查看文件源代码功能实现

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;
        }

}

本文转自 randy_shandong 51CTO博客，原文链接：http://blog.51cto.com/dba10g/855193，如需转载请自行联系原作者

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