http断点续传简单实现（java)

/* -us:!p1T  
**SiteFileFetch.java V''fmWo7  
*/ |g'ceG-  
package NetFox; 3H|drj:KV  
import java.io.*; ,(&Fb~r]  
import java.net.*; M 5$JBnN  
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public class SiteFileFetch extends Thread { `g<0FQA  
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SiteInfoBean siteInfoBean = null; //文件信息Bean z[@i=avPG  
long[] nStartPos; //开始位置 \/b[V3<"  
long[] nEndPos; //结束位置 F"1tPWn  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 N 1ydL
 
long nFileLength; //文件长度 gq@8Z AWn  
boolean bFirst = true; //是否第一次取文件 ;*0nPhBw0>  
boolean bStop = false; //停止标志 2.vmZaKP  
File tmpFile; //文件下载的临时信息 CY.
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DataOutputStream output; //输出到文件的输出流 iNc!zA4  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） iCCe8nK  
public SiteFileFetch(SiteInfoBean bean) throws IOException = 5[%%Lf  
{  n(|rs  
siteInfoBean = bean; HD& Cp  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); T2_iH=u  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Z}{]/=h  
if(tmpFile.exists ()) Xppv  
{ Uf MQ?(,  
bFirst = false; CM%;/[WBxy  
read_nPos(); ?J-
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} yL),G*[p\}  
else >TiEYMW  
{ mX!*|$bs  
nStartPos = new long[bean.getNSplitter()]; sWB@'P:x  
nEndPos = new long[bean.getNSplitter()]; ([^#.x)hz  
} :@a0h
  
