http断点续传简单实现（java)

/* nstUMr6  
**SiteFileFetch.java '1M7M(va  
*/ m0v:\?S:  
package NetFox; `jwa<N4e@  
import java.io.*; \&H nKhI  
import java.net.*; &|/| ''A)  
L!=QR8?@E  
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public class SiteFileFetch extends Thread { 4:U?u  
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! u:Weoz  
SiteInfoBean siteInfoBean = null; //文件信息Bean qUly\b 47  
long[] nStartPos; //开始位置 e^.Fa59  
long[] nEndPos; //结束位置 `Od5Gh  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 )/
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long nFileLength; //文件长度 Mn)@{
^  
boolean bFirst = true; //是否第一次取文件 mdRU^n  
boolean bStop = false; //停止标志 jQ:OKh<Y  
File tmpFile; //文件下载的临时信息 d/i`l*  
DataOutputStream output; //输出到文件的输出流 &197P7&o  
x
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） !Q#{o^{Y~  
public SiteFileFetch(SiteInfoBean bean) throws IOException lT(oL|{#P  
{ ;3'.C~  
siteInfoBean = bean; kT;S4B  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); -wjN"g<  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); <:?r:fQX  
if(tmpFile.exists ()) OF\rgz
 
{ L'u\w  
bFirst = false; 2Lx3=k  
read_nPos(); aG^4BpIP  
} }Hn/I,/  
else k{'0[,mx#  
{ Yb E-6|cz  
nStartPos = new long[bean.getNSplitter()];  EW3(cQbK  
nEndPos = new long[bean.getNSplitter()]; k1QpKn*  
} y-1 pR  
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} ~Q\3pI. |  
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public void run() >yULC|'F&~  
{ Z,=7Tu bR#  
//获得文件长度 Y'
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//分割文件 '#k0a,<N  
//实例FileSplitterFetch |`cKD >  
//启动FileSplitterFetch线程 B'fb^n<  
//等待子线程返回 l,kUhZ@W  
try{ }`@728E  
if(bFirst) ?]*^xL;x?  
{ &uO%_6J  
nFileLength = getFileSize(); x@*SEa  
if(nFileLength == -1) -]QD|w3dp  
{ HaP}Y:p  
System.err.println("File Length is not known!"); WVI{oso#  
} -?0qf,W.  
else if(nFileLength == -2) yxH ( c  
{ ?Orxmxc 2  
System.err.println("File is not access!"); t2lS ~l)  
} QDu2?EYZq  
else o#skR4lwe  
{ Rb.SY{}C  
for(int i=0;i<nStartPos.length;i++) g[3)P+  
{ 9^j &VmF  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); !P-^O  
} IP(Vr7-v  
for(int i=0;i<nEndPos.length-1;i++) L|,!?cSAT  
{ ;UfCj5`Q)4  
nEndPos = nStartPos[i+1]; Z-l=\ekJ  
} PS[+~>%  
nEndPos[nEndPos.length-1] = nFileLength; mFi&YpHu3  
} %T~ig[GstX  
} v&=gF/$  
o|$AyS{1  
@~%r5pz6  
//启动子线程 kOed ]>H  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; "T|PS6R~  
for(int i=0;i<nStartPos.length;i++) *m#Za<_Gv  
{ `5C,N!d8X  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y 1t\iU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Wr( y)D<y}  
nStartPos,nEndPos,i); =17t- [  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); H XmS|PX  
fileSplitterFetch.start(); FAj)OTI2S  
} WS`qVL]^&  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 'L8' '(eZ^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); R.yC(r  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", w$Rro)?}7  
nEndPos = " + nFileLength); sNLs\4v  
// fileSplitterFetch[nPos.length-1].start(); aXoVy&x=  
jJ5W>Q1mK$  
[Lz
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//等待子线程结束 oomT)gO 6*  
//int count = 0; 4B^ZnFJ%m  
//是否结束while循环 } x2DT8u  
boolean breakWhile = false; fc |GArL#}  
@CT;g
\4  
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while(!bStop) 8/=L2fNN[  
{ dzDqZQY$  
write_nPos(); z[3L2U~6  
Utility.sleep(500); +w+}b^4  
breakWhile = true; lhBT@5Dm9  
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for(int i=0;i<nStartPos.length;i++) /|D
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{ tQBRA/  
if(!fileSplitterFetch.bDownOver) , T8>}U(  
{ vuoQz\  
breakWhile = false; {\:{[{qF  
break; 6,0_)O}\b  
} K~| 4[\  
} L{8xlx`  
if(breakWhile) !y@6Mm  
break; o}* hY"&  
%*L:sTj(  
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//count++; <psZQdH  
//if(count>4) .n~M(59  
