http断点续传简单实现（java)

/* [9mL $;M W  
**SiteFileFetch.java wU`!B<,j  
*/ K{cbn1\,H  
package NetFox; cPn+<M#  
import java.io.*; !&]z*t  
import java.net.*; oc{EuW{Ag  
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public class SiteFileFetch extends Thread { u>.y:>  
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SiteInfoBean siteInfoBean = null; //文件信息Bean IeF keE  
long[] nStartPos; //开始位置 x`Fjf/1T*m  
long[] nEndPos; //结束位置 9l+{OA  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 8cm@a*2%  
long nFileLength; //文件长度 jU=<
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boolean bFirst = true; //是否第一次取文件 5V-jMB  
boolean bStop = false; //停止标志 $R^AEa7  
File tmpFile; //文件下载的临时信息 Q;h3v1GC\P  
DataOutputStream output; //输出到文件的输出流 |@j_2Q,  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） .~=HgOJ  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,smF^l   
{ Psa@@'w  
siteInfoBean = bean; znZ7*S >6\  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ~# 7wdP  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); uCzii o`S  
if(tmpFile.exists ()) Y:x/!-  
{ V*65b(q)  
bFirst = false; AxCI 0  
read_nPos(); PI|`vC|yy&  
} VY'Q|[  
else ; !$m1
 
{ dEp/dd~(&  
nStartPos = new long[bean.getNSplitter()];  ?RD *1  
nEndPos = new long[bean.getNSplitter()]; i(HByI  
} J\W-dI  
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}++5_Z_  
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} l+ T,2sd  
8?jxDW a  
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public void run() [}""@?  
{ T$b\Q  
//获得文件长度 d$1#<-yP  
//分割文件 QjukK6#W  
//实例FileSplitterFetch Ao`_",E  
//启动FileSplitterFetch线程 b%0BkS*  
//等待子线程返回 ]G1R0
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try{ ^eTZn[qH>w  
if(bFirst) kMe@+ysL  
{ Oje|bxQ  
nFileLength = getFileSize(); ]Ti$ztJ  
if(nFileLength == -1) cS~!8`Fwy  
{ _Y YP4lEL  
System.err.println("File Length is not known!"); mrnxI#6  
} MTB@CP!u  
else if(nFileLength == -2) ATO 5  
{ nGZ\<-  
System.err.println("File is not access!"); Ff/Ig]Lb  
} x*mc -&N  
else )y\BY8  
{ >Pkdu}xP3  
for(int i=0;i<nStartPos.length;i++) 3}M\c)
 
