http断点续传简单实现（java)

/* j@Y'>3  
**SiteFileFetch.java P] qL&_  
*/ LAU\.d  
package NetFox; 1t< nm)  
import java.io.*; |)b:@q3k+n  
import java.net.*; lD@`xq.M;  
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public class SiteFileFetch extends Thread { pij%u<  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ,*d<hBGbh  
long[] nStartPos; //开始位置 {*AYhZ  
long[] nEndPos; //结束位置 \jHIjFwQ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 w ;xbQZ|+  
long nFileLength; //文件长度 m53
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boolean bFirst = true; //是否第一次取文件 d9.~W5^fC  
boolean bStop = false; //停止标志 m-MfFEZ  
File tmpFile; //文件下载的临时信息 "aJfW  
DataOutputStream output; //输出到文件的输出流 Q;0g  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） @XN|R  
public SiteFileFetch(SiteInfoBean bean) throws IOException M|}V6F_y  
{ L<[%tvV  
siteInfoBean = bean; y5`$Aa4~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9;`E,w  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); <@J0 770  
if(tmpFile.exists ()) HCZVvsG  
{ G)3Q|Vc  
bFirst = false; P|QM0GI  
read_nPos(); 4~Jg\@  
} +vO;J  
else /DoSU>%hK  
{ 91ndr@*|  
nStartPos = new long[bean.getNSplitter()]; c^x5 E`{  
nEndPos = new long[bean.getNSplitter()]; @"O|[%7e  
} gfly?)VnF  
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} l$g \t]  
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public void run() 5LJ0V  
{ qcGsx2  
//获得文件长度 -DL"Yw}  
//分割文件 dd:vQOF;  
//实例FileSplitterFetch ZXC_kmBN/  
//启动FileSplitterFetch线程 MWJ}  
//等待子线程返回 e^yfoE<7  
try{ b&2N7%  
if(bFirst) _Z_R\  
{ jkV9$W0  
nFileLength = getFileSize(); I T?~`vi  
if(nFileLength == -1) );=0cnr3  
{ s|!lw  
System.err.println("File Length is not known!"); lAJP X  
} jAak,[~;  
else if(nFileLength == -2) *
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{ 1w'W)x  
System.err.println("File is not access!"); 6\vaR#  
} yz^
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else *~Sv\L  
{  SGK 5  
for(int i=0;i<nStartPos.length;i++) =;~*YD(%/  
{ #R*7y%cO  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ?(Ytc)  
} H_FT%`iM  
for(int i=0;i<nEndPos.length-1;i++) ob]j1gYb  
{ UM:]QbaIn  
nEndPos = nStartPos[i+1]; tX~*.W:  
} *NCkC ~4  
nEndPos[nEndPos.length-1] = nFileLength; R^&.:;Wi>  
} 2"IDz01ne  
} \Sv8c}8  
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//启动子线程 #T++5G  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; K8RV=3MBLD  
for(int i=0;i<nStartPos.length;i++) l-$5CO  
{ U<I
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), t 09-y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ?.^n,[2  
nStartPos,nEndPos,i); tP4z#0r2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9xaie
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fileSplitterFetch.start(); REWW(.3o  
} ;L[N.ZY!  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q#zU0K*^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ^X ~S}MX  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ti!kJ"q  
nEndPos = " + nFileLength); 2B b,ZC*  
// fileSplitterFetch[nPos.length-1].start(); Hq#q4Y  
]DjnzClx  
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//等待子线程结束 $ D.*r*c6  
//int count = 0; E?
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//是否结束while循环 m\G
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boolean breakWhile = false; 0( q:K6zI}  
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while(!bStop) {$Z S 27  
{ Tly*i"[&  
write_nPos(); SvQ!n4 $  
Utility.sleep(500); *yYeqm  
breakWhile = true; 8(g}/%1mt3  
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for(int i=0;i<nStartPos.length;i++) #=N6[:,  
{ @6b4
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if(!fileSplitterFetch.bDownOver) uc aa;zj  
{ eh}|Wd7J  
breakWhile = false; B*:W`}G]_c  
break; iX-.mq$  
} m=rMx]k  
} q\xsXM  
if(breakWhile) Zs2;VW4RW  
break; ]z8Th5a?o  
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//count++; %LBf'iA  
//if(count>4) }kSP p  
// siteStop(); ndu$N$7+  
} b8**M'k  
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System.err.println("文件下载结束！"); |

