http断点续传简单实现（java)

/* Rw$ @%o%  
**SiteFileFetch.java azE>uEsE  
*/ )>TA|W]@  
package NetFox; zQ)[re)  
import java.io.*; {K[+nX=#  
import java.net.*; 8d Ftp3(  
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public class SiteFileFetch extends Thread { G1| Tu"  
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SiteInfoBean siteInfoBean = null; //文件信息Bean AiO,zjM=  
long[] nStartPos; //开始位置 i"_f46rP  
long[] nEndPos; //结束位置 #jDO?Y Sa  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 55,vmDd  
long nFileLength; //文件长度 QFX|ZsmK  
boolean bFirst = true; //是否第一次取文件 J~c]9t  
boolean bStop = false; //停止标志 -P.) 0d(  
File tmpFile; //文件下载的临时信息 g2iSc  
DataOutputStream output; //输出到文件的输出流 5R o5Cg~  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） c=@=lGgo  
public SiteFileFetch(SiteInfoBean bean) throws IOException Z.h`yRhO  
{ r@ejU'uz  
siteInfoBean = bean; uQ8
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); kkzXv`+  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); JVXBm]  
if(tmpFile.exists ()) f(##P|3>R  
{ .(`u'G=  
bFirst = false; #p_ ~L4iW  
read_nPos(); iqOd]H]v  
} /iukiWeW  
else F,lQj7  
{ B<0lif|  
nStartPos = new long[bean.getNSplitter()]; $}HSU>,%  
nEndPos = new long[bean.getNSplitter()]; W?6RUyMC$T  
} [q(7Jv  
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} cFH,fj  
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public void run() ;)clCm46  
{ ,u\M7,a^  
//获得文件长度
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//分割文件 ~L}0)FZ\9  
//实例FileSplitterFetch fx_7B (  
//启动FileSplitterFetch线程 vWj|[| <rX  
//等待子线程返回 F]~`57  
try{ I[F.M}5
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if(bFirst) ^l iyWl  
{ bfrBHW#  
nFileLength = getFileSize(); b,{?+
8  
if(nFileLength == -1) VqYe0-^=P  
{ w
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System.err.println("File Length is not known!"); yWX:`*GV  
} HPt"  
else if(nFileLength == -2) NB,iC [e  
{ W=G[hT5L{  
System.err.println("File is not access!"); =;T971L`  
} Hi|Oeu  
else .c BJA&/  
{ pX2 Ki^)]  
for(int i=0;i<nStartPos.length;i++) -bE{yT)7  
{ 5HJ6[.HO  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ]54V9l:  
} `Th!bk  
for(int i=0;i<nEndPos.length-1;i++) _A%z^&k(i  
{ /Wzic+v<>  
nEndPos = nStartPos[i+1]; SM@1<OCc  
} h#`qEK&u  
nEndPos[nEndPos.length-1] = nFileLength; %=_Iq\lC  
}  ,?`$~8  
} .CmwR$u&  
_#-(XQa  
G>H&M#7K  
//启动子线程 4}=]QQoE  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; dIK!xOStA  
for(int i=0;i<nStartPos.length;i++) RL
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{ M%6{A+(  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), u2BVQ<SA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 1UmV&  
nStartPos,nEndPos,i); o&X!75^G>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9i9VDk{  
fileSplitterFetch.start(); D^f;dT;-  
} k^ID  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), oOSw>23x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); l tQ:c  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %n{E/06f  
nEndPos = " + nFileLength); Z*kg= hs^  
// fileSplitterFetch[nPos.length-1].start(); *^QfTKN  
uTn(fs)D  
<0Q`:'\.>  
//等待子线程结束 UT>\u
 
//int count = 0;  \
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//是否结束while循环 ~>+}(%<,  
boolean breakWhile = false; S .1~#  
Hk.+1
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+:oHI[1HG  
while(!bStop) KcY 2lTvx  
{ K);
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write_nPos(); s8 3_Bd  
Utility.sleep(500); m]&d TZV  
breakWhile = true; rTK/WZ
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YY$K;t{dk  
N?R1;|Z]  
for(int i=0;i<nStartPos.length;i++) R3.tkFZq]  
{ 0oM~e  
if(!fileSplitterFetch.bDownOver) }CQGvH  
{ +#n[55d  
breakWhile = false; \Mt(9jNK  
break; @(oz`|*  
} 8l)^#"ySA  
} _DH,$evS%  
if(breakWhile) kOJs;k  
break; [UFLL:_sC  
!U*i13  
J6
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//count++; ~6{;3"^<  
//if(count>4) : h-N  
// siteStop(); aS62S9nwX  
} nq A> }A  
~ ]o .Mv a  
|'1[\<MM3  
System.err.println("文件下载结束！"); whxE[Xnv  
} :?yv0Iu  
catch(Exception e){e.printStackTrace ();} u:"mq.Q  
} 8 =J6{{E  
|W{z,e01x  
^Cpvh}1#  
//获得文件长度 z\Qg 3BS  
public long getFileSize() He&dVP  
{ ]<TgBo|  
int nFileLength = -1; epz2
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try{ mltN$b%G=d  
URL url = new URL(siteInfoBean.getSSiteURL()); =yvyd0|35  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Nluy]h &  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;M\H#%G.  
