http断点续传简单实现（java)

/* Q%M_   
**SiteFileFetch.java :R3P 58>  
*/ :Fo4O'UC  
package NetFox; Uir*%*4:  
import java.io.*; ?+Hp?i$1  
import java.net.*; kXCY))vnn  
)DRkS,I  
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public class SiteFileFetch extends Thread { \AHY[WKx  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 'oCm.~;_  
long[] nStartPos; //开始位置 2b!j.T#u  
long[] nEndPos; //结束位置 *k!(ti[  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9c6'  
long nFileLength; //文件长度 W{\EE[XhCf  
boolean bFirst = true; //是否第一次取文件 =1Ri]b  
boolean bStop = false; //停止标志 T(&kXMaB  
File tmpFile; //文件下载的临时信息 BP:(IP!&  
DataOutputStream output; //输出到文件的输出流 CX.SYr&!R  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Q-jf8A]  
public SiteFileFetch(SiteInfoBean bean) throws IOException hLSTSD}  
{ (`F|nG=X  
siteInfoBean = bean; jF4csO=E  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); (>mi!:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?^Pq/V
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if(tmpFile.exists ()) KZW'O b>[  
{ $(XgKq&xWZ  
bFirst = false; db^a
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read_nPos(); @$EjD3Z-  
} yqYhe-"  
else 8Kk3_ y  
{ ^pN 5NwC5  
nStartPos = new long[bean.getNSplitter()]; CQ$::;  
nEndPos = new long[bean.getNSplitter()]; ;Na^]32  
} sK`<
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} 0s)cVYppe  
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public void run() d&5c_6oW  
{ >6IXuq  
//获得文件长度 hR!}u}ECd  
//分割文件 ;m''9z)2  
//实例FileSplitterFetch E*OG-r   
//启动FileSplitterFetch线程 A3z/Bz4]:#  
//等待子线程返回 z'_&|-m  
try{ .#sz|0  
if(bFirst) ,%[LwmET  
{ Yg[ v/[]  
nFileLength = getFileSize(); 0hFH^2%UY  
if(nFileLength == -1) F. }l(KuJ  
{ %v_IX2'  
System.err.println("File Length is not known!"); G5Je{N8W  
} 2YE7 23H=Z  
else if(nFileLength == -2) _O"L1Let  
{ C1KfXC*|L  
System.err.println("File is not access!"); Q js2hj-$  
} Sf=F cb  
else O@nqHZ  
{ QH4k!^  
for(int i=0;i<nStartPos.length;i++) TeKC} NW  
{ H_Iim[v#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Jc`Rs"2  
} \Bt=bu>Z  
for(int i=0;i<nEndPos.length-1;i++) gxI&f  
{ ~:T3|  
nEndPos = nStartPos[i+1]; r}ZLf  
} c6t2Q6zV  
nEndPos[nEndPos.length-1] = nFileLength; >6OCKl  
} sTt9'P`  
} Ze#Jhn@  
Ir!2^:]!  
] xb]8]  
//启动子线程 $pjf#P8U  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; TH<fbd  
for(int i=0;i<nStartPos.length;i++) d[)_sa  
{ qC\]"Z`m  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), n"mJEkHE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), T~s&)wD  
nStartPos,nEndPos,i); {a]pF.^kf  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nDyvX1]  
fileSplitterFetch.start(); =E&24  
} "!xvpsy  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $U~=.!_du  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); zpbcmQB*  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", tp#Z@5=  
nEndPos = " + nFileLength); zwMQXI'k83  
// fileSplitterFetch[nPos.length-1].start(); e)*mC oR  
tB GkRd!  
wTHK=n\i  
//等待子线程结束 s`;0 t YG  
//int count = 0; jaK'
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//是否结束while循环 aZI>x^X  
boolean breakWhile = false; #!w:_T%  
{An8/"bv}  
lr`?yn1D(  
while(!bStop) r49UJE  
{ 'uPxEu4 >4  
write_nPos(); Sc%aJ1  
Utility.sleep(500); /z/hUa  
breakWhile = true; *Hxj_  
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for(int i=0;i<nStartPos.length;i++) W"W@WG9X0  
{ BO8%:/37[4  
if(!fileSplitterFetch.bDownOver) cC b>zI  
{ ;>inT7?3|  
breakWhile = false; 9@(O\xr  
break; 5tN%a>D%  
} ARmu{cL  
} BXT80a\  
if(breakWhile) n"XdHW0  
break; Tq9,c#}&  
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)WaX2uDA?  
