http断点续传简单实现（java)

/* "_UdBG  
**SiteFileFetch.java ENVk{QE!  
*/ d~J-|yyT  
package NetFox; l\0w;:N3  
import java.io.*; &C<yfRDu  
import java.net.*; jhgX{xc  
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public class SiteFileFetch extends Thread { R7jmv n  
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SiteInfoBean siteInfoBean = null; //文件信息Bean B;6]NCxD  
long[] nStartPos; //开始位置 iRo.RU8>  
long[] nEndPos; //结束位置 ;h=*!7:  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 k*rZ*sSp  
long nFileLength; //文件长度 `>(W"^  
boolean bFirst = true; //是否第一次取文件 y;cUl, :v  
boolean bStop = false; //停止标志 zdl%iop3
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File tmpFile; //文件下载的临时信息 = {'pUU  
DataOutputStream output; //输出到文件的输出流 uE/T2BX*  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Yj|eji7y  
public SiteFileFetch(SiteInfoBean bean) throws IOException Vgb *% I  
{ inb^$v  
siteInfoBean = bean; 9I7\D8r  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }GMbBZ:nKK  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^jB8Q  
if(tmpFile.exists ()) %VJ85^B3  
{ lf<S_2i  
bFirst = false; ZIR0PQh\  
read_nPos(); 6d[_G$'nk  
} gU^$Sx7'  
else -Y#sI3o*R8  
{ @!N-RQ&A  
nStartPos = new long[bean.getNSplitter()]; _ZB\L^j)  
nEndPos = new long[bean.getNSplitter()]; ]Y>h3T~  
} 7tM9u5FF  
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} O`GsS{$sS  
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public void run() >>b3ZE|5  
{ ,C.:;Ime({  
//获得文件长度 D-Vai#Cd  
//分割文件 )5j;KI%t  
//实例FileSplitterFetch V3;.{0k  
//启动FileSplitterFetch线程 ]?1Y e8>Y<  
//等待子线程返回 Pz#7h*;cw.  
try{ G|w=ez  
if(bFirst) , ^F)L|  
{ -4rDbDsr  
nFileLength = getFileSize(); kd:$oS_*s  
if(nFileLength == -1) c3*t_!@oC  
{ 1axQ)},o@p  
System.err.println("File Length is not known!"); Ab%;Z5$fr  
} jCAC `  
else if(nFileLength == -2) 4(neKr5\#  
{ =p^He!  
System.err.println("File is not access!"); unJid8Lo  
} 87%*+n:?*  
else EpS(o>'  
{ jc[_I&Oc_  
for(int i=0;i<nStartPos.length;i++) 8[CB>-9  
{ $8USyGi3J  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); m=AqV
:%|  
} X{n- N5*  
for(int i=0;i<nEndPos.length-1;i++) Ut-B^x)gl  
{ {qW~"z*  
nEndPos = nStartPos[i+1]; UX3BeUi.)  
} ;@,Q&B2eM  
nEndPos[nEndPos.length-1] = nFileLength; $&s=68  
} Om'+]BBN  
} CM)Q&:  
g*)K/Z0pJ$  
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//启动子线程 cfox7FmW  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]eQV,Vt  
for(int i=0;i<nStartPos.length;i++) oRKEJNps  
{ KIA 2"KbjG  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J89Dull  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), n?\ nn3  
nStartPos,nEndPos,i); `nKH"TaX  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )b<k#(i@#  
fileSplitterFetch.start(); fP tm0.r  
} (>6*#9#p  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), IKMeJ(:S  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #j#_cImE  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", |py6pek|  
nEndPos = " + nFileLength); uPYmHA}_/  
// fileSplitterFetch[nPos.length-1].start(); ANIz,LS  
+_v$!@L8  
;Sd\VR  
//等待子线程结束 lZ8CY  
//int count = 0; 72sD0)?A  
//是否结束while循环 6C>_a*w  
boolean breakWhile = false; }pk#!
N  
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while(!bStop) }R3=fbe,\  
{ +$xeoxU>;  
write_nPos(); mS#zraJn5  
Utility.sleep(500); ccCzu6  
breakWhile = true; H/M Au7  
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/vY_Y3k#  
for(int i=0;i<nStartPos.length;i++) Zh5RwQNE~  
{ p~ 
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if(!fileSplitterFetch.bDownOver) `c/*H29  
{ Y+4o B  
breakWhile = false; O\K_q7iO6  
break; ;!o]wHmA  
} *5zrZ]^  
} ) xbO6V  
if(breakWhile) ^mAYBOE  
break; ]0;864X0  
M :3u@06a  
] 2DH;  
//count++; $F.([?)k?  
