http断点续传简单实现（java)

/* a=6@} l1<  
**SiteFileFetch.java T#vY(d  
*/ Rv.IHSQUo  
package NetFox; vV"I}L  
import java.io.*; QcjsQTAbk  
import java.net.*; 2av=W  
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public class SiteFileFetch extends Thread { vjA!+_I6  
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SiteInfoBean siteInfoBean = null; //文件信息Bean /fU-0a8  
long[] nStartPos; //开始位置 Fr2F&NN`D  
long[] nEndPos; //结束位置 YHxQb$v)  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :lK8i{o  
long nFileLength; //文件长度 Mq#Hi9SKY  
boolean bFirst = true; //是否第一次取文件 .LbAR u  
boolean bStop = false; //停止标志 46B'Ec  
File tmpFile; //文件下载的临时信息 Q:'r p  
DataOutputStream output; //输出到文件的输出流 bX
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） +I}!)$/  
public SiteFileFetch(SiteInfoBean bean) throws IOException 0sCWIGUW  
{ }j!C+
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siteInfoBean = bean; Lg7dJnf  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); p1T0FBV L  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~aXJ5sY"f&  
if(tmpFile.exists ()) ,F+,A].wG  
{ >\3N#S"PF  
bFirst = false; R0|4KT-i  
read_nPos(); ;hh.w??  
} AOz~@i^  
else U r8JG&,  
{ rX)_!mR  
nStartPos = new long[bean.getNSplitter()]; ]u:Ij|.'y0  
nEndPos = new long[bean.getNSplitter()]; kxmsrQ
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} tJGK9!MH{(  
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} Z
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public void run() Kk|)N3AV:  
{ "I@akM$x  
//获得文件长度 -KZ9TV # R  
//分割文件 ;wZplVB7y  
//实例FileSplitterFetch xlh<}Vtp  
//启动FileSplitterFetch线程 K~fWZT3]  
//等待子线程返回 xU(b:D Z  
try{ st>%U9  
if(bFirst) rqKK89fD'  
{ ^b^buCYw  
nFileLength = getFileSize(); n]>L"D,  
if(nFileLength == -1) =c%gV]>G  
{ #RKd>ig%  
System.err.println("File Length is not known!"); _<l)4A3rS  
} o WAy[  
else if(nFileLength == -2) FtDF
}  
{ 3FMYs&0r4  
System.err.println("File is not access!"); ^Cj3\G4,  
} |D[LU[<C  
else Or55_E  
{ E5
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for(int i=0;i<nStartPos.length;i++) aY DM)b}  
{ pr1kYMrqri  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); \FnR'ne  
} nj-LG!"a  
for(int i=0;i<nEndPos.length-1;i++) 1KjzKFnb  
{ G'wyH[ d/  
nEndPos = nStartPos[i+1]; $J0o%9K   
} !LsIHDs
4  
nEndPos[nEndPos.length-1] = nFileLength; nB}eJD|  
} PtGFLM9R  
} 8?w#=@s  
~3|)[R=+p1  
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//启动子线程 9"}5jq4*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; o :j'd  
for(int i=0;i<nStartPos.length;i++) )q[Wzx_ j<  
{ s%A?B8,  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), aPX'CG4m  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), =<AG}by![  
nStartPos,nEndPos,i); j!@,r^(  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `H9!Z$7G  
fileSplitterFetch.start(); OU*skc>  
} j@4]0o  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mILCC}Kt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); f?(g5o*2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", o?I`n*u"X  
nEndPos = " + nFileLength); 8:Dkf
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// fileSplitterFetch[nPos.length-1].start(); J?1Eh14KZ  
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//等待子线程结束 *zdUCX  
//int count = 0; n-1  
//是否结束while循环 P!{J28dj  
boolean breakWhile = false; anORoK.  
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while(!bStop) TxTxyYd  
{ /2 qxJvZ  
write_nPos(); pi/&WMZ<  
Utility.sleep(500); A[^k
4>  
breakWhile = true; bzZ7L-yD  
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)X3A(^  
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for(int i=0;i<nStartPos.length;i++) OD?y  
{ mt[ #=Yba  
if(!fileSplitterFetch.bDownOver) gOp81)  
{ !
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breakWhile = false; HaRx(p0  
break; 5JG`FRW!  
