http断点续传简单实现（java)

/* *m"mt  
**SiteFileFetch.java l1:j/[B=  
*/ .6"7Xxe]<  
package NetFox; 95<:-?4C;W  
import java.io.*; RTU:J67E  
import java.net.*; S;c=6@"  
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public class SiteFileFetch extends Thread { )5t_tP
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SiteInfoBean siteInfoBean = null; //文件信息Bean dg!sRm1iZ:  
long[] nStartPos; //开始位置 uJO
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long[] nEndPos; //结束位置 /Yh([P>  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 f6"j-IW[z  
long nFileLength; //文件长度 us cR/d  
boolean bFirst = true; //是否第一次取文件 E.6\(^g  
boolean bStop = false; //停止标志 }n=NHHtJ  
File tmpFile; //文件下载的临时信息 bk?\=4B:E  
DataOutputStream output; //输出到文件的输出流 y,x~S\>+  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） O>Sbb2q?"  
public SiteFileFetch(SiteInfoBean bean) throws IOException Kaa*;T![  
{ =,'Z6?%p  
siteInfoBean = bean; 8vRiVJ8QS:  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); lrE0)B5F  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); M,@SUu v"  
if(tmpFile.exists ()) Z~|J"2.  
{ QEgv,J{  
bFirst = false; b?$09,{0  
read_nPos(); 8j$q%g  
} 6vA5L_  
else 3pp w_?k  
{ R3PhKdQ"
 
nStartPos = new long[bean.getNSplitter()]; *O5+?J Z!  
nEndPos = new long[bean.getNSplitter()]; Q.\>+4]1&&  
} s7e'9Bx  
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} qcot T\rq  
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public void run() 8if"U xV(  
{ v(^rq  
//获得文件长度 M<)2  
//分割文件 Wg%-m%7O  
//实例FileSplitterFetch t>fB
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//启动FileSplitterFetch线程 8zCAy@u  
//等待子线程返回 3KKe4{oG  
try{ ]| yH8m  
if(bFirst) twtDyo(\  
{ ,fw[J  
nFileLength = getFileSize(); H1[aNwLr  
if(nFileLength == -1) zi ,Rk.  
{ agYKaM1N  
System.err.println("File Length is not known!"); K9q~Vf  
} :tqjm:  
else if(nFileLength == -2) $-Rh
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{ 3$8}%?i  
System.err.println("File is not access!"); ="DgrH  
} ttnXEF  
else 
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{ ["}A#cO652  
for(int i=0;i<nStartPos.length;i++) Cf7\>U->  
{ M\&~Dmd  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); UjaC( c  
} v#|c.<].  
for(int i=0;i<nEndPos.length-1;i++) z aF0nov  
{ }WbN)  
nEndPos = nStartPos[i+1]; Bkc-iC}F
 
} XV>6;!=E  
nEndPos[nEndPos.length-1] = nFileLength; 4m*(D5Y=|  
} 8j}
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} wM)w[  
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|pqpF?h5|  
//启动子线程 k)py\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; `<zb  
for(int i=0;i<nStartPos.length;i++) 2M?lgh4"  
{ {nefS\#{  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .6NSt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), =T)2wcXBB  
nStartPos,nEndPos,i); lt4jnV2"a  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fn OkH  
fileSplitterFetch.start(); d_uy;-3  
} *u/|NU&X  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0EOX@;}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); s%oAsQ_y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", j6vZ{Fx;w  
nEndPos = " + nFileLength); $:[BB,$  
// fileSplitterFetch[nPos.length-1].start(); #!jRY!2Vt  
>!1f`  
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//等待子线程结束 e<4z)  
//int count = 0; ?+5{HFx  
//是否结束while循环 I_G>W3  
boolean breakWhile = false; !&O/7ywe  
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while(!bStop) C|\^uR0  
{ Wk?|BR]O  
write_nPos(); Oq,
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Utility.sleep(500); sjI[Vq  
breakWhile = true; s;s-6%p  
@/~k8M/  
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for(int i=0;i<nStartPos.length;i++) 1fW4=pF-K  
{ uV_)JZW,L  
if(!fileSplitterFetch.bDownOver) "g%:#'5  
{
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breakWhile = false; xm|4\H&Bg  
break; .)>/!|i  
} 9>3Ltnn0  
} sBtG}Mo)  
if(breakWhile) MQ(/l_=zQ  
break; _(`X .D  
mN{ajf)@  
d._gH#&v  
//count++; Q *]`t@q  
//if(count>4)
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// siteStop(); IS2Ij  
} x}<G
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System.err.println("文件下载结束！"); R}wwC[{  
} l5';?>!s  
catch(Exception e){e.printStackTrace ();} p@8krOo`  
} kgI=0W>  
@P"`=BU&  
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//获得文件长度 f=_?<I{  
public long getFileSize() IHbow0'  
{ cm@oun  
int nFileLength = -1; U.Chf9a-  
try{ *OOa)P{^D  
URL url = new URL(siteInfoBean.getSSiteURL()); {0vbC/?]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V\K m% vP  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;D"P9b]9$  
}gi1?a59  
.;Utkf'I  
int responseCode=httpConnection.getResponseCode(); Z#Zzi5<  
if(responseCode>=400) 7lDaok  
{ )SL@>Cij  
processErrorCode(responseCode); ~|Ih JzDt  
return -2; //-2 represent access is error wGzXp5 dl  
} 'RV\}gqZ  
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String sHeader; |:=b9kv  
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for(int i=1;;i++) Rhv".epz  
{ t6bWSz0  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ! jX+ox  
//Utility.log(in.readLine()); nhP~jJn  
sHeader=httpConnection.getHeaderFieldKey(i); oyN+pFVB:$  
if(sHeader!=null) ccN&h  
{ ay:\P.`5)  
if(sHeader.equals("Content-Length")) NkA6Cp[Q,1  
{ [wy3Ld  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); S?nNZW\6[  
break; Tc3ih~LvG  
} z<[.MH`ln  
} <S8I"8{Mb  
else *M5$ h*;v  
break; dVVvG]
  
