http断点续传简单实现（java)

/* f3t.T=S  
**SiteFileFetch.java pYh!]0n  
*/ \u8,!) 4i  
package NetFox; [-58Ezyr  
import java.io.*; Qc3?}os2  
import java.net.*; )E~_rDTl  
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public class SiteFileFetch extends Thread { nsl*Dm"*F  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 7}o6_i  
long[] nStartPos; //开始位置 :l`i4
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long[] nEndPos; //结束位置 I.9o`Q[8&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 h!Y?SO.b  
long nFileLength; //文件长度 /{R3@,D[]  
boolean bFirst = true; //是否第一次取文件 bg1un@%!l  
boolean bStop = false; //停止标志 $m8leuo)  
File tmpFile; //文件下载的临时信息 O#G| ~'.,  
DataOutputStream output; //输出到文件的输出流 lR}%)3_k  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） QT;Va#a  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1LyT7h  
{ @'HT;Q!\Vd  
siteInfoBean = bean; xE1rxPuq)d  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )-q\aX$])  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); c
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if(tmpFile.exists ()) iokPmV  
{ HtUG#sc&`{  
bFirst = false; gn`zy9PU  
read_nPos(); ls]H6z*q  
} C$K+=jT  
else Xl?YBZ}  
{ Y-]YDXrPQ  
nStartPos = new long[bean.getNSplitter()]; e`AUYli"  
nEndPos = new long[bean.getNSplitter()]; fkG##!  
} !&JiNn('  
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} :A#+=O0\z  
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public void run() !EM#m@kZ{  
{ `*d{PJTv  
//获得文件长度 K%PxA#P}  
//分割文件 Gh=<0WaF=  
//实例FileSplitterFetch ?} X}#  
//启动FileSplitterFetch线程 kXEtuO5FUM  
//等待子线程返回 Of#K:`1@  
try{ esteFLm`6  
if(bFirst) $l#{_~ "m7  
{ '%ebcL  
nFileLength = getFileSize(); Efvq?cG&  
if(nFileLength == -1) CrO`=\  
{ ]hKgA~;  
System.err.println("File Length is not known!"); ]4GZ'&m}  
} C d|W#.6  
else if(nFileLength == -2) %wtXo BJ  
{ zHqhl}  
System.err.println("File is not access!"); ,{+6$h3  
} ?rQc<;b  
else Q)T+r~#2B  
{ /yp/9r@T0  
for(int i=0;i<nStartPos.length;i++) ssT@<Tk^4  
{ }1F6?do3&  
nStartPos = (long)(i*(nFileLength/nStartPos.length));
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} EIPnm%{1  
for(int i=0;i<nEndPos.length-1;i++) c"qPTjY  
{ 6+)x7g1PL  
nEndPos = nStartPos[i+1]; shNE~TA  
} %Gu][_.L  
nEndPos[nEndPos.length-1] = nFileLength; wn1, EhHt  
} *(p7NYf1  
} }+_9"YQ:  
s,kU*kHn  
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//启动子线程 cafsMgrA  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *.3y2m,bZ  
for(int i=0;i<nStartPos.length;i++) 7O9n!aJ  
{  ;b|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), '{CWanTPi  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), B#:E?a;{  
nStartPos,nEndPos,i); L&'l3|  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L:i+}F;M)s  
fileSplitterFetch.start(); gZ*hkKN6  
} t*s!0'Y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]\`w1'*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %}ixgs7*c0  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", I5Q~T5Ar  
nEndPos = " + nFileLength); jNIUsM8e  
// fileSplitterFetch[nPos.length-1].start(); j6}$+!E  
~ttKI4  
@C07k^j=U  
//等待子线程结束 ",QPb3  
//int count = 0; >HX)MwAP  
//是否结束while循环 3AvcJ1  
boolean breakWhile = false; M_; w%FV  
 VmYBa(  
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while(!bStop) Y6a$gXRT  
{ ,$ mLL  
write_nPos(); I^@.Awt  
Utility.sleep(500); mQL8QW[c  
breakWhile = true; V>r j$Nc]  
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for(int i=0;i<nStartPos.length;i++) &<@%{h@=  
{ rXuAixu!t  
if(!fileSplitterFetch.bDownOver) k0knPDbHv  
{ (qbc;gBy  
breakWhile = false; UC(9Dz  
break; *.xZfi_|  
} ij!*CTG  
} 7G2vYKC'  
if(breakWhile) IX?@~'  
break; egbb1+tY  
zG<0CZQ8  
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//count++; 'cYQ?;  
//if(count>4) ^ISQ{M#_  
// siteStop(); _Po#ZGm~  
} !bieo'
c  
8| Sba<d  
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System.err.println("文件下载结束！"); ^h`!f vyH  
} \1~I04'=  
catch(Exception e){e.printStackTrace ();} )#Y|ngZ_>  
} UFos E|r:  
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@ E >eq.m  
//获得文件长度 0T=jR{j!o  
public long getFileSize() K/~Y!?:Jr  
{ C_C$5[~-:  
int nFileLength = -1; 9X.gg$P  
try{ ]2P/G5C3tU  
URL url = new URL(siteInfoBean.getSSiteURL()); #c:9V2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); VGfD;8]z  
httpConnection.setRequestProperty("User-Agent","NetFox"); e`vUK.UoW  
{;\%!I  
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int responseCode=httpConnection.getResponseCode(); 3JTU^-S<  
if(responseCode>=400) 9W$mDw6f  
{ E $<;@  
processErrorCode(responseCode); w9'H.Lq  
return -2; //-2 represent access is error {Qm6?H  
} ?F9hDLX  
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String sHeader; 3b,=  
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for(int i=1;;i++) {rs6"X^  
{ JE/l#Q!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); O3!Ouh&  
//Utility.log(in.readLine()); 2YaTT& J  
sHeader=httpConnection.getHeaderFieldKey(i); GCZu<,  
if(sHeader!=null) t;oT {Hge  
{ G[vUOEU~O  
if(sHeader.equals("Content-Length")) a pKa4nI  
{ g<0w/n!jmC  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Ja^7$WY
 