{ 5!:._TcO  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); u&3EPu  
} @f=RL)$|  
for(int i=0;i<nEndPos.length-1;i++) vb}/
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{ Qg>L,ZO  
nEndPos = nStartPos[i+1]; cHn;}l!I  
} Rrz'(
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nEndPos[nEndPos.length-1] = nFileLength; U+!UL5k  
} U2&HSE|2J  
} UT-ewXh  
pYGYy'%A'  
D%GGu"@GO  
//启动子线程 ~j}J<4&OvC  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]S]"`;Wh  
for(int i=0;i<nStartPos.length;i++) q6)p*}-  
{ s*{mT6s+T  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }B*,mn2N  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9L
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nStartPos,nEndPos,i); |M _%QM.  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )=(n/vckM  
fileSplitterFetch.start(); O2@" w23  
} 
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H:E5xz3VQ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); I3ho(Kdi
  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", gL,"ef+nM  
nEndPos = " + nFileLength); p[;8  
// fileSplitterFetch[nPos.length-1].start(); b.6ZfB,+G  
KQW!\y?$"  
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//等待子线程结束 s9:%s*$u  
//int count = 0; ^OjvL6A/p  
//是否结束while循环 V4oak!}?  
boolean breakWhile = false; -}AE\qXs/  
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while(!bStop) aC}vJ93i  
{ )j(fWshP  
write_nPos(); Vy&f"4~  
Utility.sleep(500); +Gp!cGaAm  
breakWhile = true; 3P3:F2S R  
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for(int i=0;i<nStartPos.length;i++) xan/ay>  
{ &,_?>.\[<  
if(!fileSplitterFetch.bDownOver) qU}lGf!dVn  
{ hQP6@KIe)  
breakWhile = false; ,?t}NZY&  
break; 1riBvBT  
} ;4R=eI  
} HUD7{6
}4  
if(breakWhile) mC%%)F'Zf  
break; ;*"!:GR%h  
''%;EW>  
#efqG=q  
//count++; %h
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//if(count>4) k>$FT`  
// siteStop(); X9z:D>   
} %e(9-M4*  
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% i%ew4  
System.err.println("文件下载结束！"); %f>X-*}NI-  
} (v|ixa  
catch(Exception e){e.printStackTrace ();} p"g1V7B  
} CL EpB2_  
)#)
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//获得文件长度 y4 dp1<t%  
public long getFileSize() kT>r<`rt  
{ e!.7no  
int nFileLength = -1; 9$:QLE+t  
try{ -MQZiq7H4  
URL url = new URL(siteInfoBean.getSSiteURL()); B-B?Ff>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Zm`'MsgFr  
httpConnection.setRequestProperty("User-Agent","NetFox"); :QxL 9&"  
+p8qsT#7  
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int responseCode=httpConnection.getResponseCode(); g?w2J6Z.`J  
if(responseCode>=400) M" xZz  
{ JTSq{NN  
processErrorCode(responseCode); 87&KQ_  
return -2; //-2 represent access is error RI#lI~&)  
} }g%KvYB_  
_ .-o%6  
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String sHeader; )[e%wPu4e  
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for(int i=1;;i++) L7i}Ga!
8  
{ 16a_GwfM  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 8=lHUn9l  
//Utility.log(in.readLine()); " whO}  
sHeader=httpConnection.getHeaderFieldKey(i); eL]{#WL  
if(sHeader!=null) RPz!UMQSD  
{ ;"d?_{>7  
if(sHeader.equals("Content-Length")) oV%( 37W9=  
{ =)mXCA^  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?Ry%c6(}  
break; ?ZSXoy-kr  
} <O <'1uO,  
} 6ctHL<^  
else a7XXhsZ  
break; ?/o2#iJx  
} /%N31  
} ws*~$x?7  
catch(IOException e){e.printStackTrace ();} Z/XM`Cy  
catch(Exception e){e.printStackTrace ();} (#fm (@T  
ccHLL6F{  
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Utility.log(nFileLength); ?Zc/upd:$N  
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return nFileLength; pDLu+}@  
} c n\k`8  
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//保存下载信息（文件指针位置） XgwMppacw  
private void write_nPos() 6Tm Rc  
{ o2[vM$]  
try{ z5|e\Z  
output = new DataOutputStream(new FileOutputStream(tmpFile)); hLDch5J5~  
output.writeInt(nStartPos.length);
n"^/UQ|#j  
for(int i=0;i<nStartPos.length;i++) CT$& zEIm  
{ h|(ZXCH  
// output.writeLong(nPos); 1YF+(fk  
output.writeLong(fileSplitterFetch.nStartPos); ?.rH;:9To  
output.writeLong(fileSplitterFetch.nEndPos); ,7n;|1`  
} }}4sh5z  
output.close(); r`&2-]  
} h"RP>fZt  
catch(IOException e){e.printStackTrace ();} y
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catch(Exception e){e.printStackTrace ();} N$=(1`zM=  
} ;~'cITL  

