http断点续传简单实现（java)

/* EwN}l  
**SiteFileFetch.java ;+%rw2Z,B  
*/ ;TYBx24vD'  
package NetFox; Dtk=[;"k2a  
import java.io.*; p+eh%2Jm  
import java.net.*; z_HdISy0  
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public class SiteFileFetch extends Thread { 5+vaE 2v  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 80I#TA6C  
long[] nStartPos; //开始位置 g#bRT*,L  
long[] nEndPos; //结束位置 ^W^OfY  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 @dKTx#gZ  
long nFileLength; //文件长度 7I}uZ/N  
boolean bFirst = true; //是否第一次取文件 'DR!9De  
boolean bStop = false; //停止标志 eFgA 8kY)  
File tmpFile; //文件下载的临时信息 ^[[P*NX3  
DataOutputStream output; //输出到文件的输出流 ax`o>_)  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Tk
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public SiteFileFetch(SiteInfoBean bean) throws IOException #"!<W0  
{ TH;
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siteInfoBean = bean; TOt dUO  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); & 21%zPm  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ZVBXx\{s  
if(tmpFile.exists ()) L0,'m
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{ 2G7Wi!J  
bFirst = false; &d!GImcxQ  
read_nPos(); >Tgv11[  
} [JiH\+XLPs  
else <I?Zk80  
{ 7.Op<  
nStartPos = new long[bean.getNSplitter()]; <E~'.p,  
nEndPos = new long[bean.getNSplitter()]; X'srL j.  
} dV_G1'  
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} kVgTGC"L=  
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public void run() V gWRW7Se  
{ Ml_^ `vn  
//获得文件长度 79gT+~z  
//分割文件 (QEG4&9  
//实例FileSplitterFetch QRUz`|U  
//启动FileSplitterFetch线程 [0!(xp^  
//等待子线程返回 01]f2.5  
try{ d{?LD?,)  
if(bFirst) us-L]S+lm  
{ j#|ZP-=1_  
nFileLength = getFileSize(); -
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if(nFileLength == -1) q9"96({\@  
{ i1UsIT  
System.err.println("File Length is not known!"); e'~3oqSvR  
} Q,g\  
else if(nFileLength == -2) 7!1S)dup  
{ 3]Ct6  
System.err.println("File is not access!"); (PLUF
T  
} m O_af  
else 2/?|&[  
{ ch]IzdD  
for(int i=0;i<nStartPos.length;i++) Q &
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{ Oketwa  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); J.a]K[ci  
} x2xRBkRg=  
for(int i=0;i<nEndPos.length-1;i++) V3Bz Mw\9r  
{ [agMfn  
nEndPos = nStartPos[i+1]; _BufO7`.  
} YK_7ip.a[  
nEndPos[nEndPos.length-1] = nFileLength; )~>YH*g  
} U^PgG|0N  
} dtDFoETz  
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&>O+}>lr9  
//启动子线程 \bXa&Lq  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; =;L|gtH"  
for(int i=0;i<nStartPos.length;i++) UQsN'r\tS  
{ #!=tDc &  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), VbYdZCC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), )%TmAaj9d  
nStartPos,nEndPos,i); F,kZU$  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mH(:?_KrS-  
fileSplitterFetch.start(); zLQx%Yg!  
} }MySaL>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >*bvw~y,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ".%k6W<n  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", P \I|,  
nEndPos = " + nFileLength); 5P bW[  
// fileSplitterFetch[nPos.length-1].start(); X$ D6Ey  
HS$r8`S?)  
ctQ/wrkU  
//等待子线程结束 :FF=a3/"6  
//int count = 0; &{:-]g\  
//是否结束while循环 gXU8hTd8  
boolean breakWhile = false; u8^lB7!e/  
`[A];]  
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while(!bStop) +@UV?"d  
{ 42{~Lhxt  
write_nPos(); (FV >m  
Utility.sleep(500); (
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breakWhile = true; hH.G#-JO  
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4H/OBR  
for(int i=0;i<nStartPos.length;i++) SbZ6t$"  
{ )b)zm2;  
if(!fileSplitterFetch.bDownOver) /Oono6j  
{ Ri'n  
breakWhile = false; ]~-r}`]  
break; XppOU  
} ZCw]m#lS  
} e20-h3h+  
if(breakWhile) $G>.\t  
break; ]:;&1h3'7  
iU-j"&L5  
'w/hw'
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//count++; <@}9Bid!o  
//if(count>4) al0L&z\  
// siteStop(); jIyQ]:*p  
} Kw}'W 8`c  
M5B# TAybC  
zs;JJk^  
System.err.println("文件下载结束！"); [Q
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} CTK;dM'uQ  
catch(Exception e){e.printStackTrace ();} *Ex|9FCt$  
} 1YA% -~  
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//获得文件长度 %y@AA>x!  
public long getFileSize() *:
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{ y(Td/rY.  
int nFileLength = -1; 9uY'E'm*  
try{ Tw% 3p=  
URL url = new URL(siteInfoBean.getSSiteURL()); 6~{C.No}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zDp2g)  
httpConnection.setRequestProperty("User-Agent","NetFox"); oU|c
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qR.Q,(b|  
-&f$GUTJ  
int responseCode=httpConnection.getResponseCode(); |{;G2G1[  
if(responseCode>=400) s
{++w5s  
{ VQI3G  
