件，则beetl从web root里加载。如果没有，则从jar里加载，或者从Db里加载。
这样，工程里大量相同的模板模板可以共用(当你的应用，有N个客户的时候，特别需要这个，更新一个jar，重启一下即可)。
最后确认CompositeResourceLoader 无法满足自己的需求。于是磕磕碰碰的自己实现了一个ResourceLoader，自定义加载模板。
直接贴代码吧
package com.jfinal.ext.beetl;
import java.io.File;
import java.net.URL;
import java.util.Map;
import org.beetl.core.GroupTemplate;
import org.beetl.core.Resource;
import org.beetl.core.ResourceLoader;
import org.beetl.core.misc.BeetlUtil;
/**
* 自定义的ResourceLoader，用于支持从文件，jar和数据库里加载模板。
* @author Neoman
*/
public class AppResourceLoader implements ResourceLoader{
private String root = null;
boolean autoCheck = false;
//模板来自文件
boolean fromFile = true;
//模板来自Db
boolean fromDb = false;
//模板来自jar包
boolean fromJar = false;
protected String charset = "UTF-8";
String functionRoot = "functions";
GroupTemplate gt = null;
String functionSuffix = "fn";
ClassLoader classLoader = null;
/**
* 使用加载beetl.jar的classloader，以及默认root为根目录
*/
public AppResourceLoader()
{
//保留，用于通过配置构造一个ResouceLoader
classLoader = this.getClass().getClassLoader();
this.root = "";
}
/** 使用指定的classloader
* @param classLoader
*/
public AppResourceLoader(ClassLoader classLoader)
{
this.classLoader = classLoader;
this.root = "";
}
/**使用指定的classloader和root
* @param classLoader
* @param root 模板路径，如/com/templates/
*/
public AppResourceLoader(ClassLoader classLoader, String root)
{
this.classLoader = classLoader;
this.root = root;
}
/**
* @param classLoader
* @param root
* @param charset
*/
public AppResourceLoader(ClassLoader classLoader, String root, String charset)
{
this(classLoader, root);
this.charset = charset;
}
/**
* @param root ，/com/templates/如其后的resourceId对应的路径是root+"/"+resourceId
*/
public AppResourceLoader(String root)
{
this();
if (root.equals("/"))
{
this.root = "";
}
else
{
this.root = root;
}
}
public AppResourceLoader(String root, String charset)
{
this(root);
this.charset = charset;
}
/*
* (non-Javadoc)
*
* @see org.beetl.core.ResourceLoader#getResource(java.lang.String)
*/
@Override
public Resource getResource(String key)
{
AppResource resource = new AppResource(root, key, this);
resource.setFromFile(fromFile);
resource.setFromDb(fromDb);
resource.setFromJar(fromJar);
return resource;
}
/*
* (non-Javadoc)
*
* @see org.beetl.core.ResourceLoader#close()
*/
@Override
public void close()
{
// TODO Auto-generated method stub
}
@Override
public boolean isModified(Resource key)
{
if (this.autoCheck)
{
return key.isModified();
}
else
{
return false;
}
}
public boolean isAutoCheck()
{
return autoCheck;
}
public void setAutoCheck(boolean autoCheck)
{
this.autoCheck = autoCheck;
}
public String getRoot()
{
return root;
}
@Override
public void init(GroupTemplate gt)
{
Map resourceMap = gt.getConf().getResourceMap();
if (resourceMap.get("root") != null)
{
String temp = resourceMap.get("root");
if (temp.equals("/") || temp.length() == 0)
{
}
else
{
if (this.root.endsWith("/"))
{
this.root = this.root + resourceMap.get("root");
}
else
{
this.root = this.root + "/" + resourceMap.get("root");
}
}
}
if (this.charset == null)
{
this.charset = resourceMap.get("charset");
}
this.functionSuffix = resourceMap.get("functionSuffix");
this.autoCheck = Boolean.parseBoolean(resourceMap.get("autoCheck"));
this.functionRoot = resourceMap.get("functionRoot");
//初始化functions
URL url = classLoader.getResource("");
this.gt = gt;
if (url!=null&&url.getProtocol().equals("file"))
{
File fnRoot = new File(url.getFile() + File.separator + root + File.separator + this.functionRoot);
if (fnRoot.exists())
{
String ns = "";
String path = "/".concat(this.functionRoot).concat("/");
BeetlUtil.autoFileFunctionRegister(gt, fnRoot, ns, path, this.functionSuffix);
}
}
}
@Override
public boolean exist(String key)
{
URL url = this.classLoader.getResource(root + key);
if(url==null){
//兼容以前的
url = this.classLoader.getClass().getResource(root + key);
}
return url!=null;
}
public String getCharset()
{
return charset;
}
public void setCharset(String charset)
{
this.charset = charset;
}
@Override