//count++; _u#/u2<  
//if(count>4) Qe7"Z  
// siteStop(); <dq,y>  
} $/4Wod*l  
h |s*i  
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System.err.println("文件下载结束！"); 3js)niT9u  
} E^oEG4X@  
catch(Exception e){e.printStackTrace ();} oN.Mra]D  
} %2^['8t#NH  
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}W- K  
//获得文件长度 d8xk&za  
public long getFileSize() :jZ*,d%1={  
{ 7'-)/Pk  
int nFileLength = -1; '}wG"0  
try{ vs5 D:cZ}  
URL url = new URL(siteInfoBean.getSSiteURL()); {KW&wsI  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6$W-?  
httpConnection.setRequestProperty("User-Agent","NetFox"); &Tf=~6  
tfi2y]{A  
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int responseCode=httpConnection.getResponseCode(); mJwv&E  
if(responseCode>=400) #B}BI8o (  
{ e7Yb=/F  
processErrorCode(responseCode); M\:"~XW  
return -2; //-2 represent access is error ?whRlh  
} VFe-#"0ZO  
d[~au=b  
^JYF1  
String sHeader; #nU@hOfg  
gg lNpzj  
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for(int i=1;;i++) j zxf"X-  
{ 5"76R Gw=  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~0VwF  
//Utility.log(in.readLine()); I>N-95  
sHeader=httpConnection.getHeaderFieldKey(i); *D,v>(  
if(sHeader!=null) [,\'V0  
{ E&
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if(sHeader.equals("Content-Length")) [VfLv.8w  
{ sq8tv]  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); OhA^UP01-  
break; E'S<L|A/  
} Ktg&G<%J0  
} }0k"SwX  
else 9b{g+lMZo  
break; UQC'(>.}  
} X}65\6  
} >m)2ox_B  
catch(IOException e){e.printStackTrace ();} o=a:L^nt,  
catch(Exception e){e.printStackTrace ();} 7?kXgR[#d  
#C;#$|d  
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Utility.log(nFileLength); kMwIu
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return nFileLength; EvGUj$  
} 'W<a54T?z  
1CF7  
44/0}v]  
//保存下载信息（文件指针位置） @&am!+z  
private void write_nPos() aT`02X  
{ |Oj,S|Z:  
try{ t<KEx^gb  
output = new DataOutputStream(new FileOutputStream(tmpFile)); EkfGw/WDw  
output.writeInt(nStartPos.length); ^c;skV&S  
for(int i=0;i<nStartPos.length;i++) (HTk;vbZm  
{ %k1q4qOG]^  
// output.writeLong(nPos); oKMg7 3*  
output.writeLong(fileSplitterFetch.nStartPos); |-cALQ  
output.writeLong(fileSplitterFetch.nEndPos); b&|YQW}~  
} hc@;}a\Y  
output.close(); ey9fbS ^I  
} !0d9<SVC  
catch(IOException e){e.printStackTrace ();} he#Tr'j  
catch(Exception e){e.printStackTrace ();} OTy4"%  
} { V=:O  
*;\ K5  
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//读取保存的下载信息（文件指针位置） 5sffDEU]A  
private void read_nPos() kBDe*K.V  
{ Poylq]F  
try{ D@YM}HXuj  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 4`^TC[
  
int nCount = input.readInt(); 5 \.TZMB  
nStartPos = new long[nCount]; N2S!.H!Wz  
nEndPos = new long[nCount]; c'wU O3S  
for(int i=0;i<nStartPos.length;i++) a*$1la'Uf  
{ duiKFNYN  
nStartPos = input.readLong(); c,[qjr#\>  
nEndPos = input.readLong(); G`3vH,  
} #h5Hi9LKf  
input.close(); -mWw.SfEZ  
} $48[!QE  
catch(IOException e){e.printStackTrace ();} i,U-H\p&  
catch(Exception e){e.printStackTrace ();} ^/5E773  
} ^*owD;]4_  
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private void processErrorCode(int nErrorCode) 4*ty&s=5OJ  
{ 'amex  
System.err.println("Error Code : " + nErrorCode); bj*v'  
} hc4`'r;  
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//停止文件下载 :h](;W>H  
public void siteStop() !Vod0j">  
{ jrMGc=KL  
bStop = true; jAQ)3ON<  
for(int i=0;i<nStartPos.length;i++) ^PCL^]W  
fileSplitterFetch.splitterStop(); (WU~e!}  
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} wxr}*Z:ZMa  
} qLktMp_  
//负责部分文件的抓取 5xn0U5U  
**FileSplitterFetch.java /[)P^L`  
*/ |RbUmuj  
package NetFox; "~,(
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import java.io.*; K+aJ`V  
import java.net.*; Q*{H]  
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public class FileSplitterFetch extends Thread { y O9pEO|W  
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& /FA>  
String sURL; //File URL 0%L$TJ.''  
long nStartPos; //File Snippet Start Position Gm?"7R.  
long nEndPos; //File Snippet End Position *IfIRR>3l(  
int nThreadID; //Thread's ID =_~'G^`tu  
boolean bDownOver = false; //Downing is over 
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boolean bStop = false; //Stop identical OG<]`!"  
