http断点续传简单实现（java)

/* 0*$?=E  
**SiteFileFetch.java BN\Y N  
*/ >F7v'-*{  
package NetFox; vU|=" #  
import java.io.*; |hGi8  
import java.net.*; kD1[6cJ!=.  
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public class SiteFileFetch extends Thread { )2
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SiteInfoBean siteInfoBean = null; //文件信息Bean R;D|To!  
long[] nStartPos; //开始位置 F&pJ faig  
long[] nEndPos; //结束位置 BhFyEY(  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 5}-e9U  
long nFileLength; //文件长度 !| ObNS  
boolean bFirst = true; //是否第一次取文件 Sy\ec{$+V]  
boolean bStop = false; //停止标志 o&-c5X4  
File tmpFile; //文件下载的临时信息 =XAFW  
DataOutputStream output; //输出到文件的输出流 HYqDaRn  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） [@K#BFA  
public SiteFileFetch(SiteInfoBean bean) throws IOException leY f
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{ ";vP77|m7R  
siteInfoBean = bean; )S~ySiJ<U  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); oW7\T!f  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &4]~s:F  
if(tmpFile.exists ()) #i6ZY^+ee  
{ Iq/V[v  
bFirst = false; *Y"j 0Yob  
read_nPos(); f\cm84  
} bSbUf%LKt  
else a[).'$S}'  
{ a
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nStartPos = new long[bean.getNSplitter()]; 1uz7E  
nEndPos = new long[bean.getNSplitter()]; ZV,1IaO  
} tZ4Zj`x|^  
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} *21foBfqh  
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public void run() BZUA/;Hz &  
{ &n 1 \^:  
//获得文件长度 IgxZ_2hO  
//分割文件 (A<'{J#5,  
//实例FileSplitterFetch bi=IIVlH  
//启动FileSplitterFetch线程 iRwlK5(&  
//等待子线程返回 F@C^nX9  
try{ A]x'!qa@=  
if(bFirst) 4|yZA*Q^  
{ @20~R/vh  
nFileLength = getFileSize(); &i/QFO7y}  
if(nFileLength == -1) WJXQM[  
{ !`UHr]HJ  
System.err.println("File Length is not known!"); %+Az X  
} %BV2 q  
else if(nFileLength == -2) )'pc1I  
{ iD/
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System.err.println("File is not access!"); '5:P,1tWU  
} B%~D`[~?  
else \@%sX24D  
{ WZ#|?pJ  
for(int i=0;i<nStartPos.length;i++) j
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{ d|~A>YZ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); k~P{Rm;F  
} ~C;1}P%9x  
for(int i=0;i<nEndPos.length-1;i++) OI0tgkG  
{ W5#5RK"uX  
nEndPos = nStartPos[i+1]; ga#Yd}G^~3  
} |N^z=g P[  
nEndPos[nEndPos.length-1] = nFileLength;  ~wX4j  
} NEY b-#v  
} h3z=tu['  
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}zK/43Vx  
//启动子线程 ohy?l  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; jT6zpi~]E  
for(int i=0;i<nStartPos.length;i++) @X\2K?c(v  
{ T@. $Zpz  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y64B"J=P9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), x?|C-v  
nStartPos,nEndPos,i); P0/B!8x  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *,Mg  
fileSplitterFetch.start(); Xy;!Q`h(  
} .JJ^w!|>#  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), NbDfD3 1GK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); G0u3*.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", s</llJ$  
nEndPos = " + nFileLength); #_zd`s3k  
// fileSplitterFetch[nPos.length-1].start(); Qey6E9eCA  
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4Pm
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//等待子线程结束 p| #gn<z}  
//int count = 0; O8J:Tw}M*  
//是否结束while循环 UdS
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boolean breakWhile = false; 6BPZ2EQ  
|B0.*te6  
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while(!bStop) lQ}e"#<  
{ &dC #nw  
write_nPos(); [H3~b=  
Utility.sleep(500); Q I.
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breakWhile = true; UpA{$@  
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for(int i=0;i<nStartPos.length;i++) BhMHT:m  
{
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if(!fileSplitterFetch.bDownOver) 9hG+?   
{ YBX7WZCR  
breakWhile = false; T21SuM  
break; 0H V-e  
} &M,"%w!  