} om6`>I*  
} 3w/z$bj  
if(breakWhile) b$tf9$f  
break; 7_eV.'h  
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{yMkd4v  
//count++; "S>VqvH3  
//if(count>4)
;R3o$ZlY  
// siteStop(); j_b/66JyN  
} Zj0h0Vt  
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System.err.println("文件下载结束！"); ('.I)n  
} ]
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catch(Exception e){e.printStackTrace ();} ~h%H;wC&  
} q35=_'\W  
g<:TsP'|  
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//获得文件长度 v7@*dg  
public long getFileSize() ciW;sK8  
{ r>rL[`p(2  
int nFileLength = -1; ]#rNz"  
try{ ^GiWU +`  
URL url = new URL(siteInfoBean.getSSiteURL()); AU;Iif6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V h5\'Sn  
httpConnection.setRequestProperty("User-Agent","NetFox"); gA19f  
CM t$)  
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int responseCode=httpConnection.getResponseCode(); ]
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if(responseCode>=400) .fK~IKA  
{ "po;[ Ia2  
processErrorCode(responseCode); \#gguq?[  
return -2; //-2 represent access is error \t? ;p-+ta  
} !HXyvyDN  
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v(,YqT>q@U  
String sHeader; T ^/\Rr  
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for(int i=1;;i++) gmOP8.g  
{ ~x J#NC+  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); CU/Id`"tW  
//Utility.log(in.readLine()); Q{ {=  
sHeader=httpConnection.getHeaderFieldKey(i); A^4#6],%v  
if(sHeader!=null) #.LI`nYA  
{
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if(sHeader.equals("Content-Length")) f^Q)lIv  
{ Q{~;4+ZD  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); "DRiJ.|APs  
break; B.);Ju  
} -y/Y%]%0  
} T6\d]  
else Ze?H  
break; }xgs]\^,73  
} dX-j3lM:#  
} FQ/z,it_i  
catch(IOException e){e.printStackTrace ();} K'[kl'  
catch(Exception e){e.printStackTrace ();} )W1[{?  
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Utility.log(nFileLength); +}BKDEb  
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return nFileLength; GMpg+rK  
} $6d5W=u$H  
K)
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oYWHO<b  
//保存下载信息（文件指针位置） U:|:Y=O?Q  
private void write_nPos() =vL >&$  
{ yx7y3TSq  
try{ ]Bz.6OR  
output = new DataOutputStream(new FileOutputStream(tmpFile)); HrRw  
output.writeInt(nStartPos.length); V\AF%=6}  
for(int i=0;i<nStartPos.length;i++) &b]_#c  
{ j(c;r>  
// output.writeLong(nPos); )t,efg  
output.writeLong(fileSplitterFetch.nStartPos); `mquGk|)  
output.writeLong(fileSplitterFetch.nEndPos); tHFUV\D;,  
} -r[O_[g w  
output.close(); m
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} HUel  
catch(IOException e){e.printStackTrace ();} Q@Cy\l  
catch(Exception e){e.printStackTrace ();} !z5Ozm+}  
} I"D}amuv  
;20sh^~  
JRDIGS_~  
//读取保存的下载信息（文件指针位置） ^+Vf*YY 8  
private void read_nPos() /^`do3a}  
{ LXRIo2ynuw  
try{ $Ut1vp1$  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); DyRU$U  
int nCount = input.readInt(); e )]  
nStartPos = new long[nCount]; =bQ\BY#  
nEndPos = new long[nCount]; ^KQZ;[B  
for(int i=0;i<nStartPos.length;i++) :=K+~?  
{ gbu)bqu2x  
nStartPos = input.readLong(); z/pxZB~"  
nEndPos = input.readLong(); 0 R>!jw  
} jori,"s  
input.close();
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} qh6Q#s>tH  
catch(IOException e){e.printStackTrace ();} O/oLQoH  
catch(Exception e){e.printStackTrace ();} 161IWos  
} QL-E4]  
[`1@`5SL-  
^,Ft7JAn  
private void processErrorCode(int nErrorCode) :7s2M  
{ U<"k-  
System.err.println("Error Code : " + nErrorCode); cfHtUv  
} D#d/?\2  
)c.!3n/pb  
2UTmQOm  
//停止文件下载 0 l
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public void siteStop() k jx<;##R8  
{ :79u2wSh  
bStop = true; < WQ ~X<1D  
for(int i=0;i<nStartPos.length;i++) ?p>m;Aq  
fileSplitterFetch.splitterStop(); "lB%"}  
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-s7a\H{~  
} zo1fUsK?  