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int responseCode=httpConnection.getResponseCode(); KxK$Y.y]  
if(responseCode>=400) K)F;^)KDHf  
{ uFG]8pj2V1  
processErrorCode(responseCode); 3'*SSZmnOB  
return -2; //-2 represent access is error kS3wa3bT  
} 8?P@<Do%  
Hza{"I*^  
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String sHeader; %6dFACv  
;l+3l ez  
c7
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for(int i=1;;i++) [%z~0\lu8  
{ z8jQaI]j  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); tAc[r)xFw  
//Utility.log(in.readLine()); V$<og  
sHeader=httpConnection.getHeaderFieldKey(i); C$ nT&06o  
if(sHeader!=null) El]Rrku  
{ j$Gb>Ex>  
if(sHeader.equals("Content-Length")) EKq9m=Ua@o  
{ VO[s:e9L  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !:a pu!  
break; ]J:?@}\^  
} UPUO8W)<Z6  
} `'.u$IBW  
else )!){4c/  
break; l9?]t;  
} kcM9 ,bG  
}
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catch(IOException e){e.printStackTrace ();} KS3 /  
catch(Exception e){e.printStackTrace ();} YD7i6A  
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Y7]N.G3,]  
Utility.log(nFileLength); j`ggg]"&$  
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,W7\AY07]  
return nFileLength; X^r HugQ  
} l[L\|hv'n  
;40!2P8t  
bgL`FW i3  
//保存下载信息（文件指针位置） u m(A3uQ  
private void write_nPos() uFL~^vz  
{ 7*~
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try{ 69TQHJ[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); \oLRNr[F  
output.writeInt(nStartPos.length); b78'yM&  
for(int i=0;i<nStartPos.length;i++) L:%; Fx2  
{ #&5m=q$EI  
// output.writeLong(nPos); _~| j~QE]  
output.writeLong(fileSplitterFetch.nStartPos); vw>O;u.]B  
output.writeLong(fileSplitterFetch.nEndPos); 4Z1-RS  
} v8Bi1,g  
output.close(); D8C@x`  
} a[[u>oHyd  
catch(IOException e){e.printStackTrace ();} j*rra  
catch(Exception e){e.printStackTrace ();} thl{IU  
} !7P 1%/  
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//读取保存的下载信息（文件指针位置） r,!7TuBl  
private void read_nPos() B&+V%~/  
{ -Q<3Q_  
try{ ]?/[& PP,  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 8L9xP'[^  
int nCount = input.readInt(); HB
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nStartPos = new long[nCount]; a UAPh  
nEndPos = new long[nCount]; sq*d?<:3  
for(int i=0;i<nStartPos.length;i++) bJmVq%>;  
{ o[!]xmj  
nStartPos = input.readLong(); +_3>T''_  
nEndPos = input.readLong(); _t'Kj\  
} #Kn=Q  
input.close(); `6?r.;wj  
} >-c;  
catch(IOException e){e.printStackTrace ();}
'9H7I! L@  
catch(Exception e){e.printStackTrace ();} \[%[`m  
} ,a~- (@  
FzXVNUMP  
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private void processErrorCode(int nErrorCode) fXS4
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{ F!tn|!~  
System.err.println("Error Code : " + nErrorCode); GG/~)^VMe  
} 0<Vw0%!  
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d_-{-@  
//停止文件下载 dNB56E)5`J  
public void siteStop() JGHQ_AI  
{ kQRNVdiz  
bStop = true; zQV$!%qR  
for(int i=0;i<nStartPos.length;i++) *.8@hPy  
fileSplitterFetch.splitterStop(); /g< T
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} IwiR2K  
} B!jT@b{  
//负责部分文件的抓取 /NNe/7'l  
**FileSplitterFetch.java 3&/5!zOg)  
*/ MR:Co4(  
package NetFox; {()8 Wr  
lGwX.cA!'  
