http断点续传简单实现（java)

/* x<8\-  
**SiteFileFetch.java X)I/%{  
*/ "_t4F4z  
package NetFox; _\p`4
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import java.io.*; /#29Y^Z)=  
import java.net.*; wtlB  
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public class SiteFileFetch extends Thread {
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SiteInfoBean siteInfoBean = null; //文件信息Bean aWdUu
id  
long[] nStartPos; //开始位置 nZe\5`  
long[] nEndPos; //结束位置 AmZuo_  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 bG52s  
long nFileLength; //文件长度 [S%J*sz~  
boolean bFirst = true; //是否第一次取文件 HP#ki!'  
boolean bStop = false; //停止标志 9_eS`,'  
File tmpFile; //文件下载的临时信息 fH&zR#T7U4  
DataOutputStream output; //输出到文件的输出流 'wa g |-
  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） %@>YNPD`E  
public SiteFileFetch(SiteInfoBean bean) throws IOException #sL
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{ $\+"qs)  
siteInfoBean = bean; Tu==49  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); NOV.Bs{ yL  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 8:~b &>  
if(tmpFile.exists ()) miPmpu!  
{ se!g4XEWD  
bFirst = false; YRXK@'[=  
read_nPos(); L+Eu d  
} AYt*'Zeg!s  
else ]Uu aN8  
{ iL+y(]  
nStartPos = new long[bean.getNSplitter()]; r9<V%PHv  
nEndPos = new long[bean.getNSplitter()]; fa"\=V2S  
} P>|Ef~j  
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} 2,+d|1(4o  
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public void run() f]c<9Q>*  
{ UBa-  
//获得文件长度 bZu$0IG  
//分割文件 L,6MF,vx  
//实例FileSplitterFetch 5|5=Y/  
//启动FileSplitterFetch线程 ad9EG#mD#  
//等待子线程返回 f:S}h-AL&  
try{ Trpgx  
if(bFirst) )x)gHY8;  
{ xwi!:PAf,o  
nFileLength = getFileSize(); t]4!{~,  
if(nFileLength == -1) vpi l$Uq  
{ &wOE\TCL  
System.err.println("File Length is not known!"); 8'+7i8e  
} _;#9!"&  
else if(nFileLength == -2) s88y{o  
{ 2g0K76=Co:  
System.err.println("File is not access!"); I-TlrW=t  
} sSNCosb  
else ),yH=6  
{ b##1hm~+9  
for(int i=0;i<nStartPos.length;i++) @bE~@4mOu  
{ 3Qa?\C&4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ]uAS+shQ&  
} '\ XsTs#L  
for(int i=0;i<nEndPos.length-1;i++) @FU~1u3d  
{ Xty#vI  
nEndPos = nStartPos[i+1]; |J\,F.{'  
} /;7ID41  
nEndPos[nEndPos.length-1] = nFileLength; h>| g2h  
} N70zjy4?fL  
} CGkI\E  
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//启动子线程 Jb9F=s+  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ~+=E"9O
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for(int i=0;i<nStartPos.length;i++) 4Mi~1iZj  
{ !M,h79NM  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), U[bgu#P;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0_Lm#fE U  
nStartPos,nEndPos,i); q1jN]H  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !8o\.uyi  
fileSplitterFetch.start(); 2Sjt=LOc="  
} ">cqt>2 A  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ZzT&$J7]`{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 8nodV 9
 
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", )Y~xIj>  
nEndPos = " + nFileLength); a&N%|b K  
// fileSplitterFetch[nPos.length-1].start(); ? -CV %l  