} .Z@iz5  
//负责部分文件的抓取 @ b}-<~  
**FileSplitterFetch.java gdg "g6b  
*/ p }3$7CR/  
package NetFox; R^yh,  
-E.fo._L5  
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import java.io.*; (:RYd6i  
import java.net.*; L!Gpk)}[i  
nlc$"(eA[H  
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public class FileSplitterFetch extends Thread { {-hu""x>  
5GURfG3{  
~8)l/I=`);  
String sURL; //File URL I-W,C&J>  
long nStartPos; //File Snippet Start Position D*g K,`  
long nEndPos; //File Snippet End Position |Pv)&'B"  
int nThreadID; //Thread's ID k:z)Sw  
boolean bDownOver = false; //Downing is over "XU)(<p  
boolean bStop = false; //Stop identical L$@qEsO  
FileAccessI fileAccessI = null; //File Access interface c7]0>nU;  
9x#Tj/5%  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Am >b7Z!  
{ r>6FJ:Tx  
this.sURL = sURL; ]#W9l\  
this.nStartPos = nStart; }eSrJgF4M  
this.nEndPos = nEnd; &3\3wcZ,q  
nThreadID = id; ~eXI}KhBw6  
fileAccessI = new FileAccessI(sName,nStartPos);//定位
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} :b,An'H  
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public void run() D_BdvWSxj  
{ {O4&HW%  
while(nStartPos < nEndPos && !bStop) UXOf  
{ |J~A )Bw?  
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try{ 4p>,
 
URL url = new URL(sURL); -v9x tNg  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -(zw80@&  
httpConnection.setRequestProperty("User-Agent","NetFox"); E*L5D4Kw  
String sProperty = "bytes="+nStartPos+"-"; ksyQ_4^SO  
httpConnection.setRequestProperty("RANGE",sProperty); pV$A?b"?*  
Utility.log(sProperty); 7s0pH+  
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InputStream input = httpConnection.getInputStream(); HE+
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//logResponseHead(httpConnection); J$S*QCo  
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byte[] b = new byte[1024]; MTn}]blH  
int nRead; 3o#K8EL  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) eyos6Qi  
{ 8o466m6/  
nStartPos += fileAccessI.write(b,0,nRead); =h/61Bl3  
//if(nThreadID == 1) ceae~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8TYoa:pZ  
} 07>D G#  
-~ Dn^B1^  
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Utility.log("Thread " + nThreadID + " is over!"); !4
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bDownOver = true; 'K|F{K  
//nPos = fileAccessI.write (b,0,nRead); 4Dasj8GsV  
} pJ/{X=y  
catch(Exception e){e.printStackTrace ();} <,JO  
} u`pw'3hY
 
} [+qB^6I+P%  
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//打印回应的头信息 2>m"CG  
public void logResponseHead(HttpURLConnection con) ;6`7 \  
{ Kn}Y7B{  
for(int i=1;;i++) pAyUQe;X#  
{ 4Td)1~zc3  
String header=con.getHeaderFieldKey(i); )#,a'~w  
if(header!=null) h3Nbgxa.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); -$`q:j  
Utility.log(header+" : "+con.getHeaderField(header)); 0"iQHi  
else :e\M~n+y  
break; 9!6u Yf+  
} |wuN`;gc"  
} <4N E)!#  
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public void splitterStop() )2R]KU_=g  
{ srH.$Y;~  
bStop = true;
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} DO~~  
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} *]ME]2qP  
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/* Jjh=zxR>  
**FileAccess.java $LtCI  
*//文件访问(定位，写) >n%ckL|rG  
package NetFox; Kp6%
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import java.io.*; 3Q_)Xs r`  
1:4u]$@E  
*7),v+ET  
public class FileAccessI implements Serializable{ dDl_Pyg4K  
@`
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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 U \jFB*U  
RandomAccessFile oSavedFile; 0VIR=Pbp  
long nPos; vSk1/  
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public FileAccessI() throws IOException ;s5JYR  
{ I3YSW  
this("",0); 
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} th+LScOX  
;B;wU.Y"  

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public FileAccessI(String sName,long nPos) throws IOException `r0MQkk  
{ T!>sL=uf  
oSavedFile = new RandomAccessFile(sName,"rw"); r`PD}6\  
this.nPos = nPos; +SkfT4*U  
oSavedFile.seek(nPos); ePTxuCf>  
} >vNE3S_  
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public synchronized int write(byte[] b,int nStart,int nLen) 2=X.$&a  
{ ]MB6++.e  
int n = -1; J n'SGR  
try{ u`u{\ xN9  
oSavedFile.write(b,nStart,nLen); ^h"@OEga?  
n = nLen; c`7dNx  
} PsN_c[+  
catch(IOException e) VRUA<x  
{ 3u9}z+q  
e.printStackTrace (); l)Mi?B~N  
} ex|h&Vma2V  
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return n; c>wne\(5H  
} iT</  
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} Oki{)Ssy  
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i.e4<|{  
/* .v['INK9  
**SiteInfoBean.java o RK:{?Y  
*/ RT[E$H  
package NetFox; "MyMByomQ  
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public class SiteInfoBean { ym2"D?P (  

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private String sSiteURL; //Site's URL {X-a6OQj  
private String sFilePath; //Saved File's Path d/\ajQ1::  
private String sFileName; //Saved File's Name !'>,37()  
private int nSplitter; //Count of Splited Downloading File dHtEyF  
+_ny{i`'  
.$ HE  
public SiteInfoBean() wM!dz&  
{//nSplitter的缺省值为5 NBA`@K~4  
//default value of nSplitter is 5 MaZS|Zei[  
this("","","",5); )oZ2,]us!  
