http断点续传简单实现（java)

/* EjR_-8@FK  
**SiteFileFetch.java GJ1;\:cQq  
*/ ~K~b`|1  
package NetFox; qIbg 4uE  
import java.io.*; rU=b?D)n!w  
import java.net.*; (C`FicY  
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[=F>#8=  
public class SiteFileFetch extends Thread { W.,% 0cZ  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 9VoDhsKk  
long[] nStartPos; //开始位置 YgE]d?_h  
long[] nEndPos; //结束位置 4M @oj  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]d@^i)2LF  
long nFileLength; //文件长度 4F05(R8k  
boolean bFirst = true; //是否第一次取文件 mje<d"bW  
boolean bStop = false; //停止标志 jM5_8nS&d  
File tmpFile; //文件下载的临时信息 =\
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DataOutputStream output; //输出到文件的输出流 r0\cc6  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） op hH9D  
public SiteFileFetch(SiteInfoBean bean) throws IOException de> ?*%<  
{ =X-^YG3x  
siteInfoBean = bean; P?9nTG  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); u0m5JD0/  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $%7I:  
if(tmpFile.exists ()) 8tb6 gZz  
{ M{`/f@z(  
bFirst = false; :s'o~  
read_nPos(); -O|&c9W.O  
} -DTB6}kw  
else r<;l{7lY_  
{ k?3S  
nStartPos = new long[bean.getNSplitter()]; ;i<$7MR.e  
nEndPos = new long[bean.getNSplitter()]; ic%?uWN  
} .6> hD1'  
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} PX;Vo~6  
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public void run() 5]
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{ CzYGq  
//获得文件长度 >(hSW~i~  
//分割文件 N>
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//实例FileSplitterFetch S8 :"<B)  
//启动FileSplitterFetch线程 &J8Z@^  
//等待子线程返回 hf;S]8|F  
try{ Q*]$)D3n  
if(bFirst) QL2Nz@|k  
{  )|v^9  
nFileLength = getFileSize();
8RVS)D''  
if(nFileLength == -1) "mP&8y9F  
{
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System.err.println("File Length is not known!"); Aj[?aL  
} sU\c#|BSC"  
else if(nFileLength == -2) x&'o
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{ M'kVL0p?vN  
System.err.println("File is not access!"); rkkU"l$v  
} led))qd@V-  
else z"tjDP  
{ 6yY.!HRkr  
for(int i=0;i<nStartPos.length;i++) ~@{w\%(AK]  
{ >DHp*$y  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); dXmV@ Noo  
} ))!Bg?t-  
for(int i=0;i<nEndPos.length-1;i++) #Mh{<gk%ax  
{ X*i/A<Y`=  
nEndPos = nStartPos[i+1]; / /'Tck  
} :z]}ZZ  
nEndPos[nEndPos.length-1] = nFileLength; {jjSJIV1  
} MhNFW'_  
} j`O7=-  
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h;-a`@rO ;  
//启动子线程 ;x-(kIiE  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; #?dUv#  
for(int i=0;i<nStartPos.length;i++) z
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{ /RGNAHtIi  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @}WNKS&m  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), blGf!4H  
nStartPos,nEndPos,i); *I0Tbc O  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); J1bA2+5.*e  
fileSplitterFetch.start(); $(ewk):  
} ^(ScgoXva  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;6ky5}z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ({4]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 9:5:`'b  
nEndPos = " + nFileLength); " Ya9~6  
// fileSplitterFetch[nPos.length-1].start(); 'Gjq/L/x  
&rp!%]+xAM  
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//等待子线程结束 P"1 S$oc  
//int count = 0; [8"ojhdV  
//是否结束while循环 #Z\
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boolean breakWhile = false; Cp#)wxi6[y  
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{
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while(!bStop) 5o#Yt  
{ ,_D"?o  
write_nPos(); h>alGLN>  
Utility.sleep(500); 1G;8MPU  
breakWhile = true; JWROYED  
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for(int i=0;i<nStartPos.length;i++) K^zDNIQU  
{ 6"U8V?E  
if(!fileSplitterFetch.bDownOver) -I":Z2.fR  
{ C9qJP^F  
breakWhile = false; 3NIUW!gr  
break; |ETiLR=&  
} ][d,l\gu+s  
} y:d{jG^
 
if(breakWhile) ;gMgj$mI  
break; F[saP0 *  
n,j$D62[  
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//count++; M\oTZ@  
//if(count>4)
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// siteStop(); WA$JI@g  
} ^N{ltgQY  
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System.err.println("文件下载结束！"); -kpswP  
} ""{|3XJe  
catch(Exception e){e.printStackTrace ();} Wkzs<y"  
} BI2; ex  
+Llo81j&  
0:&ZnE}##  
//获得文件长度 ~GJN@ka4%  
public long getFileSize() 15{Y9
!  
