http断点续传简单实现（java)

/* XXPn)kmWR  
**SiteFileFetch.java 9kHVWDf  
*/ %PM&`c98z7  
package NetFox; "ngULpb{R  
import java.io.*; JlR$"GU  
import java.net.*; ~@=(#tO.  
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public class SiteFileFetch extends Thread { EMQGP<[  
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SiteInfoBean siteInfoBean = null; //文件信息Bean G%iTL"6  
long[] nStartPos; //开始位置 %e^GfZ  
long[] nEndPos; //结束位置 ,4:=n$e 0  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ' Dp;fEU$  
long nFileLength; //文件长度 o=J-Ju
 
boolean bFirst = true; //是否第一次取文件 % bfe_k(  
boolean bStop = false; //停止标志 d^MRu#]  
File tmpFile; //文件下载的临时信息 'b)qP|  
DataOutputStream output; //输出到文件的输出流 DK)T2{:  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） O,6Wdw3+-3  
public SiteFileFetch(SiteInfoBean bean) throws IOException MH=7(15R  
{ P q0%oz  
siteInfoBean = bean; .
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); (Zg'])  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 50_[n$tqE  
if(tmpFile.exists ()) plL|Ubn  
{ J-#V_TzJ?  
bFirst = false; NNt n  
read_nPos(); i/j53towe  
} CRBj>  
else Z<^;Ybw{`Z  
{ w=pr?jt1:  
nStartPos = new long[bean.getNSplitter()]; 'X<4";$mU  
nEndPos = new long[bean.getNSplitter()]; m8@&-,T   
} !iO2yp  
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} w4(L@1  
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public void run() +F-EgF+J  
{ b7XB l  
//获得文件长度 4 km^S9  
//分割文件 2n)?)w]!M  
//实例FileSplitterFetch p^CTHk_|  
//启动FileSplitterFetch线程 85YUqVi9  
//等待子线程返回 84vd~Cf9  
try{ aaP_^m O  
if(bFirst) NV7k@7_{B  
{ !_vxbfZO  
nFileLength = getFileSize(); SE'!j]6jI  
if(nFileLength == -1) Z
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{ N_IKH)  
System.err.println("File Length is not known!"); Cb1w8l0  
} LH)XD[  
else if(nFileLength == -2) I)tiXcJw  
{ ]?pQu'-(  
System.err.println("File is not access!"); (`S^6-^  
} ia7<AwV  
else m8ts!6C  
{ DmpT<SI+!  
for(int i=0;i<nStartPos.length;i++) H
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{ -8xf}v~u  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Wl |5EY  
} As<B8e]  
for(int i=0;i<nEndPos.length-1;i++) +x(#e'6p  
{ R*:>h8  
nEndPos = nStartPos[i+1]; [% C,&h5  
} s bj/d~$N  
nEndPos[nEndPos.length-1] = nFileLength; H T|DT  
} Keozn*fzI  
} 'C/yQvJ  
GL=}Vu`(*  
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//启动子线程 oQ 2$z8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; )rq |t9kix  
for(int i=0;i<nStartPos.length;i++) >~SS^I0  
{ r/2= nE  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5?lc%,-&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^Jp,&  
nStartPos,nEndPos,i); )V\@N*L`ik  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); TWzLJ63*  
fileSplitterFetch.start(); 1h&`mqY)L.  
} IdQ./@?  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), X/yq<_ g  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); p&h?p\IF  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", z Fo11;*D  
nEndPos = " + nFileLength); Zge(UhZ  
// fileSplitterFetch[nPos.length-1].start(); H+4j.eVzZU  
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?@ F2Kv  
//等待子线程结束 3''Sx8p  
//int count = 0; q0iJy@?A  
//是否结束while循环 maXg(Lu  
boolean breakWhile = false; d'RvpoM  
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while(!bStop) g1s
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{ 8NWo)y49H  
write_nPos(); pFvu,Q"  
Utility.sleep(500); X H-_tvB  
breakWhile = true; HeOdCr-PN  
){*+s RBW  
c2

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for(int i=0;i<nStartPos.length;i++) r3W3;L  
{ 4f([EV[6dK  
if(!fileSplitterFetch.bDownOver) lH}KFFbp  
{ c-sjYJXKM*  
breakWhile = false; {_QdB;VwH  
break; FQ]/c#J  
} zaqX};b  
} xG9Sk  
if(breakWhile) 6qWUo3  
break; ;]u9o}[ 2  
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//count++; DN*5q9.  
