Java线程、Process、ProcessBuilder

2010 年 6 月 20 日

文章内容描述了使用Java执行外部Oracle导出命令备份数据库功能的示例，依据此例子进行修改制造一些bug，然后将会对Java外部命令这块会有一个更加清晰的认知(个人观点仅供参考，不许拍砖，哈)

小细节 ·试着把innerTh.start()这段给注释掉，然后再把用户名或密码写错。·有些程序是不会在命令行有输出的，比如最直接的plsqldev.exe、MindManager.exe·试着把将要执行的命令改成我们本地相关.exe程序，如上面所例或干脆TM.exe试试。

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代码示例:

package org.ybygjy.basic.oracle;import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.nio.ByteBuffer; import java.nio.channels.Channels; import java.nio.channels.FileChannel; import java.nio.channels.ReadableByteChannel; import java.util.ArrayList; import java.util.List; import java.util.Map;/*** java外部系统命令模式备份数据库* @author WangYanCheng* @version 2010-6-19*/ public class BackupOracleDatabase {/*** 封装执行入口*/public void doWork() {InnerClass innerInst =new InnerClass("DB_USER", "DB_PASS", "127.0.0.1:1521/ORCL", "E:/dbback/BACK201006.DMP");Thread thInst = new Thread(innerInst);thInst.start();}/*** 用于分担执行命令* @author WangYanCheng* @version 2010-6-19*/class InnerClass implements Runnable {/** 用户名 */private String userName;/** 密码 */private String userPass;/** 服务地址 */private String serverAddr;/** 输出文件路径 */private String outFilePath;/*** constructor* @param userName userName* @param userPass userPass* @param serverAddr 服务地址必须带<strong>端口</strong>/<strong>SID</strong>* @param outFilePath outPath*/public InnerClass(String userName, String userPass, String serverAddr, String outFilePath) {this.userName = userName;this.userPass = userPass;this.serverAddr = serverAddr;this.outFilePath = outFilePath;}/*** 提供执行的命令串* @return commStr 命令串*/private List doBuildCommand() {List rtnList = new ArrayList();rtnList.add("EXP");rtnList.add("@USER@/@PASSWORD@@@SERVER@".replaceAll("@USER@", this.userName).replaceAll("@PASSWORD@", this.userPass).replaceAll("@SERVER@", this.serverAddr));rtnList.add("FILE=/"@FILE@/"".replaceAll("@FILE@", this.outFilePath));rtnList.add("TABLES=(SY_TABLE_DEF)");return rtnList;}/*** 构建ProcessBuilder实例* @param workDir 当前进程工作目录* @return pbInst ProcessBuilder实例* @see ProcessBuilder*/private ProcessBuilder buildProcessBuilder(File workDir) {new ProcessBuilder();List commandArray = (doBuildCommand());ProcessBuilder pbInst = new ProcessBuilder(commandArray);pbInst.command(commandArray);Map envMap = pbInst.environment();envMap.clear();envMap.putAll(System.getenv());pbInst.directory(workDir);pbInst.redirectErrorStream(true);return pbInst;}/*** 线程执行入口*/public void run() {File tmpOutFile = new File(this.outFilePath);File outDir = tmpOutFile.getParentFile();ProcessBuilder pbInst = buildProcessBuilder(outDir);try {Process proInst = pbInst.start();final InputStream ins = proInst.getInputStream();File outFile = new File(outDir, "exp.log");outFile.createNewFile();final FileChannel focInst = new FileOutputStream(outFile).getChannel();Thread innerTh = new Thread() {ByteBuffer byteBuffer = ByteBuffer.allocate(1024);public void run() {ReadableByteChannel rbcObj = Channels.newChannel(ins);try {while (rbcObj.read(byteBuffer) != -1) {byteBuffer.flip();focInst.write(byteBuffer);byteBuffer.clear();}} catch (IOException ioe) {ioe.printStackTrace();}}};// innerTh.setDaemon(true);innerTh.start();} catch (IOException ioe) {ioe.printStackTrace();}}}/*** 测试入口* @param args 参数列表*/public static void main(String[] args) {new BackupOracleDatabase().doWork();} }

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