http断点续传简单实现（java)

/* ^HTvw~]5  
**SiteFileFetch.java w_~tY*IwB  
*/ oz|+{b}%  
package NetFox; ]y$/~(OW  
import java.io.*; 1sJz`+\  
import java.net.*; B !
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public class SiteFileFetch extends Thread { tF<&R&=  
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SiteInfoBean siteInfoBean = null; //文件信息Bean P~x4h{~Gd  
long[] nStartPos; //开始位置 )`gxaT>&l  
long[] nEndPos; //结束位置 g@?R"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Gtv
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long nFileLength; //文件长度 YETGq-  
boolean bFirst = true; //是否第一次取文件 ).Iifu|
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boolean bStop = false; //停止标志 m|]"e@SF2  
File tmpFile; //文件下载的临时信息 F`Z?$ 1  
DataOutputStream output; //输出到文件的输出流 S~|\bnE  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） jsKKg^g  
public SiteFileFetch(SiteInfoBean bean) throws IOException $0~1;@`rQ6  
{ AnZy oa  
siteInfoBean = bean; }<'ki ;  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /:,}hy+U  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); s~5rP
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if(tmpFile.exists ()) tpgD{BY^wJ  
{ fX1Ib$v  
bFirst = false; e%9zY{ABR%  
read_nPos(); AmCymT3P*e  
} K&-uW_0  
else [8acan+ 2l  
{ Fd%JF#
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nStartPos = new long[bean.getNSplitter()]; rTST_$"_6  
nEndPos = new long[bean.getNSplitter()]; E429<LQI/  
} YWk+}y}^d  
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} ZF<$6"4N  
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public void run() diK
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{ * COC&  
//获得文件长度 (7??5gjh  
//分割文件 |#(y?! A^  
//实例FileSplitterFetch , $cpm=1  
//启动FileSplitterFetch线程 :{KpnJvd  
//等待子线程返回 {~'Iu8TvZ  
try{ ,"?8  
if(bFirst) &hM7y
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{ )]zsAw`/  
nFileLength = getFileSize(); owA.P-4  
if(nFileLength == -1) PM)nw;nS  
{ yy`XtJBWWs  
System.err.println("File Length is not known!"); j:HIcCp  
} ;[:IC^9fv  
else if(nFileLength == -2) *(Z\"o!  
{ aR)w~s\6  
System.err.println("File is not access!"); PJ<9T3Fa  
} Y/L*0M.<  
else c?Mbyay  
{ g6OPYUPg  
for(int i=0;i<nStartPos.length;i++) NjO_Y t  
{ ?YF2Uc8z%2  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ]L k- -\  
} 59X XmVg  
for(int i=0;i<nEndPos.length-1;i++) }LoMS<O-[  
{ }V 4u`=  
nEndPos = nStartPos[i+1]; _9<Mo;C  
} Q5Epq sKyC  
nEndPos[nEndPos.length-1] = nFileLength; ;Qq7@(2y  
} [|\#cVWs  
} 6$H`wDh#(&  
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//启动子线程 V \/Qik{h  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; $dsLU5]1o  
for(int i=0;i<nStartPos.length;i++) bR?xz-g%<3  
{ ONFx -U]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), I]WvcDJ}C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9!ARr@ ;  
nStartPos,nEndPos,i); :G&:v  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6d3YLb4M$i  
fileSplitterFetch.start(); ; FHnu|  
} h\+8eeIl  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `$vf9'\+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ~6+>2|wIS  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", e2L>"/  
nEndPos = " + nFileLength); 35:R
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// fileSplitterFetch[nPos.length-1].start(); .eyJ<b9  
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//等待子线程结束 VHvL:z  
//int count = 0; -vc ,O77z"  
//是否结束while循环 "6v_<t`q"  
boolean breakWhile = false; S>jOVWB  
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while(!bStop) Vt:\llsin  
{ G"".;}AV  
write_nPos(); i`?yi-R&  
Utility.sleep(500); 
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breakWhile = true; 9Q\RCl_1  
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for(int i=0;i<nStartPos.length;i++) z0F55<i  
{ N2
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if(!fileSplitterFetch.bDownOver) C'S_M@I=  
{ P,rLyx  
breakWhile = false; 9D;
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break; bfkFk  
} yV31OBC:  
} !(3[z>  
if(breakWhile) fuWAw^&  
break; Pon0(:#1  
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//count++; ?v'CuWS  
//if(count>4) 'Zqt~5=5  
// siteStop(); u#Bj#y!  
} i+lq:St  
}iLi5Qkx  
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System.err.println("文件下载结束！"); "#iO{uMWb  
} MYR\W*B'b  
catch(Exception e){e.printStackTrace ();} SzFh  
} jaMpi^C  
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//获得文件长度 Z&h:3;  
public long getFileSize() ^;?
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{ c;=St1eoz  
int nFileLength = -1; wzZ]| C(vp  
try{ Zjs
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URL url = new URL(siteInfoBean.getSSiteURL()); y{XNB}E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?q0a^c?A^  
httpConnection.setRequestProperty("User-Agent","NetFox"); %O{FZgi%wA  
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int responseCode=httpConnection.getResponseCode(); 0XE(vc!  
if(responseCode>=400) .dvs&+I  
{ ol`q7i.  
processErrorCode(responseCode); ,V&E"D{u  
return -2; //-2 represent access is error rERtOgi  
} 715J1~aRNr  
+.$:ZzH#  
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String sHeader; F(,SnSam  
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for(int i=1;;i++) -7EwZRS@9  
{ j",*&sy  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -'i[/{  
//Utility.log(in.readLine()); lHu/pSu@k  
sHeader=httpConnection.getHeaderFieldKey(i); $A(3-n5=  
if(sHeader!=null) Exat_ L'
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{ C?\HB#41  
if(sHeader.equals("Content-Length")) J.0&gP V  
{ ~{6}SXp4U  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); TdoH((nY  
break; i-x/h-  
} _ CzAv%  
} 0bGQO&s [  
else 2J`LZS  
break; eJEcLK3u  
} rhN"
#?  
} E/E|*6R  
catch(IOException e){e.printStackTrace ();} %<h2^H\O  
catch(Exception e){e.printStackTrace ();} ldG$hk'  
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Utility.log(nFileLength); c>C!vAg  
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return nFileLength; CY)[{r  
} Ba n^wX  
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//保存下载信息（文件指针位置） TG.\C8;vFh  
private void write_nPos() B{1yMJA  
{ _^^5  
try{ a & 6-QVk  
output = new DataOutputStream(new FileOutputStream(tmpFile)); H]Gj$P=k  
output.writeInt(nStartPos.length); 5)M#hx%]#  
for(int i=0;i<nStartPos.length;i++) "l6Ob
 