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//等待子线程结束 jx'
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//int count = 0; V'C-'Ythwf  
//是否结束while循环 vcwK6G  
boolean breakWhile = false; HZ{n&iJ  
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while(!bStop) puA|NT  
{ ![).zi+m  
write_nPos(); +O4(a.  
Utility.sleep(500); o_(0  
breakWhile = true; 7pP+5&*  
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for(int i=0;i<nStartPos.length;i++) 4QO/ff[ o  
{ =tnTdp0F  
if(!fileSplitterFetch.bDownOver) 9{$8\E9*nd  
{
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breakWhile = false; Fh^ox"3c  
break; nGns}\!7'  
} ;$z7[+M  
} /z
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if(breakWhile) 'u1=XX h  
break; ~GA8_B  
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//count++; o)p[ C   
//if(count>4) u0g*O]Y  
// siteStop(); 4~Dax)  
} UUH;L  
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System.err.println("文件下载结束！"); OT;
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} MUB37  
catch(Exception e){e.printStackTrace ();} QkL@JF]Re  
} @iRO7 6m  
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//获得文件长度 P:^=m*d  
public long getFileSize() 
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{ ~#q;bS  
int nFileLength = -1; ;:T9IL  
try{ .&PzkqWZ  
URL url = new URL(siteInfoBean.getSSiteURL()); Je@kiE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); kN.B/itvA  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^SAq^3^P!  
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int responseCode=httpConnection.getResponseCode(); 8kS~ENe?o  
if(responseCode>=400) sl^n6N  
{ @mNJ=mEV  
processErrorCode(responseCode); m:3J!1  
return -2; //-2 represent access is error Z7KXWu+6`m  
} CL1 oAk  
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String sHeader; `s%QeAde  
/ gu3@@h  
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for(int i=1;;i++) kW
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{ ).Gd1pE  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); :3 y_mf>  
//Utility.log(in.readLine()); $kl$D"*0  
sHeader=httpConnection.getHeaderFieldKey(i); nj  
if(sHeader!=null) E(;i>   
{ x2m]Us@LIU  
if(sHeader.equals("Content-Length")) qv uxhzF  
{ &[~[~m|  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); # 66e@  
break; >XnO&h
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} -njQc:4W,-  
} ;ctU&`  
else ;cLUnsB\  
break; 3~<}bee5|q  
} i.M2E$b|  
} G0/>8_Q>Nr  
catch(IOException e){e.printStackTrace ();} !oGQ8 e  
catch(Exception e){e.printStackTrace ();} ?+\E3}:  
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Utility.log(nFileLength); auL^%M|$R  
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return nFileLength; 0+j}};   
} [e1L{_*l  
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//保存下载信息（文件指针位置） ESv:1o`?n  
private void write_nPos() T>F9Hs W  
{ /AR]dcL@76  
try{ dhtb?n{  
output = new DataOutputStream(new FileOutputStream(tmpFile)); OpQ8\[X+  
output.writeInt(nStartPos.length); KuXkI;63J>  
for(int i=0;i<nStartPos.length;i++) $H;+}VQ  
{ KoF iQ?  
// output.writeLong(nPos); vYdlSe=6G  
output.writeLong(fileSplitterFetch.nStartPos); m|1n x  
output.writeLong(fileSplitterFetch.nEndPos); ?
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} VDpxk$a  
output.close(); DEtf(lW_  
} {cR3.%wX  
catch(IOException e){e.printStackTrace ();} 3\+N`!  
catch(Exception e){e.printStackTrace ();} l;0y-m1  
} A?,A(-0C  
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//读取保存的下载信息（文件指针位置） F. T@)7  
private void read_nPos() 'Sa!5h  
{ 1.0J2nZpt  
try{ {i;6vRr  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Vhph`[dC{  
int nCount = input.readInt(); aS/`A  
nStartPos = new long[nCount]; FUqt)YHi  
nEndPos = new long[nCount]; Xm@aYNV  
for(int i=0;i<nStartPos.length;i++) v20~^gKo=m  
{ P7r4ePtLk{  
nStartPos = input.readLong(); C0(s
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nEndPos = input.readLong(); 8W,*e
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} ox4W$YdMG  
input.close(); C0<YH "  
} U&Ab#m;  
catch(IOException e){e.printStackTrace ();} |^iA6)Q  
catch(Exception e){e.printStackTrace ();} y\z > /q  
} A{(T'/~"  
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private void processErrorCode(int nErrorCode) YxyG\J\|,  
{ ANb"oX c  
System.err.println("Error Code : " + nErrorCode); n_P(k-^U*  
} }p{;^B  
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//停止文件下载 f[}|rf  
public void siteStop() <\ETPL,<  
{ 1Z 6SI>p  
bStop = true; QiU_hz6?v  
for(int i=0;i<nStartPos.length;i++) r0Z+RB^I  
fileSplitterFetch.splitterStop(); H+`*Y<F@  
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} TPK@*9rI  
} T V;BNCg  
//负责部分文件的抓取 TvM24Orct  
**FileSplitterFetch.java Sn ^Aud  
*/ KZ )Ys  
package NetFox; i~8DSshA  
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import java.io.*; "5|\X<f  
import java.net.*; t'aSF{%  
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public class FileSplitterFetch extends Thread { g ;LVECk  
)!a$#"'  
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String sURL; //File URL D$hQyhz'  
long nStartPos; //File Snippet Start Position bpp*  
long nEndPos; //File Snippet End Position ytz8=\p_b  
int nThreadID; //Thread's ID (#z;(EN0t  
boolean bDownOver = false; //Downing is over <r;o6>+  
boolean bStop = false; //Stop identical Yrsp%<qj  
FileAccessI fileAccessI = null; //File Access interface G/(*foT8SE  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException O9*p0%ug  
{ y\Dn^  
this.sURL = sURL; S+pP!YX  
this.nStartPos = nStart; \xeVDKJH+n  
this.nEndPos = nEnd; =qX*
]  
nThreadID = id; $',3Pv  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 !qw4mN  
} ,R}Z=w#  
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public void run() ^6qjSfFW}  
{ 0I^Eo|  
while(nStartPos < nEndPos && !bStop) ~d>uXrb  
{ ~bGnq, .$  
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try{ 1LyT7h  
URL url = new URL(sURL); @'HT;Q!\Vd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )UP8#|$#T  
httpConnection.setRequestProperty("User-Agent","NetFox"); )-q\aX$])  
String sProperty = "bytes="+nStartPos+"-"; c
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httpConnection.setRequestProperty("RANGE",sProperty); N5KEa]k1nw  
Utility.log(sProperty); ^K.*.|  
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InputStream input = httpConnection.getInputStream(); a[i>;0  
//logResponseHead(httpConnection); -ek1$y9)  
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byte[] b = new byte[1024]; B52H(sm  
int nRead; o\60n  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) pUhc3L  
{ 0\wiam-  
nStartPos += fileAccessI.write(b,0,nRead); L;Vq j]_  
//if(nThreadID == 1) L~ 2q1  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0d`5Gy_D%  
} M8zE3;5  
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Utility.log("Thread " + nThreadID + " is over!"); 3I\m,Ob  
bDownOver = true; ]9@X?q  
//nPos = fileAccessI.write (b,0,nRead); %y
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} /Zx8nx'{V  
catch(Exception e){e.printStackTrace ();} :ol6%Z's  
} )Oe`s(O@[I  
} N33AcV!*8  
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//打印回应的头信息 ig$jKou F  
public void logResponseHead(HttpURLConnection con) x5PP
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{ /6jGt'^U  
for(int i=1;;i++) wibwyzo  
{ &N9IcNP  
String header=con.getHeaderFieldKey(i); 9N1#V K  
if(header!=null) [9HYO  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 1
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Utility.log(header+" : "+con.getHeaderField(header)); 8H_l[/  
else $W*|~}F/Ap  
break; F"v:}Vy|   
} 9M]^l,
 