//if(count>4) ELh8ltLY  
// siteStop(); Xi?b]Z  
} pE{yv1Yg  
2,lqsd:xM  
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System.err.println("文件下载结束！"); &U+ _ -Ph  
} \BWyk
A>  
catch(Exception e){e.printStackTrace ();} 7r|(}S  
} Q0Nyqhvi  
ZcuA6#3B  
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//获得文件长度 P5lqSA{6  
public long getFileSize() H$af/^
 
{ 7nbB^2  
int nFileLength = -1; _#$*y  
try{ ?JV|dM  
URL url = new URL(siteInfoBean.getSSiteURL()); U yw-2]!n  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); s5RjIa0$7  
httpConnection.setRequestProperty("User-Agent","NetFox"); v+jsC`m  
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int responseCode=httpConnection.getResponseCode(); =9kN_:-  
if(responseCode>=400) |F.)zC5{  
{ 7?B.0>$3>V  
processErrorCode(responseCode); o!:8nXw  
return -2; //-2 represent access is error @&D?e:|!U  
} ;> m"x  
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String sHeader; h^ -.]Y  
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!6Sd(2  
for(int i=1;;i++) !*2%"H*  
{ dd?x(,"A`  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ;q0uE:^S  
//Utility.log(in.readLine()); {lth+{&L#  
sHeader=httpConnection.getHeaderFieldKey(i); 2_Wg!bq  
if(sHeader!=null) 64-#}3zL  
{ xEuN   
if(sHeader.equals("Content-Length")) _"4xKh)  
{ GE>[*zN  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9Pw0m=4  
break; 1 T130L  
} 0Z|FZGRP  
} %{6LUn  
else OMwsbp&  
break; 7Cjd.0T=(  
} lTU$0CG  
} 'qdPw%d  
catch(IOException e){e.printStackTrace ();} 2,aPr:]  
catch(Exception e){e.printStackTrace ();} IrMl:+t\  
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9Lh|DK,nV/  
Utility.log(nFileLength); X0-IRJ[  
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return nFileLength; Mg#j3W}]  
} 2MA]jT  
#_mi `7!B#  
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//保存下载信息（文件指针位置） %gnM(pxl  
private void write_nPos() gX{
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{ k%y9aO  
try{ T0
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output = new DataOutputStream(new FileOutputStream(tmpFile)); 3]-_q"Co4f  
output.writeInt(nStartPos.length); `nUO l  
for(int i=0;i<nStartPos.length;i++) rbT)=-(  
{ p;?*}xa  
// output.writeLong(nPos); d--y  
output.writeLong(fileSplitterFetch.nStartPos); x.1-)\  
output.writeLong(fileSplitterFetch.nEndPos); $,xnU.n  
} bqanFQj  
output.close(); O4<g%.HC6  
} r%DFve:%  
catch(IOException e){e.printStackTrace ();} 50dGBF  
catch(Exception e){e.printStackTrace ();} %AOIKK5  
} 8G>>i)Sbg  
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V|)>{Xdn  
//读取保存的下载信息（文件指针位置） VL9-NfeqR  
private void read_nPos() -C#PQV  
{ n;R#,!<P  
try{ >zkRcm  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); oJKa"H-jL  
int nCount = input.readInt(); "m{
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nStartPos = new long[nCount]; 7VK}Dy/Vvn  
nEndPos = new long[nCount]; .oEmU+  
for(int i=0;i<nStartPos.length;i++) X0{/ydGF8  
{
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nStartPos = input.readLong(); :V)lbn\  
nEndPos = input.readLong(); B12$I:x`  
} C0=9K@FCb  
input.close(); Iqs+r?  
