http断点续传简单实现（java)

/* RAPR-I;{  
**SiteFileFetch.java ><^ ,  
*/ @w?hXK=  
package NetFox; '_>8_  
import java.io.*; 'Y`or14E  
import java.net.*; DY1UP(y  
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public class SiteFileFetch extends Thread { OF-$*  
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SiteInfoBean siteInfoBean = null; //文件信息Bean .]24V!J(1w  
long[] nStartPos; //开始位置 q-}qrg  
long[] nEndPos; //结束位置 R `  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 c<Fr^8  
long nFileLength; //文件长度 /?VwoSgV^  
boolean bFirst = true; //是否第一次取文件 g[4pG`z  
boolean bStop = false; //停止标志 &#_c,c;  
File tmpFile; //文件下载的临时信息 ^zn&"@  
DataOutputStream output; //输出到文件的输出流 J#ujIe  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） hT go  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3RJsH:u8  
{ `)?N7g[\u  
siteInfoBean = bean; 0o7*5| T4  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /fv;`?~d*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); #TS:|
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if(tmpFile.exists ()) ,v,#f .  
{ Qh3BI?GZ'3  
bFirst = false; }LeizbU  
read_nPos(); wwUa+6?  
} (ZSd7qH"  
else d;@"Naw  
{ ~HBQQt  
nStartPos = new long[bean.getNSplitter()]; VUmf;~  
nEndPos = new long[bean.getNSplitter()]; cao=O \Y7  
} %?2y2O,;  
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} zl $mt'\y  
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public void run() e|> 5 R  
{ Ui|z#{8&  
//获得文件长度 }ff+RGxLIG  
//分割文件 z*k(` '  
//实例FileSplitterFetch mUA!GzJ~u-  
//启动FileSplitterFetch线程 SR_<3WW  
//等待子线程返回 v9*31Jx  
try{ ]"ou?ot }  
if(bFirst) s k_TKN`+  
{ Uhs/F:E[A  
nFileLength = getFileSize(); 4Dy|YH$>S  
if(nFileLength == -1) *\gYs{,  
{ +cWo^d.  
System.err.println("File Length is not known!"); 1 K(0tG:5  
} 0#Ae<  
else if(nFileLength == -2) 717S3knlv  
{ 3LRBH+Tt  
System.err.println("File is not access!"); ^m Ua5w  
} 6U9FvPJ  
else ~)CGwST[  
{ qf T71o(  
for(int i=0;i<nStartPos.length;i++) 7w\L<v
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{ };Pdn7;1G:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); g~p43sVV  
} BD,J4xH;  
for(int i=0;i<nEndPos.length-1;i++) fj|X`,TiZ;  
{ tJ$gH;  
nEndPos = nStartPos[i+1]; 2Y>#FEW/  
} U'@#n2p:k  
nEndPos[nEndPos.length-1] = nFileLength; +N}yqgE  
} ;"B@QPX  
} []:&WA9N  
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//启动子线程 d0V*[{  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 7y4jk  
for(int i=0;i<nStartPos.length;i++) \&/V p`  
{ X6<Ds'I  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l#IN)">1
 
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), YJGP8  
nStartPos,nEndPos,i);
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [[#zB-|  
fileSplitterFetch.start(); m`BE{%  
} |BBo  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $+|. @ss  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); E5qt~:C|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", i0nu5kD+d  
nEndPos = " + nFileLength); ?t)Mt]("  
// fileSplitterFetch[nPos.length-1].start(); a(IUAh*mO  
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//等待子线程结束 TXT!Ae  
//int count = 0; _9yW; i-  
//是否结束while循环 2q4-9vu  
boolean breakWhile = false; >N~orSw%  
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while(!bStop) j-#h^3l1?  
{ )=nB32~J"  
write_nPos(); b$q~(Z}  
Utility.sleep(500); V3Ep&<=/  
breakWhile = true; %6\L^RP  
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for(int i=0;i<nStartPos.length;i++) 9zl-C*9vj  
{ MbxJ3"@  
if(!fileSplitterFetch.bDownOver) Q[Gs%/>  
{ (QTQxZ
 
breakWhile = false; "[ieOFI  
break; M1=eS@  
} {>UT'fa-  
} .On3ZN  
if(breakWhile) h<G7ocu!  