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} g%okYH?  
catch(Exception e){e.printStackTrace ();} Pq1j  
} Ml6}47n  
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//获得文件长度 s
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public long getFileSize() baGV]=j  
{ `jec|i@oO  
int nFileLength = -1; u)vS,dzu  
try{ IZuP{7p$  
URL url = new URL(siteInfoBean.getSSiteURL()); +I+RNXR/{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C!Jy
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httpConnection.setRequestProperty("User-Agent","NetFox"); \+"Jg/)ij  
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int responseCode=httpConnection.getResponseCode(); F`>qg2wO  
if(responseCode>=400) x"A\Z-xxz  
{ = u&dU'@q  
processErrorCode(responseCode); f9t+x+ Z  
return -2; //-2 represent access is error I#;.;%u  
} 3gYtu-1  
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String sHeader; a:s$[+'Y  
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for(int i=1;;i++) *;T'=u_lR  
{ &5*t*tI  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); *Ag3qnY  
//Utility.log(in.readLine()); uK0L>
  
sHeader=httpConnection.getHeaderFieldKey(i); qp{~OW3  
if(sHeader!=null) nfh<3v|kvR  
{ !QCErE;r  
if(sHeader.equals("Content-Length")) h6?o)Q>N  
{ pZ]&M@Ijp  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); <) -]'@*c  
break; ~MP/[,j`  
} EqOhzII^  
} loUZD=Ph  
else Oj8D+sC{  
break; $`P]%I}  
} :lu"14  
} bI8')a  
catch(IOException e){e.printStackTrace ();} #mD_<@@  
catch(Exception e){e.printStackTrace ();} ?rziKT5OOC  
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Utility.log(nFileLength); _+Z5qUmQ  
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return nFileLength; ExF6y#Y G<  
} h@J3+u<  
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//保存下载信息（文件指针位置） PP]7_h^2  
private void write_nPos() C3~O6<,Jh  
{ &UO/p/a
 
