http断点续传简单实现（java)

/* VVP:w%yW  
**SiteFileFetch.java \>QF(J [8  
*/ n\z,/'d"  
package NetFox; Z|"p*5O,  
import java.io.*; j _L@U2i  
import java.net.*; ,#?uJTLH  
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public class SiteFileFetch extends Thread { &0zT I?c  
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SiteInfoBean siteInfoBean = null; //文件信息Bean zOgTQs"ZH  
long[] nStartPos; //开始位置 L2Pujk  
long[] nEndPos; //结束位置 uvP2Wgt  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 6(d}W2GP  
long nFileLength; //文件长度 Rp7ntI:  
boolean bFirst = true; //是否第一次取文件 rE9I>|tX  
boolean bStop = false; //停止标志 G6@M&u5RT  
File tmpFile; //文件下载的临时信息 =L;] ;i  
DataOutputStream output; //输出到文件的输出流 I`KQ|h0%  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） kHw_ S-  
public SiteFileFetch(SiteInfoBean bean) throws IOException Bw%Qbs0Q  
{ +5VLw  
siteInfoBean = bean; *}k;L74|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^sN (
  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); yeDsJ/L  
if(tmpFile.exists ()) ^V$Ajt  
{ a<}#HfC;'  
bFirst = false; ]0hrRA`  
read_nPos(); Mj[f~  
} B(xN Gs  
else >{\7&}gz  
{ ./Q,  
nStartPos = new long[bean.getNSplitter()]; %NL^WG:  
nEndPos = new long[bean.getNSplitter()]; ;bHV  
} _=CZR7:O  
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} ]BR,M4   
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public void run() ?T+q/lt4  
{ 2^8%>,  
//获得文件长度 cuy1DDl  
//分割文件 zg-2C>(6a  
//实例FileSplitterFetch x#Sqn#  
//启动FileSplitterFetch线程 F 8B#}%JE  
//等待子线程返回 g1t0l%_7^  
try{ ,U(1NK8o  
if(bFirst) AL>$HB$  
{ Jgnhn>dHe  
nFileLength = getFileSize(); ?QE,;QtpK  
if(nFileLength == -1) [1.+HyJ}  
{ @v}/zS  
System.err.println("File Length is not known!"); UTXSeNP  
} g8PTGz  
else if(nFileLength == -2) (?nCyHC%g  
{ _h}kp\sps  
System.err.println("File is not access!"); `ZC<W]WYX/  
} EkziAON  
else jH_JmYd  
{ $56,$K`H  
for(int i=0;i<nStartPos.length;i++) xyI}y(CN1  
{ /7gOSwY  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); As>_J=8} 3  
} ?lP':'P  
for(int i=0;i<nEndPos.length-1;i++) 9K1oZ?)_z  
{ %2v4<icvq  
nEndPos = nStartPos[i+1]; ,\NFt`]j  
} lok=  
nEndPos[nEndPos.length-1] = nFileLength; \L"kV!>  
} =UV`.d2[  
} u*hSj)vr1  
>$4d7.^hb/  
!"Oh36  
//启动子线程 cTG|fdgMW  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; IIbYfPiO  
for(int i=0;i<nStartPos.length;i++) W*2U="t  
{ |P%Jw,}]9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %n*-VAfE\  
nStartPos,nEndPos,i); aA,!<^&}  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); K.0:C`C  
fileSplitterFetch.start(); Hw4%uS==V  
} M3q|l7|9  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), x)@G;nZ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); w!D|]LoE  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", irfp!(r  
nEndPos = " + nFileLength); 6fw(T.Pe  
// fileSplitterFetch[nPos.length-1].start(); DY`kx2e!  
