http断点续传简单实现（java)

/* ;(M`Wy]2  
**SiteFileFetch.java i_T8Bfd:  
*/ VKRj 1LXz  
package NetFox; AA34JVm]  
import java.io.*; oyV@BHJO@  
import java.net.*; xgP/BK2"  
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public class SiteFileFetch extends Thread { b?`8-g  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ~3
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long[] nStartPos; //开始位置 ]5b%r;_  
long[] nEndPos; //结束位置 %IGcn48J  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 lgp-/O"T  
long nFileLength; //文件长度 biFy*+|  
boolean bFirst = true; //是否第一次取文件 F<y$Q0Z}  
boolean bStop = false; //停止标志 j2NnDz'  
File tmpFile; //文件下载的临时信息 lAuI?/E  
DataOutputStream output; //输出到文件的输出流 P_)h8-!+ $  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） g,/gApa  
public SiteFileFetch(SiteInfoBean bean) throws IOException |KFRC)g  
{ >e
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siteInfoBean = bean; fnV^&`
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); xe5|pBT  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !X721lNP  
if(tmpFile.exists ()) g|_-O"l  
{ Kj;gxYD>6  
bFirst = false; HH/bBM!  
read_nPos(); A\J|eSG'$  
} !DFT}eu  
else KsI[  
{ ((L=1]w  
nStartPos = new long[bean.getNSplitter()]; "1P8[  
nEndPos = new long[bean.getNSplitter()]; #:"F-3A0  
} 7+';&2M)n~  
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} L ;5uB2  
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public void run() tEP~`$9  
{ ;QbMVY  
//获得文件长度 h;105$E1  
//分割文件 bp Q/#\Z  
//实例FileSplitterFetch V~p/P  
//启动FileSplitterFetch线程 |~vo  
//等待子线程返回 1?s]nU  
try{ Sgp$B:  
if(bFirst) lN"%~n
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{ t~m >\(&  
nFileLength = getFileSize(); V"=(I'X
 
if(nFileLength == -1) G/ToiUY  
{ mEsOYIu{  
System.err.println("File Length is not known!"); Nb/W+& y  
} f,{O%*PUA  
else if(nFileLength == -2) h ,;f6  
{ ?h)Z ;,}  
System.err.println("File is not access!"); D.?Rc'yD  
} 9C[i#+_3M  
else B;.]<k'3  
{ `0a=A#]1o  
for(int i=0;i<nStartPos.length;i++) /Zs;dam  
{ ./nq*4=  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); QV/o;  
} WO{V,<;  
for(int i=0;i<nEndPos.length-1;i++) hd*bPj;  
{ Cisv**9  
nEndPos = nStartPos[i+1]; Ul#||B .c{  
} 6}bUX_!&s  
nEndPos[nEndPos.length-1] = nFileLength; b z3&  
} `BA wef  
} f4Aevh:  
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//启动子线程 \]pRu"  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;ew j  
for(int i=0;i<nStartPos.length;i++) <:=}1t.Z  
{ B;f\H,/59  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), U_!Wg|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), QRbiO  
nStartPos,nEndPos,i); PYWp2V/  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); X1Vx6+[  
fileSplitterFetch.start(); \%Wu`SlDp9  
} 5&V0(LT]C  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R7YLI1ov  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); (3kz(6S  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3(D!]ku~
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nEndPos = " + nFileLength); _ZUtQ49  
// fileSplitterFetch[nPos.length-1].start(); Y] Q=kI  
NYopt?Xg  
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//等待子线程结束 R:49Gn:F  
//int count = 0; HmxA2 ~C  
//是否结束while循环 $RA8U:Q!1e  
boolean breakWhile = false; 
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while(!bStop) CMk0(sztU_  
{ Y"J' 'K  
write_nPos(); q)S70M_1  
Utility.sleep(500); x;d*?69f]  
breakWhile = true; Uu
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for(int i=0;i<nStartPos.length;i++) w
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{ C>\0 "}iD  
if(!fileSplitterFetch.bDownOver) h>>KH*dQ  
{ ]:Y@pZ  
breakWhile = false; (.6~t<DRv  
break; a "*DJ&  
} 8}9B*m  
} &fH;A X.  
