http断点续传简单实现（java)

/* V]=22Cxi'~  
**SiteFileFetch.java #2{-6ey  
*/ {%V(Dd[B6  
package NetFox; T
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import java.io.*; IGdiIhH~2  
import java.net.*; ^|]&"OaB Z  
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public class SiteFileFetch extends Thread { \iuR+I  
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7
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SiteInfoBean siteInfoBean = null; //文件信息Bean "s2_X+4oY  
long[] nStartPos; //开始位置 OxlA)$.hpu  
long[] nEndPos; //结束位置 '%N?r,x C  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 b+rxin".  
long nFileLength; //文件长度 ,T/Gv;wa2  
boolean bFirst = true; //是否第一次取文件 D -}>28  
boolean bStop = false; //停止标志 ~f/|bcep  
File tmpFile; //文件下载的临时信息 <Vat@e  
DataOutputStream output; //输出到文件的输出流 {!"UBALxc  
*$tXm4 O[  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 3<0b_b  
public SiteFileFetch(SiteInfoBean bean) throws IOException )DSeXS[ e  
{ (`x_MTLL  
siteInfoBean = bean; 6#=jF[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); P*|N)S)X%  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); q!Du J  
if(tmpFile.exists ()) A~zn;  
{ cG|fau<G  
bFirst = false; U( YAI%O  
read_nPos(); +&GV-z~o  
} #NS|9jW  
else 6x+ujUBkK  
{ i_Kwxn$  
nStartPos = new long[bean.getNSplitter()]; i2F7O"f.  
nEndPos = new long[bean.getNSplitter()]; Ss3p6%V/  
} ^QK`z@B  
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} Z%t_1t  
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public void run() })g<I+]Hf9  
{ ]33!obM  
//获得文件长度 TOwd+]B  
//分割文件 &?<uR)tl  
//实例FileSplitterFetch X Xque-  
//启动FileSplitterFetch线程 dkQ4D2W*\  
//等待子线程返回 (jc@8@Wo.  
try{ <2$vo  
if(bFirst) #mxOwvJ  
{ &Mh.PzO=b  
nFileLength = getFileSize(); L^J4wYFTO  
if(nFileLength == -1) ]e>qvSuYh  
{ 6g(;2gY  
System.err.println("File Length is not known!"); bLqy7S9x  
} agIqca;  
else if(nFileLength == -2) p{f R$-d  
{ 8-Abg:)  
System.err.println("File is not access!");  |/Nh#  
} 18&"j 8'm  
else eYOY   
{ P/%7kD@5;  
for(int i=0;i<nStartPos.length;i++) 6h 0qtXn-  
{ _`$Q6!Z)l  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ?&B8:<qy;L  
} 6'qkD<  
for(int i=0;i<nEndPos.length-1;i++) ;pnF%co9  
{ 6$u/
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nEndPos = nStartPos[i+1]; wu <0or2  
} i:lc]B  
nEndPos[nEndPos.length-1] = nFileLength; 0PzSp ]  
} qu=~\t1[6  
} Jo?LPR \6  
VB |?S|<  
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//启动子线程 
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3efOgP=L  
for(int i=0;i<nStartPos.length;i++) "LBMpgpU  
{ u$ts>Q;5  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )aS:h}zn  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Q*DT" W/0  
nStartPos,nEndPos,i); m\:^9A4HCg  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); MZgaQUg  
fileSplitterFetch.start(); Y
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} bnxp[Qk|5  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1p&.\^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 5100fX}  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", {K^5q
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nEndPos = " + nFileLength); bz*@[NQ  
// fileSplitterFetch[nPos.length-1].start(); 'L/)9.29  
.N(R~_  
7e_4sxg'(3  
//等待子线程结束 ~ua(Qm  
//int count = 0; -[mmT'sS  
//是否结束while循环
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boolean breakWhile = false; QiCia#_  
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while(!bStop) O=K lc+Oo  
{ _u]Z+H"  
write_nPos(); 92TuuN#{  
Utility.sleep(500); FFT)m^4p.  
breakWhile = true; x39tnf/F  
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for(int i=0;i<nStartPos.length;i++) xP8/1wd.  