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import java.io.*; 6-{QU] #  
import java.net.*; RM|<(kq  
>t.2!Z_RQ  
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public class FileSplitterFetch extends Thread { KcF2}+iM  
xwW[6Ah  
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String sURL; //File URL H^Ik FEVs  
long nStartPos; //File Snippet Start Position =mxmJFA  
long nEndPos; //File Snippet End Position vq B)PL5)  
int nThreadID; //Thread's ID lBvQ?CJ<y  
boolean bDownOver = false; //Downing is over .ZJt  
boolean bStop = false; //Stop identical nsqc^ K^  
FileAccessI fileAccessI = null; //File Access interface aF1pq  
\/p\QT@mm  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException M~t S *
 
{ D"oyl`q  
this.sURL = sURL; Y?=+A4v  
this.nStartPos = nStart; 8sOM%y9M  
this.nEndPos = nEnd; 79AOvh  
nThreadID = id;  P 1X8  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 `r &IA  
} >j{phZ  
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public void run() x>8=CiUE  
{ 9He>F7J:p'  
while(nStartPos < nEndPos && !bStop) .h-:)e*  
{ (
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try{ mWZoo/xtT  
URL url = new URL(sURL); Fyrr,#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &Y;z[+(P  
httpConnection.setRequestProperty("User-Agent","NetFox"); D:sQHJ.y  
String sProperty = "bytes="+nStartPos+"-"; &]iX>m.  
httpConnection.setRequestProperty("RANGE",sProperty); o /AEp)8  
Utility.log(sProperty); 'KMyaEh.u  
-
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\/I@&$"F  
InputStream input = httpConnection.getInputStream(); /Li?;H  
//logResponseHead(httpConnection); m*tmmP4R  
a02@CsH  
~rN~Ql%S  
byte[] b = new byte[1024]; GxL5yeN@(  
int nRead; C s?kZ %  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) i=#<0!m  
{ BX;Z t9"*  
nStartPos += fileAccessI.write(b,0,nRead); }:P/eY  
//if(nThreadID == 1) !run3ip`Z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0&E{[~Pv  
} Jb Hn/$  
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Utility.log("Thread " + nThreadID + " is over!"); @
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bDownOver = true; @x3x/gU  
//nPos = fileAccessI.write (b,0,nRead); J)D/w[w  
} -bd
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catch(Exception e){e.printStackTrace ();} WBL
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} D|} y{~  
} by,"Orpwq;  
23BzD^2a  
f8'D{OP"G  
//打印回应的头信息 r%A-  
public void logResponseHead(HttpURLConnection con) c&z@HEzV7  
{ vG`R.  
for(int i=1;;i++) _ #288`bU  
{ .YKqYN?y4  
String header=con.getHeaderFieldKey(i); C vfm ,BL  
if(header!=null) dp\pkx7  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); M^DYzJ  
Utility.log(header+" : "+con.getHeaderField(header)); {SVd='!V  
else `6koQZm  
break; D6@c&  
} rTT Uhd  
} hdJW#,xq  
/MKcS%/H/  
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public void splitterStop() !%>p;H%0  
{ PB*mD7"  
bStop = true; /co^swz  
} CKeT%3  
'+LC.lM  
tYK 5?d  
} JK34pm[s  
7KXc9:p+  
>xb}AY;  
/* m?VA 1  
**FileAccess.java GY%lPp  
*//文件访问(定位，写) Z_Ffiw(p  
package NetFox; fw Ooi'jb  
import java.io.*; p3>p1tC  
t$m~O?I  
sr1`/  
public class FileAccessI implements Serializable{ ")T;3/c  
LK5,GWF;  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 h BD .IB  
RandomAccessFile oSavedFile; ]E$h7I  
long nPos; b7 %Z~
 
{3cT\u  
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public FileAccessI() throws IOException /@-!JF#g  
{ Ey7SQb  
this("",0); w'E&w)Z]  
} Gv?3T Am8  
;5QdT{$H  
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public FileAccessI(String sName,long nPos) throws IOException CmKbpN*  
{ |X@ZM  
oSavedFile = new RandomAccessFile(sName,"rw"); LPO:Ka  
this.nPos = nPos; PoTJ4z  
oSavedFile.seek(nPos); 6wK>SW)#&j  
} g93-2k,  
;G_{$)P.o  
CR3<9=Lv>  
public synchronized int write(byte[] b,int nStart,int nLen) YQGVQ[P  
{ OOJg%y*H  
int n = -1; BnJpC<xm  
try{ r/o1a't;  
oSavedFile.write(b,nStart,nLen); uL| Wuq  
n = nLen; o6L\39v_  
} hq
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catch(IOException e) }n/6.%  
{ W u?A} fH  
e.printStackTrace (); !c+,OU[  
} EY'kIVk  
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return n; _M[@a6?  