{ GKiukX$'  
int nFileLength = -1; v>A=2i*j  
try{ Q7gY3flg  
URL url = new URL(siteInfoBean.getSSiteURL()); ,e`'4H  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ifK%6o6  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~]'pY  
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 npp[@*~  
int responseCode=httpConnection.getResponseCode(); ^j)BKD-  
if(responseCode>=400) K93p"nHN  
{ ]"~51HQZ  
processErrorCode(responseCode); X"q!Y#)  
return -2; //-2 represent access is error k~3.MU  
} bU54-3Ox*  
hWo=;#B*  
]3Dl)[R   
String sHeader; ,xI%A, (,;  
'b/<x|  
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for(int i=1;;i++) 28andfl  
{ gNpJ24QK  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ;WU<CKYG*  
//Utility.log(in.readLine()); >dzsQ^Nj  
sHeader=httpConnection.getHeaderFieldKey(i); E7zm{BX]  
if(sHeader!=null) Bi3+)k>u7  
{ ,#]t$mzbQ(  
if(sHeader.equals("Content-Length")) x3pND  
{ aqU' T  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); i/So6jW  
break; ]@^coj[  
} X
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} Yw;D:Y(  
else 5 BtX63  
break; _-~`03 `!  
} Zm ogM7B  
} sJ z@7.  
catch(IOException e){e.printStackTrace ();} wJ<Oo@snm  
catch(Exception e){e.printStackTrace ();} h*B|fy4K9U  
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Utility.log(nFileLength); c`*TPqw(B[  
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return nFileLength; *Vw\'%p*  
} 8qEK+yi,  
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A@
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%  
//保存下载信息（文件指针位置） efP&xk  
private void write_nPos() '3IC*o"  
{ x35cW7R}T_  
try{ LPYbHo3fq  
output = new DataOutputStream(new FileOutputStream(tmpFile)); E\nv~Y?SG  
output.writeInt(nStartPos.length); X>YsQrK(ig  
for(int i=0;i<nStartPos.length;i++) 0c^>eq]  
{ X[gn+6WB%  
// output.writeLong(nPos); L6Wt3U`l  
output.writeLong(fileSplitterFetch.nStartPos); dsx]/49<  
output.writeLong(fileSplitterFetch.nEndPos); BvrB:%_:  
} fFvF\  
output.close(); Zk8|K'oHx  
} 6]
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catch(IOException e){e.printStackTrace ();} =qy=-j]  
catch(Exception e){e.printStackTrace ();} 4_v]O  
} {O<l[|Ip  
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//读取保存的下载信息（文件指针位置） {gNV[45  
private void read_nPos() r|e-<t4.9L  
{ D]a<4a18  
try{ !\8 ;d8  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); VQ5nq'{v
  
int nCount = input.readInt(); D?yG+%&9  
nStartPos = new long[nCount]; |t iUej  
nEndPos = new long[nCount]; %1 vsN-O}8  
for(int i=0;i<nStartPos.length;i++) C;QAT  
{ jn >d*9u  
nStartPos = input.readLong(); ^.k |SK`U  
nEndPos = input.readLong(); BBG3OAyg_  
} #GDe08rOw  
input.close(); ,#d? _?/:O  
} ~=<}\a~  
catch(IOException e){e.printStackTrace ();} rNjn~c  
catch(Exception e){e.printStackTrace ();} ZQ^r`W9_+  
} C98
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private void processErrorCode(int nErrorCode) :c9U>1`g&  
{ 6 5y+Z  
System.err.println("Error Code : " + nErrorCode); Y{v(p7pl  
} Hn>B!Bm*  
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;,i]w"*  
//停止文件下载 i wxVl)QL  
public void siteStop() )[mwP.T=  
{ 5zFR7/p{  
bStop = true; \I"Z2N>^z  
for(int i=0;i<nStartPos.length;i++) ]?x: Qm'yo  
fileSplitterFetch.splitterStop(); <<=WY_m}  
#P]#9Ty:  
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} J_Ltuso  
} #ET/=  
//负责部分文件的抓取 LK6; ?m  
**FileSplitterFetch.java A;\7|'4  
*/ Q#h 9n]5  
package NetFox; &B! o,qp  
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import java.io.*; C2Xd?d  
import java.net.*; jM-)BP6f4  
1]
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public class FileSplitterFetch extends Thread { "S3wk=?4  
V[-jD8='3  