try{ 93
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output = new DataOutputStream(new FileOutputStream(tmpFile)); V."cmtf  
output.writeInt(nStartPos.length); v=cX.^
L  
for(int i=0;i<nStartPos.length;i++) ~du U& \  
{ zjSHa'9*  
// output.writeLong(nPos); 5mZwg(si  
output.writeLong(fileSplitterFetch.nStartPos); CZ>Ujw=&k  
output.writeLong(fileSplitterFetch.nEndPos); qRz /$|.  
} ( X+2vN  
output.close(); S;oRE'kk  
} J&B5Ll  
catch(IOException e){e.printStackTrace ();} I9xkqj  
catch(Exception e){e.printStackTrace ();} FI~=A/:  
} +G+1B6S  
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//读取保存的下载信息（文件指针位置） NC iBn>=:  
private void read_nPos() Tl#2w=  
{ TD78&a#  
try{ jvpv1>KYV  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); F+L%Ho;@P  
int nCount = input.readInt(); . g- HB'  
nStartPos = new long[nCount]; }}bMq.Q'  
nEndPos = new long[nCount]; =J]M#6N0  
for(int i=0;i<nStartPos.length;i++) 9W-1P}e,  
{ 8"p rWAN  
nStartPos = input.readLong(); |:,`dQfw  
nEndPos = input.readLong(); /lhk} y^  
} 4J?\JcGs  
input.close(); /2MZ
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} 8~T=p:z'  
catch(IOException e){e.printStackTrace ();} tY:,9eh7B  
catch(Exception e){e.printStackTrace ();} _xBhMu2f  
} Aj
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private void processErrorCode(int nErrorCode) X":2o|R  
{ d= ?lPEzSA  
System.err.println("Error Code : " + nErrorCode); D(WV
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} Nq|y\3]  
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//停止文件下载 m"6K_4r]  
public void siteStop() p#3G=FV  
{  m3^D~4  
bStop = true; IkxoW:L  
for(int i=0;i<nStartPos.length;i++) `$FB[Z} &  
fileSplitterFetch.splitterStop(); DghqSL^s  
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} AYfe_Dj  
} s,l*=<  
//负责部分文件的抓取 BuUM~k&SY  
**FileSplitterFetch.java T0.sL9  
*/ P>^$X  
package NetFox; "z=~7g  
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import java.io.*; =k;X}/  
import java.net.*; OMd:#cWsQ  
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public class FileSplitterFetch extends Thread { /LtbmV  
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String sURL; //File URL 7#X`D  
long nStartPos; //File Snippet Start Position [Z&<# -  
long nEndPos; //File Snippet End Position Zq H-]?)  
int nThreadID; //Thread's ID t:v>W8N53  
boolean bDownOver = false; //Downing is over 2izBB,# "  
boolean bStop = false; //Stop identical M@p<L VP  
FileAccessI fileAccessI = null; //File Access interface ?6L8#"=  
9
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException b!teSf  
{ [57`V&c5  
this.sURL = sURL; x<@i3Y{[  
this.nStartPos = nStart; 7]i6 Gk  
this.nEndPos = nEnd; 8dJ+Ei~M  
nThreadID = id; T)Q_dF.N  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "L8Hgwg  
} Ekh)l0 l  
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public void run() .q!
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{ H+@?K6{h  
while(nStartPos < nEndPos && !bStop) jl>wvY||  
{ /b/  6*&  
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try{ ^+gD;a|t  
URL url = new URL(sURL); : #so"O  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Zv?"1Y< L  
httpConnection.setRequestProperty("User-Agent","NetFox"); y{~tMpo<  
String sProperty = "bytes="+nStartPos+"-"; I|;C}lfp  
httpConnection.setRequestProperty("RANGE",sProperty); W7{^/s5r  
Utility.log(sProperty); B|{E[]
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InputStream input = httpConnection.getInputStream(); ZS`Kj(D  
//logResponseHead(httpConnection); QIJ/'72  
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byte[] b = new byte[1024]; D=Yr/qc?  
int nRead; Fq%NY8KNE  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) +8"P*z,  
{ bQPO'
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nStartPos += fileAccessI.write(b,0,nRead); (m=1yj9  
//if(nThreadID == 1)  -rT#Wi  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2^nws  
} ][YuJUK8  
{M=*>P]E  
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Utility.log("Thread " + nThreadID + " is over!"); XN{zl*`  
bDownOver = true; a:4!z;2 |  
//nPos = fileAccessI.write (b,0,nRead); i CB:p  
} 4Y4zBD=<  
catch(Exception e){e.printStackTrace ();} @RL'pKab9  
} u:B=lZ[  
} &5[+p{2  
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//打印回应的头信息 .YP&E1lNi  
public void logResponseHead(HttpURLConnection con) 73SH[
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{ {.DY\;Q  
for(int i=1;;i++) ^+k= ;nl  
{ [$:L|V!{  
String header=con.getHeaderFieldKey(i); ]Zc\si3i&  
if(header!=null) nwqA\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); xVN!w\0  
Utility.log(header+" : "+con.getHeaderField(header)); {+3g*s/HI  
else C@<gCMj,"  
break; #7}YSfm^6  
} xr7M#n  
} F[W0gjUc  
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public void splitterStop() <(yAat$H  
{ ;:>q;
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bStop = true; <P@O{Xi+K  
} ! CJ*zZ*  
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} ?IoA;GBg  
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/* lvNi/jk  
**FileAccess.java Pv3G?u=4  
*//文件访问(定位，写) S/RChg_L5  
package NetFox; (Jk[%_b>_  
import java.io.*; b)E<b{'W  
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public class FileAccessI implements Serializable{ 'C#[iRG4  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \'iy(8i  
RandomAccessFile oSavedFile; ]!a?Lr  
long nPos; 9wO2`e )  
/NobS'd  
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public FileAccessI() throws IOException ?,%PemN  
{ whrDw1>(  
this("",0); BNFYUcVP  
} S_RP&+!7  
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public FileAccessI(String sName,long nPos) throws IOException NA`8 ^PZ  
{ g-NrxyTBlx  
oSavedFile = new RandomAccessFile(sName,"rw"); ra_v+HR7  
this.nPos = nPos; j'hWhLax  
oSavedFile.seek(nPos); %T\2.vl  
} J8Vzf$t};  
 acQHqR  
*Tr{a_{~C  
public synchronized int write(byte[] b,int nStart,int nLen) 8F's9c,  
{ } j;es(~D  
int n = -1; mG0_&'"YIG  
try{ L.}sN.  
oSavedFile.write(b,nStart,nLen); "*(a2k3J  
n = nLen; ~ tN/  
} BglbQ'6p  
catch(IOException e) {y%@1q%"  
{ 5@I/+D  
e.printStackTrace (); % I2JS  
} gFfKK`)}D'  
\ Z5160  
v-Q>I5D;:  
return n; $+Z2q<UT  
} )e6sg]#  
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} FP*kA_z$  
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9RkNRB)8  
/* t)~$p#NS  
**SiteInfoBean.java 9-24c  
*/ ZA@zs,o%  
package NetFox; o=xMaA  
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public class SiteInfoBean { ziM@@$.F  
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private String sSiteURL; //Site's URL ^gR~~t;@  
private String sFilePath; //Saved File's Path ;lhW6;oI'  
private String sFileName; //Saved File's Name P6=5:-Hh  
private int nSplitter; //Count of Splited Downloading File ^),t=!;p  
YRd`G3J  
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public SiteInfoBean() k72NXagh  
{//nSplitter的缺省值为5 :C,}DyZy  
//default value of nSplitter is 5 'Z#>K*  
this("","","",5); _u6MSRX[6$  
} iU3PlF[B/o  
e#F3KLSL`  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *!3qO^b?  
{ c>+68<H  
sSiteURL= sURL; ,pQ[e$u1  
sFilePath = sPath; 7m?fvKy  
sFileName = sName; >}JEX]V  
this.nSplitter = nSpiltter; }LLQ+  
5 [4{1v  
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} HYY+Fv5  
Q|2*V1"r<2  
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public String getSSiteURL() NZFUCD)  
{ :()K2<E  
return sSiteURL; OIjG`~Rx  
} L&uPNcZ`-  
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public void setSSiteURL(String value) a( N;|<  
{ @uG/2'
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sSiteURL = value; ;z+}|>!  
} 78?cCj{e  
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public String getSFilePath() X gtn}7N.  
{ L;+e)I]  
return sFilePath; CUBL/U\=  
} +[$Td%6  
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public void setSFilePath(String value) r
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{ &4l!2  
sFilePath = value; [MKt\(  
} }h8U.k?v  
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public String getSFileName() G9K& }_,  
{ 8H8Q
  