processErrorCode(responseCode); K,]=6Rj  
return -2; //-2 represent access is error N [@?gFtT  
} Vi}_{ Cy  
g`^x@rj`E  
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String sHeader; =43auFY-P  
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for(int i=1;;i++) <VcQ{F  
{ MDN--p08  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 4 :=]<sc,  
//Utility.log(in.readLine()); DlT{`  
sHeader=httpConnection.getHeaderFieldKey(i); @;kSx":b  
if(sHeader!=null) |}1dFp  
{ hph4`{T  
if(sHeader.equals("Content-Length")) h![#;>(  
{ 8fb'yjIC  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); >7r!~+B"9'  
break; ,[Fb[#Qqb  
}
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} u>$t'  
else X8|EHb<  
break; xPgBV~  
} "L1Zi.)  
} d3Rw!slIq  
catch(IOException e){e.printStackTrace ();} ^.G$Q#y,  
catch(Exception e){e.printStackTrace ();} Je@v8{][|  
;=@0'xPEa-  
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Utility.log(nFileLength); iLz@5Zj8  
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return nFileLength; h~26WLf.  
} -&;TA0~;  
1}37Q&2  
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//保存下载信息（文件指针位置） cAy3^{3:  
private void write_nPos() q;U,s)Uz^  
{ 9kojLqCT  
try{ 2oU_2P  
output = new DataOutputStream(new FileOutputStream(tmpFile)); GL JMP^p  
output.writeInt(nStartPos.length); &{RDM~  
for(int i=0;i<nStartPos.length;i++) G j1_!.T  
{ 7|D+Ihy;  
// output.writeLong(nPos); {[(h[MW#  
output.writeLong(fileSplitterFetch.nStartPos); OTp]Xe/  
output.writeLong(fileSplitterFetch.nEndPos); \1`O_DF~o  
} j4b4!^fV  
output.close(); AEuG v}#  
} )i<j XZ:O  
catch(IOException e){e.printStackTrace ();} eq"]%s  
catch(Exception e){e.printStackTrace ();} S$k&vc(0  
} +{>=^9%X  
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fatf*}eln  
//读取保存的下载信息（文件指针位置） >MK98(F  
private void read_nPos() 9Ee'Cm  
{ sr}E+qf  
try{ i&k7-<  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6Iw\c  
int nCount = input.readInt();
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nStartPos = new long[nCount]; cFv8 Od  
nEndPos = new long[nCount]; qVPeB,kIz  
for(int i=0;i<nStartPos.length;i++) r
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{ CNIsZv@Q  
nStartPos = input.readLong(); h1{3njdr  
nEndPos = input.readLong(); ~v83pu1!2s  
} kR9-8I{J  
input.close(); 0Qd:`HF[  
} Jl<2>@  
catch(IOException e){e.printStackTrace ();} lLD12d  
catch(Exception e){e.printStackTrace ();} rH>)oThA#  
} 875od  
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private void processErrorCode(int nErrorCode) LF7SS;&~f  
{ Gc!x|V;T  
System.err.println("Error Code : " + nErrorCode); hEk$d.!}  
} 1U\z5$V  
"mNq&$  
}`"6aM   
//停止文件下载 X?$_Sd"G+5  
public void siteStop() Vg23!E  
{ njw|JnDv  
bStop = true; .mAjfP*  
for(int i=0;i<nStartPos.length;i++) }&e5$lB  
fileSplitterFetch.splitterStop(); "]iB6  
X jX2]  
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} \;-|-8Q  
} :Yks|VJ1  
//负责部分文件的抓取 s@DLt+ O5  
**FileSplitterFetch.java iX\X>W$P  
*/ Z8oK2Dw  
package NetFox; ?s _
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import java.io.*; Dxxm="FQZ  
import java.net.*; :yjFQ9^?&  
$kKjgQS(  
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public class FileSplitterFetch extends Thread { >*n0n!vF  
yWya&|D9  
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String sURL; //File URL =ruao'A  
long nStartPos; //File Snippet Start Position _y>~ yZx  
long nEndPos; //File Snippet End Position /=, nGk>  
int nThreadID; //Thread's ID Faf&U%]*`  
boolean bDownOver = false; //Downing is over ~nPtlrQa#*  
boolean bStop = false; //Stop identical %#}Zy   
FileAccessI fileAccessI = null; //File Access interface Lxk[;j+  
rD>f|kA?L  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException hL5|69E  
{ nLiY%x`S  
this.sURL = sURL; `g})|Gx  
this.nStartPos = nStart; @vB!u[{  
this.nEndPos = nEnd; 39|MX21k  
nThreadID = id; 4H-'Dr=G  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 rt|7h>RQ  
} ^KELKv,_  
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'  
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public void run() l (%1jC8  
{ JLJ;TM'4=  
while(nStartPos < nEndPos && !bStop) ,1##p77.  
{ N"1B/u  
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try{ |&[EZ+[  
URL url = new URL(sURL); AvHCO8h|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @gtQQxf"  
httpConnection.setRequestProperty("User-Agent","NetFox"); pBPl6%C.X-  
String sProperty = "bytes="+nStartPos+"-"; 2>H24F  
httpConnection.setRequestProperty("RANGE",sProperty); 5BJmA2L  
Utility.log(sProperty); Wr5V`sM  
{>%&(  
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InputStream input = httpConnection.getInputStream(); 
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//logResponseHead(httpConnection); (3&?wy_l  