{ 3d_g@x#
9  
// output.writeLong(nPos); x2g=%K=  
output.writeLong(fileSplitterFetch.nStartPos); W1Om$S1  
output.writeLong(fileSplitterFetch.nEndPos); CWnRRZ}r  
} ;{g>Z|  
output.close(); A2B]E,JMp  
} V}4u1oG  
catch(IOException e){e.printStackTrace ();} o(xt%'L`t  
catch(Exception e){e.printStackTrace ();} =5h,ZB2A  
} hQDl&A  
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//读取保存的下载信息（文件指针位置） vLM-v  
private void read_nPos() 4[K6ZDBU  
{ $2k9gO  
try{ ?yvjX90  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6x! q  
int nCount = input.readInt(); "ODs.m oq  
nStartPos = new long[nCount]; luO4ap]*  
nEndPos = new long[nCount]; $ ?YSAD1  
for(int i=0;i<nStartPos.length;i++) 0 oHnam  
{ "H)D~K~*  
nStartPos = input.readLong(); {+|Em(M  
nEndPos = input.readLong(); ww~gmz  
} c(!{_+q"  
input.close(); <(2,@_~@
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} -r6LndQs  
catch(IOException e){e.printStackTrace ();} }m-+EUEo9  
catch(Exception e){e.printStackTrace ();} n6 AP6PK7  
} Z_?r5M;  

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private void processErrorCode(int nErrorCode) OYNPZRu
 