} BBg&ZIYEh  
if(breakWhile) C~5-E{i  
break; E9Q?@'h  
;-G!jWt6Zi  
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//count++; 7 %P?3  
//if(count>4) ]/d4o  
// siteStop(); ,8F?v~C  
} >%"Q]p  
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kRk=8^."By  
System.err.println("文件下载结束！"); zn4Yo  
} 10/N-=NG18  
catch(Exception e){e.printStackTrace ();} FC= %_y  
} n.m6n*sf7  
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MRB>(}  
//获得文件长度 3xW;qNj:!l  
public long getFileSize() ;'Pi(TA)  
{ 'z#{'`$a  
int nFileLength = -1; (VPT% l6  
try{ !n`ogzOh  
URL url = new URL(siteInfoBean.getSSiteURL()); jH*+\:UP-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); VesO/xG<  
httpConnection.setRequestProperty("User-Agent","NetFox"); o3;u*f0rWn  
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int responseCode=httpConnection.getResponseCode(); zN\~v  
if(responseCode>=400) C/P,W>8  
{ {C%/>e2-%  
processErrorCode(responseCode); S|A?z)
I  
return -2; //-2 represent access is error %@!Vx  
} HY]vaA`  
{PM)D [$i  
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String sHeader; X7sWu{n  
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for(int i=1;;i++) -(n[^48K  
{ qj71 rj  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Ru?Ue4W^b  
//Utility.log(in.readLine()); Ii?"`d+JA  
sHeader=httpConnection.getHeaderFieldKey(i); .P=uR8  
if(sHeader!=null) 9?*BN
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{ Z_qs_/y  
if(sHeader.equals("Content-Length")) b; SFnZa8  
{ S.+)">buH  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); @o+T<}kWX  
break; SnbH`\U"  
} IbpE@C  
} N(?yOB4gt  
else xG_ ;F  
break; {rWu`QT  
} +q]  
} a9GOY+;bf  
catch(IOException e){e.printStackTrace ();} R]%ZqT{PS  
catch(Exception e){e.printStackTrace ();} h2Ifq!(:  
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Utility.log(nFileLength); laM0W5  
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return nFileLength; gKg2Ntx
j  
} )o[ O%b  
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xZ@H{):  
//保存下载信息（文件指针位置） b?oT|@  
private void write_nPos() VEd#LSh  
{ O0"i>}g4  
try{ a4,bP*H  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Do(7LidC5  
output.writeInt(nStartPos.length); qy@gW@IU  
for(int i=0;i<nStartPos.length;i++) [E(DGt  
{ J`O4]XRY  
// output.writeLong(nPos); 1!\!3xaV  
output.writeLong(fileSplitterFetch.nStartPos); xIF z@9+k  
output.writeLong(fileSplitterFetch.nEndPos); RlX;c!K  
} jh]wHG  
output.close(); ',0~\V  
} vj
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catch(IOException e){e.printStackTrace ();} ]}9y>+>  
catch(Exception e){e.printStackTrace ();} #;H,`r  
} `QR2!W70o3  
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//读取保存的下载信息（文件指针位置） wC
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private void read_nPos() ja~b5Tf9  
{ @( 9#\%=  
try{ Ts;W,pgP  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Wuosr3P  
int nCount = input.readInt(); mN?'Aey  
nStartPos = new long[nCount]; "yc/8{U  
nEndPos = new long[nCount]; 1X2oz  
for(int i=0;i<nStartPos.length;i++) C[rYV
a .  
{ U:MkA(S%c  
nStartPos = input.readLong(); <_ */  
nEndPos = input.readLong(); _\"P<+!  