return sFileName; \]\h,Y8  
} K2V?[O#  
t?=V<Yd1  
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public void setSFileName(String value) $~?)E;S  
{ e:_[0#  
sFileName = value; mmCGIX  
} EZhk(LE  
mGoC8t}iP  

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public int getNSplitter() yD8Qy+6L  
{ \{ C ~B;=  
return nSplitter; q^<;B Y  
} .G"T;w6d  
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public void setNSplitter(int nCount) w7vQ6j
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{ [=u@6Y  
nSplitter = nCount; 0}T56aD=!  
} k ,r*xt  
} st#^pWL  

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qQ,(O5$|  
/* dwiLu&]u  
**Utility.java Gvr>n@n  
*/ '] _7Xa'  
package NetFox; t_(Se  
t$R0UprK  
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public class Utility { DQ0 UY  
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public Utility() `/WOP`'zM  
{ 2+R]q35-  
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} %0 U@k!lP  
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//线程睡眠 FR]u
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public static void sleep(int nSecond) %Rk0sfLvn  
{ 2o W'B^-  
try{ tlI]);iE,  
Thread.sleep(nSecond); *ODc[k'(  
} <UGM/+aO  
catch(Exception e) ygUX]*m!  
{ !L/.[:X  
e.printStackTrace (); (+BrC`  
} 7&L8zl|K  
} "ZmxHMf  
+]hc!s8  
//日志 jDj=a->e^  
public static void log(String sMsg) >:J1Gc  
{ EFu>  
System.err.println(sMsg); tM;+U  
} vJ&35nF&  
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H3Zt3l1u+  
public static void log(int sMsg) 1Eryw~,,9i  
{ a<((\c_8G  
System.err.println(sMsg); *;lb<uLv  
} xz7CnW1  
} F^=y+}]=  
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/* -}8r1jQH;  
**TestMethod.java e >7Ka\  
*/ G2:.8ok  
package NetFox; vQDR;T"]  
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public class TestMethod { )>;387'Y  
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public TestMethod() |(Xxi  
{ ///xx/weblogic60b2_win.exe .Lm`v0'w  
try{ c-Qa0Q  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); i}))6   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _e|-O>#pl  
SiteFileFetch fileFetch = new SiteFileFetch(bean); B5;94YIN  
fileFetch.start(); eYv+tjIF  
} clIn}wQ  
catch(Exception e){e.printStackTrace ();} X{h[   
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} 9HlM0qE5b  
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public static void main(String[] args) owO&[D/  
{ p\]rxtm  
new TestMethod(); 1}CJ&  
} SNHALF  
} P>|sCF  
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