原创作品，允许转载，转载时请务必以超链接形式标明文章 原始出处 、作者信息和本声明。否则将追究法律责任。http://dba10g.blog.51cto.com/764602/855193
我们经常遇到，查看文件源代码的功能。Struts 自带的例子是这样的。
其中思路是这样的：将文件流转换为List 输出出来。
用到了
第一种：读取Class
InputStream in = getClass().getResourceAsStream(className);
第二种：一般文件
InputStream in = ClassLoaderUtil.getResourceAsStream(page.substring(indexOf+1), getClass());
//or
in = servletContext.getResourceAsStream(page);
第三种：配置文件
new URL(config).openStream()
/*
* $Id: ViewSourceAction.java 570518 2007-08-28 18:26:48Z jholmes $
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.struts2.showcase.source;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import org.apache.struts2.ServletActionContext;
import org.apache.struts2.util.ServletContextAware;
import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.util.ClassLoaderUtil;
/**
* Processes configuration, page, and action class paths to create snippets
* of the files for display.
*/
public class ViewSourceAction extends ActionSupport implements ServletContextAware {
private String page;
private String className;
private String config;
/**
* 数据行列表
*/
private List pageLines;
private List classLines;
private List configLines;
private int configLine;
private int padding = 10;
private ServletContext servletContext;
public String execute() throws MalformedURLException, IOException {
if (page != null && page.trim().length() > 0) {
int indexOf = page.indexOf("//");
InputStream in = ClassLoaderUtil.getResourceAsStream(page.substring(indexOf+1), getClass());
page = page.replace("//", "/");
if (in == null) {
in = servletContext.getResourceAsStream(page);
while (in == null && page.indexOf('/', 1) > 0) {
page = page.substring(page.indexOf('/', 1));
in = servletContext.getResourceAsStream(page);
}
}
pageLines = read(in, -1);
if (in != null) {
in.close();
}
}
if (className != null && className.trim().length() > 0) {
className = "/"+className.replace('.', '/') + ".java";
InputStream in = getClass().getResourceAsStream(className);
if (in == null) {
in = servletContext.getResourceAsStream("/WEB-INF/src"+className);
}
classLines = read(in, -1);
if (in != null) {
in.close();
}
}
String rootPath = ServletActionContext.getServletContext().getRealPath("/");
if (config != null && config.trim().length() > 0 && (rootPath == null || config.startsWith(rootPath))) {
int pos = config.lastIndexOf(':');
configLine = Integer.parseInt(config.substring(pos+1));
config = config.substring(0, pos).replace("//", "/");
configLines = read(new URL(config).openStream(), configLine);
}
return SUCCESS;
}
/**
* @param className the className to set
*/
public void setClassName(String className) {
this.className = className;
}
/**
* @param config the config to set
*/
public void setConfig(String config) {
this.config = config;
}
/**
* @param page the page to set
*/
public void setPage(String page) {
this.page = page;
}
/**
* @param padding the padding to set
*/
public void setPadding(int padding) {
this.padding = padding;
}
/**
* @return the classLines
*/
public List getClassLines() {
return classLines;
}
/**
* @return the configLines
*/
public List getConfigLines() {
return configLines;
}
/**
* @return the pageLines
*/
public List getPageLines() {
return pageLines;
}
/**
* @return the className
*/
public String getClassName() {
return className;
}
/**
* @return the config
*/
public String getConfig() {
return config;
}
/**
* @return the page
*/
public String getPage() {
return page;
}
/**
* @return the configLine
*/
public int getConfigLine() {
return configLine;
}
/**
* @return the padding
*/
public int getPadding() {
return padding;
}
/**
* Reads in a strea, optionally only including the target line number
* and its padding
*
* @param in The input stream
* @param targetLineNumber The target line number, negative to read all
* @return A list of lines
*/
private List read(InputStream in, int targetLineNumber) {
List snippet = null;
if (in != null) {
snippet = new ArrayList();
int startLine = 0;
int endLine = Integer.MAX_VALUE;
if (targetLineNumber > 0) {
startLine = targetLineNumber - padding;
endLine = targetLineNumber + padding;
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(in));
int lineno = 0;
String line;
while ((line = reader.readLine()) != null) {
lineno++;
if (lineno >= startLine && lineno <= endLine) {
snippet.add(line);
}
}
} catch (Exception ex) {
// ignoring as snippet not available isn't a big deal
}
}
return snippet;
}
public void setServletContext(ServletContext arg0) {
this.servletContext = arg0;
}
}
本文出自 “简单” 博客，请务必保留此出处http://dba10g.blog.51cto.com/764602/855193