{ 0h-NT\m  
if(!fileSplitterFetch.bDownOver) gtKih  
{ O,$*`RZpx  
breakWhile = false; fB2ILRc  
break; ak7%  
} \XDiw~0  
} \f,<\mJ#  
if(breakWhile) }8'_M/u\  
break; LkbD='\=  
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//count++; V&zeC/xSq  
//if(count>4) oodA&0{)d  
// siteStop(); 6 AO(A *  
} KOixFn1  
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System.err.println("文件下载结束！"); g *5_m(H  
} g[cnaS|?  
catch(Exception e){e.printStackTrace ();} u#6s^ )W  
} [s}W47N1  
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*q}yfa35eR  
//获得文件长度 ydWr&E5  
public long getFileSize() GRc)3 2,  
{ L15)+^4n  
int nFileLength = -1; s}zR@ !`  
try{ :3F[!y3b  
URL url = new URL(siteInfoBean.getSSiteURL()); ^EIuGz1@0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0fc;H}B*  
httpConnection.setRequestProperty("User-Agent","NetFox"); \Z.r Pq  
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int responseCode=httpConnection.getResponseCode(); enk`I$Xx  
if(responseCode>=400) ch#)XomN  
{ 3MQHoxX  
processErrorCode(responseCode); WUS%
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return -2; //-2 represent access is error _'p/8K5)=  
} m2SJ\1 J=  
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String sHeader; 0hY3vBQ!  
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for(int i=1;;i++) gmp@ TY=:L  
{ @tT`s^e  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); O%%Q./oh  
//Utility.log(in.readLine()); $uLTYu  
sHeader=httpConnection.getHeaderFieldKey(i); Mg >%EH/'  
if(sHeader!=null) P`rfDQoZ  
{ &D<6Go/)_*  
if(sHeader.equals("Content-Length")) >p&"X 2 @  
{ &5}YTKe}|  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ]ty$/{hx'  
break; vhZXgp0X  
} p,=IL_  
} kB+$Kt<]L  
else o0WwlmB5  
break; ybpOk  
} )[eTZg  
} _J*l,]}S  
catch(IOException e){e.printStackTrace ();} qt:B]#j@  
catch(Exception e){e.printStackTrace ();} xst-zfkH`  
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Utility.log(nFileLength); r?KRK?I
 
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return nFileLength; ;$tdn?|  
} @de  ZZ  
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//保存下载信息（文件指针位置） {~&]  
private void write_nPos() IlF_g`  
{ X$<pt,}%  
try{ U_jW5mgsG  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Mn5(Kw?o2J  
output.writeInt(nStartPos.length); yR5XcPoKI  
for(int i=0;i<nStartPos.length;i++) } ew{WD  
{ ,`U>BBBLv  
// output.writeLong(nPos);  /$93#$  
output.writeLong(fileSplitterFetch.nStartPos); 7!qeIz  
output.writeLong(fileSplitterFetch.nEndPos); a<*+rG
I  
} '*[7O2\%/  
output.close(); 5NkF_&S_1  
} e'
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catch(IOException e){e.printStackTrace ();} Uhu?G0>O  
catch(Exception e){e.printStackTrace ();} 8K^#$,.."  
} xlcCL?qQj  
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//读取保存的下载信息（文件指针位置） hxdjmc-  
private void read_nPos() kM-8%a2i  
{ vEjf|-Mb9  
try{ R;,5LS&*a  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); |`yU \  
int nCount = input.readInt(); uv5NqL&  
nStartPos = new long[nCount]; NXLb'm
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nEndPos = new long[nCount]; <|'ETqP<+  
for(int i=0;i<nStartPos.length;i++) Sj)?!  
