ClassFileLoader1.java

package com.github.ipk2015.coding2017.minijvm.loader;



import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;



public class ClassFileLoader1 {

	private List<String> clzPaths = new ArrayList<String>();
	
	public byte[] readBinaryCode(String className) throws IOException {
		className=getCompleteClassName(className);
		File file=null;
		for(String path:clzPaths){
			file=new File(path+"\\"+className);
			if(file.exists()){
				break;
			}
		}
		if(null==file){
			throw new FileNotFoundException(className);
		}
		ByteArrayOutputStream bos=new ByteArrayOutputStream((int)file.length());
		BufferedInputStream in=new BufferedInputStream(new FileInputStream(file));
		int size=1024;
		byte[] buffer=new byte[size];
		int length=0;
		while((length=in.read(buffer, 0, size))!=-1){
			bos.write(buffer,0,length);
		}
		return bos.toByteArray();	
	}
	
	
	public void addClassPath(String path) {
		clzPaths.add(path);
	}
	
	
	
	public String getClassPath(){
		StringBuffer buffer=new StringBuffer();
		for(String path:clzPaths){
			buffer.append(path+";");
		}
		buffer.deleteCharAt(buffer.length()-1);
		return buffer.toString();
	}

	private String getCompleteClassName(String name){
		if(!name.endsWith(".class")){
			name=name+".class";
		}
		int pointPos=name.lastIndexOf(".", name.length()-7);
		if(pointPos>-1){
			name=name.substring(pointPos+1);
		}
		return name;
	}
	// ------------------------------backup------------------------
    public String getClassPath_V1(){
		
		StringBuffer buffer = new StringBuffer();
		for(int i=0;i<this.clzPaths.size();i++){
			buffer.append(this.clzPaths.get(i));
			if(i<this.clzPaths.size()-1){
				buffer.append(";");
			}
		}
		return buffer.toString();
	}
	
	private byte[] loadClassFile_V1(String clzFileName) {
		
		BufferedInputStream bis = null;
		
		try {
			
			File f = new File(clzFileName);
			
						
			bis = new BufferedInputStream(new FileInputStream(f));
			
			ByteArrayOutputStream bos = new ByteArrayOutputStream();
			
			
			byte[] buffer = new byte[1024];
			int length = -1;
			
			while((length = bis.read(buffer)) != -1){
				bos.write(buffer, 0, length);				
			}
			
			byte [] codes = bos.toByteArray();
			
			return codes;
			
		} catch(IOException e){
			e.printStackTrace();
			
		} finally{
			if(bis != null){
				try {
					bis.close();
				} catch (IOException e) {					
					e.printStackTrace();
				}
			}
		}
		return null;
		
	}

	

}