}
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catch(IOException e){e.printStackTrace ();} e&eW|E  
catch(Exception e){e.printStackTrace ();} ;M]C1!D9#  
} yGg,$WM  
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private void processErrorCode(int nErrorCode) CukC6ub  
{ sBv>E}*R  
System.err.println("Error Code : " + nErrorCode); Khh0*S8.K  
} m~Ld~I"  
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//停止文件下载 kF7(f|*  
public void siteStop() *`( <'Z  
{ T^Ab!O  
bStop = true; lCW8<g^  
for(int i=0;i<nStartPos.length;i++) ~}Z\:#U  
fileSplitterFetch.splitterStop(); ,(a5@H$f  
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} `ovtHl3Q  
} [nxE)D  
//负责部分文件的抓取 X &2oPo  
**FileSplitterFetch.java hP J4Oj1O  
*/ X\p,%hk \  
package NetFox; \b}~2oX  
MH|]\  
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import java.io.*; T+LJ*I4  
import java.net.*; 7z_;t9Y  
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public class FileSplitterFetch extends Thread { Es5  
OT %nrzP  
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String sURL; //File URL n(~\l#o@  
long nStartPos; //File Snippet Start Position L.6WiVP)  
long nEndPos; //File Snippet End Position 'H9=J*9oG  
int nThreadID; //Thread's ID Bs`$i ;&  
boolean bDownOver = false; //Downing is over ^4%Zvl  
boolean bStop = false; //Stop identical -ZW0k@5g  
FileAccessI fileAccessI = null; //File Access interface 9Pd*z>s  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException n{*e 9Aw  
{ (Lh#`L?x  
this.sURL = sURL; s!/TU{8J  
this.nStartPos = nStart; vUC!fIG  
this.nEndPos = nEnd; /R X1UQ.s  
nThreadID = id; df+t:a  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 P`U<7xF~  
} M8w5Ob  
}4co)B"  
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public void run() 4VN aq<8  
{ Z?i /r5F  
while(nStartPos < nEndPos && !bStop) }aB#z<B6  
{ `Lyq[zg8  
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try{ j:5%ppIY  
URL url = new URL(sURL); ')+0nPV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O?bK%P]ay  
httpConnection.setRequestProperty("User-Agent","NetFox"); m9M FwfZ  
String sProperty = "bytes="+nStartPos+"-"; 7#;vG>]  
httpConnection.setRequestProperty("RANGE",sProperty); X fz`^x>M  
Utility.log(sProperty); E04l|  
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InputStream input = httpConnection.getInputStream(); mxrG)n6Y  
//logResponseHead(httpConnection); v}Wmd4Y'  
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byte[] b = new byte[1024]; ^[TV;9I*  
int nRead; }:iBx  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) NTs;FX~g[  
{ nbofYI$rd&  
nStartPos += fileAccessI.write(b,0,nRead); t$^l<ppQ  
//if(nThreadID == 1) D)='8jV7  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0Flu\w/+P  
} x)5V.q  
j{#Wn !,  
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Utility.log("Thread " + nThreadID + " is over!"); =4C}{IL  
bDownOver = true; j'Y/ H5  
//nPos = fileAccessI.write (b,0,nRead); Ex@`O+  
} tP ~zKU  
catch(Exception e){e.printStackTrace ();} .M|>u_<Qd  
} zxD,E@lF  
} (g/7yO(s  
M%Ku5X6:/  
5''*UFIF1  
//打印回应的头信息 {}e^eJ  
public void logResponseHead(HttpURLConnection con) !7H6i#g*  
{ zLjgCS<7  
for(int i=1;;i++) <v]9lw'  
{ 4h 5_M8I  
String header=con.getHeaderFieldKey(i); \Z)1 ?fq  
if(header!=null) Uv?'m&_  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 8?TKN~ja  
Utility.log(header+" : "+con.getHeaderField(header)); U/MFhD(06  
else ateUpGM QU  
break; q/@dR{-  
}
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} Xer@A;c  
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V:K;] h*!  
public void splitterStop() hsce:TB  
{ u7]<=*V]  
bStop = true; ayp b  
} 5P^U_  
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} B5=3r1Ly  
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/* -R+zeu(e'  
**FileAccess.java ;'kI/(;;C  
*//文件访问(定位，写) T@+ClZi  
package NetFox; OS7RQw1  
import java.io.*; 10N,?a  
B< ;==|  
cFfTYP9  
public class FileAccessI implements Serializable{ Zy$Lrr!  
2PC5^Ni/9@  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \d68-JS@~  
RandomAccessFile oSavedFile; E1q%gi4Q%  
long nPos; 4!%]fg}Um  
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public FileAccessI() throws IOException w-
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{ ySX/=T:<;  
this("",0); XSD%
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} _'iDF  
HFh /$VM  
f'/ KMe%<  
public FileAccessI(String sName,long nPos) throws IOException b;vNq  
{ ]S/G\z  
oSavedFile = new RandomAccessFile(sName,"rw"); tW6#e(^l6  
this.nPos = nPos; u*R7zY  
oSavedFile.seek(nPos); ?iSGH'[u  
} r%MyR8'k]  
R$0U<(/  
t{(Mf2GR1  
public synchronized int write(byte[] b,int nStart,int nLen) 0<P(M:a  
{ !'c|N9  
int n = -1; uCUu!Vfeg  
try{ c8Pb  
oSavedFile.write(b,nStart,nLen); jPwef##~7  
n = nLen; Z.jCera.  