{ 8E\6RjM  
System.err.println("Error Code : " + nErrorCode); uVV;"LVK~  
} 'B$qq[l]S  
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//停止文件下载 {!7 ^w  
public void siteStop()  k/}E(_e  
{ [|\BuUT'  
bStop = true; ih/MW_t=m=  
for(int i=0;i<nStartPos.length;i++) NhA_dskvo  
fileSplitterFetch.splitterStop(); :g=z}7!s  
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} &B5
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} o w<.Dh  
//负责部分文件的抓取 RA~%Cw4t  
**FileSplitterFetch.java H{3A6fb<  
*/ Gdf*x<T1  
package NetFox; Y!|*`FII  
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import java.io.*; lnoK.Vk9,  
import java.net.*; RwC1C(ZP  
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public class FileSplitterFetch extends Thread { jP9)utEm6  
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String sURL; //File URL FF"`F8-w>Z  
long nStartPos; //File Snippet Start Position )q48cQ  
long nEndPos; //File Snippet End Position 0oFRcU  
int nThreadID; //Thread's ID <|'C|J_!  
boolean bDownOver = false; //Downing is over wv8WqYV  
boolean bStop = false; //Stop identical 7VdG6`TDR  
FileAccessI fileAccessI = null; //File Access interface qh)o44/ $  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException gL+8fX2G6  
{ "&ElKy 7j  
this.sURL = sURL; =sk]/64h``  
this.nStartPos = nStart; NyTv~8A`)  
this.nEndPos = nEnd; K 5SHt'P  
nThreadID = id; >d&_e[j  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Ih]'OaE   
} _T 5ZL  
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public void run() P7;=rSW  
{ %z&=A%'a  
while(nStartPos < nEndPos && !bStop) c:
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{ fCL5Et  
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try{ &n.7~C]R  
URL url = new URL(sURL); LB|FVNW/S  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); gQJy"f  
httpConnection.setRequestProperty("User-Agent","NetFox"); }kaU0 P  
String sProperty = "bytes="+nStartPos+"-"; ON{
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httpConnection.setRequestProperty("RANGE",sProperty); mJaWzR  
Utility.log(sProperty); M~Yho".  
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InputStream input = httpConnection.getInputStream(); &}P{w  
//logResponseHead(httpConnection); E"e<9  
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byte[] b = new byte[1024]; ZW$P
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int nRead; 0Bx.
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) V&x6ru#  
{ Tti]H9g_  
nStartPos += fileAccessI.write(b,0,nRead); 8-Ik .,}  
//if(nThreadID == 1) Y]ML-smN  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4@D 8{?$~Q  
} V45\.V  
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Utility.log("Thread " + nThreadID + " is over!"); I4kN4*d!N,  
bDownOver = true; Z!Njfq5  
//nPos = fileAccessI.write (b,0,nRead); &h.
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} SqL8MKN)  
catch(Exception e){e.printStackTrace ();} }R#YO$J7  
} %/17K2g  
} :jB8Q$s  
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//打印回应的头信息 !BD+H/A.{  
public void logResponseHead(HttpURLConnection con) }~Z1C0t  
{ Np>[mNmga  
for(int i=1;;i++) dALJlRo"  
{ <^?64  
String header=con.getHeaderFieldKey(i); 8<}f:9/  
if(header!=null) PYDf|S7  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ay'2!K,I  
Utility.log(header+" : "+con.getHeaderField(header)); *k:Sg*neVq  
else G*_$[|H  
break; y#HDJ=2  
} ,6U
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} d&n&_
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public void splitterStop() e*w2u<HP  
{ 5/<?Y&x  
bStop = true; VmM?KlC  
} F;l*@y Tq  
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} i9?$BZQ[R  
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/* )0Av:
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**FileAccess.java ,TY&N-  
*//文件访问(定位，写) J{"<Hgb  
package NetFox; ||TKo967]  
import java.io.*; d6ZJhxJ  
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public class FileAccessI implements Serializable{ 8w &A89  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 _<x4/".}B3  
RandomAccessFile oSavedFile; |U}al[  
long nPos; XKqUbi  
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public FileAccessI() throws IOException #?h#R5:0  
{ {bB;TO<b`  
this("",0); 4#H~g @  
} TqURYnNd  
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public FileAccessI(String sName,long nPos) throws IOException I6}ineps  
{ GY9CU=-  
oSavedFile = new RandomAccessFile(sName,"rw"); FbRq h|  
this.nPos = nPos; xf/ SUO F  
oSavedFile.seek(nPos); +/,
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} kqJ\kd  
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public synchronized int write(byte[] b,int nStart,int nLen) (9bFIvMc  
{ Y>}[c   
int n = -1; /$v0Rq9  
try{ $ K>.|\
 