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[sW3l:^  
//等待子线程结束 j:VbrR  
//int count = 0; b9l;a+]d  
//是否结束while循环 *6VF $/rP  
boolean breakWhile = false; fZoHf\B]{  
>Z5gSs0  
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while(!bStop) >6?__v]9G  
{ 62zYRs\Y)X  
write_nPos(); 9gmW&{6q  
Utility.sleep(500); !_Wi!Vr_  
breakWhile = true;  a24"yT  
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for(int i=0;i<nStartPos.length;i++) n^g|Ja  
{ (=om,g}  
if(!fileSplitterFetch.bDownOver) maNl^i
 
{ 3eF-8Z(f  
breakWhile = false; r[*Vqcz  
break; va0{>Dc+  
} sr{a(4*\  
} 6}!#;@D~
 
if(breakWhile) *+#8mA(  
break; J|qZ+A[z
 
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//count++; 2I,^YWR  
//if(count>4) 9J2NH|]c  
// siteStop(); ++^l]8  
} fSokm4]vg  
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System.err.println("文件下载结束！"); eLfk\kk]Pc  
} 7Mg=b%IYs  
catch(Exception e){e.printStackTrace ();} $adbCY\  
} 6V7B;tB  
)!P)U(*v  
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//获得文件长度 # mV{#B=  
public long getFileSize() 9[.8cg*  
{ >LOjV0K/  
int nFileLength = -1; pu2tY7Ja  
try{ G?Q3/y(  
URL url = new URL(siteInfoBean.getSSiteURL()); kH G"XTL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q
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httpConnection.setRequestProperty("User-Agent","NetFox"); |Uc_G13Y{D  
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int responseCode=httpConnection.getResponseCode(); sTn<#l6  
if(responseCode>=400) hHV";bk  
{ zem8G2#c  
processErrorCode(responseCode); "eB$k40-  
return -2; //-2 represent access is error uM_wjP  
} hhCrUn"  
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String sHeader; cj$[E]B3V*  
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for(int i=1;;i++) x|pg"v&[  
{ RBs-_o+%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Vf]
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//Utility.log(in.readLine()); A#EDkU,  
sHeader=httpConnection.getHeaderFieldKey(i); 1H6<[iHW  
if(sHeader!=null) "@iK' c^  
{ :bwjJ
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if(sHeader.equals("Content-Length")) pKpUXfQu  
{ X-K=!pET  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {zQ8)$CQ  
break; ChGYTn`X   
} a
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} _Xk.p_uh  
else -?V-*jI  
break; bk;?9%TW  
} H[,i{dD  
} +BETF;0D  
catch(IOException e){e.printStackTrace ();} TQpfQ  
catch(Exception e){e.printStackTrace ();} dfKF%27  
,!#*GZ.ix  
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Utility.log(nFileLength); jB%lB1Q|  
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return nFileLength; }$SavB#SBP  
} (l^3Z3zf&  
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//保存下载信息（文件指针位置） D$ dfNiCH  
private void write_nPos() Xg|B \\  
{ /:~\5}tW  
try{ 6e9
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output = new DataOutputStream(new FileOutputStream(tmpFile)); ,)Me  
output.writeInt(nStartPos.length); MQ5R O;RY  
for(int i=0;i<nStartPos.length;i++) *>7>g"  
{ m% -g~q  
// output.writeLong(nPos); j*
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output.writeLong(fileSplitterFetch.nStartPos); HN=V"a  
output.writeLong(fileSplitterFetch.nEndPos); P
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} dJJP3}M/  
output.close(); Q=;U@k@>  
} Mo?~_|}  
catch(IOException e){e.printStackTrace ();} V58wU:li  
catch(Exception e){e.printStackTrace ();} *|%@6I(  
} =,spvy'"*C  
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//读取保存的下载信息（文件指针位置） A9I{2qW9+Z  
private void read_nPos() 8@i7pBl@  
{ $HHs^tW  
try{ :W!7mna  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ]m g)Q:d,  
int nCount = input.readInt(); G&D7a
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nStartPos = new long[nCount]; qE&v ;  
nEndPos = new long[nCount]; YVQN&|-  
for(int i=0;i<nStartPos.length;i++) BLfTsNzmt  
{ *scVJ  
nStartPos = input.readLong(); C7lH]`W|/  
nEndPos = input.readLong(); '\Giv!>  
} {> eXR?s/  
input.close(); "c3Grfoz  
} 0b+Wc43}K  
catch(IOException e){e.printStackTrace ();} Jj!v
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catch(Exception e){e.printStackTrace ();} (G zb  
} "6MVvpy"  
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private void processErrorCode(int nErrorCode) wvO|UP H\  
{ MLw7}[  
System.err.println("Error Code : " + nErrorCode); l~c@^!  
} sGyeb5c  
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//停止文件下载 =XA;[PVx:#  
public void siteStop() UW N*j_9i  
{ Oft-w)cYz,  
bStop = true; -I*^-+>H  
for(int i=0;i<nStartPos.length;i++) qkt0**\  
fileSplitterFetch.splitterStop(); = s>T;|  
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} &+Z,hs9%  
} !\zWF  
//负责部分文件的抓取 ?5C!<3gM)  
**FileSplitterFetch.java LPZF)@|`  
*/ *7CV^mDm  
package NetFox; :[wsKFaV+  
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import java.io.*; ]NUl9t*N4  
import java.net.*; JlH&??  