-)/$M(Pu"  
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byte[] b = new byte[1024]; -Vhw^T1iV  
int nRead; uOGw9O-d9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ilva,WFa^  
{ -o.:P>/  
nStartPos += fileAccessI.write(b,0,nRead); W"3ph6[eW  
//if(nThreadID == 1) )];K .zP  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5P$4 =z91  
} 0P(!j_
2m  
1>&]R=  
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Utility.log("Thread " + nThreadID + " is over!");  ^Va1f'g  
bDownOver = true; H$KTo
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//nPos = fileAccessI.write (b,0,nRead); F*K_+ ?m  
}  _\HQvH  
catch(Exception e){e.printStackTrace ();} 4YX3+oS  
} 7`hP?a=  
} =6#Eh=7N  
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//打印回应的头信息 -7(@1@1  
public void logResponseHead(HttpURLConnection con) I,'
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{ jMDY(mwt  
for(int i=1;;i++) <1COZ)  
{ 9RI-Lq`  
String header=con.getHeaderFieldKey(i); m<g~H4  
if(header!=null) CWP2{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); I15{)o(8$  
Utility.log(header+" : "+con.getHeaderField(header)); c\V7i#u[d;  
else )@'}\_a3[]  
break; ]}(H0?OQR  
} P}G+4Sk  
} D{~fDRR  
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public void splitterStop() iRi-cQVy  
{ %-e 82J1  
bStop = true; s&!a  
} x~j`@k,;  
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} QW~1%`  
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/* lR6x3C H@  
**FileAccess.java pQ<Y:-`c  
*//文件访问(定位，写) az|N-?u  
package NetFox; 5j-YM  
import java.io.*; _Z,\Vw:\F  
^Zy%fv,  
*~j@*{u  
public class FileAccessI implements Serializable{ Vr1<^Ib  
(41|'eB\\  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^4Ah_U  
RandomAccessFile oSavedFile; 9Ly]DZ;L  
long nPos; qH6>!=00  
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public FileAccessI() throws IOException usL* x
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{ f[^Aw(o  
this("",0); 84pFc;<  
} =+MPFhvg!  
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public FileAccessI(String sName,long nPos) throws IOException x`IEU*z#  
{ ([LSsZ]sj  
oSavedFile = new RandomAccessFile(sName,"rw"); 4u47D$=  
this.nPos = nPos; ["e3Ez  
oSavedFile.seek(nPos); U\<?z Dw  
} 7y@Pa&^8  
WYYa/,{9.  
)$bS}.  
public synchronized int write(byte[] b,int nStart,int nLen) do+.aOC  
{ @)&=%  
int n = -1; n%s]30Xs  
try{ "?I y(*^  
oSavedFile.write(b,nStart,nLen); 2WV
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n = nLen; (<oyN7NT  
} ?r2` Q  
catch(IOException e) LRG6
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{ pWsDzb6?%  
e.printStackTrace (); fG(SNNl+D  
} TNh1hhJ$b  
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return n; \:ak ''  
} |(L
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} 8j %Tf;  
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/* O[)kboY  
**SiteInfoBean.java 5m(^W[u `  
*/ Q &K  
package NetFox; rOOT8nkR#  
b4ONh%  
A_5P/ARmI  
public class SiteInfoBean { 0h\smqm  
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private String sSiteURL; //Site's URL vucxt }Ti  
private String sFilePath; //Saved File's Path Om@C X<(9C  
private String sFileName; //Saved File's Name :GP]P^M;G@  
private int nSplitter; //Count of Splited Downloading File ApV~(k)W  
Uu(SR/R}  
V<uR>TD(  
public SiteInfoBean() z]?N+NHOA  
{//nSplitter的缺省值为5 l6 H|PR{  
//default value of nSplitter is 5 \(Y\|zC'0$  
this("","","",5); {I#]@,  
} mFaZio0GK  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) (/j/>9iro  
{ T iiWp!mX  
sSiteURL= sURL; H>B&|BO_[  
sFilePath = sPath; {Um)15K  
sFileName = sName; wlk4*4dKn  
this.nSplitter = nSpiltter; (HE9V]  
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} E:}r5S)4  
Ww%=1M]e-  
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public String getSSiteURL() 4$S;(  
{ ~h85BF5  
return sSiteURL; q~ZNd3O  
} ?!cvf{a  
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71gT.E  
public void setSSiteURL(String value) $5<#n@  
{ $#S&QHyEe  
sSiteURL = value; b+6\JE^Mz  
} A '5,LfTu  
DYxCQ D  
v+`N*\J_  
public String getSFilePath() pDIVZC  
{ vchm"p?9)  
return sFilePath; uPG4V2  
} 2fR02={-  
2Mmz%S'd  
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public void setSFilePath(String value) s,=i_gyPQ  
{ orfO^;qTY  
sFilePath = value; !0@Yplj  
} U4-g^S[  
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public String getSFileName() M#VE]J  
{ /ZPyN<@  
return sFileName; `~Zs0  
} QQ~-  
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public void setSFileName(String value) 0#&5.Gr)  
{ - 'W++tH=  
sFileName = value; uv(Sdiir8  
} -Sx\Xi"<o=  
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Vz)`nmO}5\  
public int getNSplitter() 