//if(count>4) =~B"8@B  
// siteStop(); CMXF[X)%  
} AcC &Q:g  
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System.err.println("文件下载结束！"); 8]ZzO(=@{  
} .T| }rB<c  
catch(Exception e){e.printStackTrace ();} 0zaK&]oY0  
} =dmr
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//获得文件长度 Vw;Z0_C  
public long getFileSize() '<R>cN"  
{ ~HZdIPcC  
int nFileLength = -1; aD^$v  
try{ n
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URL url = new URL(siteInfoBean.getSSiteURL()); i[v4[C=WB!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); OT9]{|7  
httpConnection.setRequestProperty("User-Agent","NetFox"); rtV`Q[E  
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int responseCode=httpConnection.getResponseCode(); p+VU:%.t  
if(responseCode>=400) .Z
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{ i
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processErrorCode(responseCode); ?sf<cFF  
return -2; //-2 represent access is error 1E+12{~m"i  
} g!'R}y  
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String sHeader; ~r1pO#r-  
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for(int i=1;;i++) M/zO|-j&  
{ U2q6^z4l  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Xz$4cI#n:  
//Utility.log(in.readLine()); g.lTNQm$u  
sHeader=httpConnection.getHeaderFieldKey(i); *
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if(sHeader!=null) ;<[X\;|'  
{ =]Wi a
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if(sHeader.equals("Content-Length")) d*gAL<M7E  
{ T
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Hiyg1  
break; XL
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} 3S^0%"fY  
} #z\ub5um  
else ;_o]$hV|  
break; ekM? '9ez  
} qt/K$'  
} "-J5!y*,Y  
catch(IOException e){e.printStackTrace ();} MdHm%Vx  
catch(Exception e){e.printStackTrace ();} E+f)Zg :  
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Utility.log(nFileLength); uDf<D.+5Ze  
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return nFileLength; ,,H"?VO  
} d9N[f>  
!?2)apM  
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//保存下载信息（文件指针位置） GG}%  
private void write_nPos() wPA^nZ^}9c  
{ __=H"UhWv  
try{ 64s;EC  
output = new DataOutputStream(new FileOutputStream(tmpFile)); AK:cDKBO  
output.writeInt(nStartPos.length); o[|[xuTm  
for(int i=0;i<nStartPos.length;i++) Y'v[2s  
{ ]lB zpD  
// output.writeLong(nPos); 5xQ-f  
output.writeLong(fileSplitterFetch.nStartPos); Cf{F"o  
output.writeLong(fileSplitterFetch.nEndPos); $ghZ<Y2}9  
} }3pM,.  
output.close(); dmFn0J-\  
} NYm"I`5w  
catch(IOException e){e.printStackTrace ();} !`DRJ)h  
catch(Exception e){e.printStackTrace ();}  T]#V  
} <`H0i*|Ued  
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//读取保存的下载信息（文件指针位置） Shn,JmR  
private void read_nPos() s|[>@~gXk  
{ / f%mYL  
try{ yI0bSu<j-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 55[ 4)*  
int nCount = input.readInt(); Dg&84,bv^  
nStartPos = new long[nCount]; jLVJ+mu  
nEndPos = new long[nCount]; 1
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for(int i=0;i<nStartPos.length;i++) y<)TYr  
{ f:c'j`  
nStartPos = input.readLong(); 8|u
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nEndPos = input.readLong(); Z;BS@e  
} rIyH/=;  
input.close(); ;b~ S/  
} PwY/VGT  
catch(IOException e){e.printStackTrace ();} tFN >]`Z  
catch(Exception e){e.printStackTrace ();} dzVi ~wt_&  
} U|^xr~q!f-  
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private void processErrorCode(int nErrorCode) P7x;G5'.  
{ 3h:j.8Z  
System.err.println("Error Code : " + nErrorCode); =ily=j"hK  
} .3!Wr*o  
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//停止文件下载 u9lZHh#V-  
public void siteStop() la!]Y-s)'4  
{ 8@3K, [Mo  
bStop = true; sI ,!+  
for(int i=0;i<nStartPos.length;i++) $Y/9SD  
fileSplitterFetch.splitterStop(); 0;Z|:\P\=  
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} .@1+}0  
} -m@o\9Ic  
//负责部分文件的抓取 uuzV,q  
**FileSplitterFetch.java .*O*@)}Ud  
*/ Z6!
