http断点续传简单实现（java)

/* 9Y- Sqk+  
**SiteFileFetch.java AiykIER/  
*/ ny|ni\6  
package NetFox; 5*{U!${a  
import java.io.*; Xlpu_H|  
import java.net.*; [2gK^o&t  
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public class SiteFileFetch extends Thread { :seo0w]  
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SiteInfoBean siteInfoBean = null; //文件信息Bean {j+w|;dZF  
long[] nStartPos; //开始位置 p\wE})mu  
long[] nEndPos; //结束位置 # nwEF QA  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 n|Iy  
long nFileLength; //文件长度 lV:R8^d  
boolean bFirst = true; //是否第一次取文件 %'nM!7w@I  
boolean bStop = false; //停止标志 ^<'5 V)  
File tmpFile; //文件下载的临时信息 Y'&A~/Adf  
DataOutputStream output; //输出到文件的输出流 + O=wKsGD  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） #Sr_PEo _  
public SiteFileFetch(SiteInfoBean bean) throws IOException -LJbx<'  
{ I#zrz3WU  
siteInfoBean = bean; T
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); IExo#\0'6  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); SEq_37  
if(tmpFile.exists ()) :D8V*F6P  
{ ='q:Io?T  
bFirst = false; 3xWeN#T0  
read_nPos(); G4vXPx%a8  
} >t&Frw/Bl  
else `$\g8Mo  
{ \Y_2Z/  
nStartPos = new long[bean.getNSplitter()]; FN NEh  
nEndPos = new long[bean.getNSplitter()]; 1@6dHFA`o  
}  /L'r L  
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} cu5Yvp  

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public void run() (ec?_N0=  
{ abh='5H|^|  
//获得文件长度 7"Sw))H|  
//分割文件 <UOx>=h  
//实例FileSplitterFetch uIvy1h9m  
//启动FileSplitterFetch线程 0tv"tA;  
//等待子线程返回 z 0]K:YV_  
try{ 6e3s |  
if(bFirst) >KmOTM<{  
{ Lg0Vn&k  
nFileLength = getFileSize(); tT'*Uu5  
if(nFileLength == -1) T$5u+4>"  
{ ?2zVWZ  
System.err.println("File Length is not known!"); \ce (/I   
} `[p*qsp_  
else if(nFileLength == -2) _]a8lr+_-  
{ ;,![Lar5L  
System.err.println("File is not access!"); T&c0j(  
} /L\
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else (xf_  
{ 5@ecZ2`)+h  
for(int i=0;i<nStartPos.length;i++) "K n JUXpl  
{ u@tJu'X  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 6:O3>'
n  
} ! /;@kXN
 
for(int i=0;i<nEndPos.length-1;i++) Fk@A;22N  
{ i_Dv+^&zV  
nEndPos = nStartPos[i+1]; /. GHR  
} FtXd6)_S  
nEndPos[nEndPos.length-1] = nFileLength; }CnqJ@>C5  
} 23 j{bK  
} SQhk)S  
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//启动子线程
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 86NAa6BW  
for(int i=0;i<nStartPos.length;i++) W iqlc  
{ 7\m.xWX e  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), sVtxh
]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <`,pyvR Kv  
nStartPos,nEndPos,i); 4A^=4"BCV  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !Z[dK{f"  
fileSplitterFetch.start(); V9[-# Ti  
} k>y68_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~SgW+sDFu  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); tgXIj5z  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", {j i;~9'Q  
nEndPos = " + nFileLength); i1k(3:ay<  
// fileSplitterFetch[nPos.length-1].start(); yQ5&S]Xk$$  
c`}-i6  
2c`m8EaJ  
//等待子线程结束 ?tS=rqc8oW  
//int count = 0; :9un6A9JS  
//是否结束while循环 Y[Jt+p]  
boolean breakWhile = false; |g<
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}#}IR5`=E  
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while(!bStop) Tap=K|b ]  
{ AoB~ZWq  
write_nPos(); VP[
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Utility.sleep(500); XDs )  
breakWhile = true; ;AMbo`YK[  
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for(int i=0;i<nStartPos.length;i++) MDn+K#
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{ 4Kjrk7GAx  
if(!fileSplitterFetch.bDownOver) vFz%#zk>  
{ e=K2]Y Q{  
breakWhile = false; V\Oe]w  
break; ^%l~