} Ife,h s  
} XuFm4DEJ  
catch(IOException e){e.printStackTrace ();} ?mYV\kDt\  
catch(Exception e){e.printStackTrace ();} j |'#5H`  
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Utility.log(nFileLength); Jl}!CE@-  
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return nFileLength; D)*_{   
} qN1e{T8u  
\9>g;qPg}  
#>E3'5b   
//保存下载信息（文件指针位置） J"D&q  
private void write_nPos() f=_Bx2ub  
{ b#Fk>j  
try{ dWW-tHv#  
output = new DataOutputStream(new FileOutputStream(tmpFile)); PK-}Ldj  
output.writeInt(nStartPos.length); )-Mn"1ia  
for(int i=0;i<nStartPos.length;i++) G {pP}  
{ kol,Qs  
// output.writeLong(nPos); |%:qhs,  
output.writeLong(fileSplitterFetch.nStartPos); )~?S0]j}  
output.writeLong(fileSplitterFetch.nEndPos); [al(>Wr9  
} 0{"dI;b%  
output.close(); 5&n988gC8  
} 4uO @`0:x  
catch(IOException e){e.printStackTrace ();} 2
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catch(Exception e){e.printStackTrace ();} 4[5lX C  
} Sr ztTfY  
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//读取保存的下载信息（文件指针位置） Jm]]>K8.3V  
private void read_nPos() vGPf`2/j.  
{ K'iS#i7  
try{ bG5^h  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); fz<|+(_>J  
int nCount = input.readInt(); EBj,p
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nStartPos = new long[nCount]; XDP6T"h  
nEndPos = new long[nCount]; r|\5'ZMx  
for(int i=0;i<nStartPos.length;i++) %67G]?EXB  
{ ?b*/ddIs  
nStartPos = input.readLong(); EaM"=g  
nEndPos = input.readLong(); 1*!c X  
} dr,B\.|jC  
input.close(); D% v:PYf  
} PEX26==  
catch(IOException e){e.printStackTrace ();} _q$0lqq~u  
catch(Exception e){e.printStackTrace ();} ONr?.MJ6j  
} :>tF_6
 
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private void processErrorCode(int nErrorCode) KD,^*FkkL  
{ AMh37Xo  
System.err.println("Error Code : " + nErrorCode); r%Q8)
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} .\ ;l
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r+[#%%}ea  
="5k\1W1M  
//停止文件下载 abTDa6 /`v  
public void siteStop() |aI|yq)  
{ g33<qYxP  
bStop = true; XI%RneuDr:  
for(int i=0;i<nStartPos.length;i++) +X* F<6mZ  
fileSplitterFetch.splitterStop(); 0%h[0jGj  
; d, JN  
6o[0sM_];  
} xE G+%Uk{  
} vI pO/m.3  
//负责部分文件的抓取 3t"~F%4-}  
**FileSplitterFetch.java n
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*/ @7Q*h   
package NetFox; RMS.1:O  
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import java.io.*; k8InbX[  
import java.net.*; b[J-ja.   
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public class FileSplitterFetch extends Thread { G?Qe"4 .  
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String sURL; //File URL V9+xL 1U#  
long nStartPos; //File Snippet Start Position =Q/w%8G  
long nEndPos; //File Snippet End Position W;3 R;  
int nThreadID; //Thread's ID Qag|nLoT  
boolean bDownOver = false; //Downing is over ;x!,g5q"q  
boolean bStop = false; //Stop identical Z-4K?;g'k  
FileAccessI fileAccessI = null; //File Access interface u4Y6B ]Q  
)^jQkfL  