} 3ut_Bt\  
catch(IOException e) 7>je6*(K  
{ #tz8{o?ebN  
e.printStackTrace (); H`|0-`q  
} K+ehr  
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return n; $[e%&h@JR  
} N du7nKG  
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} m#ad6 \  
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/* wXCyj+XB*  
**SiteInfoBean.java {visv{R<  
*/ }u
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I  
package NetFox; ]7<m1Lg  
N{pa) /  
D0M!"c>\  
public class SiteInfoBean {  GVp  
hmzair3X  
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private String sSiteURL; //Site's URL sMJ#<w}Q  
private String sFilePath; //Saved File's Path g\J)= ,ju,  
private String sFileName; //Saved File's Name )+B=z}:Nfz  
private int nSplitter; //Count of Splited Downloading File GMb!Q0I8  
W:B}u\)C  
= o+7xom  
public SiteInfoBean() @^HwrwRA  
{//nSplitter的缺省值为5 RK
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//default value of nSplitter is 5 fk\5D[j^  
this("","","",5); _W+Q3Jx-(  
} $~o3}&az  

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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) N l|^o{#  
{ z|%Bh  
sSiteURL= sURL; t'Htx1#Zc[  
sFilePath = sPath; cUM_ncYOP  
sFileName = sName; jaa/k@OG  
this.nSplitter = nSpiltter; 8l?w=)Qy  
/C7svH  
Ns
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} G;9|%yvd8  
{.#j1
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public String getSSiteURL() Ps|QW  
{ Ei~]iZ}  
return sSiteURL; yUj;4vd  
} Ctj8tK
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)+k[uokj  
jDp]R_i  
public void setSSiteURL(String value) JchA=n  
{ AG=9b  
sSiteURL = value; 7(5]Ry:  
} yHtGp%j  
8tC+ lc  
5D-BIPn=JV  
public String getSFilePath() clC~2:  
{  3:"AFV  
return sFilePath; kFnUJM$r  
} %IPyCEJD  
3liq9P_  
k$?&]! <o  
public void setSFilePath(String value) !yk7HaP  
{ X`tOO  
sFilePath = value; sF
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} s|KfC>#  
D~7%};D[  
y#nSk%"t"  
public String getSFileName() w0\4Wa  
{ @u<0_r t  
return sFileName; l#|J rU!  
} 'H FwP\HX  
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public void setSFileName(String value) krwf8!bI  
{ )*+u\x_Hx  
sFileName = value; Jn60i6/  
} wo$|~ Hr  
(kdC1,E  
]&
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public int getNSplitter() CARq^xI-  
{ fg< (bXC  
return nSplitter; +-'`Q Ae  
} |zg=+  
*di&%&f  
.;cxhgU  
public void setNSplitter(int nCount) <&*#famX  
{ &boj$ k!g[  
nSplitter = nCount; i<0D Z_rub  
} =nw,*q +  
} YcEtgpz@  
}i
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8x`Kl(  
/* ,d3Q+9/  
**Utility.java t4C<#nfo  
*/ VoWA
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package NetFox; G!-7ic_4  
Hs.6;|0%  
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public class Utility { J,.j_ii`!  
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public Utility() 5XhK#X%:
A  
{ i#Ne'q;T  
ll 6]W~[ZC  
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} (X0`1s  
$(Z]TS$M&  
//线程睡眠 G*8+h  
public static void sleep(int nSecond) cA2^5'$$  
{ s0_-1VU  
try{ wE-Ji<1HJ  
Thread.sleep(nSecond); O-y6!u$6&  
} ?r^ hmu"a  
catch(Exception e) >Iu]T{QNO  
{ u4`mQ6  
e.printStackTrace (); +R3\cRM  
} 3(cU)  
} A%.J%[MVz  
Q:'qw#P/C  
//日志 'Wo?%n  
public static void log(String sMsg) ocb%&m;i  
{ !hwzKm=%N  
System.err.println(sMsg); ^aGZJiyJ  
} 3P%w-qT!N  

|G|*  
=$&7IQ?  
public static void log(int sMsg) /5L'9e  
{ V[BY/<z)A  
System.err.println(sMsg);  muK'h`  
} hr)+Pk  
} "#_)G7W+e  
jh<TdvF2$  
#i
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/* /k
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**TestMethod.java OpWC2t)  
*/ .
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package NetFox; chvrHvByS  
(=S"Kvb~#  
^KaqvG$ed  
public class TestMethod { z v L>(R  
12%z3/i  
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public TestMethod() ~`nm<
  
{ ///xx/weblogic60b2_win.exe =;'ope(?S  
try{ F[o+p|nF  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); &hSnB~hi  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 2)HxW
}o  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 1NE!=;VOl  
fileFetch.start(); q\\8b{~  
} tEpIyC  
catch(Exception e){e.printStackTrace ();} 1kz
9>;Ud6  
#;qFPj- v  
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} |o;j0  
glOqft&>`  
}mtC6G41Q  
public static void main(String[] args) Q
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{ wHBHkz  
new TestMethod(); CrRQPgl+u  
} 60U{ e}Mkb  
} !0!P.Q8>&  
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