if(breakWhile) tNsiokOm  
break; <\i}zoPO  
v
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vFuf{ @P  
//count++; Z)=S. )  
//if(count>4) P,.<3W"4i  
// siteStop(); ?[~"$  
} $$my,:nH  
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System.err.println("文件下载结束！"); FdrH,  
}
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catch(Exception e){e.printStackTrace ();} 34k}7k~n  
} )a:j_jy  
_ U/[n\oC  
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//获得文件长度 \^=Wp'5R  
public long getFileSize() p'# (^  
{ rl#[HbPM  
int nFileLength = -1; 46U?aHKW@|  
try{ "Me)'  
URL url = new URL(siteInfoBean.getSSiteURL()); k 4|*t}o7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Snm m(.  
httpConnection.setRequestProperty("User-Agent","NetFox"); R.KqTEs<k  
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int responseCode=httpConnection.getResponseCode(); ldEZ_g^  
if(responseCode>=400) C?IvXPlV  
{ @y3u'Y,B  
processErrorCode(responseCode); AawK/tfs  
return -2; //-2 represent access is error  U~%V;*|4  
} EbTjBq  
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String sHeader; lHg&|S&J  
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for(int i=1;;i++) IP)?dnwG  
{ ^;on  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ?|Q[QP  
//Utility.log(in.readLine()); _oOEMQb  
sHeader=httpConnection.getHeaderFieldKey(i); 9wR-0E )  
if(sHeader!=null) E:EXp7  
{ 6Xu^cbD  
if(sHeader.equals("Content-Length")) <>!Y[Xr^  
{ 8&q|*/2  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2|J>e(&akY  
break; F_KPhe$  
} j2oHwt6"  
} 3Zy$NsY3  
else HH_w!_f  
break; %O9kq  
} +o{]0~y  
} CYIp 3D'k  
catch(IOException e){e.printStackTrace ();} uU_0t;oR3  
catch(Exception e){e.printStackTrace ();} x6=Yt{  
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Utility.log(nFileLength); jt({@;sU[<  
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() l#}H`m  
return nFileLength; qU ESN!  
} a'sa{>  
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//保存下载信息（文件指针位置） %by8i1
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private void write_nPos() k91ctEp9>  
{ R-lB.9e#M  
try{ T6 K?Xr{_  
output = new DataOutputStream(new FileOutputStream(tmpFile)); aSu6SU  
output.writeInt(nStartPos.length); ifo^ M]v  
for(int i=0;i<nStartPos.length;i++) &C_0JyT  
{ d%IM`S;fh  
// output.writeLong(nPos); wi{qN___  
output.writeLong(fileSplitterFetch.nStartPos); yrp;G_  
output.writeLong(fileSplitterFetch.nEndPos); Tt,<@U[/}  
} P)h
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output.close(); FlWgTn>  
} <r[5 S5y  
catch(IOException e){e.printStackTrace ();} [&6VI?  
catch(Exception e){e.printStackTrace ();} egOZ.oV  
} H;#3S<  
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//读取保存的下载信息（文件指针位置） ^|h5*Tb  
private void read_nPos() F*&A=@/3  
{ XiP xg[;  
try{ ]h]|PdN  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); y)`f$Hl@1  
int nCount = input.readInt(); -2)6QKh~D  
nStartPos = new long[nCount]; O26'|w@$  
nEndPos = new long[nCount]; ]_8bX}_n  
for(int i=0;i<nStartPos.length;i++) mM6g-)cV  
{ =Gka;,n  
nStartPos = input.readLong(); -pWnO9q  
nEndPos = input.readLong(); (e:@7W)L  
} O$'BJKj-4  
input.close(); ?*2DR:o>@  
} (k{rn3,  
catch(IOException e){e.printStackTrace ();} ~Y- !PZ  
catch(Exception e){e.printStackTrace ();} X\?PnD`,  
} v() wngn  
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private void processErrorCode(int nErrorCode) --(e(tvf  
{ jgc
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System.err.println("Error Code : " + nErrorCode); oCl $ 0x  
} QkEIV<T&)l  
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//停止文件下载 8T:?C~"  
public void siteStop() x.=Np\#\G-  
{ S4r-s;U-v/  
bStop = true; "OIra2O  
for(int i=0;i<nStartPos.length;i++) ||M;[-JoJ  
fileSplitterFetch.splitterStop(); R)p+#F(s  
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} br
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} ?Ek 3<7d  
//负责部分文件的抓取 3M5+!H  
**FileSplitterFetch.java K>!+5A$6i  
*/ Q]Kc<[E  
package NetFox; TLBIM  
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import java.io.*; [8-. T4  
import java.net.*; 15o<'4|=Lm  
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public class FileSplitterFetch extends Thread { Dy_ayxm  
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String sURL; //File URL 29W~<E8K-  
long nStartPos; //File Snippet Start Position Dz<"eyB\  
long nEndPos; //File Snippet End Position .ZV-]jgr  