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} +]Ca_`  
} Y2709LWmP  
if(breakWhile) par|j]  
break; KNT(lA0s  
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//count++; v Yt-Nx  
//if(count>4) 7L~LpB  
// siteStop(); > w:+nG/r  
} fDyFkhc  
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System.err.println("文件下载结束！"); @V{s'V   
} Tdtn-  
catch(Exception e){e.printStackTrace ();} Y@x }b{3  
} HDqPqrWm  
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#?%akQ
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//获得文件长度 KWtLrZ(j  
public long getFileSize() rmpx8CY"  
{ k8fvg4  
int nFileLength = -1; o=i)s2  
try{ %gj's-!!  
URL url = new URL(siteInfoBean.getSSiteURL()); (2J_Y*N~>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n';"c;Ye)  
httpConnection.setRequestProperty("User-Agent","NetFox"); +~, q
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int responseCode=httpConnection.getResponseCode(); {!5"Y(>X  
if(responseCode>=400) XVwaX2=L  
{ ga0>J_  
processErrorCode(responseCode); 7^$PauAv  
return -2; //-2 represent access is error XrR@cDNx{  
}  E~oQ%X~  
#N%ATV  
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String sHeader; tY$ .(2Ua  
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for(int i=1;;i++) xK4b(KJj  
{ Co6ghH7T  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); weQC9e~d{-  
//Utility.log(in.readLine()); I)$`@.  
sHeader=httpConnection.getHeaderFieldKey(i); e='bc7$  
if(sHeader!=null) lK;/97Ze  
{ V[D[MZ  
if(sHeader.equals("Content-Length")) BM bT:)%  
{ x`N_tWZ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); jR~2mf!h*e  
break; S"?py=7  
} p x;X}Cd  
} A:Y]<jt  
else
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break; \m @8$MK  
} b|U
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} z9mmZqhK\  
catch(IOException e){e.printStackTrace ();} \(UEjlo  
catch(Exception e){e.printStackTrace ();} fdr.'aMf%  
#PYTFB%  
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Utility.log(nFileLength); 'Y23U7 n0B  
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return nFileLength; 9/Q_Jv-Q  
} Bkg/A;H  
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//保存下载信息（文件指针位置） $Yfm>4  
private void write_nPos() `q Sfo`  
{ }\5^$[p  
try{ vn;_|NeSf  
output = new DataOutputStream(new FileOutputStream(tmpFile)); G=4Da~<ij  
output.writeInt(nStartPos.length); @}@`lv65}  
for(int i=0;i<nStartPos.length;i++) p"^^9'`=  
{ R03V+t=  
// output.writeLong(nPos); Bv
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output.writeLong(fileSplitterFetch.nStartPos); 5=CLR  
output.writeLong(fileSplitterFetch.nEndPos); nA8]/r1k  
} YpQ/ )fSEV  
output.close(); d
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} dt
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catch(IOException e){e.printStackTrace ();} X$,#OR  
catch(Exception e){e.printStackTrace ();} 2YvhzL[um  
} 7aTo!T  
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//读取保存的下载信息（文件指针位置） 9:0JWW^so  
private void read_nPos() yO Cv-zm  
{ e9r#r~Qq|  
try{ 2GRh8G&5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); uiq)?XUKv  
int nCount = input.readInt(); i|u3Qt5  
nStartPos = new long[nCount]; .v[8ie  
nEndPos = new long[nCount]; I^
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for(int i=0;i<nStartPos.length;i++) @DK,ka(  
{ )mO|
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nStartPos = input.readLong(); b{H&%Jx)  
nEndPos = input.readLong(); kE QT[Lo  
}
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input.close(); r.M8#YL  
} CFD& -tED&  
catch(IOException e){e.printStackTrace ();} }x% ;y]S  
catch(Exception e){e.printStackTrace ();} L+Q"z*W  
} +=I_3Wtth  
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private void processErrorCode(int nErrorCode) +) 2c\1  
{ * bmdY=#7  
System.err.println("Error Code : " + nErrorCode); Tysh~C|1  
} 4&/u1u0  
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//停止文件下载 $5nOiaQL  
public void siteStop() rly3f  
{ X~abn7_  
bStop = true; |x3&#(Tf  
for(int i=0;i<nStartPos.length;i++) a
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fileSplitterFetch.splitterStop(); ?b, eZ+t  
6 )eO%M`  
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} K'N`rx.7  
} |;{^Mci%  
//负责部分文件的抓取 c>d+q9M  
**FileSplitterFetch.java `.nkC_d  
*/ jeMh  
package NetFox; #:L|-_=a  
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import java.io.*; sAS\-c'6  
import java.net.*; SiHZco I  
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public class FileSplitterFetch extends Thread { P7d" E  
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String sURL; //File URL 1R9hA7y&,/  
long nStartPos; //File Snippet Start Position LoUi Yf  
long nEndPos; //File Snippet End Position C)`ZI8  
int nThreadID; //Thread's ID |mV*HdqU  
boolean bDownOver = false; //Downing is over s&Y~48{  
boolean bStop = false; //Stop identical ;hNnF&l  
FileAccessI fileAccessI = null; //File Access interface k7)H%31;  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException c ;`  
{ l/;O
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this.sURL = sURL; oH!sJ&"#_  
this.nStartPos = nStart; 4W}8?&T  
this.nEndPos = nEnd; tUv@4<~,/  
nThreadID = id; Y[Us"K`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "v4;m\g&:  
} 3nf+imAF  
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public void run() 1eI>Yy>}  
{ *\m 53mb  
while(nStartPos < nEndPos && !bStop) h;f5@#F  
{ 
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try{ y!GjC]/  
URL url = new URL(sURL); \\ M2_mT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q?n} ~(%&  
httpConnection.setRequestProperty("User-Agent","NetFox"); -cNh5~p=  
String sProperty = "bytes="+nStartPos+"-"; S(mJ;C  
httpConnection.setRequestProperty("RANGE",sProperty);
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Utility.log(sProperty); 5+:b#B  
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1 9a"@WB@  
InputStream input = httpConnection.getInputStream(); j(6: 
 