} p,#t[K  
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/,#HGu]q'  
} ,=!_7'm
 
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ZYf0FC=-  
/* ?}p~8{ '  
**SiteInfoBean.java rD^ b{]E3  
*/ R]L$Ld< ij  
package NetFox; = cQK^$6(  
uW4)DT9[5  
,i0Dw"/u  
public class SiteInfoBean { NL`}rj  
8x":7 yV&  
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private String sSiteURL; //Site's URL ]=Im0s  
private String sFilePath; //Saved File's Path SLI(;, s  
private String sFileName; //Saved File's Name /Mq9~oC  
private int nSplitter; //Count of Splited Downloading File }.`no  
s}3g+T\l1w  
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public SiteInfoBean() Ss>ez8q  
{//nSplitter的缺省值为5 -lICoRO#  
//default value of nSplitter is 5 VS.~gHx  
this("","","",5); Jkf%k3H3I*  
} LdAWCBLS  
:@x_& b  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Vz4/u|gt  
{ ,v
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sSiteURL= sURL; {nQ?+o3  
sFilePath = sPath; NA@<v{z  
sFileName = sName; pf&H !-M  
this.nSplitter = nSpiltter; | R\PQ/)  
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k/  
OO$YwOKS  
} 8s+9PE  
lk/T|0])  
vMD%.tk  
public String getSSiteURL() 9x4%M&<Z9a  
{ Mk=
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return sSiteURL; r1pj-   
} {Sl#z}@s  
,Q%q!#@  
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public void setSSiteURL(String value) /2s=;tA1  
{ Hsdcv~Xr;l  
sSiteURL = value;  kD}w5 U  
} ZwzN=03T  
u4eA++eT  
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public String getSFilePath() $%:=;1Jl  
{ \t=ls  
return sFilePath; [:Upn)9  
} 0eMO`8u[A  
0R21"]L_M  
Ka4KsJN  
public void setSFilePath(String value) .<fn+]  
{ r]+/"~a  
sFilePath = value; ?:$aX@r  
} '}$]V>/  
r
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}F B]LLi  
public String getSFileName() iNO}</7?  
{ v~B "Il  
return sFileName; )I{~Pcq  
} R(t1Ei.-?  
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2%{(BT6  
public void setSFileName(String value) FN+x<VXo(  
{ z<
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sFileName = value; r$Tu``z \  
} qpEK36Js  
XJSI/jpa@  
&mPR[{  
public int getNSplitter() ;#/Uo8  
{ /l%+l@  
return nSplitter; w/49O;rV  
} m=K46i+NE  
+|K/*VVn`  
[gkOwU=?  
public void setNSplitter(int nCount) Zws[C  
{  8MZ:=  
nSplitter = nCount; lWyg_YO@  
} n1Z
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} 8V?*Bz-4`  
}VU7wMk  
Can:!48  
/* NScUlR"nE  
**Utility.java
A[hvT\X  
*/ eWk W,a  
package NetFox; 6Zx'$F.iqK  
:OKU@l|  
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public class Utility { zcE`.)y  
p|`[8uY?  
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public Utility() Ib}~Q@?2  
{ IM(=
j  
D:56>%y@  
M>rertUR  
} ).i :C(|  
K&IHt?vh!  
//线程睡眠 Y$4dqn  
public static void sleep(int nSecond) X[E!q$ag  
{ m\"X%Y#  
try{ na`8ulN_  
Thread.sleep(nSecond); Aq*,cOF+  
} .a_xQ]eQ  
catch(Exception e) IKFNu9*"h  
{ KB`">zq$u  
e.printStackTrace (); 8(@Y@`/  
} '-2|GX_o  
} j"4]iI+{"  
hmES@^n!_  
//日志 NGp^/PZX0  
public static void log(String sMsg) }nt,DG!r  
{ /I@`B2  
System.err.println(sMsg); Y{`hRz`  
} aSMSuX8  
3;er.SF
u{  
a IgV"3  
public static void log(int sMsg) WW3! ,ln_  
{ o%3VE8-  
System.err.println(sMsg); j\%m6\{n|  
} =|O><O|  
} "tUc  
"o>` Y  
7: .bqRu  
/* eCy]ugsi%  
**TestMethod.java Bc1MKE5  
*/
zz[[9Am!  
package NetFox; 9oA-Swc[  
;yDXo\gm  
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public class TestMethod { Y}hz UKJ  
hB1Gtc4n  
I`
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public TestMethod() $[HpY)MSRw  
{ ///xx/weblogic60b2_win.exe Q^|aix~ K  
try{ f'&   
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Zoyo:vv&  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); jx-8%dxtZ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); N,?D<NjXl  
fileFetch.start(); 40Z/;,wp{  
} - *_"
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catch(Exception e){e.printStackTrace ();} /e50&
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} ECf
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i=s>a;*#  
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public static void main(String[] args) 1+NmiGKg  
{ aj6{  
new TestMethod(); od`:w[2\  
} :}[[G2|9  
} TM$Ek^fQ.  
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