break; J6= w:c  
} 1k*n1t):  
} MM=W9#  
else O\3r%=TF  
break; LRhP7D+A  
} }rFThI  
} (R,NV3m?w  
catch(IOException e){e.printStackTrace ();} A>H*`{}  
catch(Exception e){e.printStackTrace ();} $>nkGb%Kp  
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Utility.log(nFileLength); U.d'a~pH  
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return nFileLength; X+/{%P!w  
} nomu$|I  
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//保存下载信息（文件指针位置） _-g-'Hr+N  
private void write_nPos() D>psh-,1  
{ V< 2IIH5^  
try{ cr2{sGn|  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ]JkpRaP$  
output.writeInt(nStartPos.length); 07~pf}  
for(int i=0;i<nStartPos.length;i++) !pG+Ak?  
{ 2O}s*C$Xav  
// output.writeLong(nPos); v+|@}9|Z  
output.writeLong(fileSplitterFetch.nStartPos); |`N$>9qN  
output.writeLong(fileSplitterFetch.nEndPos); ?
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} %ZJ),9+  
output.close(); ';i"?D?NAk  
} Wm];pqN  
catch(IOException e){e.printStackTrace ();} ^yzo!`)fso  
catch(Exception e){e.printStackTrace ();} a*pXrp@  
} ?{y
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//读取保存的下载信息（文件指针位置） #fJ/KY
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private void read_nPos() WO.}DUfG+  
{ 'YBLU)v[  
try{ Lf$Q %eM0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); <=B1"'\  
int nCount = input.readInt(); IMl9\U  
nStartPos = new long[nCount]; '8]
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nEndPos = new long[nCount]; &!H~bzg  
for(int i=0;i<nStartPos.length;i++) g
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{ BH.:_Qrbh[  
nStartPos = input.readLong(); ^bZ<9}  
nEndPos = input.readLong(); k~'?"'  
} l}U~I 3}).  
input.close(); [)C)p*!Y)  
} FZeN,  
catch(IOException e){e.printStackTrace ();} LAu+{'O\  
catch(Exception e){e.printStackTrace ();} 0KWy?6 X  
} 3n}sCEt=  
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private void processErrorCode(int nErrorCode) I@y2HxM  
{ ~;!i)[-  
System.err.println("Error Code : " + nErrorCode); ="'rH.n #  
} $9j>VGf=
 
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//停止文件下载 nr<}Hc
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public void siteStop() u&l>cJ'
 