int nThreadID; //Thread's ID AW;ncx;  
boolean bDownOver = false; //Downing is over 7P&O{tl(  
boolean bStop = false; //Stop identical y:C=Ni&,"  
FileAccessI fileAccessI = null; //File Access interface ]c67zyX=%  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 5_|Sm=  
{ }bU1wIW9I  
this.sURL = sURL; G*oqhep  
this.nStartPos = nStart; (%bqeI!ob  
this.nEndPos = nEnd; )D_\~n/5  
nThreadID = id; 5:oteNc
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 cph&\ V2jt  
} SFj:|S=v6j  
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public void run() X&s@S5=r]  
{
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while(nStartPos < nEndPos && !bStop) y4jJ&  
{ jrF#DDH?I  
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try{ ^HO'"/tB@D  
URL url = new URL(sURL); GN&-`E]-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~
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httpConnection.setRequestProperty("User-Agent","NetFox");  T:~c{S4&  
String sProperty = "bytes="+nStartPos+"-"; uR;m<wPH,f  
httpConnection.setRequestProperty("RANGE",sProperty); )z:"P;b"Nl  
Utility.log(sProperty); C(4r>TNm  
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InputStream input = httpConnection.getInputStream(); n7CwGN%  
//logResponseHead(httpConnection); lhp.zl  
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byte[] b = new byte[1024]; s-S#qGZ  
int nRead; bhqV2y*'  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {.,-lFb\  
{ +NM`y=@@  
nStartPos += fileAccessI.write(b,0,nRead); 3Z taj^v  
//if(nThreadID == 1) pA~eGar_J  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +\Zr\fOe|%  
} 4s <|8  
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Utility.log("Thread " + nThreadID + " is over!"); <w9<G  
bDownOver = true; ZQ MK1  
//nPos = fileAccessI.write (b,0,nRead); [M;B 9-2$  
} K6..N\7  
catch(Exception e){e.printStackTrace ();} @xqjAcfg  
} OYbgt4  
} h)~i?bq!/  
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//打印回应的头信息 <kc9KE  
public void logResponseHead(HttpURLConnection con) +nOa&d\  
{ t,v=~LE  
for(int i=1;;i++) x%$as;  
{ 4ayZ.`aK  
String header=con.getHeaderFieldKey(i); )<>1Q{j@  
if(header!=null) E
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); ]:K[{3iM  
Utility.log(header+" : "+con.getHeaderField(header)); v 7g?  
else DJ]GM|?  
break; 5N5Deb#V  
} #rps2nf
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} %F.^cd"  
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public void splitterStop() ]"T1clZKd(  
{ u A=x~-I  
bStop = true; MlVVST  
} u?a4v\  
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} ]ssX,1#Xh  
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/* xnp5XhU  
**FileAccess.java $bho]~  
*//文件访问(定位，写) "m'roU  
package NetFox; &%infPI'  
import java.io.*; #[<XNs!"  
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public class FileAccessI implements Serializable{ ej^pFo  
'|jN!y^2p  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 v;_k*y[VV$  
RandomAccessFile oSavedFile; >'MT]@vez  
long nPos; Y`tv"v2  
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public FileAccessI() throws IOException 920 o]Dh=t  
{ {i!@C(M3  
this("",0); %aHQIoxg  
} 9NPOdt:@  
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public FileAccessI(String sName,long nPos) throws IOException 
2 yY.rs  
{ 0;6^fiSY;  
oSavedFile = new RandomAccessFile(sName,"rw"); zF-M9f$_PY  
this.nPos = nPos; FKVf_Ncf%
 
oSavedFile.seek(nPos); A2xfNY<  
} 1#OM~v6B  
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public synchronized int write(byte[] b,int nStart,int nLen) iAd3w6  
{ ^~65M/  
int n = -1; S(Ej: H  
try{ ,!{/Y7PmJ  
oSavedFile.write(b,nStart,nLen); $Lf-Gi  
n = nLen;
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} o$[alh;c+W  
catch(IOException e) t(sQw '>  
{ '_`O&rbT  
e.printStackTrace (); &|j^?ro6  
} tXu_o6]  
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return n; jykY8;4  
} 8t$w/#'@  
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} !JOM+P:  
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/* Dg_Ao
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**SiteInfoBean.java ^@a|s Sb  
*/ 2uajK..b  
package NetFox; *H'
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public class SiteInfoBean { bFt$u]Yvo  
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private String sSiteURL; //Site's URL *|F ;An.N^  
private String sFilePath; //Saved File's Path 'nR'o /!  