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} n_:EWm$\  
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public void run() ooBBg@  
{ S^
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//获得文件长度 b- bvkPN  
//分割文件 j dz IU  
//实例FileSplitterFetch UWhJkJsX  
//启动FileSplitterFetch线程 'IT]VRObP  
//等待子线程返回 /Kq'3[d8  
try{ 'Ebjn>"  
if(bFirst)
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{ }!?RB v'W  
nFileLength = getFileSize(); Gs,e8ri!  
if(nFileLength == -1) ;)wk^W  
{ e ;^}@X  
System.err.println("File Length is not known!"); @WJ\W`P  
} M< .1U?_#  
else if(nFileLength == -2) ^do6?e`?-  
{ >#'?}@FWQN  
System.err.println("File is not access!"); ^b}Wl0Fn  
} Od^Sr4C  
else -Sn'${2  
{ LAY
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for(int i=0;i<nStartPos.length;i++) X;2LK!x;y  
{ fms(_Q:R?  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); cA|vH^:  
} yimK"4!j5A  
for(int i=0;i<nEndPos.length-1;i++)
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{ =FI[/"476  
nEndPos = nStartPos[i+1]; bC~I}^i\  
} 5pC}ZgEa<  
nEndPos[nEndPos.length-1] = nFileLength; mlCg&fnDB  
} 1
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} ekU%^R<  
BFg&@7.X  
3Pgokj   
//启动子线程 >\3\&[#"  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; vU5}E\Ny  
for(int i=0;i<nStartPos.length;i++) (CgvI*O  
{ VumM`SH  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), k#u)+e.'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), D6|-nl  
nStartPos,nEndPos,i); 0xO*8aKT  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); n\V7^N  
fileSplitterFetch.start(); biBMd(6  
} jwBJG7\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <pjxJ<1l  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Sk1t~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", f8aY6o"i  
nEndPos = " + nFileLength); eG8l^[  
// fileSplitterFetch[nPos.length-1].start(); U djYRf
k  
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HyOrAv <  
//等待子线程结束 UqyW8TCf?  
//int count = 0; jWV}Ua  
//是否结束while循环 yP>025o't  
boolean breakWhile = false; 2H0BNrYM  
<<E9MIn_  
EU>`$M&w-  
while(!bStop) ^]'_Qbi]}  
{ al-rgh  
write_nPos(); NdSuOkwwt  
Utility.sleep(500); Ej 5_d  
breakWhile = true; X{H
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for(int i=0;i<nStartPos.length;i++) EApbaS}Up  
{ 5ya^k{`+ZO  
if(!fileSplitterFetch.bDownOver) tl\<:8pI"  
{ {V[}#Mf  
breakWhile = false;
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break; %=Z/Frd  
} _MLf58  
} %D8.uGsh  
if(breakWhile) 3+s$K(%I  
break; W]7/
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.|5$yGEF_+  
//count++; **kix  
//if(count>4) >:> W=  
// siteStop(); ,7c Rd}1Y  
} .RJMtmp  
X-kOp9/.  
+egwZ$5I  
System.err.println("文件下载结束！"); n*A1x
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} Rz|@BxB>n  
catch(Exception e){e.printStackTrace ();} gGUKB2)  
} u:2Ll[ eo  
Iz#4!E|<  
.(.
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//获得文件长度 !|i #g$  
public long getFileSize() qy)~
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{ +kQ=2dva  
int nFileLength = -1; ^]D1':  
try{ \`xlD&F@U  
URL url = new URL(siteInfoBean.getSSiteURL()); %)?jaE}[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7>BfHb  
httpConnection.setRequestProperty("User-Agent","NetFox"); w4Df?)Z  
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int responseCode=httpConnection.getResponseCode(); la_c:#ho  
if(responseCode>=400) C!Srv7  
{ xk% 62W  
processErrorCode(responseCode); 25-h5$s  
return -2; //-2 represent access is error megTp  
} 0kOwA%m  
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String sHeader; S6JXi>n  
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for(int i=1;;i++) /*,_\ ;  
{ ktx| c19  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Q N#bd~  
//Utility.log(in.readLine()); j]<K%lwp  
sHeader=httpConnection.getHeaderFieldKey(i); ""a$[[ %WC  
if(sHeader!=null) OQB7C0+ &  
{ H(K PU1lDw  
if(sHeader.equals("Content-Length")) [K\b"^=<  
{ ;-kDJi  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); BR@m*JGajz  
break; URrx7F98  
} B6k<#-HAT  
} 6X%g-aTs  
else )3:0TFS}}k  
break; >>$`]]7  
} +jwHYfAK)  
} `w\P- q  
catch(IOException e){e.printStackTrace ();} 9yC22C:  
catch(Exception e){e.printStackTrace ();} tOLcnWt   
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Utility.log(nFileLength); %J^x `P  
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return nFileLength; 2*V[kmD/3  
} #xw*;hW<  
!h7.xl OpN  
5HV+7zU5  
//保存下载信息（文件指针位置） ,_RNZ sa;&  
private void write_nPos() %csrNf  
{ Dz6xx?  
try{ 3yKmuu!  
output = new DataOutputStream(new FileOutputStream(tmpFile)); rFQWgWD  
output.writeInt(nStartPos.length); n@p@@  
for(int i=0;i<nStartPos.length;i++) ={zTQ+7S`  
{ > ]^'h  
// output.writeLong(nPos); uI/ wR!  
output.writeLong(fileSplitterFetch.nStartPos); G#GZt\)F  
output.writeLong(fileSplitterFetch.nEndPos); %NxQb'  
} \>- M&C  
output.close(); }QE*-GVv]  
} u/u(Z&  
catch(IOException e){e.printStackTrace ();} c Pf_B=  
catch(Exception e){e.printStackTrace ();} #6<1 =I'j  
} OpEH4X.Z  
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j/d}B
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//读取保存的下载信息（文件指针位置） y]fI7nu&  
private void read_nPos() 6~x'~T  
{ 2]]v|Z2M4  
try{ P$#:$U@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6
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int nCount = input.readInt(); nO
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nStartPos = new long[nCount]; Ct w<-'  
nEndPos = new long[nCount]; UgC65O2  
for(int i=0;i<nStartPos.length;i++) \}?X5X>  
{ w&aZ 97{  
nStartPos = input.readLong(); 8'8`xu$  
nEndPos = input.readLong(); j,+]tHC-  
} ]$[sfPKA  
input.close(); ujX;wGje  
} V^5d5
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catch(IOException e){e.printStackTrace ();} Km8aHc]O~  
catch(Exception e){e.printStackTrace ();} Ptv'.<-  
} :]m.&r S,  
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private void processErrorCode(int nErrorCode) p2i?)+z  
{ +SH{`7r  
System.err.println("Error Code : " + nErrorCode); d}h{#va*  
} w>&*-}XX
 