} iK8jX?  
[ic%ZoZ_  
f\H1$q\p\  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 4j<[3~:0 o  
{ 1eI_F8I U  
sSiteURL= sURL; @su!9]o  
sFilePath = sPath; l$m}aQ%h  
sFileName = sName; UtHloq
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this.nSplitter = nSpiltter; J@qLBe(v  
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} =sk#`,,:  
{5c]\{O?[  
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public String getSSiteURL() Qki
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{ I 1Yr{(ho  
return sSiteURL; Nr`v|_U  
} Pxgul7  
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public void setSSiteURL(String value) -:Bgp*S  
{ 9rT"_d#  
sSiteURL = value; A|yU'k  
} \!IEZ  
9G4os!x)  
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public String getSFilePath() IaO*{1re  
{ l/A!ofc#)  
return sFilePath; 6Y9<| .  
} W?n/>DML  
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^grDP*;W  
public void setSFilePath(String value) lLI%J>b@  
{ *pyC<4W  
sFilePath = value; ?
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} .p(r|5(b  
WZ UeW*#=  
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public String getSFileName() nIqF:6/  
{ A:5P  
return sFileName; X,D ]S@  
} bb$1zSA  
E CPSE{  
,Qj\_vr@  
public void setSFileName(String value) 8#HQ05q>  
{ 0f9U:)1z  
sFileName = value; x!u6LDq0  
} e1hf{:&/G@  
,Bj]j -\Y  
\!*F:v0g^  
public int getNSplitter()

&%T*sR  
{ juxAyds  
return nSplitter; cG4}daK]d  
} ~w(A3I.  
W >|'4y)  
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public void setNSplitter(int nCount) >L$9fn/J  
{ *p|->p6,u  
nSplitter = nCount; SKGnx  
} !e('T@^u6u  
} ?\zyeWK0L  
#;UoZJ B  
845\u&  
/* "@rHGxK  
**Utility.java (U:6vk3Q  
*/ %cASk>
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package NetFox; Bo ??1y  
milQxSpj  
1/SB[[g  
public class Utility { GE\({V.W  
%h v-3L#V  
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public Utility() Pt'=_^Io  
{ 2L=(-CH9]  
\!k\%j9  
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} >
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Se(apQH  
//线程睡眠 &+GbklUB~  
public static void sleep(int nSecond) !ED,'d%J  
{ 5xa!L@)`wF  
try{ Vc+~yh.)  
Thread.sleep(nSecond); ;}k_  
} M->#WGl\B  
catch(Exception e) f|2QI~R  
{ ~O 4@b/!4  
e.printStackTrace (); i(xL-&{  
} zoj w^%W  
} ZT+{8,  
8an_s%,AW  
//日志 k0xm-  
public static void log(String sMsg) @"m+
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{ 9xL`i-7]  
System.err.println(sMsg); 2-^['R  
} w7~&Xxa/  
8_3WCbe/  
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public static void log(int sMsg) ,u14R]  
{ uC2 5pH"  
System.err.println(sMsg); +\J+?jOC4S  
}
0- u,AD  
} CC]q\%y-_  
#?~G\Ux0/  
,Uy~O(Ft  
/* Po.izE!C  
**TestMethod.java zhU^~4F  
*/ g5 y*-t  
package NetFox; ^;@!\Rc  
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e(9K.3@{  
public class TestMethod { e{.P2rnh  
xP 3>8Y  
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public TestMethod() r1sA^2g.  
{ ///xx/weblogic60b2_win.exe t_qX7P8+'  
try{ /q^_ 'Lp  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `U{#;  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); w^S]HzMd  
SiteFileFetch fileFetch = new SiteFileFetch(bean); yRz l}  
fileFetch.start(); I2?
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} DhG{hQ[[  
catch(Exception e){e.printStackTrace ();} @>[3[;  
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} $EZr@n  
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^_o:Ddz?l"  
public static void main(String[] args) = Ruq  
{ 3.%jet1  
new TestMethod(); KzB9 mMrO  
} +b{tk=Q:  
} &9xcP.3  
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