http断点续传简单实现（java)

/* ai<qK3!O  
**SiteFileFetch.java pT,8E(*l2  
*/ 9nAP%MA`  
package NetFox; 2^'Ec:|f  
import java.io.*; ys`-QlkB  
import java.net.*; fG0
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public class SiteFileFetch extends Thread { m"!SyN}&9?  
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SiteInfoBean siteInfoBean = null; //文件信息Bean y.Z_\@  
long[] nStartPos; //开始位置 l= {Y[T&  
long[] nEndPos; //结束位置 j@4MV^F2c  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _[[0rn$  
long nFileLength; //文件长度 %IO*(5f  
boolean bFirst = true; //是否第一次取文件 4Fp[94b  
boolean bStop = false; //停止标志 DdR0u0JH0  
File tmpFile; //文件下载的临时信息 e|k]te
  
DataOutputStream output; //输出到文件的输出流 QT c{7&  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） h7Uj "qH  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?s2-iuMPd  
{ ZUS-4'"$  
siteInfoBean = bean; O
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /si<Fp)z  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 
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if(tmpFile.exists ()) .=eEuH  
{ 1]/;qNEv  
bFirst = false; iZNS? ^U  
read_nPos(); Mxl;Im]!`.  
} =q VT  
else D&FDPaJM  
{ tdK&vqq  
nStartPos = new long[bean.getNSplitter()]; |Ahf 01  
nEndPos = new long[bean.getNSplitter()]; `}ak]Z_  
} ;a?<7LIx  
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e 6mZ;y5_  
} r|l?2 eO~  
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public void run() i bzY&f  
{ /phMrL=  
//获得文件长度 QD7KE6KP'  
//分割文件 =DdPwr 0Op  
//实例FileSplitterFetch Rrh6-]A  
//启动FileSplitterFetch线程 4bk`i*-O  
//等待子线程返回 "s|P,*Xf  
try{ K+)3 LR^  
if(bFirst) 6,5h4[eF*  
{ NFTv4$5d  
nFileLength = getFileSize(); a{xJ#_/6  
if(nFileLength == -1) qy'-'UlIr  
{ {dxFd-K3  
System.err.println("File Length is not known!"); tMw65Xei6b  
} U5C]zswL  
else if(nFileLength == -2) ,\i*vJ#f  
{ X$UK;O  
System.err.println("File is not access!"); ?3~t%Q`  
} vb[0H{TT2  
else g(pr.Dw6  
{ (#y2RF8j  
for(int i=0;i<nStartPos.length;i++) g7! LX[  
{ Md4Q.8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ?EC\.{  
} ;~0q23{+;U  
for(int i=0;i<nEndPos.length-1;i++) (9`dLw5  
{ *IOrv)
 
nEndPos = nStartPos[i+1]; |?V7E\S  
} :;_}Gxx  
nEndPos[nEndPos.length-1] = nFileLength; B& @ pZYl  
} 81EEYf  
} AZ(zM.y!#_  
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{#kCqjWG  
//启动子线程 I3 "6"  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; GeJ}myD O  
for(int i=0;i<nStartPos.length;i++) s'yR2JYv  
{ 2Vti|@JYp  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /k/X[/WO  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), m}z6Bbis0  
nStartPos,nEndPos,i); -
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); q;[HUyY,  
fileSplitterFetch.start(); $9?:P}$v  
} x_~_/&X5  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), WOn<JCh]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); curYD~7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", oaQW~R`_  
nEndPos = " + nFileLength); (eF[nfM  
// fileSplitterFetch[nPos.length-1].start(); Q
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-Kg.w*\H7/  
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//等待子线程结束 f_)#  
//int count = 0; s=:)!M.i  
//是否结束while循环 6hj[/O)E  
boolean breakWhile = false; Y-bTKSn  
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while(!bStop) pnuo;rs  
{ (W#CDw<ja  
write_nPos(); 4 xqzdR_  
Utility.sleep(500); :4AIYk=q  
breakWhile = true; w)|9iL8  
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for(int i=0;i<nStartPos.length;i++) '4M{Xn}@  
{ m!KEK\5M?  
if(!fileSplitterFetch.bDownOver) NxF:s,a6  
{ g$NUu  
breakWhile = false; x:0swZ5Z  
break; AM=> P7  
} k6"(\d9o  
} F5X9)9S  
if(breakWhile) C7F\Y1Wj  
break; 4AzDWK@/  
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Lxv;[2XsW)  
//count++; JkN*hm?  