} #rV=!j||  
input.close(); @DkPJla&  
} N)RWC7th{  
catch(IOException e){e.printStackTrace ();} _OcgD<  
catch(Exception e){e.printStackTrace ();} }QncTw0  
} fB"3R-H?O  
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private void processErrorCode(int nErrorCode) 5]; 8
 
{ ;k7` `  
System.err.println("Error Code : " + nErrorCode); 6kT l(+  
} xbo-~{  
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VR_+/,~  
//停止文件下载 Q|gun}  
public void siteStop() D5T\X-+]O  
{ 6FSw_[)  
bStop = true; .2 UUU\/5  
for(int i=0;i<nStartPos.length;i++) 2k"a%#H8  
fileSplitterFetch.splitterStop(); /~7H<^}  
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} FEaf&'G]  
} P xpz7He  
//负责部分文件的抓取 Di*+Cz;gK  
**FileSplitterFetch.java An[*Jx  
*/ 4>Uo0NfL  
package NetFox; l(=#c
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import java.io.*; r=L9x/r  
import java.net.*; qR]4m]o  
![abDT5![  
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public class FileSplitterFetch extends Thread { &O0+\A9tP  
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String sURL; //File URL }~QB2&3  
long nStartPos; //File Snippet Start Position mSwOP  
long nEndPos; //File Snippet End Position 5Tu#o()  
int nThreadID; //Thread's ID l`I]eTo)^  
boolean bDownOver = false; //Downing is over {k
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boolean bStop = false; //Stop identical f[.hN  
FileAccessI fileAccessI = null; //File Access interface W]
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException h%=b"x  
{ ;\<?LTp/r  
this.sURL = sURL; Z(as@gjH  
this.nStartPos = nStart; c_ygwO3.Q  
this.nEndPos = nEnd; }lpcbm  
nThreadID = id; [po+a@ %  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 kOdS^-  
} =53LapTPJ  
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public void run() @/$mZ]|T  
{ F|P2\SPL  
while(nStartPos < nEndPos && !bStop) "bf8[D  
{ n+Ag|.,|  
Z7.)[ ;  
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try{ BLaXp0  
URL url = new URL(sURL); 'dU$QO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Jh466; E  
httpConnection.setRequestProperty("User-Agent","NetFox"); [0&Lvx  
String sProperty = "bytes="+nStartPos+"-"; &/JnAfmYqt  
httpConnection.setRequestProperty("RANGE",sProperty);
wkJB5i^<w  
Utility.log(sProperty); GV[%P  
_L$)~},cT  
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InputStream input = httpConnection.getInputStream(); E0O{5YF^T  
//logResponseHead(httpConnection); FJU)AjS~  
^w&TTo(  
)D[xY0Y~  
byte[] b = new byte[1024]; }7.q[ ^oF  
int nRead; akCl05YW  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) M;iaNL(  
{ l?FNYvL  
nStartPos += fileAccessI.write(b,0,nRead); C>K/C!5?  
//if(nThreadID == 1) _ZS<zQ'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); t9`NCng 5  
} dhVwS$O )  
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1MahFeQ[  
Utility.log("Thread " + nThreadID + " is over!"); 8OFrW.>[  
bDownOver = true; vq5I 2  
//nPos = fileAccessI.write (b,0,nRead); <M&]*|q>g%  
} n/|/Womr  
catch(Exception e){e.printStackTrace ();} epG;=\f}m`  
} w5*18L=O\  
} ^U`q1Pg5  
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//打印回应的头信息 njq-
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public void logResponseHead(HttpURLConnection con) &pba~X.u  
{ 2(c#m*Q!b  
for(int i=1;;i++) kcOpO<oE  
{ Xj@Kt|&`k  
String header=con.getHeaderFieldKey(i); ]yIy~V  
if(header!=null) wlpbfO e/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ):|)/ZiC'  
Utility.log(header+" : "+con.getHeaderField(header)); ?Jr<gn^D  
else /N^+a-.Qd  
break; u?J(l)gd  
} CD tYj  
} Q-au)R,  
-[`W m7en  
5:PZ=jPR  
public void splitterStop() B}FF |0<  
{ R|M:6]}   
bStop = true; s24H.>Z  
} C {,d4KG  
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} f7W=x6Z4  
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/* (\I =v".  
**FileAccess.java 0=5i\*5 p  
*//文件访问(定位，写) B~ez>/H^  
package NetFox; 2?ednMoE  
import java.io.*; >lj3MNSH  
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public class FileAccessI implements Serializable{ s6]f#s5o  
bc"N  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 POG5x  
RandomAccessFile oSavedFile; +OH."4Z  
long nPos; V&nN/CF  
.=FJ5?:4i%  
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public FileAccessI() throws IOException 2X]\:<[4  
{ B>mQ\Q  
this("",0); !INr  
} M@K[i*e  
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public FileAccessI(String sName,long nPos) throws IOException onlyvH4  
{ /PCQv_Y&,/  
oSavedFile = new RandomAccessFile(sName,"rw"); yh)q96m-V=  
this.nPos = nPos; BdKwWgi+a  
oSavedFile.seek(nPos); **"P A8  
} @hvq,[  
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hJ@nW5CI  
public synchronized int write(byte[] b,int nStart,int nLen) ^v'Lu!\f  
{ {8MF!CG]  
int n = -1; 9x1Dyz 2?F  
try{ Z4!3I@yZ  
oSavedFile.write(b,nStart,nLen); |eqDT,4  
n = nLen; 5 9vGLN!L  
} tc',c},h~,  
catch(IOException e) :+=*  
{ IviWS84  
e.printStackTrace (); Pm
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} 21[F%,{.),  
*+z({S_Nv  
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return n; Pla EI p  
} 88K*d8m  
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} /$=^0v+  
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/* 24Fxx9g  
**SiteInfoBean.java Bz{ g4!ku  
*/ S`G\Cd;5  
package NetFox; [ZbK)L+_  
4
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v+G:,Tc"  
public class SiteInfoBean { ;D1IhDC  
+\%zy=  

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private String sSiteURL; //Site's URL SMyg=B\x?7  
private String sFilePath; //Saved File's Path 1dcy+ !>  
private String sFileName; //Saved File's Name MlZ`g,{  
private int nSplitter; //Count of Splited Downloading File L7-n
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nM`)`!/  
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public SiteInfoBean() -,dQ&Qf?  