// siteStop(); Np"exFqN k  
} j
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R~S
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System.err.println("文件下载结束！"); Z\k&gio5C^  
} \Hn>oonph  
catch(Exception e){e.printStackTrace ();} \Ol kM<  
} _tYx~J2.Q  
;N0~;I  
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//获得文件长度 /K.!sQ$  
public long getFileSize() "-+\R}q$  
{
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int nFileLength = -1; '2[albxSc  
try{  O4og?h>  
URL url = new URL(siteInfoBean.getSSiteURL()); n6BQk2l  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Y\$ySvZ0  
httpConnection.setRequestProperty("User-Agent","NetFox"); s=0BMPDgm  
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int responseCode=httpConnection.getResponseCode(); //s:5S<Z  
if(responseCode>=400) !X;1}  
{ LdL/399<  
processErrorCode(responseCode); Wwr;-Qa}g  
return -2; //-2 represent access is error H*$jc\ dC  
} d'G0m9u2  
6jC`8l:  
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String sHeader; 4X+ifZO  
j,"@?Wt7  
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for(int i=1;;i++) 5'X ]k@m_  
{ K*X_FJ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); P_Gw-`L5T  
//Utility.log(in.readLine()); (q(~de  
sHeader=httpConnection.getHeaderFieldKey(i); "O%gFye  
if(sHeader!=null) MP4z-4Y  
{ ZHm7Isa1  
if(sHeader.equals("Content-Length")) }MH0L#Tu  
{ )|DM~%$QM  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); `s8{C b=}1  
break; nv~%#|v_W  
} 8[E!E)
4M  
} 3%%o?8ES  
else =9fajRFTt  
break; f (F)1  
} ".<DAs j  
} {;:/-0s  
catch(IOException e){e.printStackTrace ();} u (em&M  
catch(Exception e){e.printStackTrace ();} &8g?4v  
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Utility.log(nFileLength); 93` AWg/T  
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return nFileLength; \ywXi~+kUv  
} iC98_o_9  
2-C!jAfd  
wv\w;'  
//保存下载信息（文件指针位置） L;'"A#Pa  
private void write_nPos() ]y1OFKYv  
{ Vp3ZwS  
try{ h3z{(-~y  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?6fnpGX@a  
output.writeInt(nStartPos.length); ?MgUY)X  
for(int i=0;i<nStartPos.length;i++) \\u<
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{ S&b*rA02zp  
// output.writeLong(nPos); YW60q0:  
output.writeLong(fileSplitterFetch.nStartPos); A8oo@z68n>  
output.writeLong(fileSplitterFetch.nEndPos); ](wvu(y\E  
} Ns7(j-  
output.close(); %0,#ADCqOe  
} R}4So1  
catch(IOException e){e.printStackTrace ();} 2IKnhBSV3  
catch(Exception e){e.printStackTrace ();} A.EbXo/  
} T^~5n6  
JAQb{KefdO  
@M5#S7q";  
//读取保存的下载信息（文件指针位置） 9+{G8$Ai  
private void read_nPos() S=e{MI  
{ O"c;|zCc>  
try{ \8?Tdx=  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .xH5fMj,"  
int nCount = input.readInt(); /iJ4{p  
nStartPos = new long[nCount]; c%'RR?Tl  
nEndPos = new long[nCount]; RWgNo#<  
for(int i=0;i<nStartPos.length;i++) JQ6zVS2SSS  
{ )`A3M)  
nStartPos = input.readLong(); Vc2A  
nEndPos = input.readLong(); n3D;"
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} d[V;&U  
input.close(); qx4I_%  
} IbP#_Vt  
catch(IOException e){e.printStackTrace ();} |,!
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catch(Exception e){e.printStackTrace ();} Ux}(?Z  
} Bhp-jq'!B  
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private void processErrorCode(int nErrorCode) Xt@Z}B))pu  
{ cxr=k%~}J  
System.err.println("Error Code : " + nErrorCode); N=QfP  
} DIzH`|Y  
b+&%1C  
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//停止文件下载 ;bLEL"x%  
public void siteStop() {yB&xj[z  
{ aM:nOt" S1  
bStop = true; $l|qk z  
for(int i=0;i<nStartPos.length;i++) "vyNxZE  
fileSplitterFetch.splitterStop(); 3T!lA  
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}  s8rE$  
} $}jssnoU  
//负责部分文件的抓取 Ksy -e{n  
**FileSplitterFetch.java j&Wl0  
*/ >w^YO25q  
package NetFox;
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import java.io.*; [3--(#R\}?  