//if(count>4) r-YJ$/J  
// siteStop(); 7vXP|8j  
} ll0y@@Iy  
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System.err.println("文件下载结束！"); K!ILO  
} `D|])^"{  
catch(Exception e){e.printStackTrace ();} `Kg!aN  
} v {r%/*  
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//获得文件长度 TgjjwcO Y  
public long getFileSize() Q3%]  
{ k={1zl ;  
int nFileLength = -1; sCw>J#@2>  
try{ mS[``$Z\!  
URL url = new URL(siteInfoBean.getSSiteURL()); #lMcAYH,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;`^_9 K  
httpConnection.setRequestProperty("User-Agent","NetFox"); x2t&Wpvt  
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int responseCode=httpConnection.getResponseCode();  I!?Xq  
if(responseCode>=400) wbJBGT{sm  
{ HI{q#  
processErrorCode(responseCode); F?tWx+N<{  
return -2; //-2 represent access is error q6rkp f,Tl  
} ,+IFV  
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String sHeader; |hj!NhBe  
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for(int i=1;;i++) 59{X;  
{ 'm`
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ZHjL8Iq  
//Utility.log(in.readLine()); ,9d]-CuP;  
sHeader=httpConnection.getHeaderFieldKey(i); ECA<%
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if(sHeader!=null) cH*")oD  
{ @.$- ^-  
if(sHeader.equals("Content-Length")) V*PL_|Q5  
{ OU.}H $x"  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )V~=B]  
break; s}". po]  
} fZ &  
} L3HC-  
else y+k^CT/u  
break; Ph]b6  
} O$r/{{I.  
} Pb;c:HeI/  
catch(IOException e){e.printStackTrace ();} 7'esJ)2  
catch(Exception e){e.printStackTrace ();} xi{r-D8Z  
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Utility.log(nFileLength); RHBQgD$  
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return nFileLength; i,^3aZwJ'  
} 6\I^]\YO  
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//保存下载信息（文件指针位置） @Q,Q"c2  
private void write_nPos() \~A qA!)6  
{ ^CLQs;zXE  
try{ s!?uLSEdb  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *GoTN  
output.writeInt(nStartPos.length); ssLswb  
for(int i=0;i<nStartPos.length;i++) g/f6N
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{ XxMZU(5
  
// output.writeLong(nPos); 
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output.writeLong(fileSplitterFetch.nStartPos); gIz!~I_U  
output.writeLong(fileSplitterFetch.nEndPos); V'{\g|)  
} UA*VqK)Y  
output.close(); ws9IO ?|&G  
} o/7u7BQl2  
catch(IOException e){e.printStackTrace ();} +'c+X^_  
catch(Exception e){e.printStackTrace ();} 8cOft ;|qB  
} 'm~=sC_uL  
}NyQ<,+mq&  
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//读取保存的下载信息（文件指针位置） WN=0s  
private void read_nPos() 0D2I)E72o  
{ p&RC#wYu  
try{ 04dz?`HuB  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); -!_8>r;Q4  
int nCount = input.readInt(); Kw`CN  
nStartPos = new long[nCount]; }~+,x#  
nEndPos = new long[nCount]; #at`7#K@  
for(int i=0;i<nStartPos.length;i++) T 'c39  
{ 4zS0kk;+  
nStartPos = input.readLong(); =[]6NjKS,  
nEndPos = input.readLong(); ciODTq?  
} cg3}33Z;6  
input.close(); O%kUj&h^  
} 1}a4AGAp  
catch(IOException e){e.printStackTrace ();} R]X 0D.  
catch(Exception e){e.printStackTrace ();} AcuF0KWw/  
}
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private void processErrorCode(int nErrorCode) <7Pp98si,u  
{ \fTQNF  
System.err.println("Error Code : " + nErrorCode); !\4B.  
} #}y8hzS$  
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9r]|P}yuS  
//停止文件下载 w1"+HJd  
public void siteStop() a)ry}E =f  
{ 4{F1GW  
bStop = true; Kb(11$U  
for(int i=0;i<nStartPos.length;i++) edo)W mn  
fileSplitterFetch.splitterStop(); x']'ODs  
)  FR7t  
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} =^u;uS[IW  
} {V6pC  
//负责部分文件的抓取 G~<UP(G  
**FileSplitterFetch.java GAgTy  
*/ * $f`ouJl  
package NetFox; ;B=aK"\  
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import java.io.*; fYUV[Gm  
import java.net.*; l{Df{1b.  