} |=u96G~N  
6+)x7g1PL  
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public void splitterStop() k{{hZ/om  
{ p_9g|B0D  
bStop = true; lZvS0JS  
} -)6;0  
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h
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} ?DRR+n _  
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:t%)5:@A  
/* dEG ]riO  
**FileAccess.java Fn> <q:  
*//文件访问(定位，写) :~i+tD  
package NetFox; i3d y  
import java.io.*; LGfmUb-{]  
jJc07r']  
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public class FileAccessI implements Serializable{ )6 k1 P  
3u4:l  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 VAg68EbnF  
RandomAccessFile oSavedFile; dxntGH< O  
long nPos; L W?&a3e  
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public FileAccessI() throws IOException !")WZq^`  
{ 'xk1o,;  
this("",0); IW mHp]  
} ,0h3x$l)  
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public FileAccessI(String sName,long nPos) throws IOException $Ba`VGP>)3  
{ Qi"'bWX@  
oSavedFile = new RandomAccessFile(sName,"rw"); j=\Mx6os  
this.nPos = nPos; ,$ mLL  
oSavedFile.seek(nPos); I^@.Awt  
} mQL8QW[c  
s6IP;}  
?jFc@t*\:  
public synchronized int write(byte[] b,int nStart,int nLen) 5Fh8*8u6hL  
{ .5NZf4:C  
int n = -1; k5C>_( A  
try{ TGtyJ3x\  
oSavedFile.write(b,nStart,nLen); ^7<[}u;qF  
n = nLen; -?Ejbko  
} ,uO?;!t  
catch(IOException e) Lj
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{ <0>[c<{V<  
e.printStackTrace (); ff[
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} j37:  
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return n; |w4(rs-  
} l%@dE7<&#Z  
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} j $KM9  
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/* ^h`!f vyH  
**SiteInfoBean.java \1~I04'=  
*/ )#Y|ngZ_>  
package NetFox; UFos E|r:  
+*<K"H|,  
1aVgwAI  
public class SiteInfoBean { ThbP;CzI#  
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EtJD'&  
private String sSiteURL; //Site's URL FGDw;lEa9[  
private String sFilePath; //Saved File's Path BJ"Ay@D*  
private String sFileName; //Saved File's Name Na-q%ru  
private int nSplitter; //Count of Splited Downloading File Up'."w_zE  
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c_t7RWV}  
public SiteInfoBean() Y5Ft96o))x  
{//nSplitter的缺省值为5 r
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//default value of nSplitter is 5 I51M}b,[d  
this("","","",5); FU'^n6[<B  
} q;KshpfRMD  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [l`^fnKt  
{ EmF]W+!z%  
sSiteURL= sURL; FW/)uf3I  
sFilePath = sPath; A<a2TXcIE3  
sFileName = sName; [GOX0}$?  
this.nSplitter = nSpiltter; NavOSlC+h  
< rv1IJ  
j\nE8WH  
} Pb*q;9  
s8{-c^G:R  
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public String getSSiteURL() .0?ss0~  
{ >\RDQ%z  
return sSiteURL; tnA_!$Y a  
} S[ws0Y60  
*1R##9\jU7  
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public void setSSiteURL(String value) neK*jdaP  
{ 5c*p2:]  
sSiteURL = value; r*c82}tc  
} )`e^F9L  
-,
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public String getSFilePath() <XU8a:w'T  
{ h5<T.vV  
return sFilePath; 5?D1][  
} q#l.A?rK\  
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X+/{%P!w  
public void setSFilePath(String value) Jii?r*"d  
{ -WQ_[t9
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sFilePath = value; uPM8GIvZX.  
} Wdei`u[  
iH($rSE  
K]*g, s+  
public String getSFileName() *Pa2bY3:  
{ &n}8Uw0440  
return sFileName; vcaBL<io  
} {yGZc3e1j  
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{vf+sf^^q  
public void setSFileName(String value) G~Sy&XJuq  
{  aOaF&6'j  
sFileName = value; N02zPC 8  
} %ZJ),9+  
';i"?D?NAk  
\=HfO?$ Ro  
public int getNSplitter() @1/Q  
{ $71i+h]_  
return nSplitter; zpBBnlq  
} !"Z."fm*  
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public void setNSplitter(int nCount) >#Grf)@"6  
{ azz#@f1  
nSplitter = nCount; 
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} t;Fbt("]:  
} COxZ
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@n5;|`)\  
+!mNm?H[!  
/* 7I@9v=xV  
**Utility.java AH"g^ gw~T  
*/ XhJP87A  
package NetFox; ]1YYrgi7  
gOBj0P8s|}  
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public class Utility { !UUmy% 9  