break; ; GEr8_7  
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//count++; !t[;~`d9  
//if(count>4) qND:LP\_v  
// siteStop(); O{p7I&  
} e(I;[G +%,  
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System.err.println("文件下载结束！"); 
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} uuQsK. S  
catch(Exception e){e.printStackTrace ();} 97dF  
} =)}Yw)
 
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//获得文件长度 >}B53.;.k  
public long getFileSize() tzY?LX[3  
{ L|8&9F\  
int nFileLength = -1; %%9T-+T  
try{ _yp<#q]  
URL url = new URL(siteInfoBean.getSSiteURL()); 1,Jy+1G0w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >y+?Sz!  
httpConnection.setRequestProperty("User-Agent","NetFox"); @O/"s~d-  
Yfx?3  
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int responseCode=httpConnection.getResponseCode(); )-m/(-  
if(responseCode>=400) zSjZTA/Z  
{ j$<g8Bg=o  
processErrorCode(responseCode); 85q!FpuH  
return -2; //-2 represent access is error '|}H,I{  
} 5&.I9}[)j  
I+QM":2  
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String sHeader; E5?$=cL?  
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for(int i=1;;i++) Wngc(+6O&  
{ _q4Yq'dI  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); cfPp>EK  
//Utility.log(in.readLine()); k(xB%>ns  
sHeader=httpConnection.getHeaderFieldKey(i); %XQJ!sC`  
if(sHeader!=null) {8 &=t8,c  
{ vXZ )  
if(sHeader.equals("Content-Length")) pgW^h
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{ %jJIR88  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Q9c*I,Oj  
break; N/[!$B0H@  
} 3vkzN  
} "MD6<H  
else A@;{#.O  
break; mKoDy`s  
} ['Qh#^p  
} l3+G]C&<  
catch(IOException e){e.printStackTrace ();} 3sgo5D-rMI  
catch(Exception e){e.printStackTrace ();} /z(d!0_q|v  
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Utility.log(nFileLength); mz<X$2]?  
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return nFileLength; Zq'FOzs  
}
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//保存下载信息（文件指针位置） nkz<t   
private void write_nPos() xVrLoAw  
{ ]z2x`P^oI  
try{ 2&=CC4<!d  
output = new DataOutputStream(new FileOutputStream(tmpFile)); %q.5;L  
output.writeInt(nStartPos.length); 6\Tq,I7  
for(int i=0;i<nStartPos.length;i++) B`w8d[cL7  
{ a|DCpU}  
// output.writeLong(nPos); IpM"k)HR  
output.writeLong(fileSplitterFetch.nStartPos); )NTpb  
output.writeLong(fileSplitterFetch.nEndPos); iVo-z#  
} eep/96G ?  
output.close(); %TO&  
} L8oqlq( 9  
catch(IOException e){e.printStackTrace ();} q^uCZnkb=  
catch(Exception e){e.printStackTrace ();} NZlCn:"  
} a p(PI?]X  
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>;#rK@*&  
//读取保存的下载信息（文件指针位置） Y5P9z{X=  
private void read_nPos()
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{ WqS$C;]%  
try{ rCb$^(w{7  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Y/LS(b*  
int nCount = input.readInt(); "Bz#5kqnl  
nStartPos = new long[nCount]; VA`VDUG,  
nEndPos = new long[nCount]; PP/#Z~.M  
for(int i=0;i<nStartPos.length;i++) $GOF'  
{ 2@Q5Ta#h  
nStartPos = input.readLong(); ].Ra=^q  
nEndPos = input.readLong(); t3*.Bm:^  
} }2^qM^,0  
input.close(); We*uZ?+  
} $@w,9J\  
catch(IOException e){e.printStackTrace ();} NBAOVYK  
catch(Exception e){e.printStackTrace ();} zn0%%x+!g  
} oTr,zRL  
CYsLyk  
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private void processErrorCode(int nErrorCode) EpTc{  
{ o5YL_=7m  
System.err.println("Error Code : " + nErrorCode);
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} >>M7#hmt  
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//停止文件下载 1;!dTh  
public void siteStop() Pa=xc>m^  
{ vbtjPse  
bStop = true; eT?vZH[N  
for(int i=0;i<nStartPos.length;i++) `uqe[u;`6  
fileSplitterFetch.splitterStop(); C0khG9,BL  
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} e&K7n
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} r1z+yx  
//负责部分文件的抓取 m:k;?p:x  
**FileSplitterFetch.java *g9VI;X  
*/ p9!jM\(  
package NetFox; ')iyD5/4  
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import java.io.*; l[<o t9P[  
import java.net.*; l*Fp}d.  