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public class FileSplitterFetch extends Thread { O<cP1TF  
;`#R9
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String sURL; //File URL ElQ?|HsQ6p  
long nStartPos; //File Snippet Start Position 7v%c.  
long nEndPos; //File Snippet End Position \_1a#|97e  
int nThreadID; //Thread's ID WSHPhhM  
boolean bDownOver = false; //Downing is over k B>F(^  
boolean bStop = false; //Stop identical AChz}N$C  
FileAccessI fileAccessI = null; //File Access interface |2q3spd  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException \nZB@u;S  
{ 12n:)yQy  
this.sURL = sURL; &Pr\n&9A  
this.nStartPos = nStart; Zigv;}#  
this.nEndPos = nEnd; :82h GU  
nThreadID = id; xrkl)7;  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 B}d&tH2^s  
} *vaYI3{qN  
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public void run() bGWfMu=n  
{ hN'])[+V  
while(nStartPos < nEndPos && !bStop) _f[Q\gK  
{ XH!#_jy  
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try{ cFL~< [>_  
URL url = new URL(sURL); ZkbE&7Z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !y_{mE?V(  
httpConnection.setRequestProperty("User-Agent","NetFox"); |Ghk8 WA  
String sProperty = "bytes="+nStartPos+"-"; Q6Gw!!Z5EA  
httpConnection.setRequestProperty("RANGE",sProperty); zi-_l  
Utility.log(sProperty); ;>?h/tS6  
Ki;SONSV~|  
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InputStream input = httpConnection.getInputStream(); 92DM1~ *  
//logResponseHead(httpConnection); 6CBk=)qH  
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byte[] b = new byte[1024]; OjUPvR2 0  
int nRead; {zFME41>g  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) p u(mHB  
{ F^O83[S  
nStartPos += fileAccessI.write(b,0,nRead); T0w_d_aS  
//if(nThreadID == 1) KG'i#(u[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]Btkoad  
} *HKw;I   
3 ~v 1
7  
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Utility.log("Thread " + nThreadID + " is over!"); 7QsD"rL  
bDownOver = true; @gI1:-chB  
//nPos = fileAccessI.write (b,0,nRead); *|A
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} ;/K2h_=3z  
catch(Exception e){e.printStackTrace ();} zU?O)w1'  
} /}?7Eni  
} !__0Vk[s  
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//打印回应的头信息 #V!a<w4_  
public void logResponseHead(HttpURLConnection con) KrE'M  
{ ntW@Fm:bw>  
for(int i=1;;i++) 9|+6@6VY!  
{ mOE *[S)  
String header=con.getHeaderFieldKey(i); 3"y 6|e/5  
if(header!=null) .9jKD*U|  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); z]G|)16  
Utility.log(header+" : "+con.getHeaderField(header)); \/NF??k,jk  
else ukWn@q*  
break; @?3
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}  js_`L#t  
} ^dQ{vL@9b9  
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public void splitterStop() 0xB2  
{ Qz~uD'Rs/  
bStop = true; isZ5s\  
} "D(Lp*3hj&  
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} bNea5u##  
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/* I~GF%$-G  
**FileAccess.java iM+`7L'  
*//文件访问(定位，写) =kd$??F  
package NetFox; 9njl,Q:  
import java.io.*; "z~ba>,-\  
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public class FileAccessI implements Serializable{ f`9Mcli!  
V ;T :Q%  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 A6&*VD  
RandomAccessFile oSavedFile; d#ir=+o{h  
long nPos; !J`lA  
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public FileAccessI() throws IOException &k}f"TX2  
{ *%j$i_  
this("",0); .G0 N+)  
} l:85 _E  
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public FileAccessI(String sName,long nPos) throws IOException ht3.e[%'b  
{ :D.0\.p  
oSavedFile = new RandomAccessFile(sName,"rw"); GtA`0B  
this.nPos = nPos; 4QL>LK  
oSavedFile.seek(nPos); }r,\0Wm  
} fr@F7s5}  
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public synchronized int write(byte[] b,int nStart,int nLen) gAqK)@8-  
{ {MUB4-@?F$  
int n = -1; W'lqNOX[v  
try{ D Ez,u^  
oSavedFile.write(b,nStart,nLen); w:~*wv  
n = nLen; sibYJKOy  
} WyL+HB}  
catch(IOException e) dAo;y.3  
{ #/)t]&n  
e.printStackTrace (); dUI5,3*  
} ~wc:/UM|  
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return n; VtreOJ+  
} A'WR!*Yt  
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} ?$r`T]>`2  