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public Utility() bxPY'&  
{ 6qz!M  
,f-T1v"  

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} H]T2$'U6  
R#[QoyJ  
//线程睡眠 ?15POY ?Z  
public static void sleep(int nSecond) e/m'a|%:  
{ ~@)-qV^~  
try{ Yc. ~qmG/z  
Thread.sleep(nSecond); -eSPoZ  
} mGMinzf  
catch(Exception e) m!FM+kge  
{ iXr`0V   
e.printStackTrace (); Ivd[U`=Q  
} /
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} rFt,36#  
@w.b |
  
//日志 ;T"m[D  
public static void log(String sMsg) )-TeDIfm  
{ #XYLVee,  
System.err.println(sMsg); `-9*@_-=M  
} 0pZ.; /<{  
V29S*  
w<I5@)i|  
public static void log(int sMsg) qxg7cj2  
{ ((hJmaq  
System.err.println(sMsg); Wf+Cc?/4  
} / %U~lr  
} 3^iQe"P%a@  
+r#=n7t  
/pSUn"3  
/* )N%1%bg^-  
**TestMethod.java FS]+s>  
*/ %0y3/W  
package NetFox; 0Tn|Q9R  
,h5-rw'  
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public class TestMethod { Hc_hO  
h
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j 44bF/  
public TestMethod() nIN%<3U2  
{ ///xx/weblogic60b2_win.exe YiQeI|{oN  
try{ 0.{oA`5N  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); X T)hPwg.  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); @88
z{  
SiteFileFetch fileFetch = new SiteFileFetch(bean); cQ8$,fo  
fileFetch.start(); V.P5v{  
} R>YMGUH~w  
catch(Exception e){e.printStackTrace ();} f@xfb ie!  
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4 L~;>]7  
} M#8Ao4 T  
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public static void main(String[] args) '#An+;x{  
{ ;&t1FH#=  
new TestMethod(); _]PfeCn:j  
} YVg}q#  
} Dry;$C}P  
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