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//读取保存的下载信息（文件指针位置） + d+hvwEM  
private void read_nPos() Mp^OL7p^^  
{
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try{ !I~C\$^U  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Z1)jRE2dl  
int nCount = input.readInt(); cuV8#: i  
nStartPos = new long[nCount]; .-O@UQx.I  
nEndPos = new long[nCount]; 8%vh6$s6/  
for(int i=0;i<nStartPos.length;i++) ]Omb :  
{ okK/i  
nStartPos = input.readLong(); rm5T=fNJ  
nEndPos = input.readLong(); T!^?d5uW#  
} Vid{6?7kh  
input.close(); tdw\Di#m  
}  Gh)sw72  
catch(IOException e){e.printStackTrace ();} A}t&-  
catch(Exception e){e.printStackTrace ();} .b_0k<M!p  
} ]<\;d B  
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private void processErrorCode(int nErrorCode) P/C+L[X=  
{ ZuFVtW@  
System.err.println("Error Code : " + nErrorCode); tn:/pPap  
} ~7,2N.vO2  
:XPC0^4s  
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//停止文件下载 uK4'n+_>\  
public void siteStop() JA SR  
{ O$<%z[  
bStop = true;
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for(int i=0;i<nStartPos.length;i++) M<#)D  
fileSplitterFetch.splitterStop(); q5'yD;[hE  
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} AihL>a%  
} qmue!Fv#g  
//负责部分文件的抓取 H/p-YtY  
**FileSplitterFetch.java Bah.\ZsYQP  
*/  ^:  
package NetFox; [U3D`V$xD  
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@o3R`ZgC]\  
import java.io.*; c
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import java.net.*; 5E\<r/FeJ  
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public class FileSplitterFetch extends Thread { w.T=Lzp  
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@ (u?=x;  
String sURL; //File URL },Y; (n'  
long nStartPos; //File Snippet Start Position (IWix){  
long nEndPos; //File Snippet End Position FVC2XxP  
int nThreadID; //Thread's ID zV_-rf  
boolean bDownOver = false; //Downing is over QNa}M{5>h  
boolean bStop = false; //Stop identical IioE<wS)  
FileAccessI fileAccessI = null; //File Access interface |W~V@n8"6  
{!{7zM%u0C  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException bWQORjnd8  
{ |qy"%W@  
this.sURL = sURL; m`yn9(1Y[  
this.nStartPos = nStart; a7v[l04  
this.nEndPos = nEnd; lM|WOmD  
nThreadID = id; QS=$#Gp  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 %.Tf u0M  
} {YKMQI^O/  
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public void run() "$V8y  
{ &x0TnW"g  
while(nStartPos < nEndPos && !bStop) ?CT^Zegmr  
{ PkCeV]`w  
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try{ 5%Fn^u:  
URL url = new URL(sURL); SX?$H~A  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^;k _  
httpConnection.setRequestProperty("User-Agent","NetFox"); l5y#i7q  
String sProperty = "bytes="+nStartPos+"-"; DKVt8/vq  
httpConnection.setRequestProperty("RANGE",sProperty); {DXZ}7w:v  
Utility.log(sProperty); yu?
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InputStream input = httpConnection.getInputStream(); 'd.@4 9  
//logResponseHead(httpConnection); MZP><Je&  
/o1)ZC$  
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byte[] b = new byte[1024]; 7f\^VG  
int nRead; \2<yZCn  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) u$%#5_k  
{ \]`(xxt1  
nStartPos += fileAccessI.write(b,0,nRead); kN9sug^  
//if(nThreadID == 1) s-N?Tzi  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 'y M:WcN  
} J,=E5T
}U^  
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Utility.log("Thread " + nThreadID + " is over!"); <9@]|  
bDownOver = true; Tvx8l m'  
//nPos = fileAccessI.write (b,0,nRead);   [aS)<^  
} w%o4MFK=!  
catch(Exception e){e.printStackTrace ();} o&F.mYnqX  
} {kRC!}  
} W7[S7kd  
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//打印回应的头信息 WmVw>.]@~  
public void logResponseHead(HttpURLConnection con) .sR&9FH  
{ IM5^E#-g7  
for(int i=1;;i++)
x5 ~E'~_  
{ qCkg\)Ks5I  
String header=con.getHeaderFieldKey(i); rU^ghF  
if(header!=null) re7\nZ<\|  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); g+/U^JIc4l  
Utility.log(header+" : "+con.getHeaderField(header)); K9M.+d4  
else k`~br249  
break; rH:X/i;D  
} ;
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} U?^|>cMr  
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public void splitterStop() @?=)}2=|?i  
{ h8-tbHgpb  
bStop = true; bfI -!,  
} Jo(}#_y?  
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} h_G7T1;L  
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/* %` [`I>  
**FileAccess.java >~>[}d;glw  
*//文件访问(定位，写) jTgh+j]AP  
package NetFox; RR[TW;  
import java.io.*; bNU^tL3QZ  
,UZE;lXJ'Q  
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public class FileAccessI implements Serializable{ r8?Lr-;  
: 8<^rP  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 3M*[a~  
RandomAccessFile oSavedFile; `oWjq6  
long nPos; J<*Mk  
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public FileAccessI() throws IOException iC+H;s5<  
{ o5x^"#  
this("",0); /0B?3&H  
} {lUl+_58  
;1k0o.3  
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public FileAccessI(String sName,long nPos) throws IOException 3}1+"? s  
{ >qvD39w  
oSavedFile = new RandomAccessFile(sName,"rw"); jeFl+K'1  
this.nPos = nPos; ]b| @<E7Y  
oSavedFile.seek(nPos); <d`UifqD  
} 6i9I 4*'  
2^M+s\p  
^ED>{UiNI  
public synchronized int write(byte[] b,int nStart,int nLen) Df3v"iCq}  
{ F X2
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int n = -1; ;l?(VqX_E  
try{ NS;8&  
oSavedFile.write(b,nStart,nLen); I_*>E
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n = nLen; {o<p{q  
} eSBf;lr=  
catch(IOException e) s?#lhI  
{ X(z-?6N4  
e.printStackTrace (); L/LNX{|  
} 6yM dl~
.  
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}B/xQsTx-  
return n; {*$J&{6V  
} HKw:fGt/o^  
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(  
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} oXkhj,{y5  
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/* P`9A?aG.Z  
**SiteInfoBean.java {Dq51  
*/ L1 VTq9[3  
package NetFox; bLF0MVLM  
v[3sg2.  
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public class SiteInfoBean { 8E%*o  
x,_Ucc.  
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private String sSiteURL; //Site's URL 5&@U
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private String sFilePath; //Saved File's Path +0 |0X {v  
private String sFileName; //Saved File's Name }TL"v|ny6;  
private int nSplitter; //Count of Splited Downloading File Tou~U[V+  
hI{Yg$H1  