{ PVQ#>_~5  
bStop = true; b#/V;  
for(int i=0;i<nStartPos.length;i++) e+d6R[`M  
fileSplitterFetch.splitterStop(); dQWA"6?i  
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} pqGf@2
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} c_D,MW\IC  
//负责部分文件的抓取 )-TeDIfm  
**FileSplitterFetch.java 3cV+A]i  
*/ #XYLVee,  
package NetFox; a!hI${Xn  
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import java.io.*; S
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import java.net.*; FrAqTz  
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public class FileSplitterFetch extends Thread { p;c_<>ws-Y  
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String sURL; //File URL r(?'Yy  
long nStartPos; //File Snippet Start Position e&FX7dsyy  
long nEndPos; //File Snippet End Position a|]%/[G@  
int nThreadID; //Thread's ID mZ& \3m=  
boolean bDownOver = false; //Downing is over @wAr[.lZ  
boolean bStop = false; //Stop identical /ut~jf`  
FileAccessI fileAccessI = null; //File Access interface UG^?a  
*x#&[>  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )N%1%bg^-  
{ ba:mO$  
this.sURL = sURL; H(DVVHx  
this.nStartPos = nStart; hK9
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this.nEndPos = nEnd; J?qcRg`1E  
nThreadID = id; ?Uy*6YS  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 YWn6wzu%Vc  
} !Xv2PdP  
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public void run() .9[8H:Fe  
{ dg'CHxU  
while(nStartPos < nEndPos && !bStop) AT'_0>x8  
{ '
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try{ .$ P2W0G  
URL url = new URL(sURL); Mh-*5Rx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `)
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httpConnection.setRequestProperty("User-Agent","NetFox"); {TxVRpiP{Z  
String sProperty = "bytes="+nStartPos+"-"; J*q=C%}.
  
httpConnection.setRequestProperty("RANGE",sProperty); nV,{w4t+  
Utility.log(sProperty); R1b )  
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InputStream input = httpConnection.getInputStream(); wYcz\uV  
//logResponseHead(httpConnection); 
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byte[] b = new byte[1024]; @y~BYiKs  
int nRead; 6UzT]"LR;  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) j O5:{%  
{ ym,Ot1  
nStartPos += fileAccessI.write(b,0,nRead); `Hp.%G(  
//if(nThreadID == 1) n[cyK$"  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #&`WMLl+8  
} &Ow?Hd0  
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Utility.log("Thread " + nThreadID + " is over!"); &L~31Ayj&  
bDownOver = true; )(|0Ka
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//nPos = fileAccessI.write (b,0,nRead); lj SR?:\  
} uI:3$  
catch(Exception e){e.printStackTrace ();} |@Idf`N$  
} #3:'lGBIK  
} dc@wf;o  
s2' :&5(  
4f@\f7\  
//打印回应的头信息 L8-[:1
  
public void logResponseHead(HttpURLConnection con) :+dWJNY:  
{ HV.|Eh_7  
for(int i=1;;i++) 52C-D+zCJ  
{ x#e\H F  
String header=con.getHeaderFieldKey(i); rEpKX  
if(header!=null) vdFQf ^l  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); V.a]IkK'K  
Utility.log(header+" : "+con.getHeaderField(header)); 4Z T  
else '14l )1g
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break; Gp3t?7S{T  
} 4k
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} e#e
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public void splitterStop() ZD]
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{ q$2taG}  
bStop = true; !L.z4n,n+  
} H1ui#5n2  
d# ?*62  
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} ;KZ2L~ THG  
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/* {arjW3~M:  
**FileAccess.java o-i.'L)X  
*//文件访问(定位，写) %?G.lej,x  
package NetFox; s8I77._s  
import java.io.*; @j8L{FGnN  
&7kSLat+9{  
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public class FileAccessI implements Serializable{ _2n/vF;I+_  
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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 n,'AFb4AF  
RandomAccessFile oSavedFile; ="TOa"Zk  
long nPos; "BNmpP  
>_%g8T'  
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public FileAccessI() throws IOException z^GGJu%vjr  
{ {Ll8@'5  
this("",0); x)sDf!d4bi  
} $bC!T  
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public FileAccessI(String sName,long nPos) throws IOException j9fL0$+FI  
{ 3eDx@8N }  
oSavedFile = new RandomAccessFile(sName,"rw"); ?*5l}y=  
this.nPos = nPos; /n}V7  
oSavedFile.seek(nPos); /<N
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} $gtT5{"PN(  
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public synchronized int write(byte[] b,int nStart,int nLen) l|QFNW[i
 