oSavedFile.write(b,nStart,nLen); %j4  
n = nLen; VFLxxFJ  
} 83io@*D  
catch(IOException e) go^?F- dZ  
{ Na8%TT>  
e.printStackTrace (); DpG|Kl|d  
} \%fl`+`  
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return n; |7G+O+j  
} WJ)( *1  
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} 59eq"08  
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/* ~/0t<^  
**SiteInfoBean.java \-A=??@H  
*/ ~V,~'W  
package NetFox; Er; @nOyD  
aYIAy]*1e  
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public class SiteInfoBean { e))fbv&V  
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private String sSiteURL; //Site's URL m:EO}ws=  
private String sFilePath; //Saved File's Path Ej
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private String sFileName; //Saved File's Name <w@ziUr  
private int nSplitter; //Count of Splited Downloading File F/BB]gUB  
}Yd7<"kp  
/b3b0VfF  
public SiteInfoBean() y#%*aV}|B  
{//nSplitter的缺省值为5 6.X| .N  
//default value of nSplitter is 5 :by EXe;3  
this("","","",5); G&P[n8Z$  
} <PCa37  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 5[^pU$Y  
{ N7/eF9  
sSiteURL= sURL; FdT@}  
sFilePath = sPath; \UKr|[P
  
sFileName = sName; "u#T0  
this.nSplitter = nSpiltter; @9yY`\"ed  
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} -)S(eqq1  
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public String getSSiteURL() kB41{Y -  
{ >Q159
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return sSiteURL; XJ\j0  
} .W>LsEk  
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public void setSSiteURL(String value) La$*)qD,
  
{ 4g^nhJP$  
sSiteURL = value; 58T<~u
7  
} |$Y0V
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public String getSFilePath() 6gUcoDD  
{ 5iz(R:P<  
return sFilePath; 7od6`k  
} RgF5w<Vd.  
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public void setSFilePath(String value) =D1%-ym  
{ Hchh2  
sFilePath = value; KW17CJ@  
} U_1syaY!  
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public String getSFileName() *U[Nn5#?  
{ Q/JX8<7K  
return sFileName; -UJ; =/  
} pA ,xDs@37  
VR/*
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public void setSFileName(String value) xy/B<.M1  
{ p>GTFXEi6  
sFileName = value; zjuU*$A4  
} Tc{n]TV  
"JHdF&  
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public int getNSplitter() +\@) 1  
{ m[k@\xS4e  
return nSplitter; =wd=TX/  
} $)V_oQSqn  
,qo"i7c{:  
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public void setNSplitter(int nCount) w=ZSyT-i  
{ Q db~I#}m'  
nSplitter = nCount; G
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} n"p|tEK  
} o.)8A8  
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/* {6V;$KqH6  
**Utility.java IWRo$Yu  
*/ )QeXA)  
package NetFox; ~Ogtgr  
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public class Utility { nDt1oM H  
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public Utility() 6/A#P$G  
{ =\t%U5  
m1](f[$  
st|;]q9?  
} L<GF1I)  
~E]ct F  
//线程睡眠 N+l 0XjZD9  
public static void sleep(int nSecond) # p?7{"Ep  
{ qUZm6)p6[a  
try{ v,=[!=8!  
Thread.sleep(nSecond); _ct18nh9  
} oNkASAd  
catch(Exception e) V>8)1)dF  
{ "kYzgi  
e.printStackTrace (); 1;e"3x"  
} ZQ&A'(tt4  
} %syFHUBw  
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//日志 `PV+.V}  
public static void log(String sMsg) C4Tn  
{ p "J^  
System.err.println(sMsg); T7wy{;  
} GT -(r+u  
F(yx/W>Br_  
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public static void log(int sMsg) xK8n~.T('  
{ n$jOk |W  
System.err.println(sMsg); MS_@ Xe  
} E[z8;A^:0  
} B4/0t:
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/* SO~]aFoYt  
**TestMethod.java t *8k3"  
*/ x_C#ALq9  
package NetFox; -zzM!1@F  
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cz2guUu  
public class TestMethod { ,b&-o?.{  
 1#G(  
w2 L'j9  
public TestMethod() ftL>oOz[  
{ ///xx/weblogic60b2_win.exe W7j-siWJ  
try{ /SXms'C  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); JTK0#+?  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); H1FD|Q3  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 4yk!T  
fileFetch.start(); (Wj2%*NT  
} i8]2y  
catch(Exception e){e.printStackTrace ();} ))pp{X2m  
(>E}{{>2r  
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} qtx5N)J6  
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public static void main(String[] args) yf2I%\p}  
{ w""5T|  
new TestMethod(); BFCF+hU^6R  
} :4{;^|RgU  
} "8bxb  
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