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//停止文件下载 y(p_Unm  
public void siteStop() r[a7">n  
{ "^n,(l*4x  
bStop = true; J{1H$[W~}  
for(int i=0;i<nStartPos.length;i++) 7~mhWPzMwB  
fileSplitterFetch.splitterStop(); 7#0buXBg  
sI
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} 3c=kYcj  
} 00QJ596  
//负责部分文件的抓取 KkA)p/  
**FileSplitterFetch.java t~->&Ja   
*/ LKu\Mh|  
package NetFox; S%i^`_=Q  
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import java.io.*; USz~l7Xs  
import java.net.*; rGyAzL]  
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public class FileSplitterFetch extends Thread { o eUi  
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>%j%Mj@8q|  
String sURL; //File URL >1Z"5F7=  
long nStartPos; //File Snippet Start Position 'rcqy1-&  
long nEndPos; //File Snippet End Position v3I^81  
int nThreadID; //Thread's ID \!-BR0+y;  
boolean bDownOver = false; //Downing is over "+F'WCJ-(*  
boolean bStop = false; //Stop identical (jM0YtrD  
FileAccessI fileAccessI = null; //File Access interface [>O!~  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException *j%x  
{ mH'~pR>t  
this.sURL = sURL; `<C<[JP:o  
this.nStartPos = nStart; 9{toPED  
this.nEndPos = nEnd; 6Yj{% G  
nThreadID = id; lM6pYYEq=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Gmz^vpQ]t  
} ai{>rO3 }I  
]%' AZ`8  
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public void run() BNu >/zGpB  
{ 0ns\:2)cEB  
while(nStartPos < nEndPos && !bStop) }Y~Dk]*  
{ zfeT>S+  
!@
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try{ +xFn~b/  
URL url = new URL(sURL); [0 F~e  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $.SBW=^V  
httpConnection.setRequestProperty("User-Agent","NetFox"); \#{PV\x:Nn  
String sProperty = "bytes="+nStartPos+"-"; *;Jb=  
httpConnection.setRequestProperty("RANGE",sProperty); /T w{JO#Q  
Utility.log(sProperty); !(GyOAb  
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InputStream input = httpConnection.getInputStream(); m9 h '!X<  
//logResponseHead(httpConnection); > N~8#C  
3
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r )F;8
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byte[] b = new byte[1024]; h.jJAVPi  
int nRead; j[G`p^ul  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) fZGY'o&5  
{ cm< #zu3~S  
nStartPos += fileAccessI.write(b,0,nRead); 8>&@"j  
//if(nThreadID == 1) m8q4t,<J  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); va6Fp2n<1*  
} !_S#8"  
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6hxZ5&;(*  
Utility.log("Thread " + nThreadID + " is over!"); kA:mB;:  
bDownOver = true; v/+ <YU  
//nPos = fileAccessI.write (b,0,nRead); {M]_]L{&7  
} D}_.D=)  
catch(Exception e){e.printStackTrace ();} 5R7x%3@L  
} s2;~FK#/  
} uoS:-v}/Y~  
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//打印回应的头信息 XB)D".\  
public void logResponseHead(HttpURLConnection con) $|N6I  
{ {213/@,  
for(int i=1;;i++) NAGM3{\5v$  
{ |N.2iN:  
String header=con.getHeaderFieldKey(i); nf.Ox.kM)  
if(header!=null) -@pjEI  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); VW-qQe  
Utility.log(header+" : "+con.getHeaderField(header)); B~p%pTS+  
else !J$r|IX5  
break; sg2;"E@  
}
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} AI|vL4*Xd  

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public void splitterStop() ?:(y  
{ =8AT[.Hh  
bStop = true; 4Yj1Etq.E  
} .ZTvOm'mB^  
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} F9K%f&0
a  
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/* HBlk~eZ  
**FileAccess.java 50,'z?-_  
*//文件访问(定位，写) !nvwRQ  
package NetFox; FY1iY/\Cn  
import java.io.*; E }L Hp  
Y|>dS8f;4  
Br1R++]  
public class FileAccessI implements Serializable{ T[oC='I+O  
u#0snw~)/  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]}2)U  
RandomAccessFile oSavedFile; akj<*,  
long nPos; a=z] tTs4  
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e &6
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public FileAccessI() throws IOException TZn 15-O  
{ %w`d  
this("",0); m'o dVZ7  
} .wfydu)3  
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d:=' Xs
 
public FileAccessI(String sName,long nPos) throws IOException g'"~'  
{ #}`sfaT  
oSavedFile = new RandomAccessFile(sName,"rw"); ~6G `k^!  
this.nPos = nPos; &7L7|{18  
oSavedFile.seek(nPos); @X==[gQ  
} q+ax]=w  
w,UE0i9I  
p.DQ|?  
public synchronized int write(byte[] b,int nStart,int nLen) >)>f~>  
{ gq=t7b  
int n = -1; *1|7%*!8  
try{ ACszx\[K3  
oSavedFile.write(b,nStart,nLen); ,06Sm]4L,  
n = nLen; DIC*{aBf  
} a<cw
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catch(IOException e) amBg<P`'_  
{ !/FRL<mp  
e.printStackTrace (); 7=^{~5#  
} U3(+8}Q  
=[B\50]  
I
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return n; .u-a+ac<  
} f ,F X# _4  
mZ)>^.N6  
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} inut'@=G/  
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?Ga8.0Z~KT  
/* Ge^`f<f  
**SiteInfoBean.java u`bD`kfT>  
*/ 'eM0i[E+`  
package NetFox; J
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_CwTe=K}  
public class SiteInfoBean { atuqo3  
4~fYG|a  
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private String sSiteURL; //Site's URL %M6OLq!K  
private String sFilePath; //Saved File's Path 4G&`&fff]  
private String sFileName; //Saved File's Name 01cBAu   
private int nSplitter; //Count of Splited Downloading File Q\Ek U.[I  
/%@;t@BK4  
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public SiteInfoBean() .9
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{//nSplitter的缺省值为5 ,H=k5WA4m  
//default value of nSplitter is 5 !KHgHKEW^  
this("","","",5); uibmQ|AQ  
} XKp&GE@Y  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) qng ~,m  
{ y`I>|5[`  
sSiteURL= sURL; +%dXB&9x|Z  
sFilePath = sPath; \&"C  
sFileName = sName; 1%Xh[  
this.nSplitter = nSpiltter; wh$bDTCj  