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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [ E$$nNs  
{ zVp[YOS&c  
this.sURL = sURL; FSW3'  
this.nStartPos = nStart; o-\ok|,)#j  
this.nEndPos = nEnd; "?oo\op  
nThreadID = id; 8eOl@}bV  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 'sm[CNzS  
} ~u_K&X  
L0X&03e=e:  
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public void run() F`YFo)W  
{ X0^zw^2W  
while(nStartPos < nEndPos && !bStop) S2koXg(  
{ p&k0Rx0Q3  
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try{ G*)s%2c>h  
URL url = new URL(sURL); (A7T}
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *)j@
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httpConnection.setRequestProperty("User-Agent","NetFox"); (/T+Wpy?  
String sProperty = "bytes="+nStartPos+"-"; Nf=C?`L  
httpConnection.setRequestProperty("RANGE",sProperty);  )x$!K[=  
Utility.log(sProperty); ,3wI~j=  
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InputStream input = httpConnection.getInputStream(); #D!$~h&i  
//logResponseHead(httpConnection); keT?,YI  
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byte[] b = new byte[1024]; iP~sft6  
int nRead; ,DE(5iDS  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 'bLP~  
{ er(8}]X8Q  
nStartPos += fileAccessI.write(b,0,nRead); Ix( 6  
//if(nThreadID == 1) i FC"!23f  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =^BqWC2~  
} Zr\2BOcc.l  
>=4sPF)  
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Utility.log("Thread " + nThreadID + " is over!"); w0#%AK  
bDownOver = true; V[#6yMU@  
//nPos = fileAccessI.write (b,0,nRead); \ua9thO
G  
} kFS0i%Sr  
catch(Exception e){e.printStackTrace ();} Rb{+Ki  
} 5/Ydv RB67  
} aF D="Zh  
x2sN\tOh^  
s ;48v  
//打印回应的头信息 eA`]KalH  
public void logResponseHead(HttpURLConnection con) u=(H#o<#  
{ t@X M /=d  
for(int i=1;;i++) 3wV86tH%  
{ TAXd,z N  
String header=con.getHeaderFieldKey(i); F?!FD>L{`  
if(header!=null) BfX%|CWh  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0Wa#lkn$I  
Utility.log(header+" : "+con.getHeaderField(header)); g;$E1U=R-E  
else ].LJt['%8  
break; f&K}IM8& #  
} Q]!6uA$A  
} cL6 6gOEL  
wG_4$kyj  
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public void splitterStop() EJO.'vQ  
{ 4;?1Kb#  
bStop = true; ?A|zRj{  
} D5=C^`$2  
fW(;
  