{ Qraq{'3  
nStartPos = input.readLong(); yfwR``F  
nEndPos = input.readLong(); A|Ft:_Y  
} =2*2$  
input.close(); 4]}d'x&  
} 8\nka5  
catch(IOException e){e.printStackTrace ();} dJzaP  
catch(Exception e){e.printStackTrace ();} DmWa!5  
} lhQMR(
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private void processErrorCode(int nErrorCode) Na]ITCVR  
{ Tb^1#O  
System.err.println("Error Code : " + nErrorCode); Yq/vym-O5  
} ZHwl9n#m  
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//停止文件下载 EAh|$~X  
public void siteStop() b L.Xby<Y  
{ +-x+c: IxA  
bStop = true; .R)Ho4CE  
for(int i=0;i<nStartPos.length;i++) I+Y Z+  
fileSplitterFetch.splitterStop(); RYl{89  
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} f% 8n?f3;u  
} Dd OK&  
//负责部分文件的抓取 &~<i" W  
**FileSplitterFetch.java +pUYFDwFx  
*/ lib^JJF  
package NetFox; (w_b  
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import java.io.*; )MV `'i  
import java.net.*; 79Aa~+i'_  
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public class FileSplitterFetch extends Thread { 6."|m+D  
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String sURL; //File URL Us6~7L00  
long nStartPos; //File Snippet Start Position *Q
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long nEndPos; //File Snippet End Position %YuFw|wO  
int nThreadID; //Thread's ID Ug[0l)  
boolean bDownOver = false; //Downing is over [ P*L`F  
boolean bStop = false; //Stop identical ee<'j~{A  
FileAccessI fileAccessI = null; //File Access interface %}  
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@Rd`/S@  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException E)'T
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{ uw>y*OLU+  
this.sURL = sURL; mmC
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this.nStartPos = nStart; X#W6;?Z\  
this.nEndPos = nEnd; B|>eKI  
nThreadID = id; I]#x0?D  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 IQ JFL +f  
} GB*^?Ii  
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public void run() f'j<v  
{ %@I= $8j  
while(nStartPos < nEndPos && !bStop) ip|l3m$Mi  
{ =m;cy0))  
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try{ mt
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URL url = new URL(sURL); 5M%)*.Y 3[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); REOWSs$'  
httpConnection.setRequestProperty("User-Agent","NetFox"); Sfi1bsK  
String sProperty = "bytes="+nStartPos+"-"; ![[:Z  
httpConnection.setRequestProperty("RANGE",sProperty); P$__c{1\  
Utility.log(sProperty); \O>;,(>i  
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InputStream input = httpConnection.getInputStream(); tB0f+ wC  
//logResponseHead(httpConnection); SphP@J<ONW  
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*X
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byte[] b = new byte[1024]; =`qEwA  
int nRead; rB =c
  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :K*/  
{ ;A?86o'?  
nStartPos += fileAccessI.write(b,0,nRead); :9|CpC`.  
//if(nThreadID == 1) L3S29-T  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C7l4X8\w  
} }F_=.w0  
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/7R0w  
Utility.log("Thread " + nThreadID + " is over!"); 9 b&HqkXX  
bDownOver = true; PmUq~YZ7  
//nPos = fileAccessI.write (b,0,nRead); e=i9l  
} dY?>:ce  
catch(Exception e){e.printStackTrace ();} 1mv8[^pF  
} /p{$HkVw  
} \NL*$SnxP  
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//打印回应的头信息 AHplvksb  
public void logResponseHead(HttpURLConnection con) a/~1CrYr  
{ 2Gc0pBqx  
for(int i=1;;i++) T mH5+  
{ zrA=?[  
String header=con.getHeaderFieldKey(i); P9gAt4i  
if(header!=null) d`xDv$QZ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *kNXju  
Utility.log(header+" : "+con.getHeaderField(header)); RPTIDA))  
else 239gpf]}  
break; Zx|VOl,;  
} E7U.>8C  
} xQs._YY  
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public void splitterStop() k|rbh.Q  
{ )tx!BJiZ[  
bStop = true; p v*f]Yzx  
} 9,wU[=.0  
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} (7|!%IO.  
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/* Wl{}>F`W[  
**FileAccess.java sWMY Lo  
*//文件访问(定位，写) )#Id=c  
package NetFox; Uclta  
import java.io.*; KCS},X_  
o=Kd9I#  
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public class FileAccessI implements Serializable{ QqB9I-_  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Dp;6CGYl?  
RandomAccessFile oSavedFile; NU%W
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long nPos; 4nD U-P#f  
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public FileAccessI() throws IOException fsV_>5I6  
{ cD9axlJ  
this("",0); I~>Ye<g#  
} +`~kt4W  
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public FileAccessI(String sName,long nPos) throws IOException fTV3lyk  
{ T@on ue7  
oSavedFile = new RandomAccessFile(sName,"rw"); DZU} p  
this.nPos = nPos; @HP7$
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oSavedFile.seek(nPos); $McbVn)~f  
} O`'r:&#W  
1y6{3AZm<  
5H/D~hr&  
public synchronized int write(byte[] b,int nStart,int nLen) 3/RNStd<L!  