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String sURL; //File URL :l|%17N  
long nStartPos; //File Snippet Start Position
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long nEndPos; //File Snippet End Position *(PL _/:  
int nThreadID; //Thread's ID &Ysosy*  
boolean bDownOver = false; //Downing is over |6=p{y  
boolean bStop = false; //Stop identical z'uK3ng\hH  
FileAccessI fileAccessI = null; //File Access interface HB Iip?  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException vSi_t K4  
{ '*\|;l#1  
this.sURL = sURL; zC_<(4$-"  
this.nStartPos = nStart; TuW%zF/  
this.nEndPos = nEnd; F(na{<g};  
nThreadID = id; h?bb/T+'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 p-1 3H0Kt  
} o9cM{ya/>  
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public void run() JaB<EL-9r2  
{ ~T) Q$  
while(nStartPos < nEndPos && !bStop) u,}{I}x_  
{ U|g:`v7  
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try{ &\apwD  
URL url = new URL(sURL); /-bO!RTwf  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); aW!@f[%~F  
httpConnection.setRequestProperty("User-Agent","NetFox"); 
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String sProperty = "bytes="+nStartPos+"-"; dt2$`X18  
httpConnection.setRequestProperty("RANGE",sProperty); (@iMLuewK  
Utility.log(sProperty); 5/po2V9)  
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InputStream input = httpConnection.getInputStream(); ]p_@@QTC  
//logResponseHead(httpConnection); 5jUYN-$GO  
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byte[] b = new byte[1024]; :1Q!$  m  
int nRead; ChCrL[2  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) keB&Bjd&  
{ UQB"v3Z  
nStartPos += fileAccessI.write(b,0,nRead); SM`w;?L:?  
//if(nThreadID == 1) +-E~6^>  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1Bpv"67  
} <{~6}6o  
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Utility.log("Thread " + nThreadID + " is over!"); gn3jy^5  
bDownOver = true; Nbp!teH6
  
//nPos = fileAccessI.write (b,0,nRead); SRDXfkoI  
} eds26(  
catch(Exception e){e.printStackTrace ();} #>j.$2G>  
} |j 6OM{@  
} ,=l7:n  
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//打印回应的头信息 i+gQE!  
public void logResponseHead(HttpURLConnection con)
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{ /="~gq@  
for(int i=1;;i++) K~22\G`  
{ 6ND`l5  
String header=con.getHeaderFieldKey(i); ei rzYt  
if(header!=null) n> ^[T[.S  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <Qxh)@ N  
Utility.log(header+" : "+con.getHeaderField(header)); H@ t'~ZO
 
else o1<_
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break; hGiz)v~  
} gdkwWoN.  
} f%V4pzOc"  
}!6\|;Qsz,  
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public void splitterStop() y.[Mnj  
{ 'Y]mOD^p  
bStop = true; NMA}Q$o s  
} ,Jd ',>3  
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} zA[0mkC?$  
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/* g&`pgmUX  
**FileAccess.java fJ ,1Ef;Z  
*//文件访问(定位，写) +Z85HY{  
package NetFox; Ek6MYc8<b~  
import java.io.*; 9]e V?yoA8  
bR V+>;L0@  
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public class FileAccessI implements Serializable{ .-<k>9S7_  
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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 B9wPU1  
RandomAccessFile oSavedFile; w+N> h;j  
long nPos; aXL{TD:]  
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public FileAccessI() throws IOException zD<or&6  
{ og0*Nt+  
this("",0); *W kIq>  
} f"St&q>[s  
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public FileAccessI(String sName,long nPos) throws IOException 95z]9U
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{ ca>Z7qT!  