//logResponseHead(httpConnection); P (jlWr$$  
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byte[] b = new byte[1024]; BIDmZU9tL  
int nRead; ^"K
 
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) yAR''>  
{ 0}hN/2}&  
nStartPos += fileAccessI.write(b,0,nRead); jfZ(5Qu3.H  
//if(nThreadID == 1) ?/)Mt(p  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :h0as!2@dp  
} D|9C|
q  
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Utility.log("Thread " + nThreadID + " is over!"); JT&CJ&#[h  
bDownOver = true; rX%#Q\
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//nPos = fileAccessI.write (b,0,nRead); -% PUY(  
} =A9>Ej/  
catch(Exception e){e.printStackTrace ();} *aS|4M-  
} 6 +^V  
} *RUB`tEL  
?2OT:/I,  
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//打印回应的头信息  a)PBC{I  
public void logResponseHead(HttpURLConnection con) )-|A|1Uo  
{ n'73DApW  
for(int i=1;;i++) ;SeDxyKG  
{ @)m[:n  
String header=con.getHeaderFieldKey(i); UP 1Y3  
if(header!=null) W"AWhi{h  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 2:MB u5**  
Utility.log(header+" : "+con.getHeaderField(header)); 3X*;.'#Z  
else f( hK>H  
break; fo&q/;l\  
} X_+`7yCi"x  
} .\X/o!xC  
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public void splitterStop() 9c9-1iS  
{ vLDMa>  
bStop = true; 2V/A%  
} ;gy_Qf2U  
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} a+)Yk8%KY  
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/* ?`AzgM[I  
**FileAccess.java tz j]c  
*//文件访问(定位，写) }fZT$'*;  
package NetFox; @jN!j*Y H  
import java.io.*; yopEqO  
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7 ;|jq39  
public class FileAccessI implements Serializable{ N'Ywn}!js  
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Ut  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 MG[?C2KA/  
RandomAccessFile oSavedFile; z 4Qz9#*"^  
long nPos; 99G/(Z}  
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public FileAccessI() throws IOException 8<0H(lj7_  
{ E,shTh%&~  
this("",0); \yNjsG@,  
} y7wy9+>l  
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public FileAccessI(String sName,long nPos) throws IOException :IV4]`  
{ {a `kPfP  
oSavedFile = new RandomAccessFile(sName,"rw"); :m_0WT  
this.nPos = nPos; 6S])IA&VJ  
oSavedFile.seek(nPos); Xp1xhb*^  
} Zg5@l3w  
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public synchronized int write(byte[] b,int nStart,int nLen) [esjR`u  
{ ETV|;>
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int n = -1; )K -@{v^|  
try{ {F6h
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oSavedFile.write(b,nStart,nLen); TGdD7n&Ehh  
n = nLen; (NOAHV0
H  
} (-(,~E  
catch(IOException e) 6|X  
{ DGO_fR5L  
e.printStackTrace (); p+snBaAo}  
} ^>h
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return n; 0fxA*]h  
}  ?Vbe  
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} RQy|W}d_  
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/* 3*CF!Y%  
**SiteInfoBean.java =\J^_g4-l  
*/ =:P9 $  
package NetFox; @Rig@  
93kSBF#  
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public class SiteInfoBean { #AyM!  
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private String sSiteURL; //Site's URL !vr">@}K  
private String sFilePath; //Saved File's Path hx+a.N
 