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} 0rV/qMo;K  
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/* OdO{xG G@  
**FileAccess.java 4"LPJX)Q  
*//文件访问(定位，写) baqn7k"  
package NetFox; 7^HpVcSM  
import java.io.*; rZ pbu>S  
C=8H)Ef,l  
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public class FileAccessI implements Serializable{ 2K Pqu:lv  
$H4=QVj6  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 6KVV z/  
RandomAccessFile oSavedFile; ki#y&{v9Be  
long nPos; K/DH / r  
XnD0eua#  
5Qb;2!  
public FileAccessI() throws IOException %?@x]B9Y8E  
{ 6s'[{Ov  
this("",0); VZ;@S3TS  
} O)l%OOv   
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public FileAccessI(String sName,long nPos) throws IOException ;D:=XA%  
{ )#C_mB$-#  
oSavedFile = new RandomAccessFile(sName,"rw"); S45'j(S=  
this.nPos = nPos; OthG7+eF  
oSavedFile.seek(nPos); Ks|gL#)*Ku  
} -P2 @mx%  
{d8^@UL  
k@
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public synchronized int write(byte[] b,int nStart,int nLen) !!9{U%s  
{ .-J`d=Krp  
int n = -1;  j|ozGO  
try{ S3;lKr  
oSavedFile.write(b,nStart,nLen); \{lE
0j7}h  
n = nLen; hX&-/fF+f  
} #0(fOHPQ  
catch(IOException e) <8$Md4r  
{ qv.n99?]  
e.printStackTrace (); @?m+Z"o|z  
} `nK
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>;m{{nj  
OqtQA#uL  
return n; )q^(T1  
} 0Qt~K#mr/  
iW'_R{)T  
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} ci;&CHa  
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/*
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**SiteInfoBean.java 1PmX."a  
*/ k2pT1QZnt  
package NetFox; :fhB*SYK  
*aI~W^N3  
3XnE y +  
public class SiteInfoBean { wBLsz/  
ZH!;z-R  
}H5/3be  
private String sSiteURL; //Site's URL ZxI]I1)  
private String sFilePath; //Saved File's Path &eU3(F`.  
private String sFileName; //Saved File's Name JfSdUWxT  
private int nSplitter; //Count of Splited Downloading File {b[
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public SiteInfoBean() +eC3?B8rN  
{//nSplitter的缺省值为5 .3(;9};  
//default value of nSplitter is 5 _Cj(fFL  
this("","","",5); mLQUcYfR  
} (NPxab8e*  
Xty#vI  
#sS9vv7i  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) h>| g2h  
{ N70zjy4?fL  
sSiteURL= sURL; n?}5!  
sFilePath = sPath; jK e.gA  
sFileName = sName; _%;M9Sg3  
this.nSplitter = nSpiltter; 3hLqAj  
72u db^  
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} zx7#)*  
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8sH50jeP  
public String getSSiteURL() BO]=vH  
{ v"/TmiZ  
return sSiteURL; ZOC#i i`:  
} >GmN~"iJ  
QTfu:m{  
RvR:e|  
public void setSSiteURL(String value) d[S#Duz<&  
{ %Sul4: D#  
sSiteURL = value; XO%~6Us^  
} *<UGgnmLE  
_Yy:s2I8B  
[t$4Tdd  
public String getSFilePath() ,&[7u9@  
{ CB6o$U  
return sFilePath; TqAtcAurM  
} (U_wp's  
]H>+m 9  
h mds(lv7  
public void setSFilePath(String value) SYeE) mI  
{ `2,a(Sk#  
sFilePath = value; LZ4xfB(  
} 8'\~%xw  
Fav^^vf*1  
}s(C^0x  
public String getSFileName() 8ZW?|-i  
{ zWb-pF|  
return sFileName; F(;jM(  
} %EWq2'/5  
:pb67Al29  
;$z7[+M  
public void setSFileName(String value) /z
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{ :6zC4Sr^  
sFileName = value; ~GA8_B  
} &kiF/F 1  
>K5~:mx#3  
w2C&%Xk  
public int getNSplitter() e62y  
{ _;7fraqX  
return nSplitter; |_, /u_  
} 0 7\02f  
><K!~pst}  
]Z/R!y?l"G  
public void setNSplitter(int nCount) "
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{ @+:4J_N  
nSplitter = nCount; gvGi%gq  
} %Ci^*zb  
} d@Q][7  
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Ok*Z  
/* @iRO7 6m  
**Utility.java HitAc8  
*/ 3}j1RYtz  
package NetFox;  VGB-h'  
VKNp,Lf  
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public class Utility { vtZ?X';wh  
>D~w}z/fk  
Z(`r-}f I  
public Utility() |(RZ/d<X\a  
{ "$DldHC  
c|Y!c!9F  
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} {-h, ZdH^  
fnWsm4  
//线程睡眠 S/fW/W*/}  
public static void sleep(int nSecond) CL1 oAk  
{ MJ\r 4n  
try{ +
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Thread.sleep(nSecond); `s%QeAde  
} / gu3@@h  
catch(Exception e) !UcOl0"6  
{ kW
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e.printStackTrace (); ).Gd1pE  
} O_AGMW/2+  
} <s
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x6%#wsvS  
//日志 {xToz]YA  
public static void log(String sMsg) Ye@t_,)x  
{ n,sY\=vB  
System.err.println(sMsg); `m, Ki69.  
} N+J>7_k   
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nE7JLtbH  
public static void log(int sMsg) SOj`Y|6^:  
{ 7k~Lttuk  
System.err.println(sMsg); ]F+K|X9-  
} sf)W~Lx5a  
} :".w{0l@  
Ihqs
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c D7FfJ  
/* d;44;*D  
**TestMethod.java a:b^!H>#  
*/ M(2`2-/xh  
package NetFox; mW +tV1XjG  
.8(%4ejJ(  
;UpJ=?W  
public class TestMethod { :Eo8v$W\RB  
wS%zWdsz  
02pplDFsM  
public TestMethod() hfv%,,e  
{ ///xx/weblogic60b2_win.exe /WYh[XKe  
try{ dhtb?n{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); OpQ8\[X+  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); KuXkI;63J>  
SiteFileFetch fileFetch = new SiteFileFetch(bean); H`el#tt_  
fileFetch.start(); NnOI:X {  
} gc,Ps  
catch(Exception e){e.printStackTrace ();} 8^vArS;  
P#*n3&Uu  
*Ru2:}?MpS  
} %E.S[cf%8&  
gt@SuX!@{^  
" '[hr$h3  
public static void main(String[] args) }dKLMNqPA  
{ @ae
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new TestMethod(); >{t+4p4k.  
} qd8pF!u|#  
} )5GQJiY  
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