oSavedFile = new RandomAccessFile(sName,"rw"); 0X^Ke(/89  
this.nPos = nPos; ;g~TWy^o  
oSavedFile.seek(nPos); /r=tI)'$  
} ~{Mn{  
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public synchronized int write(byte[] b,int nStart,int nLen) .B\5OI,]  
{ "U\4:k`:  
int n = -1; kS!viJwtT  
try{ ,dx3zBI  
oSavedFile.write(b,nStart,nLen); A]DTUdL  
n = nLen; G8;w{-{m  
} fXcm|U,ho  
catch(IOException e) ="g*\s?r  
{ $ >EY
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e.printStackTrace (); phgm0D7
 
} aAB`G3  
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return n; f{FDuIln  
} =XY\iV1J*  
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} YiPoYlD*n<  
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/* U\R}`l  
**SiteInfoBean.java Rb{U+/gq  
*/ X#e1KZ  
package NetFox; MzL1Bh!M  
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public class SiteInfoBean { *;fw%PW  
=|YxDas  
;]pJj6J&v  
private String sSiteURL; //Site's URL D`VM6/iQR  
private String sFilePath; //Saved File's Path ph-ATJ"  
private String sFileName; //Saved File's Name X0n~-m"m  
private int nSplitter; //Count of Splited Downloading File QI3Nc8t_2  
9J?wO9rI  
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public SiteInfoBean() E~_]Lfs)  
{//nSplitter的缺省值为5 E8~}PQW:I  
//default value of nSplitter is 5 :Cp'm'omb  
this("","","",5); /=gOa\k|p  
} 2^l[(N  
=hMY2D  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [!U?}1YQ  
{ !H}vu]R  
sSiteURL= sURL; iV eC=^1  
sFilePath = sPath; .3MIcj=p  
sFileName = sName; /\WQxe  
this.nSplitter = nSpiltter; <0PT"ij  
,.qMEMm  
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} "1HRLci  
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public String getSSiteURL() gR}35:$Z-  
{ 1)[]x9]^q'  
return sSiteURL; G3{=@Z1  
} 
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public void setSSiteURL(String value) >G~R,{6U  
{ >z.<u|r2  
sSiteURL = value; ?|ZTaX6A  
} ti<;7Yb  
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public String getSFilePath() ME=/|.}D<  
{ Rh>}rGvCUN  
return sFilePath; *>+,(1Fz  
} Uv4`6>Ix  
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X 51Yfr  
public void setSFilePath(String value) T0]*{k(FR  
{ ]7/ b/J  
sFilePath = value; 
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} dF~8XYo  
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/mK?E5H'r1  
public String getSFileName() _Y[jyD1>  
{ 56Vb+0J'  
return sFileName; gL3"Gg3  
} D2,z)O%VK  
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public void setSFileName(String value) 6HlePTf8  
{ ,yTjU{<"  
sFileName = value; <fs2fTUeqF  
} s\P2Bp_{  
?Oc{bF7  
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public int getNSplitter() 2~t[RY  
{ ]$,UPR/3  
return nSplitter; >N.]|\V  
} -@Uqz781  
q/4 [3
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public void setNSplitter(int nCount) YLVPAODY  
{ 51QRM32Y  
nSplitter = nCount; A|@_}h"WG  
} d` [HT``  
} E~AjK'Z  
;-Jb1"5  
+L5\;  
/* "XT"|KF|D  
**Utility.java STJJU]H  
*/ -> J_ ~  
package NetFox; C*G=cs\i  
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IO/4.m-aN#  
public class Utility { 41_SRh7N  
.n=Z:*JqQ  
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public Utility() SM^-Z|d?  
{ ai0Ut  
+nT'I!//  
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} TET`b7G  
1=]kWp`i  
//线程睡眠 !L95^g  
public static void sleep(int nSecond) jU5}\o
P@  
{ 7^Yk`Z?|a  
try{ wm+})SOX9  
Thread.sleep(nSecond); Rtjqx6-B;  
} /By)"  
catch(Exception e) mB0l "# F  
{ 1U,1)<z~u  
e.printStackTrace (); QL$S4 J"  
} %xQ
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} .WQ+AE8Q  
oQL59XOT4  
//日志 8+Td-\IMk  
public static void log(String sMsg) {vE
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{ aceZ3U>W  
System.err.println(sMsg); ehA;i.n  
} 42\-
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qSejLh6  
public static void log(int sMsg) /N-_FMl?  
{ ,Hgc-7g@Y  
System.err.println(sMsg); W k}AmC  
} X.TI>90{  
} nJbbzQ,e  
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/* )}L??|#  
**TestMethod.java BJS-Jy$-  
*/ ~j'l.gQb  
package NetFox; "p3_y`h6+  
9TAj) {U%'  
SI6B#u-i  
public class TestMethod { [>|FB'  
>\!4Mk8  
Bu]t*$  
public TestMethod() LA[g(i 7  
{ ///xx/weblogic60b2_win.exe jp+_@S>  
try{ Pe2wsR"_U  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -TV?E%r  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); %AW4.3()8  
SiteFileFetch fileFetch = new SiteFileFetch(bean); n$:IVX"2b  
fileFetch.start(); "+uNmUUnm  
} Ap$y%6  
catch(Exception e){e.printStackTrace ();} > MG>=A  
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-!({BH-M_  
} pDhse2  
\sA*V%n  
Yh)Isg|0>  
public static void main(String[] args) :L 3&FA  
{ sFDG)  
new TestMethod(); W~Z<1[  
} a83g\c5   
} <*EZ@XoN>  
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