FileAccessI fileAccessI = null; //File Access interface ysP/@;jC  
}X.8.S'  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException l#(g&x6J  
{ ~'YSVx& )  
this.sURL = sURL; I7-PF?  
this.nStartPos = nStart; w `9GygS  
this.nEndPos = nEnd; UVuuIW0k  
nThreadID = id; 0O9 Lg}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :ftyNaq'  
} L[9+xK^g  
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public void run() XzR
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{ ovRCF(Og,  
while(nStartPos < nEndPos && !bStop) <k8rSxn{  
{ ]KII?{<k  
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try{ 7Bb@9M?i  
URL url = new URL(sURL); 7}HA_@[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,2L,>?r6  
httpConnection.setRequestProperty("User-Agent","NetFox"); 
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String sProperty = "bytes="+nStartPos+"-"; qb/!;U_  
httpConnection.setRequestProperty("RANGE",sProperty); Y&:\s8C  
Utility.log(sProperty); }jy7,+  
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InputStream input = httpConnection.getInputStream(); 4xC6#:8  
//logResponseHead(httpConnection); !P3tTL!*L  
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byte[] b = new byte[1024]; G37L 9IG-M  
int nRead; ^rZ+H@p:6  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) J'&?=|  
{ ^|axtVhMO  
nStartPos += fileAccessI.write(b,0,nRead); X=RmCc$:  
//if(nThreadID == 1) 78}%{7YY  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =:T:9Y_i  
} ,PtR^" Mf4  
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Utility.log("Thread " + nThreadID + " is over!"); d=Ihl30m  
bDownOver = true; PzG:M7  
//nPos = fileAccessI.write (b,0,nRead); @!tmUme1c  
} 2/W0y!qh1  
catch(Exception e){e.printStackTrace ();} e&I.kC"j6  
} R~u7
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} D}=i tu  
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//打印回应的头信息 Ts *'f  
public void logResponseHead(HttpURLConnection con) (?=(eo<N  
{ ku8Z;ONeH  
for(int i=1;;i++)  
rs KE  
{ A^jm<~  
String header=con.getHeaderFieldKey(i); ~wV98u-N  
if(header!=null) X>YOo~yS5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); wH5O>4LO  
Utility.log(header+" : "+con.getHeaderField(header)); x~I1(l7r  
else VY26Cf"  
break; NQ{Z
   
} gnK!"!nL  
} IBHG1<
3  
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public void splitterStop() MjosA R  
{ :)S4MoG  
bStop = true; z^a?t<+  
} r]vBr^kq  
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} eHZl-|-  
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/* W..>Ny;'3  
**FileAccess.java Ji:@z%osr  
*//文件访问(定位，写) 2{q
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package NetFox; k0=y_7 =(5  
import java.io.*; PhL5EYn  
2]KPW*V  
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public class FileAccessI implements Serializable{ T"lqPbK  
MO+0]uh:  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Ft>8 YYyU  
RandomAccessFile oSavedFile; l"g%vS,;`  
long nPos; lJ2/xE]  
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public FileAccessI() throws IOException %5w)}|fw  
{ =?x=CEW  
this("",0); \M^4DdAy  
} M& L0n%,y5  
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public FileAccessI(String sName,long nPos) throws IOException FX%E7H  
{ :jCaDhK  
oSavedFile = new RandomAccessFile(sName,"rw"); JG$J,!.\  
this.nPos = nPos; KPrxw }P  
oSavedFile.seek(nPos); G->@  
} $fG/gYvI\  
@AyW9!vV;3  
ZPog)d@!  
public synchronized int write(byte[] b,int nStart,int nLen) tV%\Jk),  
{ WWs>
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int n = -1; LB0=V
0|  
try{ 2)]*re)  
oSavedFile.write(b,nStart,nLen); [^P2Kn  
n = nLen; Unk+@$E&  
} &?pAt30K:  
catch(IOException e) bm|8Jbsb&  
{ jt*@,+e|  
e.printStackTrace (); %gB0D8,vo  
} <\NXCUqDpo  
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return n; "aH]4DO  
} $9$NX/P  
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} 6ng9 o6  
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cE?
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/* yx4c+(J^8  
**SiteInfoBean.java cV,URUD  
*/ `_kRvpi  
package NetFox; 5T*7HC[  
,]'!2?  