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public class FileSplitterFetch extends Thread { `|6'9  
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String sURL; //File URL /qMG=Z  
long nStartPos; //File Snippet Start Position "@%7-nu  
long nEndPos; //File Snippet End Position 0H6(EzN  
int nThreadID; //Thread's ID i!J8 d"  
boolean bDownOver = false; //Downing is over S=5<^o^h3  
boolean bStop = false; //Stop identical OVm\  
FileAccessI fileAccessI = null; //File Access interface X &uT
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException wT;0w3.Z  
{ (}{G`N>.{  
this.sURL = sURL; uD\?(LM  
this.nStartPos = nStart; <v)1<*I  
this.nEndPos = nEnd; DK$X2B"cV  
nThreadID = id; JLnH&(O  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 cJ{ Nh;"  
} I;e=0!9U  
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public void run() W#^2#sjO  
{ 0t Fkd  
while(nStartPos < nEndPos && !bStop) ^A!Qc=#
z}  
{ 4]yOF_8h  
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try{ 6VS4y-N  
URL url = new URL(sURL); ~D<IB#C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D&od?3}E  
httpConnection.setRequestProperty("User-Agent","NetFox"); "Ue.@>  
String sProperty = "bytes="+nStartPos+"-"; Mmxlp.l  
httpConnection.setRequestProperty("RANGE",sProperty); 5*+!+V^?X  
Utility.log(sProperty); Kf>A\l^X7  
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InputStream input = httpConnection.getInputStream(); BcL{se9<  
//logResponseHead(httpConnection); R9'b-5q  
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byte[] b = new byte[1024]; kO,zZF&  
int nRead; V}J)\VZ2#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <vUbv  
{ Z3#P,y9@  
nStartPos += fileAccessI.write(b,0,nRead); U}6B*Xx'  
//if(nThreadID == 1) qs
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4A8;tU$&  
} G'oG</A  
syWG'(>  
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Utility.log("Thread " + nThreadID + " is over!"); 4,sJE2"[9  
bDownOver = true; \DYWy*p
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//nPos = fileAccessI.write (b,0,nRead); W }8'Pf  
} w\(.3W7  
catch(Exception e){e.printStackTrace ();} NL!u<6y  
} ABQa 3{v  
} OjFLPGRCh  
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&:/hrighH  
//打印回应的头信息 TV<'8L  
public void logResponseHead(HttpURLConnection con) R%{a1r>9h  
{ Rtb7|  
for(int i=1;;i++) K@sV\"U(*E  
{ f({Ei`|  
String header=con.getHeaderFieldKey(i); {{B%f.  
if(header!=null) ix([mQg  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); q#T/  
Utility.log(header+" : "+con.getHeaderField(header)); Hc>m;[M)l  
else gG]Eeu+z   
break; H| 8Qp*  
} >d,jKlh^.%  
} Z1 Bp+a3  
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3 ^>l\,  
public void splitterStop() byLft1  
{ b:Wm8pp?  
bStop = true; xCg52zkH#  
} ox(j^x]NC  
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} C1jHz  
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q
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/* v-#Q7T  
**FileAccess.java #pb92kA'  
*//文件访问(定位，写) e4!:c^?  
package NetFox; X'd9[).  
import java.io.*; )\eI;8  
%+j8["VEC  
]~aF2LJ_q  
public class FileAccessI implements Serializable{ QWD'!)Zb  
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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 j/fzzI0@  
RandomAccessFile oSavedFile; eM$
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long nPos; [Jogt#Fj ]  
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public FileAccessI() throws IOException W+PJZn  
{ HkO7R `  
this("",0); *VFf.aPwYi  
} g+pml*LJ  
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public FileAccessI(String sName,long nPos) throws IOException )2bvQy8K  
{ 4x  
oSavedFile = new RandomAccessFile(sName,"rw"); (#Wu#F1;  
this.nPos = nPos; 1DE1.1  
oSavedFile.seek(nPos); ;A]@4
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} {@+Ty]e  
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public synchronized int write(byte[] b,int nStart,int nLen) 2 lj'"nm  
{ MRb-H1+Xf  
int n = -1; OR%'K2C6S  
try{ U%<koD[,  
oSavedFile.write(b,nStart,nLen); d/[; `ZD+  
n = nLen; }s(N6a&(  
} ~\Hc,5G   
catch(IOException e) EdlTdn@A  
{ <kGU,@6PF  
e.printStackTrace (); 3QG7C{  
} K_RjX>q%N  
+
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return n; | N[<x@  
} t5y;CxL  