{//nSplitter的缺省值为5 D|o@(V  
//default value of nSplitter is 5 R;o_*  
this("","","",5); dc)Gk  
} _+En%p.m  
)R4<* /C:w  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) u_BSWhiW  
{ [XXN0+ /  
sSiteURL= sURL; W<Lrfo&=Y]  
sFilePath = sPath;
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sFileName = sName;
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this.nSplitter = nSpiltter; y#+o*(=fRE  
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} J%)2,szn0  
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5[_8N{QC;  
public String getSSiteURL() o1Ln7r.  
{ zTLn*?  
return sSiteURL; Pcs@`&}7r  
} Q-v[O4y~  
lND[anB!  
3p4?-Dd|_$  
public void setSSiteURL(String value) :3f2^(b~^  
{ &}O!l'  
sSiteURL = value; jvQ"cs$.  
} kdCOcJB  
{P&^Erx  
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public String getSFilePath() 9f,:j  
{  >9`ep7  
return sFilePath; m+vEs,W.  
} i7V~LO:gq  
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public void setSFilePath(String value) jhv1 D'>6  
{ cqx1NWlY  
sFilePath = value; }=a4uCE  
} `Ny8u")=  
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5>)jNtZ  
public String getSFileName() / JB4#i7  
{ )*h~dx_cm  
return sFileName; 9#ft;c  
} @ WaYU  
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public void setSFileName(String value) $0T"YC%  
{ 4-_lf(#i  
sFileName = value; 2-aYqMmT;  
} sv"mba.J  
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s2~dmZ_B|_  
public int getNSplitter() AF]!wUKxy  
{ S:/RYT"  
return nSplitter; 1i:g /H  
} OL5HofgNm  
on?/tHys  
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public void setNSplitter(int nCount) 9^ p{/Io  
{ |+-i'N9  
nSplitter = nCount; RWCS u$  
} &pjV4m|j<  
} ~aAJn IO  
b6&NzUt34V  
!"%sp6Wc  
/* @BUqQ9q:  
**Utility.java 3^>a TU<Z  
*/ od*Z$Hb>'  
package NetFox; vN:[  
)C]&ui~1  
?VQLY=?  
public class Utility {  /;6@M=6u  
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public Utility() 2Fgt)`{!  
{ +<9 eN  
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} D1~x  
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//线程睡眠 < iI6@X>  
public static void sleep(int nSecond) ([b!$o<v  
{ y*h1W4:^-  
try{ #Jz&9I<OKx  
Thread.sleep(nSecond); 9zYiG3 d  
} NjN?RB/5  
catch(Exception e) cvE.r330|  
{ LG{inhbp  
e.printStackTrace (); 7'i#!5  
} 6\fMzm  
} RS `9?c:  
U!?gdX  
//日志 5}bZs` C  
public static void log(String sMsg) D%UZ'bHN*  
{ q|i%)V`)-  
System.err.println(sMsg); $?J+dB  
} [[]SkLZHg  
 G].__]  
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public static void log(int sMsg) #z!Hb&Qi\  
{ RB7AI!'a?  
System.err.println(sMsg); $>"e\L4Kp  
} L'XdX\5  
} |F@xwfgb  
xX/s1(P  
IAF;mv}'  
/* Secq^#]8  
**TestMethod.java xVkTRCh  
*/ ( *>/w$%  
package NetFox; 30 [#%_* o  
{&=qM!2e  
w
p%FM  
public class TestMethod { wK'!xH^  
OssR[$69  
(s$u_aq77  
public TestMethod() KBw9(  
{ ///xx/weblogic60b2_win.exe r<X4ER  
try{ %aH$Tb%`hc  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ] @)!:<+  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); XQ3*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 4Kn9*V  
fileFetch.start(); mvq7G  
} PB(  
catch(Exception e){e.printStackTrace ();} mPfUJ#rS  
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} qwF*(pTHq  
S2&9#6  
%8bzs?QI  
public static void main(String[] args) +an^e'  
{ ^{*f3m/
 
new TestMethod(); 2Za,4'  
} w;c#drY7S  
} E {KS a  
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