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public SiteInfoBean() xyz86r ^u  
{//nSplitter的缺省值为5 v72 dE  
//default value of nSplitter is 5 7Z3qaXPH  
this("","","",5); :|3C-+[  
} U.(_n  
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 E/;YhFb[  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \c}r6xOr  
{ >C3 9`1  
sSiteURL= sURL; [1CxMk~"[  
sFilePath = sPath; .utL/1Ej  
sFileName = sName; )^sfEYoA  
this.nSplitter = nSpiltter; u;g}N'"  
[rsAY&.  
cA2]VL.r>C  
} yqI|BF`  
~A4WuA  
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public String getSSiteURL() uu.N
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{ e)"cm;BJ^P  
return sSiteURL; Lr:K0A.Ch  
} m 0PF"(  
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public void setSSiteURL(String value) {rLOAewr  
{ Su#1yw>  
sSiteURL = value; +-d>Sl (  
} Cz)D3Df^  
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heA\6W:u&  
public String getSFilePath() jqedHnx  
{ |-D.  
return sFilePath; V485Yn!$(  
} +Ti@M1A&  
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public void setSFilePath(String value) Z9I./s9  
{ q'tT)IgD  
sFilePath = value; kw'D2692  
} B,T.bgp\  
`^vD4qD|  
:Ej)AfS  
public String getSFileName() EMbsKG  
{ C:{'0m*jKs  
return sFileName; K%Bi8d  
} XZGyhX7  
BW 7[JD  
'QU ?O[CH  
public void setSFileName(String value) W9~datIh>  
{ 17d$gZ1O:  
sFileName = value; ^(:Rbsl  
} Qafg/JU  
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w"|c;E1;_  
public int getNSplitter() >0oc=9H8  
{ [^f`D%8o  
return nSplitter; 'C<=bUM  
} p?@
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bT}
WJ2}  
LlJvuQ 28  
public void setNSplitter(int nCount) d+'+z %s%  
{ }kDrUnBk  
nSplitter = nCount; sx\7Z#|  
} ]\lw^.%  
} E?uv&evPK7  
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C
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/* H<"j3qt  
**Utility.java _guY%2%yR  
*/ (k~c]N)v  
package NetFox; v*LL7b0A  
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public class Utility { dmO|PswW  
~-/AKaK}  
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public Utility() O{V"'o  
{ qDW/8b\^  
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} iVcBD0 q)  
i747( ^  
//线程睡眠 iDsjIW\j  
public static void sleep(int nSecond) 9^tyjX2  
{ {PKER$C  
try{ \!3='~2:=o  
Thread.sleep(nSecond); j3><J  
} LmE-&  
catch(Exception e) 3'wBX  
{ p:jrqjLp  
e.printStackTrace (); mfvQ]tz_+  
} x@=7M'vr%  
} ~cjvo?)&e;  
gNeCnf#Xa  
//日志 rgCId@R  
public static void log(String sMsg) eMwf'*#  
{ r[x7?cXsW  
System.err.println(sMsg); 5tL6R3  
} *QX$Mo^E  
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J
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public static void log(int sMsg) 4/4IZfznX  
{ I}X8-WFB  
System.err.println(sMsg); u(R`}C?P'  
} *))
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} _u0dt) $  
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/* 0Ju{6x(|  
**TestMethod.java >Vvc55z  
*/ JpDkf$kM  
package NetFox; ! [X<
>  
X {$gdz8S9  
1X5\VY>S`h  
public class TestMethod { ;k0*@c*  
f
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dj=n1f+;[  
public TestMethod() R+\5hI@ >i  
{ ///xx/weblogic60b2_win.exe };*5+XY^  
try{ iq#Z\Y(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); (:1j-  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?6Gq &  
SiteFileFetch fileFetch = new SiteFileFetch(bean); w%ForDB>P  
fileFetch.start(); O
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} ]q j%6tz  
catch(Exception e){e.printStackTrace ();} L2$%h1  
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#

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} }Y[.h=X  
6=
 
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public static void main(String[] args) D"MNlm  
{ VioVtP0  
new TestMethod(); mXr)lA  
} &zZSWNW  
} ^%L$$V nG  
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