-(  
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} iV&6nh(  
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/* %Z):>
'  
**SiteInfoBean.java *=(lyx_O  
*/ gDQ1?N'8{t  
package NetFox; 9y<*8bI  
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public class SiteInfoBean { 1][4.}?F[  
!HnXXVW  
nQ5n-A&["  
private String sSiteURL; //Site's URL _F$aUtb%O  
private String sFilePath; //Saved File's Path VU&7P/\f%  
private String sFileName; //Saved File's Name U<DZ:ds?T  
private int nSplitter; //Count of Splited Downloading File Cj{1H([-  
}+C2
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public SiteInfoBean() ?QFpv#4  
{//nSplitter的缺省值为5 wVEm:/;z&  
//default value of nSplitter is 5 AaWs}M  
this("","","",5); uTKD 4yig  
} 2QJ{a46}  
_$ +^q-  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) z^#;~I @M  
{ KX'{[7}m'  
sSiteURL= sURL; *7ZN]/VRT  
sFilePath = sPath; a1_GIM0  
sFileName = sName; Jl#%uU/sx  
this.nSplitter = nSpiltter; vb<oi&X  
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} 7?GIS '  
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public String getSSiteURL() .k%[4:Fe  
{ ?~hHGf\^b6  
return sSiteURL; Qo;
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} VJickXA  
{<R2UI5m5  
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public void setSSiteURL(String value) 'VzP};  
{ q|!-0B@  
sSiteURL = value; e=B|==E10M  
} 6L"%e!be6  
qz0;p=$8Z  
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public String getSFilePath() , udTvI  
{ }bdmomV  
return sFilePath; e?JW   
} i36eBjT  
 SL#0kc0x  
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public void setSFilePath(String value) &jslyQ#  
{ mID"^NOi#  
sFilePath = value; 3?V_BUoON  
} c'%-jG)\  
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public String getSFileName() Yu)NO\3&  
{ f!I[>&n  
return sFileName; ^c^#dpn  
} Fcd3H$Na;  
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public void setSFileName(String value) @~!wDDS  
{ 8FKXSqhVM  
sFileName = value; 5=v}W:^v.  
} RS)tO0  
'98VYCL  
kEOS{C%6R  
public int getNSplitter() "B3N*R(["  
{ bdC8zDD  
return nSplitter; mS(fgq6  
} UNom-  
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public void setNSplitter(int nCount) K/i*w<aPb7  
{ *h!28Ya(~  
nSplitter = nCount; r+":'/[x  
} v"b+$*  
} K{|p~B  
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/* $c]fPt"i  
**Utility.java 9N@W\DT  
*/ ,z;cbsV-{  
package NetFox; &O9 |#YUq  
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public class Utility { 0ZZZoPo  
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public Utility() LhOa{1SY  
{ +jS|2d  
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} qU%/W|LY  
nuk*.Su  
//线程睡眠 =Xi07_8Ic<  
public static void sleep(int nSecond) v|uAzM{73  
{ ABQ('#78  
try{ oW ::h
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Thread.sleep(nSecond); s5CXwM6cx  
} 7 n8"/0kc:  
catch(Exception e) fI&t]  
{ coW:DFX  
e.printStackTrace (); &;^YBW:I  
} z\K"Rg~J  
} yE:+Lo`>  
R=gb'  
//日志 lR )
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public static void log(String sMsg) ,?>s>bHV  
{ X:HacYqtC  
System.err.println(sMsg); >/l? g5{  
} i,>khc  
K#6P}tf  
&J[:awQX  
public static void log(int sMsg) "iy  
{ %zG;Q@  
System.err.println(sMsg); F*IzQ(#HW  
} &"yx<&c}  
} t;W0"ci9  
\.MR""@y`{  
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/* B3We|oe!  
**TestMethod.java rDm~h~u5  
*/ b*a#<K$T_  
package NetFox; yA)/Q Yge  
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X <f8,n
 
public class TestMethod { [xSF6  
B Wk/DVue  
l4F%VR4KT  
public TestMethod() 2BQ j  
{ ///xx/weblogic60b2_win.exe Cn,d?
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try{ z[b@V  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); aS{|uE]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); BmbyH{4  
SiteFileFetch fileFetch = new SiteFileFetch(bean); cqQ#p2<%  
fileFetch.start(); o_XflzC  
} g%sluT[#  
catch(Exception e){e.printStackTrace ();} C'9Cr}cZ.  
arIf'
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} my(2;IJ#{  
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public static void main(String[] args) *Fy2BZH%Q  
{ ) pzy  
new TestMethod(); Fq0i`~L~  
} dMh:ulIY>  
} 3eb%OEMYk  
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