private String sFileName; //Saved File's Name "7RnT3  
private int nSplitter; //Count of Splited Downloading File .V.x0  
nxZ[E.-\  
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public SiteInfoBean() wFHbz9|@I  
{//nSplitter的缺省值为5 #y4+O;{  
//default value of nSplitter is 5 Ki_8
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this("","","",5); cf7UV6D g  
} hCX_^%  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^]A,Q%1q^  
{ $^XCI%DH  
sSiteURL= sURL; {G^f/%  
sFilePath = sPath; P+j5_V{\b  
sFileName = sName; q4wS<,3  
this.nSplitter = nSpiltter; XzH"dDAVE  
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} QT\=>,Fz _  
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public String getSSiteURL() x_K8Gr#Z0  
{ '9R.$,N  
return sSiteURL; $Z2Y%z6y  
} 4{Q{>S*h  
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public void setSSiteURL(String value) "{igrl8  
{ I\FBf&~  
sSiteURL = value; "-U`E)]w*[  
} <hA1[S}  
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public String getSFilePath() w$2
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{ ET[vJnReC  
return sFilePath; 8:=EA3  
} hfBZ:es+  
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public void setSFilePath(String value) [Jjb<6[o  
{ ;94e   
sFilePath = value; [IgB78_$  
} ^ rB7&96C,  
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(> {CwtH][  
public String getSFileName() MkCq$MA  
{ erW[q  
return sFileName; s?g`ufF.t  
} {@7{!I|eD  
s,*kWy"jp  
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public void setSFileName(String value) P t)Ni  
{ 8>KBh)q  
sFileName = value; "yo~;[  
} 3r[}'ba\  
_K#LOSMfj/  
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public int getNSplitter() 42Vz6 k:  
{ <.HDv:  
return nSplitter; ktu{I  
} :{YOJD
tR  
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public void setNSplitter(int nCount) u*aFWl]=  
{  >>n
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nSplitter = nCount; e7cqm*Qi  
} Gd]!D~[1  
} +F9)+wT~;q  
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/* \en}8r9cy  
**Utility.java 
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*/ I\|x0D  
package NetFox; n> >!dg Og  
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public class Utility { wP <)  
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public Utility() 5dPPm%U{  
{ lg(*:To3B  
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} 0CTUcVM#9  
E[Rd=/P6  
//线程睡眠 E`DsRR <  
public static void sleep(int nSecond) Pz/bne;=  
{ X;hV+|Bo  
try{ )<vU F]e~  
Thread.sleep(nSecond); k70o=}  
} Jp0*Y-*Y  
catch(Exception e) 0rjH`H]M  
{ UZ`GS$D@  
e.printStackTrace (); +-VkRr#  
} %]zaX-2dm!  
} (eOzntp8  
,Qd;t  
//日志 4Hk eXS.  
public static void log(String sMsg) '}Tf9L%  
{ POl[]ni=>  
System.err.println(sMsg); $Eo)i  
} "K7{y4  
4]VoIUIuN  
mo$`a6[h<  
public static void log(int sMsg) |BO!q9633V  
{ lhyWlO  
System.err.println(sMsg); 905%5\Y  
} NJVAvq2E.  
} RwG@C|sG  
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[|XMR=\>  
/* }=+J&cR  
**TestMethod.java ?3x7_=4t@  
*/ "-pQL )f  
package NetFox; 4t%g:9]vr  
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rr@S|k:|  
public class TestMethod { ~.FZF  
zB8 @Wl  
" ^t3VjN  
public TestMethod() u+&t"B  
{ ///xx/weblogic60b2_win.exe -UHa;WH  
try{ @F+zME   
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); tqn
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//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); sO5~!W>Z  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (sXR@Ce$  
fileFetch.start(); E*uz|w3S)Y  
} !c;Z<@  
catch(Exception e){e.printStackTrace ();} #LGAvFA*_F  
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} v*Fr#I0U  
* mzJ)4A  
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public static void main(String[] args) KqM!7  
{ [SFX;v!9  
new TestMethod(); KfSI6 Y_  
} ,-C%+S
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} y@5{.jsr_  
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