private String sFileName; //Saved File's Name kMo;<Z  
private int nSplitter; //Count of Splited Downloading File U;i:k%Bzy  
pTOS}A[dh  
?q7VB  
public SiteInfoBean() @Q!f^  
{//nSplitter的缺省值为5 {O5;V/00}  
//default value of nSplitter is 5 f6PXcV   
this("","","",5); 64#~p)  
} McNj TD  
vs{i2!^  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^.mQ~F  
{ <6mXlK3N0  
sSiteURL= sURL;  %3KWc-  
sFilePath = sPath; 1'"o; a]k/  
sFileName = sName; 
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this.nSplitter = nSpiltter; sw'20I  
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} ~kS~v  
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public String getSSiteURL() "@ Zy+zLU  
{ }pu2/44=W  
return sSiteURL; 4Yt:PN2  
} F04`MY"  
&~6Z)}  
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public void setSSiteURL(String value) }bIEWho  
{ @0A0\2  
sSiteURL = value; O1JGv8Nr  
} FGr0W|?v  
fH`P8?](x  
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public String getSFilePath() O#H`/z  
{ YCeE?S1gk3  
return sFilePath; ZJP.-`U  
}
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.7g^w+W  
public void setSFilePath(String value) j Z3N+_J1  
{ v8y77:  
sFilePath = value; +'=^/!  
} ?fnJ`^|-r  

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public String getSFileName() ~fAdOh  
{ ^^}  
return sFileName; 67}y/C]
<  
} 7eQ7\,^H  
F{[2|u(4  
[bJ"*^M)  
public void setSFileName(String value) 4eU};Pv  
{ '@AK0No\W  
sFileName = value; >Hic tH  
} _&XT =SW}  
{tu* =
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public int getNSplitter() Mn7 y@/1  
{ wI #_r_  
return nSplitter; }qc[ysDK]  
} H 
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public void setNSplitter(int nCount) `2J6Dz"W  
{ `;hsOfo  
nSplitter = nCount;  3i?{E^  
} &hB~Z(zS!  
} Z!G;q}zZ!  
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;  
/* w{F8]N>0<  
**Utility.java cGsP0LkHC  
*/ {h&*H[Z z  
package NetFox; yIXM}i:  
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public class Utility { feIAgd},  
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=(Mv@eA"  
public Utility() f|Z3VS0x  
{ iWCN2om  
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\ CV(c]  
} fT[6Cw5w`  
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//线程睡眠 qnrf%rS  
public static void sleep(int nSecond) &I:X[=;g  
{ Gd%6lab  
try{ 6\\B{%3R2  
Thread.sleep(nSecond); > :!faWX  
} lr+Kwve  
catch(Exception e) +@Fy) {C7  
{ qq[2h~6
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e.printStackTrace (); }!Qo wG  
} .3{S
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} d+fmVM?p  
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//日志 -66|Y  
public static void log(String sMsg) #T#&qo#  
{ z.e%AcX  
System.err.println(sMsg); 1 YMaUyL 1  
} SN?jxQ  
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public static void log(int sMsg) wy&VClT  
{ o7/_a/  
System.err.println(sMsg); 7g  
} m?;)C~[  
} o%M~Q<wf  
baR{  
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/* H",yVD  
**TestMethod.java 73Mh65  
*/ r$k *:A$%  
package NetFox; Ad@))o2  
F8_pwJUpf-  
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public class TestMethod { "!E(=W?  
fR6ot#b  
:Q+rEjw+  
public TestMethod() 9
VV  
{ ///xx/weblogic60b2_win.exe H$(%FWzQ%  
try{ r.-NfK4  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .X_k[l9  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); pSE"]N  
SiteFileFetch fileFetch = new SiteFileFetch(bean); S.t+HwVodO  
fileFetch.start(); Vfg144FG'  
} @,M!&l  
catch(Exception e){e.printStackTrace ();} _m3PAD4  
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\ts:'  
} b'Mg  
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#OJ^[Zi<  
public static void main(String[] args) vq(@B  
{ "4`h -Y  
new TestMethod(); c#u-E6  
} %pL ,A5M  
} J^n(WnM*F  
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