public String getResourceId(Resource resource, String id)
{
if (resource == null)
return id;
else
return BeetlUtil.getRelPath(resource.getId(), id);
}
public ClassLoader getClassLoader() {
return classLoader;
}
public void setClassLoader(ClassLoader classLoader) {
this.classLoader = classLoader;
}
@Override
public String getInfo() {
return "ClassLoader:"+this.classLoader+" Path:"+root;
}
public boolean isFromFile() {
return fromFile;
}
public void setFromFile(boolean fromFile) {
this.fromFile = fromFile;
}
public boolean isFromDb() {
return fromDb;
}
public void setFromDb(boolean fromDb) {
this.fromDb = fromDb;
}
public boolean isFromJar() {
return fromJar;
}
public void setFromJar(boolean fromJar) {
this.fromJar = fromJar;
}
}
AppResourceLoader基本复制之前org.beetl.core.resource.WebAppResourceLoader的。init 注册函数的时候，还是仅仅读取web root里的目录。因为我自己的是代码里注册了，所以，也没去实现从jar加载function
package com.jfinal.ext.beetl;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.UnsupportedEncodingException;
import java.net.URL;
import org.beetl.core.Resource;
import org.beetl.core.ResourceLoader;
import org.beetl.core.exception.BeetlException;
import com.jfinal.kit.PathKit;
/**
* 模板资源读取，支持从db，文件，classpath，jar 里读取模板资源：
* 先从webroot的文件里读取，如果没有，则读取数据库，如何还找不到，读取jar或者classpath里的
* @author Neoman
*
*/
public class AppResource extends Resource{
String root = null;
File file = null;
long lastModified = 0;
//模板来自文件
boolean fromFile = true;
//模板来自Db
boolean fromDb = false;
//模板来自jar包
boolean fromJar = false;
public AppResource(String root, String key, ResourceLoader resourceLoader)
{
super(key, resourceLoader);
this.root = root;
}
@Override
public Reader openReader()
{
InputStream is = null;
Reader br;
AppResourceLoader loader = (AppResourceLoader) this.resourceLoader;
try
{//从文件里读取，一般的web root里
file = new File(PathKit.getWebRootPath() + root, id);
if (file.exists() && fromFile) {
is = new FileInputStream(file);
}
//从数据库里读取,暂未实现
if (is == null && fromDb) {
}
//从jar 或者classpath里读取
if (is == null && fromJar) {
ClassLoader cs = loader.getClassLoader();
URL url = cs.getResource(root + id);
if(url==null){
//兼容以前的写法
url = resourceLoader.getClass().getResource(root + id);
}
if (url == null)
{
BeetlException be = new BeetlException(BeetlException.TEMPLATE_LOAD_ERROR);
be.resourceId = this.id;
throw be;
}
is = url.openStream();
}
if (is == null) {
BeetlException be = new BeetlException(BeetlException.TEMPLATE_LOAD_ERROR, " 模板不存在: " + loader.getInfo());
be.resourceId = this.id;
throw be;
}
br = new BufferedReader(new InputStreamReader(is, loader.charset));
return br;
}
catch (UnsupportedEncodingException e)
{
return null;
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
BeetlException be = new BeetlException(BeetlException.TEMPLATE_LOAD_ERROR, " 模板根目录为 " + loader.getRoot());
be.resourceId = this.id;
throw be;
} catch (IOException e) {
// TODO Auto-generated catch block
BeetlException be = new BeetlException(BeetlException.TEMPLATE_LOAD_ERROR, " 模板根目录为 " + loader.getRoot());
be.resourceId = this.id;
throw be;
}
}
/**
* 目前，只能跟踪文件的变化
*/
@Override
public boolean isModified()
{
if (fromFile && file != null && file.exists())
{
return file.lastModified() != this.lastModified;
}
//String refresh = SysConfig.dao.queryConfig("beetl.template.refresh", "0");
//if (!"0".equals(refresh)) {//不等于0，刷新模板
//SysConfig.dao.updateConfig("beetl.template.refresh", "0");
//return true;
//}
//jar里，肯定要重启了
if (fromJar)
{
return false;
}
//db里 判断时间--暂未 实现
if (fromDb)
{
return false;
}
return false;
}
@Override
public String getId()
{
return id;
}
public boolean isFromFile() {
return fromFile;
}
public void setFromFile(boolean fromFile) {
this.fromFile = fromFile;
}
public boolean isFromDb() {
return fromDb;
}
public void setFromDb(boolean fromDb) {
this.fromDb = fromDb;
}
public boolean isFromJar() {
return fromJar;
}
public void setFromJar(boolean fromJar) {
this.fromJar = fromJar;
}
}
暂时未用到从db加载，所以没去实现了。不过也很简单了。AppResource 主要是 openReader 里面判断资源从哪里加载。
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