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{ &<J[Q%2  
return nSplitter; Uo>]sNP~  
} 2hkRd>)&
5  
5>j)kx=J9
 
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public void setNSplitter(int nCount) TAF PawH  
{ h`k"A7M  
nSplitter = nCount; /[)qEl2]K  
} 6&l+0dq  
} rIhl.5Y  
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s,n0jix@  
/* `gb5"`EZ  
**Utility.java ez^@NK
 
*/ %S nd\  
package NetFox; #Av.iAs  
;@Z#b8aM}  
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public class Utility { "xHgqgFyO  
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public Utility() 3G~@H>j  
{ Z1Z1@2 T
 
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} oifv+oY  
B'EKM)dA  
//线程睡眠 /)(#{i*  
public static void sleep(int nSecond) ;Tc`}2  
{ xs:n\N  
try{
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Thread.sleep(nSecond); ~UjGSO)z}  
} uYil ?H{kH  
catch(Exception e) nwaxz>;  
{ ]=";IN:SU  
e.printStackTrace (); GBFtr
 
} [7S} g  
} dW~*e2nq  
j;3[KLmuK%  
//日志 o1Q7Th  
public static void log(String sMsg) fasgmi}  
{ FE!lok  
System.err.println(sMsg); sHl>$Qevz  
} 3?P
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#ap9Yoyk\  
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public static void log(int sMsg) ixQJ[fH10  
{ XWs"jt  
System.err.println(sMsg); pV,P|>YTf  
} GJp85B!PlO  
} qfz8jY]  
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oK%K}{`  
/* hcbv;[bG  
**TestMethod.java A\#P*+k0  
*/ jR#~I@q^  
package NetFox; dwd:6.J(  
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public class TestMethod { >Ll$p0W  
@wC5 g 4E  
i'wAE:Xe  
public TestMethod() /'DsB%7g  
{ ///xx/weblogic60b2_win.exe YH
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try{ -!L"'
)  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); X'% ;B  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); QZhjb
  
SiteFileFetch fileFetch = new SiteFileFetch(bean); g HbxgeL  
fileFetch.start(); 6]pX>Xho  
} Y.U[wL>  
catch(Exception e){e.printStackTrace ();} T%n2$  
{Gw.l."  
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} V-r3-b  

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public static void main(String[] args) &o97u4xi  
{ 3lq Mucr  
new TestMethod(); TkO[rAC  
} 4bJZmUb  
} Mz;[+p  
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