{

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int n = -1; W p* v Vv  
try{ `2~Ea_Z  
oSavedFile.write(b,nStart,nLen); +fR`@HI  
n = nLen; Xwq2;Bq  
} Q-%=ZW Z  
catch(IOException e) tZ2iSc  
{ 30v1VLR_)  
e.printStackTrace ();
b,V=B{(~  
} lxJ.h&"P  
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return n; U`4Zj1y  
} IHMyP~{  
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} c oz}VMp  
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/* n>+W]I&E  
**SiteInfoBean.java [5:7WqB  
*/ @wZ_VE7B  
package NetFox; sbhEZ#7#  
-~aEqj#?  
juZ3""  
public class SiteInfoBean { _NN{Wk/3w  
P@![P Ij  
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private String sSiteURL; //Site's URL bg. KkJMrR  
private String sFilePath; //Saved File's Path {v'Fg  
private String sFileName; //Saved File's Name /[T8/7;_l  
private int nSplitter; //Count of Splited Downloading File *\+'tFT6  
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j[eEyCW[)  
public SiteInfoBean() b,A1(_pzi  
{//nSplitter的缺省值为5 5Rp2O4Z  
//default value of nSplitter is 5 tzN;;h4C  
this("","","",5); /Bu5kBC  
} d> AmM!J  
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~ZC=!|Q#  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) N4N
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{
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sSiteURL= sURL; W5;sps  
sFilePath = sPath; LA Vgf>  
sFileName = sName; {vlh,0~  
this.nSplitter = nSpiltter; Oz7v hOU  
1 niTkop  
#-,`4x$m|  
} GlZDuU  
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5!%/j,?  
public String getSSiteURL() #8|NZ6x,  
{ eci\
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return sSiteURL; &Wk<F3qN  
} 5X-(@Gw
N  
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public void setSSiteURL(String value) 2p ,6=8^v  
{ (8R M|&  
sSiteURL = value; l<6/ADuS  
} Y{@[)M{<  
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public String getSFilePath() m%3Kq%?O  
{ 6w,xb&S  
return sFilePath; ITiw) M  
} v836nxLM  
?g.w%Mf*  
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public void setSFilePath(String value) 2kve?/  
{ \59hW%Di  
sFilePath = value; u] b6>  
} ;_ton?bF  
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public String getSFileName() lU&IS?^?  
{ iiscm\  
return sFileName; DdgFBO  
} S3fBZIPp  
/#5ZP\e  
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public void setSFileName(String value) Bnv%W4  
{ q<7n5kJ~  
sFileName = value; JTJ4a8DE  
} kA0^~  
Lf9h;z>#  
^g\%
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public int getNSplitter() f*Bc`+G  
{ yvvR%]!.  
return nSplitter; ER+[gT1CQ  
} uy~j$lrn  
v\C+G[MV7  
E{J
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public void setNSplitter(int nCount) F\;1:y~1  
{ tWuQKN`_  
nSplitter = nCount; ;7hr8?M|  
} $Izk]o;X~  
} _De;SB%V  
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= '[@UVH(Z  
/* 5KzU&!Zh9  
**Utility.java kE}?"<l  
*/ xuF_^  
package NetFox; %LyB~X  
V ALYA=w/  
[<hiOB  
public class Utility { ^M"g5+q  
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public Utility() H2}i .  
{ f?QD##~;  
!Fi)-o  
{Bx\Z0+'&  
} hSmM OS{  
gqG"t@Y+  
//线程睡眠 !O*n6}nPE  
public static void sleep(int nSecond) $[Ns#7K  
{ X+iULr.^`~  
try{ YeVhWPn@  
Thread.sleep(nSecond); joq ;N]S  
} k?,g:[4!  
catch(Exception e) aU@z\sQ  
{ 9w1)Mf}  
e.printStackTrace (); RA}PM?D/  
} 9]iDNa/D  
} Qi M>59[  
81&!!qhfS  
//日志 i2DR}%U  
public static void log(String sMsg) )? xg=o/?  
{ I g`#U~  
System.err.println(sMsg); -zt\weqA  
} G>j/d7  
f 36rU  
dO2cgY}  
public static void log(int sMsg) EHOdst  
{ M6>l%[  
System.err.println(sMsg); +t f=  
} yd k  
} @gd-lcMYW  
4'M#m|V  
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/* HDYf^mcW  
**TestMethod.java kI]1J  
*/ w[XW>4xK  
package NetFox; BLRrHaX0  
!u"Hf7/  
Y+E@afsKs  
public class TestMethod { $[d}g  
eUl[gHP  
()iJvf>
@  
public TestMethod() I('l)^m%  
{ ///xx/weblogic60b2_win.exe ]TQjk{X<  
try{ LxbVRw  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); F]&9Lp} "  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); G} p~VLf  
SiteFileFetch fileFetch = new SiteFileFetch(bean); C/XOI>  
fileFetch.start(); pT <H&  
} <NUZPX29  
catch(Exception e){e.printStackTrace ();} cWi2Sls  
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uQDu<@5^[  
} NJ~'`{3v  
WJ%b9{<  
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public static void main(String[] args) ^m~=<4eX  
{ ` H"5nQRV  
new TestMethod(); NQb?&.C   
} 8/=2N  
} L.5GX 29  
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