import java.net.*;
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public class FileSplitterFetch extends Thread { =MLcm^b  
OC<5E121>Y  
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String sURL; //File URL -QmO1U  
long nStartPos; //File Snippet Start Position Q&eQQ6b^Ih  
long nEndPos; //File Snippet End Position FWHNj.r  
int nThreadID; //Thread's ID A3S<..g2  
boolean bDownOver = false; //Downing is over ~;&m*2 |V  
boolean bStop = false; //Stop identical HO}Hh[{V9  
FileAccessI fileAccessI = null; //File Access interface 2g>SHS@1>  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 3 "Q=Vl"  
{ [>1OJY.S}T  
this.sURL = sURL; FTQ%JTgT  
this.nStartPos = nStart; km1~yQ"bH  
this.nEndPos = nEnd; lAJxr8 .  
nThreadID = id; (3#Cl 1]f  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 0#S W!b|%  
} K?zH35f$  
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public void run() ],J
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{
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while(nStartPos < nEndPos && !bStop) eZdu2.;<  
{ JZD[NZ<  
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try{ a8i]]1Blz  
URL url = new URL(sURL); W034N[9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /Ya_>+oo  
httpConnection.setRequestProperty("User-Agent","NetFox"); NCk r /#!  
String sProperty = "bytes="+nStartPos+"-"; U
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httpConnection.setRequestProperty("RANGE",sProperty); z3K6%rb-  
Utility.log(sProperty);
3+G@g#MY  
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InputStream input = httpConnection.getInputStream(); $d)ca9  
//logResponseHead(httpConnection); l:<?{)N`  
[-;_ZFS{  
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byte[] b = new byte[1024]; 72Iy^Y[MX  
int nRead; "Za>ZRR  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) k=B]&F  
{ (jFGa2{  
nStartPos += fileAccessI.write(b,0,nRead); YH%'t= <m  
//if(nThreadID == 1) D[mSmpjE6&  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OVko+X`  
} 8rMX9qTO@  
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=|%Cu&  
Utility.log("Thread " + nThreadID + " is over!"); ]&i.b+^  
bDownOver = true; 2GWMlI  
//nPos = fileAccessI.write (b,0,nRead); -"h;uDz|z  
} !\"5rNy  
catch(Exception e){e.printStackTrace ();} MV\|e1B}  
} W'.s\e?gh  
} >b6-OFJx  
k?z98 >4  
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//打印回应的头信息 _',prZ*  
public void logResponseHead(HttpURLConnection con) ,Td!|~I|j6  
{ 'eJ+JM<0%
 
for(int i=1;;i++) bD[!/'4eJ  
{ '6xQT-sUih  
String header=con.getHeaderFieldKey(i); i 4%xfN  
if(header!=null) dz*7gL;7G  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Sk:ws&D1u  
Utility.log(header+" : "+con.getHeaderField(header)); ?I[8'  
else .Y3pS/VI  
break; z(fAnn T?  
} +S R+x/?z  
} kRTwaNDOD  
_%B^9Yl3(  
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public void splitterStop() qZh1`\G  
{ ;I
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bStop = true; 8ZKo_I\  
} h|h>u ^@  
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} n
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/* `S2[5i  
**FileAccess.java 8g:;)u4$P  
*//文件访问(定位，写) BVr0Gk  
package NetFox; GW$.lo1|)  
import java.io.*; xZQg'IT  
9$Xu,y  
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public class FileAccessI implements Serializable{ H]$)Eg%6  
lNL6M%e$Q  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 't_[dSO  
RandomAccessFile oSavedFile; ;Ww7"-=sw  
long nPos; =Uj-^qcE  
"v`  
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public FileAccessI() throws IOException )E,\H@A  
{ y
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this("",0);  -Y H<  
} :k3Nt5t!  
1XnZy5fEo  
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public FileAccessI(String sName,long nPos) throws IOException ]]&M@FM2z  
{ qWx][D"  
oSavedFile = new RandomAccessFile(sName,"rw"); (vB<%l.&  
this.nPos = nPos; @E-\ J7 yh  
oSavedFile.seek(nPos); uFLx  
} nIoPC[%_  
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public synchronized int write(byte[] b,int nStart,int nLen)  k0  
{ X*,%&6O*  
int n = -1; sL@

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try{ OzQ -7|m'J  
oSavedFile.write(b,nStart,nLen); ]Lm9^q14m  
n = nLen; 7yx$Nn`(  
} >A<bBK#  
catch(IOException e) vk?sk
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{ <7n4_RlF!  
