简介： 今天为网友提供的是JAVA源码

				package com.power.lpsolver.LPSolve;				import java.util.*;				import java.io.*;				import java.net.*;								import com.power.pipe.*;								import com.power.util.Message.*;				import com.power.util.urltools.*;								public class LPURLWriter				{				   private static final LPURLWriter INSTANCE =				                              new LPURLWriter();								    private BufferedWriter _myFileWriter; //initialized in subclass								   // Private constructor supresses				   // default public constructor				    private LPURLWriter( ) {				    }								    public static LPURLWriter getInstance( ) {				        return INSTANCE;				    }								    private StringBuffer content = new StringBuffer();				    private String urlAddr = GlobalConfig.getInstance().getLPServerURL() +				                             "com.power.pipeengine.LP_ReadWriteFile";													public void write( String outDir ) {								        printObj();								        Vector allCons = Model.getInstance().getModelConstraints().getConstraints();				        MessageArea.getInstance().addMessage( "Total number of constraints: " + allCons.size() + "\n");										for( int i=0; i							Constraint con = (Constraint) allCons.elementAt( i );							printCon( con );								            if( (i%100) == 0 ) {				                MessageArea.getInstance().addMessage( "Number of consrtaints generated: " + i+ "\n");				            }						}												        URLFileWriter.getInstance().write( urlAddr,				                                           "c:\\paraster\\lpsolver\\model.lp",				                                           "WriteModel",				                                           content.toString() );									}													public void printObj() {						content.append( "Min" + ": ");						Enumeration allElems = Model.getInstance().getObjectiveFunction().getElements().elements();						ModelVariables mdlVars = Model.getInstance().getModelVariables();										while( allElems.hasMoreElements() ) {							Element elem = (Element) allElems.nextElement();							Variable var = mdlVars.getVariable( elem.getColumnNumber() );							if( elem.getCoefficient() > 0 ) {								content.append(" + ");							} else {								content.append(" - ");							}							content.append(Math.abs( elem.getCoefficient() ));							content.append(var.getMPSName());						}										content.append(";\n");					}								    /**				     * Prints the constraint in a readable format (LP format).				     */					public void printCon( Constraint con ) {						Enumeration allElems = con.getElements().elements();						ModelVariables mdlVars = Model.getInstance().getModelVariables();														while( allElems.hasMoreElements() ) {							Element elem = (Element) allElems.nextElement();							Variable var = mdlVars.getVariable( elem.getColumnNumber() );							if( elem.getCoefficient() > 0 ) {								content.append(" + ");							} else {								content.append(" - ");							}							content.append(Math.abs( elem.getCoefficient() ));							content.append(var.getMPSName());						}										content.append(" " + con.getSign() + " " + con.getRHS() + ";\n");					}								}