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eI #Gx_mg  
/* yV30x9i!2  
**SiteInfoBean.java gv#\}/->4  
*/ !3ggQG!e  
package NetFox; $o^Z$VmL  
*{o7G a  
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public class SiteInfoBean { `?Rq44=  
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private String sSiteURL; //Site's URL H=t"qEp  
private String sFilePath; //Saved File's Path ZzT
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private String sFileName; //Saved File's Name s='+[*&&  
private int nSplitter; //Count of Splited Downloading File DL]tg[w{  
pl[J!d.c  
" \$^j#o  
public SiteInfoBean() @[$_cGR7  
{//nSplitter的缺省值为5 y4V:)@P  
//default value of nSplitter is 5 s0kp(t!fiu  
this("","","",5); gT+/nSrLV  
} enoj4g7em^  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &hCbXs=  
{ '6
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sSiteURL= sURL; 'j
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sFilePath = sPath; EeIDlm0o  
sFileName = sName; }\pI`;*O|  
this.nSplitter = nSpiltter; PT"}2sR)  
}Q7y tE  
4#U}bN  
} *[Hrbln  
#;!&8iH  
'sNZFB#  
public String getSSiteURL() W&z jb>0b0  
{ *O?c~UJhhV  
return sSiteURL; _n&Nw7d2 M  
} ngY%T5-  
n,la<N]  
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public void setSSiteURL(String value) 7  ,Rg~L  
{ :Pud%}'  
sSiteURL = value; c:R?da  
} g7oY
1;  
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|HazM9=  
public String getSFilePath() xO$P C,  
{ @hLkU4S  
return sFilePath; q76POytV|  
} \& JZ >h  
jDzQw>TX  
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public void setSFilePath(String value) ]@q%d
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{ en<mm#Ab  
sFilePath = value; Lu.zc='\  
} UHBXq;?&q  
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public String getSFileName() 9&Y@g)+2  
{ @Z)|_  
return sFileName; \l+v,ELX=  
} $ /VQsb  
 %Bq~b$  
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public void setSFileName(String value) :1v,QEb\  
{ Iq$| ?MH  
sFileName = value; )U^=`* 7  
} m 2H4V+M+  
$JE,u'JQ  
k.T=&0J_1  
public int getNSplitter() LZ*8YNp1'  
{ -@TY8#O#-  
return nSplitter; 9tiZIm93]  
} D0. )%  
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public void setNSplitter(int nCount) ?H{[u rLn  
{ {>&~kM@  
nSplitter = nCount; 'r;mm^cS?  
} O"m7r ds  
} wjarQog5Y  
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/* WhPP4 #  
**Utility.java tRjv-  
*/ ]5Cr$%H=  
package NetFox; ,5DJ54B!  
b|#=kPVgL}  
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public class Utility { OV>&`puL  
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public Utility() HR>Y?B{  
{ p8Vqy-:  
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} oOFTQB_6  
~uQ*u.wi  
//线程睡眠 )'shpRB;1  
public static void sleep(int nSecond) Spm 0`  
{ 6F\ 6,E  
try{ *D5 xbkH=.  
Thread.sleep(nSecond); blc?[ [,!  
} [-~pDkf:  
catch(Exception e) .qBc;u  
{ tr<~:&H4T  
e.printStackTrace (); wmVmGa R  
} Pk?$\  
} U S^% $Z:  
*yq65yZi5  
//日志 {q>%Sr]9  
public static void log(String sMsg) {QG.> lB  
{ a`O'ZY  
System.err.println(sMsg); .jrNi=BP*  
} .#EU@Hc
  
\S}/2]* 1  
4,RPidv%O  
public static void log(int sMsg) E^8|xT'h6  
{ xd Z$|{,  
System.err.println(sMsg); Z)!8a$M~  
} i'Y8-})  
} =NB[jQ :(  
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/VR~E'Cy%  
/* g_>&
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**TestMethod.java #UGSn:D<i  
*/ 1NYR8W]2  
package NetFox; NAYLlW}A  
*V>?m6y/  
7FX4|]  
public class TestMethod { Pz)lq2Zm9  
h nydH-;cz  
i_qY=*a?y  
public TestMethod() Mj0,Y#=76  
{ ///xx/weblogic60b2_win.exe CmEqo;Is  
try{ WjD885Xo  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); J)nK9  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); z} fpV T  
SiteFileFetch fileFetch = new SiteFileFetch(bean); AD?zBg Zu  
fileFetch.start(); O'4G'H)   
} |)x7qy`  
catch(Exception e){e.printStackTrace ();} Ek+R  
s$Vl">9#  
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} zs$r>rlO  
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9A|A@E#  
public static void main(String[] args) }[
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{ ^ h=QpH  
new TestMethod(); DrRK Sc(u9  
} +n^M+ea;  
} JCWTB`EB>  
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