e.printStackTrace (); qpsvi.S  
} L9@&2?k  
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return n; n':!,a[  
} .p=sBLp8  
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} .-IkL|M  
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/* b L]erYm  
**SiteInfoBean.java r)1'eP
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*/ WJ d%2pO]  
package NetFox; s-RQMK}H  
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:T._ba3|  
public class SiteInfoBean { v\,N5  
,i0b)=!o  
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private String sSiteURL; //Site's URL f_imyzP  
private String sFilePath; //Saved File's Path -YjA+XP  
private String sFileName; //Saved File's Name \/SQ,*O  
private int nSplitter; //Count of Splited Downloading File H{AMZyV0/d  
PI~1GyJr@;  
[b/k3&O'  
public SiteInfoBean() tBm_YP[  
{//nSplitter的缺省值为5 H> '>3]G  
//default value of nSplitter is 5 Hzhceeh_+  
this("","","",5); e+]6OV&+  
} m "M("%  
ncX/L[L  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 
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{ je6CDFqw  
sSiteURL= sURL; p[@5&_u(z  
sFilePath = sPath; <n:}kQTT  
sFileName = sName; O4g+D#Lu  
this.nSplitter = nSpiltter; s (0*  
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} s%!`kWVJ.  
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public String getSSiteURL() Y'u7 IX}  
{ Hh4 n  
return sSiteURL; Ic{F*nnM  
} p)=~% 7DV  
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4:sjH.u<  
public void setSSiteURL(String value) ~+H"
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{ -wv6s#"u  
sSiteURL = value; .p ls!  
} cNKUu~C+  
W>=o*{(YO  
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public String getSFilePath() KYkS9_yF  
{ i`0v#P  
return sFilePath; t9_E$w^U  
} z*a8sr  
?|1Mv1C?  
:qvI%1cP=  
public void setSFilePath(String value) )g|xpb
 
{ a6h>=uT [  
sFilePath = value; `' 153M]  
} s3 ;DG  
e
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public String getSFileName() ;@nFVy>U  
{ ]O` {dnP  
return sFileName; {&[9iIf  
} j.i#*tN//  
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: 5U"XY x@  
public void setSFileName(String value) ;D.h65rr  
{ m))<!3  
sFileName = value; &5%dhc4&!&  
} cDrebU  
2T)sXBu  
6QNs\Ucb+  
public int getNSplitter() !'f3>W\   
{ /:\3 \{?0m  
return nSplitter; P(SZ68  
} 45@]:2j  
8CC/BOe  
oW$s xS  
public void setNSplitter(int nCount) }Z`(aDH  
{ T}D<Sc  
nSplitter = nCount; t0#[#I1+  
} 8seBT;S  
} f{lZKfrp  
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/* kJ(A,s|  
**Utility.java qUo-Dq>  
*/ %>WbmpIyc  
package NetFox; Vh<A2u3&  
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public class Utility { ]fe
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3"UsZyN:  
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public Utility() l12$l<x&M  
{ (X6sSO  
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} H<ZU#U0FZf  
Sg] J7;]  
//线程睡眠 S='syq>Aok  
public static void sleep(int nSecond) O{k
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{ ]Y.deVw3i  
try{ fA! 6sB  
Thread.sleep(nSecond); q6wr=OWD  
} G_Ay   
catch(Exception e) m=b~i^@  
{ (D{Ys'{q  
e.printStackTrace (); 5M23/= N  
}
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} s(&;q4|  
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//日志 q9dLHi<1  
public static void log(String sMsg) 4S L_-Hm.  
{ }~o ikN:  
System.err.println(sMsg); z8Q"%
@  
} ]v5-~E!  
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HXJ9xkrr  
public static void log(int sMsg) -U>7 H`5  
{ (tl}q3U  
System.err.println(sMsg); rwpgBl
 
} 0]x;n+G[q  
} s6=YV0w(  
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j1$
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/* WA LGIW  
**TestMethod.java =V|Nn0E  
*/ ?z"KnR+?Q  
package NetFox; `<j_[(5yb  
}`9`JmNM  
X^< >6|)  
public class TestMethod { 16@);Ot  
"A]Y~iQ  
zfjTQMaxh  
public TestMethod() (:Cc3  
{ ///xx/weblogic60b2_win.exe %^9:%ytt  
try{ <]8^J}8T{D  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); B;-2$ 77  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); c6b0*!D"}  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ZM~`Gd9K0E  
fileFetch.start(); el'j
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} 98*x 'Wp  
catch(Exception e){e.printStackTrace ();} H_X?dj15  
C=VIT*=  
00M`%c/  
} p\U*;'hv  
DMkhbo&+  
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public static void main(String[] args) '&?47+W  
{ 9=rYzA?)+  
new TestMethod(); \&R}JK  
} ZA2y  
} kC01s  
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