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public class FileSplitterFetch extends Thread { .Q{VY]B^  
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String sURL; //File URL i?V:+0#q\]  
long nStartPos; //File Snippet Start Position 7f*b5$+r  
long nEndPos; //File Snippet End Position |o^mg9  
int nThreadID; //Thread's ID j'Gezx^.<e  
boolean bDownOver = false; //Downing is over &g=6K&a$a  
boolean bStop = false; //Stop identical {$7vd  
FileAccessI fileAccessI = null; //File Access interface .
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ,>nf/c0.  
{ !<F5W<V  
this.sURL = sURL; .3>q3sS  
this.nStartPos = nStart; ^rGuyW#  
this.nEndPos = nEnd; ];eJ'#  
nThreadID = id; d"a\`#  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9)n3f^,Oj*  
} QVmJ_WT  
!,sQB_09C  
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public void run() Wd7qpWItjQ  
{ m!(dk]  
while(nStartPos < nEndPos && !bStop) &#9HV  
{ )Ofwfypc  
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try{ \_)mWK,h  
URL url = new URL(sURL); p77=~s  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '*`1uomeo  
httpConnection.setRequestProperty("User-Agent","NetFox"); Z4{N
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String sProperty = "bytes="+nStartPos+"-"; T:!H^  
httpConnection.setRequestProperty("RANGE",sProperty); sdKm@p|/|  
Utility.log(sProperty); fF5\\_,  
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InputStream input = httpConnection.getInputStream(); XAB/S8e  
//logResponseHead(httpConnection); 7{VN27Fa_  
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byte[] b = new byte[1024]; 0OnqKgf  
int nRead; }_Y\6fcd  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) a,:Nlr3  
{  Sg(\+j=  
nStartPos += fileAccessI.write(b,0,nRead); &$h#9  
//if(nThreadID == 1) MB6lKLy6~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nFefDdP  
} ,8DjQz0ZPo  
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Utility.log("Thread " + nThreadID + " is over!"); ~!e(e2  
bDownOver = true; \}gITc).j  
//nPos = fileAccessI.write (b,0,nRead); Re1}aLd  
} awLSY:JI  
catch(Exception e){e.printStackTrace ();} GwG(?_I"  
} MEtKFC|p  
} V9;IH<s:  
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jk])S~xl?  
//打印回应的头信息 ph3dm\U.  
public void logResponseHead(HttpURLConnection con) C2L=i3R  
{ 0{stIgB$  
for(int i=1;;i++) DRRy5+,I  
{ }9Q<<
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String header=con.getHeaderFieldKey(i); &hWYw+yH\  
if(header!=null) Q:]v4/MT  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); WVx^}_FD0  
Utility.log(header+" : "+con.getHeaderField(header)); `Tr !Gj_  
else '=UsN_@  
break; ~S0T+4$  
} l i%8X.  
} \'B%lXh  
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public void splitterStop() !6J+#  
{ Enhrkk  
bStop = true; zbDK$g6  
} p0pA|  
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} Xs)?PE[   
)!sjXiC!h  
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/* wNl "y  
**FileAccess.java 8]JlYe  
*//文件访问(定位，写) GJBMaT  
package NetFox; K3`48,`?wA  
import java.io.*; >NA{**$0  
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public class FileAccessI implements Serializable{ wR9gx-bE 4  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 vARZwIu^D  
RandomAccessFile oSavedFile; :]`JcJ  
long nPos; %z["TVH  
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public FileAccessI() throws IOException p
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{ oN(F$Nvk  
this("",0); ;!<@Fm9W  
} f'u[G?C  
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public FileAccessI(String sName,long nPos) throws IOException .1[pO_  
{ I!~3xZ  
oSavedFile = new RandomAccessFile(sName,"rw"); QaAMiCZFR  
this.nPos = nPos; ^K!R4Y4t  
oSavedFile.seek(nPos); ;Y$d!an0  
} )GJlQ1x  
z_:r&UP`"  
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public synchronized int write(byte[] b,int nStart,int nLen) :LD+B1$y  
{ XQj+]-m  
int n = -1; wKy4Ic+RV  
try{ SXmh@a"*\  
oSavedFile.write(b,nStart,nLen); K(}<L-cv  
n = nLen; ns&(
g^  
} `u7twW*U2  
catch(IOException e) Ap`D{u/  
{ ~h444Hp=  
e.printStackTrace (); \3cg\Q+~  
} OLDEB.@  
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{ALOs^_-  
return n; -V}ZbXJD  
} &fifOF#[e  
[&{NgUgu"  
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} )H1chNI)  
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/* 4\2~wS
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**SiteInfoBean.java OC2%9Igx0  