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package NetFox; B#sCB&(  
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import java.io.*; N&9o
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import java.net.*; T j$'B[cv  
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public class FileSplitterFetch extends Thread { o%d TcoCN  
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String sURL; //File URL SzULy >e  
long nStartPos; //File Snippet Start Position ou,[0B3n0  
long nEndPos; //File Snippet End Position kZ]H[\Fs  
int nThreadID; //Thread's ID GP:<h@:798  
boolean bDownOver = false; //Downing is over xtV+Le%  
boolean bStop = false; //Stop identical %sa?/pjK  
FileAccessI fileAccessI = null; //File Access interface j"W>fC/u  
+UzQJt/>>  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6FS%9.Ws  
{ kY0HP a  
this.sURL = sURL; XS<>0YM  
this.nStartPos = nStart; $vn6%M[  
this.nEndPos = nEnd; 3JazQU  
nThreadID = id; 2e48L677-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 d;i|s[6ds`  
} A5l Cc b  
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public void run() |/.J{=E0K  
{ 5Qgu:)}  
while(nStartPos < nEndPos && !bStop) AFLtgoXn:  
{ ?K1B^M=8  
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try{ h~dQ5%  
URL url = new URL(sURL); #w$Y
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {Jr1K,  
httpConnection.setRequestProperty("User-Agent","NetFox"); &L|oqXE0L  
String sProperty = "bytes="+nStartPos+"-"; 8|&,JdT  
httpConnection.setRequestProperty("RANGE",sProperty); -4Qub{Uym  
Utility.log(sProperty); #2R
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InputStream input = httpConnection.getInputStream(); 2.qPMqH  
//logResponseHead(httpConnection); H MOIUd  
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byte[] b = new byte[1024]; Q*M#e  
int nRead; _3IT3mb2n  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) +qi& ?}  
{ \Ne`9k  
nStartPos += fileAccessI.write(b,0,nRead); VQ
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//if(nThreadID == 1) ':4cQ4Z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ucCf%T\:  
} _~FfG!H ^X  
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s 6Wp"V(  
Utility.log("Thread " + nThreadID + " is over!"); BR|!ya+_2  
bDownOver = true; S"bN9?;#u  
//nPos = fileAccessI.write (b,0,nRead); nz 10/nw  
} R'c*CLaiE  
catch(Exception e){e.printStackTrace ();} q~{) {t;  
}
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} gC7!cn  
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//打印回应的头信息 5Ds[?  
public void logResponseHead(HttpURLConnection con) [@$ SLl^Y  
{ 
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for(int i=1;;i++) ?G{0{c2  
{ >t+ ENYb  
String header=con.getHeaderFieldKey(i); &61U1"&$R  
if(header!=null) lZzW- %K  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )@]%:m!ER  
Utility.log(header+" : "+con.getHeaderField(header)); 7w )?s@CD  
else KQ~y;{h?b  
break; oZ{,IZ45  
} HG"ZN)~  
} oXo
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public void splitterStop() }G4I9Py  
{ "&L8d(ZuA  
bStop = true; ,%!m%+K9a  
} /*C!]Z>.  
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} Lg4|6.Ez|P  
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/* _z p<en[  
**FileAccess.java =7!s8D,[  
*//文件访问(定位，写) rfV'EjiM}  
package NetFox; (Ypy}  
import java.io.*; n"iS[uj,  
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public class FileAccessI implements Serializable{ 2gWR2 H@  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节  9qX$  
RandomAccessFile oSavedFile; YS3~sA  
long nPos; WZa6*pF  
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}L0 [Jo:  
public FileAccessI() throws IOException (bm^R-SbB  
{ MqJTRBs%  
this("",0); Zo UeLU  
} B*/!s7c.  