53
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public class SiteInfoBean { ;trR'~  
/zAx`H  
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private String sSiteURL; //Site's URL :a`m
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private String sFilePath; //Saved File's Path HRh".!lxy  
private String sFileName; //Saved File's Name o$;x[US  
private int nSplitter; //Count of Splited Downloading File ^4i3#}  
WR%iUO40  
|'#NDFI>}  
public SiteInfoBean() -JkO[IF  
{//nSplitter的缺省值为5 0}!lN
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//default value of nSplitter is 5 *?\Nioii  
this("","","",5); <#Dc(VhT  
} =0|e
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c7 -j  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) jiDYPYx;I  
{ F[Up  
sSiteURL= sURL; m5*RB1  
sFilePath = sPath; 3._fbAN%e  
sFileName = sName; 0SYkDI  
this.nSplitter = nSpiltter; C7:Ry)8'I  
0>Nq$/!  
pDT6>2t  
} |\ L2q/u  
wq#3f#3V  
9 R1]2U$|  
public String getSSiteURL() ^~$ o-IX  
{ L|Iq#QX|  
return sSiteURL; )kUw,F=6  
} =lnz5H  
wXnt3)e  
^
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public void setSSiteURL(String value) 7y3; F7V  
{ *!kg@ _0K  
sSiteURL = value; sa($3`d  
} hJM0A3(Cm  
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public String getSFilePath() =r2d{  
{  ?auiq  
return sFilePath; fyeS)  
} ]Ea6Z  
.nN7*))Fj  
~%ZO8X:^  
public void setSFilePath(String value) 82<
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{ pY@+.V`a  
sFilePath = value; ;f?bb*1  
} kaLRI|hC  
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l/5/|UE9  
public String getSFileName() ObUQB
+  
{ i`X{pEKP+  
return sFileName; f~Su F,o@h  
} O(VV-n7U  
X"]ZV]7(]s  
'n=D$j]X  
public void setSFileName(String value) }Z|a?J@CZm  
{ P'+*d#*S  
sFileName = value; ?5D7n"jY  
} e0P1FD<@  
0NGokaD)H  
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public int getNSplitter()
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{ (~~=<0S  
return nSplitter; 2=  _.K(  
} .6*A~%-=[d  
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3 V<8  
public void setNSplitter(int nCount) jB;+tDC!Co  
{ %AFy{l
  
nSplitter = nCount; R?(j#bk  
} GUxhCoxb  
} &fcRVku  
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/* Z=xrjE  
**Utility.java |[ge,MO:  
*/ c=5$bo]LI  
package NetFox; C,E 5/XW  
AG?oA328  
n1ICW 9  
public class Utility { @'QBrE  
7Vi[I< *  
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public Utility() bFpwq#PDW>  
{ A6d+RAx  
*\/UT  
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} Je/R'QP^8  
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//线程睡眠 ^l9S5 {  
public static void sleep(int nSecond) <MYD
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{ q&vr;fB2  
try{ j<c_*^/'9  
Thread.sleep(nSecond); TM+7>a$  
} 8L#sg^1V  
catch(Exception e) D`ZYF)[}J  
{ r`=d4dK-  
e.printStackTrace (); mVxS[Gq  
} '&`Zy pq  
} K \O,AE  
(b(iL\B$D=  
//日志 #q\C"N5ip  
public static void log(String sMsg) \ZC7vM"h  
{ b@7 ItzD  
System.err.println(sMsg); o,29C7Ii  
} h:|aQJG5  
nPKj%g3h  
A 9u9d\  
public static void log(int sMsg) #pIb:/2a_  
{ [mm5?23g  
System.err.println(sMsg); wDsEx!\#  
} Y!5-WXH  
} $ZA71TzMV  
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/* /h_BF\VBs  
**TestMethod.java n@*NQ`(_  
*/ [P^ .=F  
package NetFox; aJub("  
xHf l>C'  
qLR)>$  
public class TestMethod { JLjx4B\  
sV-9 xh)i  
LB>!%Vx  
public TestMethod() ~ ^K[pA ?  
{ ///xx/weblogic60b2_win.exe GR"Jk[W9  
try{ !nTq"d%(W  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); W<~(ieu:K~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); km *$;Nli  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $ED<:[3N  
fileFetch.start(); 3N;X|pa  
} MQhL>oQ  
catch(Exception e){e.printStackTrace ();} @6\8&(|  
-Z @cj  
]g:VvTJ;?  
} -gzk,ymp  
$Q62 7  
Mq$e5&/  
public static void main(String[] args) BsxQW`>^y  
{ f;QWlh"9  
new TestMethod(); NbSwn}e_  
} =x=#Etj|  
} |S/nq_g]  
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