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4X
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} 7|,L{~  
: |'(T[~L  
w~Tg?RH:  
public String getSSiteURL() 05d0p|},
 
{ d |17G  
return sSiteURL; yw1&I^7  
} Xu$>$D#a  
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public void setSSiteURL(String value) g5V\R*{  
{ &Ok1j0~~  
sSiteURL = value; =p5D

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} <-VBb[M#  
s.J4&2Q  
c^}y9% 4c  
public String getSFilePath() 80lei  
{ '*J+mZtN  
return sFilePath; ?=1eHnP!R  
} qb>ULP0  
r:*G{m-  
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public void setSFilePath(String value) j=r1JV @  
{ IeYYG^V<A  
sFilePath = value; g~hMOI?KK^  
} omE- c  
=AIts[!qd  
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public String getSFileName() dq93P%X24  
{ ]?^V xB7L  
return sFileName; adLL7  
} z33UER"  
nCQtn%j't  
=%<=Bn  
public void setSFileName(String value) hGtz[u#p  
{ PR8nJts W5  
sFileName = value; Pn,I^Ej.  
} <KMCNCU\+  
*b{IWOSe^  
\<{a=@_k9  
public int getNSplitter() aTcz5g0"  
{ ACRuDY  
return nSplitter; Ht[$s40P  
} &'uP?r9c$  
;cMQ0e  
Oeh A3$|#  
public void setNSplitter(int nCount) sT^R0Q'>  
{ ddQ+EY@!  
nSplitter = nCount; wJC[[_"3 I  
} D$l!lRu8+L  
} lV\iYX2#  
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JduO^Fit  
/* J"aw 1  
**Utility.java LG[N\%<!H  
*/ `~XksyT  
package NetFox; ,,Qg"
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public class Utility { nxZz{&  
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public Utility() wgFX')l:  
{ SkjG}  
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} T5:Q_o]  
|Y3w6!$  
//线程睡眠 XvI~"}  
public static void sleep(int nSecond) 9pLe8D  
{ x Lan1V  
try{ ]0UYxv%]  
Thread.sleep(nSecond);
$@PruY3[  
} o GuAF q  
catch(Exception e) $;^|]/-  
{ WARiw[  
e.printStackTrace (); mG[jR*JW  
} 6 byeO&d  
} bdL= ?KS  
7yE\,  
//日志 [* <x)  
public static void log(String sMsg) S~/2Bw!2  
{ :E9pdx+  
System.err.println(sMsg); /EjXyrn2  
} )Rn\6ka  
gX"-3w  
\c2x udU  
public static void log(int sMsg) cZVx4y%kz
 
{ \,13mB6  
System.err.println(sMsg); '8 .JnCg  
} 2Mx\D  
} riW9l6s'  
J _rrc;F  
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/* }H ~-oYMu  
**TestMethod.java j|KDgI<0  
*/ -,y
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package NetFox; ]Thke 4  
q/@2=$]hH3  
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public class TestMethod { (.UU40:t  
n.g-%4\q  
8:0/Cj  
public TestMethod() gvI!Ice#  
{ ///xx/weblogic60b2_win.exe l`"?KD  
try{ bTJ<8q  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); p8'$@:M\  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); qur2t8gnxq  
SiteFileFetch fileFetch = new SiteFileFetch(bean); lie,A  
fileFetch.start(); ,zgz7  
} ,sitOy}ks  
catch(Exception e){e.printStackTrace ();} o< @![P  
rd7p$e=i  
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} xt}.0dC!/%  
O}i+1  
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public static void main(String[] args) C:Jfrg`  
{ /Bt!xSI  
new TestMethod();  26p[x'W  
} !7DDPJ~  
} LK DfV  
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