{ <):= mr7  
int n = -1; ; Ne|H$N  
try{ Y2P%0
 
oSavedFile.write(b,nStart,nLen); Qg gx:  
n = nLen; gP>`DPgb^  
} f/%QMhM:  
catch(IOException e) nCdxn#|  
{ Nr0}*8#j  
e.printStackTrace (); oz/Nx{bg  
} ;+R  
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,&rHBNS  
return n; rL<a^/b/=  
} bjB4  
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} >jg"y  
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bv4G!21]*;  
/* W3 2]#M=  
**SiteInfoBean.java >Ef{e6  
*/ oC1Nfc+  
package NetFox;  ^#&:-4/  
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public class SiteInfoBean { 5
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private String sSiteURL; //Site's URL NT<vs"<B  
private String sFilePath; //Saved File's Path DjveMs$d  
private String sFileName; //Saved File's Name NVq3h\[X  
private int nSplitter; //Count of Splited Downloading File VL| q`n  
}ujl2uhM  
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public SiteInfoBean() 3.<E{E!F  
{//nSplitter的缺省值为5 qfl#ki`,  
//default value of nSplitter is 5 b]xE^zM-I`  
this("","","",5); /m(v5v7(  
} 5.zv0tJku  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) IO}5
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{ ><3!J+<?  
sSiteURL= sURL; /{*0 \`;  
sFilePath = sPath; ~mK|~x01@  
sFileName = sName; 9 Aq\1QC  
this.nSplitter = nSpiltter; !OL[1_-4|K  
1CpIK$/  
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} s>1Wjz2M  
IH$ZPux  
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public String getSSiteURL() xdkC>o4>  
{ u#~q86k  
return sSiteURL; K *xca(6  
} ,7mB`0j>  
\9`76*X6 c  
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public void setSSiteURL(String value) 0m 7_#g4$L  
{  Va3/#is'  
sSiteURL = value; 8a,pDE  
} L@>$ Aw  
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public String getSFilePath() (hFyp}jkk  
{ $hq'9}ASOL  
return sFilePath; SVJt= M  
} RSK5 }2  
$Z[W}7{pt#  
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public void setSFilePath(String value) a5nA'=|}i  
{ FoB^iA6e  
sFilePath = value; gvu1  
} '4]_~?&x  

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public String getSFileName() o GN*p_g  
{ m*H' Cb  
return sFileName; ?:+sjHzXT  
} \<0xg[  
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G
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public void setSFileName(String value) bTbF  
{ UNJAfr P  
sFileName = value; 1Zt>andBF  
} \^]*T'>b  
?`T-A\A=  
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public int getNSplitter() q!4eVg*  
{ M~,N~ N1  
return nSplitter; &"'Z)iWm  
} uN+]q qCf  
"^NsbA+  
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public void setNSplitter(int nCount) Z)'gj  
{ w:c9Z=KX  
nSplitter = nCount; Z,1b$:+  
} ~>B`T%=H  
} r}i}4
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45.Vr[FS.  
8~ wP?  
/* pxb4x#CC  
**Utility.java 8KMo!p\i  
*/ t+Au6/Dx?  
package NetFox; |*n B2  
,Vfjt=6]}  
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public class Utility {  *"Uf|  
/_qW?LKG/  
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public Utility() &(X67  
{ +sT S1t  
/X;/}fk  
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} vo>i36  
XJe}^k  
//线程睡眠 2KtK.2;7  
public static void sleep(int nSecond) TXo`P_SE  
{ 2Og<e|  
try{ _"[Ls?tRX  
Thread.sleep(nSecond); qT~a`ou:  
} Q)Q1
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catch(Exception e) |Pi! UZB  
{ xO&qo8*  
e.printStackTrace (); " 6ScVa5)  
} .,F`*JVFq  
} vEw8<<cgg  
M@+Pq/f:  
//日志 mI'&!@WG  
public static void log(String sMsg) -car>hQq  
{ +t%1FkI\  
System.err.println(sMsg); E
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} {"c`k4R  
6/6{69tnr  
otbr8&?-  
public static void log(int sMsg) nzU;Bi^m  
{ xauMF~*  
System.err.println(sMsg); ==AmL]*  
} NG_7jZzXA9  
} gY!?JZC-0  
<$??Z;6  
Xo$SQ0K  
/* foUB/&Ee  
**TestMethod.java >&ENrvaJ  
*/ >t{-_4Yv?  
package NetFox; n8tw8o%&[  
AuT:snCzR  
!e:_$$j  
public class TestMethod { }N&?8s=  
|DYgc$2pN  
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public TestMethod() ny
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{ ///xx/weblogic60b2_win.exe 3Ak'Ue  
try{ N\|BaZ%>|  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); q@g#DP+C  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); O?ODfO+>  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Kq5i8L
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fileFetch.start(); &(lQgi+^!  
} v*OV\h.  
catch(Exception e){e.printStackTrace ();} ..zX  
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1R;@v3  
} 5mS/,fs@  
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yj=OR|v  
public static void main(String[] args) 3b|=V  
{ E*h!{)z@F  
new TestMethod(); 5KP\#Y  
} Ii&p v  
} 0' oXA'L-J  
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