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public FileAccessI(String sName,long nPos) throws IOException x,nl PU  
{ LhG\)>Y%  
oSavedFile = new RandomAccessFile(sName,"rw"); {S0-y  
this.nPos = nPos; av'D
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oSavedFile.seek(nPos); CU=sQfE  
} D5gj*/"  
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public synchronized int write(byte[] b,int nStart,int nLen) "#)|WVa=BM  
{ /xX7:U b  
int n = -1; f@}>:x  
try{ f y2vAwl  
oSavedFile.write(b,nStart,nLen); w|dfl *  
n = nLen; ss-W[|cHU  
} (]w6q&,  
catch(IOException e) j$T12  
{ AojL4H|  
e.printStackTrace (); y\v#qFVOZ  
} !B`z|#  
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return n; re*Zs}(N\  
} @
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} ~q`f@I  
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/* ,h=a+ja8  
**SiteInfoBean.java ,^bgk -x-  
*/ B}[CU='P*  
package NetFox; zS:2?VXxq  
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public class SiteInfoBean { 1;[KBYUH  
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private String sSiteURL; //Site's URL { 
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private String sFilePath; //Saved File's Path ;PaU"z+Je~  
private String sFileName; //Saved File's Name NU=2*gM  
private int nSplitter; //Count of Splited Downloading File rp\`uj*D  
1v&!%9  
!4Aj#`)  
public SiteInfoBean() 7R:j^"I@  
{//nSplitter的缺省值为5 HGAi2+&  
//default value of nSplitter is 5 s(py7{ ^K  
this("","","",5); 'goKYl#1Q  
} *=i&n>  
<ll?rPio"  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) JDf>Qg{  
{ ]Y?Y$>  
sSiteURL= sURL; 3;buC|ky  
sFilePath = sPath; A+^okT37r  
sFileName = sName; {m!5IR  
this.nSplitter = nSpiltter; 0{vT`e'  
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gcnX^[`S  
} * WV=Xp  
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public String getSSiteURL() (Y'cxwj%  
{ IP/%=m)\%  
return sSiteURL; W,EIBgR(R5  
} Yuw:W:wY  
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7j)ky2r#  
public void setSSiteURL(String value) GXxI=,L8F  
{ ~~Bks{"BS  
sSiteURL = value; cFc(HADM`r  
} 56JQ h  
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public String getSFilePath() /e"iYF  
{ WzstO}?P(  
return sFilePath; inh:b .,B  
} ^mn!;nu  
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public void setSFilePath(String value) U',C-56z  
{ msxt'-$M  
sFilePath = value; d4ecF%R  
} w:lj4Z_  
A:Wr5`FJ  
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public String getSFileName() MrzD ah9UG  
{ T^Ia^B-%}g  
return sFileName; Q>D//_TF  
}  >SQzE
 
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public void setSFileName(String value) Y_Fn)(  
{ 6 eryf?  
sFileName = value; /pjl6dJ t  
} "LTw;& y  
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public int getNSplitter() Mv%Qze,\V^  
{ 6HZtdRQF  
return nSplitter; FBwG3x  
} ~qQZhu"  
L9O;K$[s  
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public void setNSplitter(int nCount) O`0r'&n  
{ \t)va:y  
nSplitter = nCount; )YgntI@  
} 3}FZg w .  
} >=97~a+
.  
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*-PjcF}Y  
/* e4Nd  
**Utility.java ^7\kvW  
*/ x?o#}:S  
package NetFox; g;=VuQuP|  
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public class Utility { o)XrC   
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public Utility() 6&0@k^7~  
{ R/x3+_.f  
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} lGr=I-=  
pC:YT/J  
//线程睡眠 n[0u&m8  
public static void sleep(int nSecond) ;>mM9^Jaf
 
{ ( jU $  
try{ ymxA<bICS8  
Thread.sleep(nSecond); ?Fx~_
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} hhaiHi!$  
catch(Exception e) ]?+i6 [6U  
{ =S{OzF  
e.printStackTrace (); :+DrV
\)  
} m[xl)/e  
} ZN#b5I2Pf  
8)bR\s  
//日志 cy.r/Z}  
public static void log(String sMsg) 'y;Kj  
{ _?H3*!>3  
System.err.println(sMsg); 2, )>F"R  
} %\ i&g$  
y@l&B+2ks  
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public static void log(int sMsg) V5(_7b#z``  
{ FA*$ dwp  
System.err.println(sMsg); P9yMf~  
} %Zk6K!MY#  
} d~qQ_2M[G  
9no<;1+j,  
WF`%7A39Af  
/* E>s+"y  
**TestMethod.java zQulPU  
*/ >fWGiFmlk  
package NetFox; " Bx@(  
GIzB1cl:  
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public class TestMethod { )9"^ D  
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public TestMethod() W"Y)a|rG%  
{ ///xx/weblogic60b2_win.exe y@7fR9hp<  
try{ @ &
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); P6.PjK!Ar  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ^+D/59I  
SiteFileFetch fileFetch = new SiteFileFetch(bean); I`{*QU  
fileFetch.start(); 3`yO&upk  
} kyAN O  
catch(Exception e){e.printStackTrace ();} xH\\#4/  
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I :<,9.   
} xg/(  
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public static void main(String[] args) Y M:9m)  
{ 9k ~8n9
  
new TestMethod(); 'r7[9[  
} 5(ZOm|3ix  
} kVQm|frUz  
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