*/ s9BdmD^|#  
package NetFox; _P{v=`]Eu  
f
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public class SiteInfoBean { /Pa<I^-#  
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private String sSiteURL; //Site's URL t($z+C<  
private String sFilePath; //Saved File's Path 6bt{j   
private String sFileName; //Saved File's Name 9;EY3[N  
private int nSplitter; //Count of Splited Downloading File  SwmX_F#_  
A>}]=Ii/  
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public SiteInfoBean() 0
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{//nSplitter的缺省值为5 x`p3I*_HT5  
//default value of nSplitter is 5 .y~~[QF}8  
this("","","",5); "RsH
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} yykyvy  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ~8G cWy6  
{ |-VbJd  
sSiteURL= sURL; w3peG^4D_  
sFilePath = sPath; |}K7Q  
sFileName = sName; `H\NJ,  
this.nSplitter = nSpiltter; \fD[Ej  
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} ki|w?0s  
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public String getSSiteURL() Q$DF3[NC  
{ k3t2{=&'&x  
return sSiteURL; [0hZg  
} 7$I *ju_  
.AZ+|?d  
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public void setSSiteURL(String value) FI(M 1iJ  
{ U>_#,j  
sSiteURL = value; WnC0T5S?U  
} GE.@*W  
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public String getSFilePath() -<B{?D  
{ NbW5a3=  
return sFilePath; <(-4?"1  
} 9 !qVYU42(  
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public void setSFilePath(String value) d@t3C8  
{ $~*d.  
sFilePath = value; L\asrdL?=  
} "n=Ih_J  
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public String getSFileName() -2Azpeh  
{ gedk  
return sFileName; %epK-q9[  
} ZI#Xh5  
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public void setSFileName(String value) b(H)8#C  
{ q! U
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sFileName = value; 7?JcB?G4  
} Dbo.N`  
*d/]-JN,K  
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public int getNSplitter() 8RR6f98FF  
{ ;]^JUmxU[d  
return nSplitter; ^@..\X9  
} +bK.{1  
mg^\"GC*8  
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public void setNSplitter(int nCount) wh;E\^',n  
{ in6iJ*E@'  
nSplitter = nCount; L)ry!BuHI  
} #FV(a~  
} o<-+y\J8K  
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?
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/* d\ Z#XzI8  
**Utility.java v+Q#O[  
*/ (_lc< Bj  
package NetFox; 'u2Qq"d+
 
?k:i3$  
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public class Utility { BOp&s>hI  
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public Utility() [2,u:0"  
{ jP";ll|c  
[Pt5c6L:  
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} ynN[N(m#  
G{ $Zg  
//线程睡眠 %R{clbbbn  
public static void sleep(int nSecond) -h8!O+7 .  
{ }?Y+GT"E  
try{ VmB/X))  
Thread.sleep(nSecond); (IR'~:W  
} W$B
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catch(Exception e) P( W8XC  
{ o;JBe"1  
e.printStackTrace (); I -obfyije  
} jjm-%W@  
} u[oYVpe)IG  
&7X0 ;<  
//日志 >:`Y]6z  
public static void log(String sMsg) ;
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{ ~I>B5^3  
System.err.println(sMsg); U9xFQ=$2  
} 'vTD7a^  
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kc8T@5+I0  
public static void log(int sMsg) *R>I%?]V3  
{ *#;rp~  
System.err.println(sMsg); !`='K +  
} +-#| M|a  
} }h>e=<  
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xZmKKKd0*  
/* /BVNJNhz  
**TestMethod.java [:!#F7O-  
*/ ,9"</\]`  
package NetFox; <S0!$.Kg*<  
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ki^[~JS>'  
public class TestMethod { N2tvP+Z6D  
Xb3vvHdI  
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public TestMethod() u6jJf@!ws  
{ ///xx/weblogic60b2_win.exe (s{%XB:K  
try{ Af0E_  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); a@,tf'Sr  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); S-yd-MtQp  
SiteFileFetch fileFetch = new SiteFileFetch(bean); xMhR;lKY  
fileFetch.start(); K"b vUH  
} Hv0sl+  
catch(Exception e){e.printStackTrace ();} p9_45u`u2  
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zAB-kE\)  
} k=bv!T_o  
n*iaNaU"'  
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public static void main(String[] args) +U%lWE%  
{ _zm<[0(  
new TestMethod(); }+#ag:M  
} qm]ljut  
} #>ci!4Gz=Z  
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