http断点续传简单实现（java)

/* tO0MYEx"  
**SiteFileFetch.java Q8]lz}  
*/ ulY8$jB  
package NetFox; V1[Cc?o  
import java.io.*; u\LbPk  
import java.net.*; *G'R+_tdE  
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public class SiteFileFetch extends Thread { 2~yYwX  
R#D>m8&}3  
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SiteInfoBean siteInfoBean = null; //文件信息Bean {s]yP_  
long[] nStartPos; //开始位置 }/dGC;p"  
long[] nEndPos; //结束位置 r]GG9si  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]r]=Q"/5  
long nFileLength; //文件长度 2vb{PQ  
boolean bFirst = true; //是否第一次取文件 >_R,^iH"  
boolean bStop = false; //停止标志 cV=0)'&<`_  
File tmpFile; //文件下载的临时信息 (jR7D"I  
DataOutputStream output; //输出到文件的输出流 "])yV    
--t"X<.z  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） BU3VXnqT[  
public SiteFileFetch(SiteInfoBean bean) throws IOException $K_G|Wyi  
{ 3>Ne_kY  
siteInfoBean = bean; h'Gs$o7#P  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >!o||Yn  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); CN7 2 E  
if(tmpFile.exists ()) N*Is_V\R  
{ hFLD2<   
bFirst = false; 7iI6._"!w  
read_nPos(); jv8diQ.  
} <xb=.xe  
else !CJh6X!  
{ B,2oA]W"S  
nStartPos = new long[bean.getNSplitter()]; \FE  
nEndPos = new long[bean.getNSplitter()]; $mH'%YDIl  
} E5>y?N  
],!7S"{97  
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} vvWje:H  
x{
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public void run() OI@;ffHSW  
{ {x&"b-  
//获得文件长度 >gj%q$@
 
//分割文件 AeQIsrAHE  
//实例FileSplitterFetch Ptj,9bf<\  
//启动FileSplitterFetch线程 $w:7$:k  
//等待子线程返回 &:]ej6V'[  
try{ ;v}f7v '  
if(bFirst) |sG@Ku7~4  
{ #km
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nFileLength = getFileSize(); -#TF&-  
if(nFileLength == -1) =N,a
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{ e!eUgD  
System.err.println("File Length is not known!"); L%hVts'  
} n]K`ofjl^  
else if(nFileLength == -2) ~s$ jiA1  
{ !)!<.x  
System.err.println("File is not access!"); mVSaC  
} do-mkvk  
else KNI* :  
{ ;!k{{Xndd  
for(int i=0;i<nStartPos.length;i++) ?PpGBm2f*  
{ |i/Iv  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); tf:4}6P1  
} ".@}]z8  
for(int i=0;i<nEndPos.length-1;i++) |FR'?y1  
{ *8WcRx  
nEndPos = nStartPos[i+1]; "OdR"M(G\  
} ?;q  
nEndPos[nEndPos.length-1] = nFileLength; rM{3
]v{~  
} K6 {0`'x  
} W7sx/O9  
u'm[wjCjc  
#iZ%CY\  
//启动子线程 A_:YpQ07@  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8J5{}4s\f  
for(int i=0;i<nStartPos.length;i++) `1
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{ .lcI"%>  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~9tPT0^+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ljS~>&  
nStartPos,nEndPos,i); Y[\ZN  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \Y
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fileSplitterFetch.start(); xn=/SIS  
} dHAI4Yf4U  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <<ze84E  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); m4 :|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", I_h8)W  
nEndPos = " + nFileLength); cTq
}H_hC  
// fileSplitterFetch[nPos.length-1].start(); Zy<gA >  
s={jwI50  
V~9s+>  
//等待子线程结束 3ZAPcpB2  
//int count = 0; ^hMJNy&R  
//是否结束while循环 X}-)io  
boolean breakWhile = false; @$e!|.{1q  
szDd!(&pv  
L{2KK]IF  
while(!bStop) 3T<aGW1  
{ RV&=B%w+  
write_nPos(); $_u9Y!  
Utility.sleep(500); N'!:  
breakWhile = true; 9"#,X36  
+O2z&a;q  
j9bn|p$DA  
for(int i=0;i<nStartPos.length;i++) ,rC$~ &  
{ BS6UXAf{|Z  
if(!fileSplitterFetch.bDownOver) I Ceb2R  
{ R _c! ,y  
breakWhile = false; | M|5Nc>W  
break; AJ:(NV1=  
} 1pM"j!  
} RTEzcJ>  
if(breakWhile) NJe^5>4`  
break; G(;C~kHX  
nO{m2&r+  
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//count++; G!^}z(Mgi  
//if(count>4) ) vKZs:  
// siteStop(); Q;'{~!=  
} h"/y$  
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}kCaTI?
@#  
System.err.println("文件下载结束！"); :M |<c9I  
} qZcRK9l]F1  
catch(Exception e){e.printStackTrace ();} mfI>1W(  
} p1O[QQ|  
7a<-}>sU  
HqZ3]  
//获得文件长度 ?FRuuAS  
public long getFileSize() ;:Yz7<>Y,  
{ t& *K  
int nFileLength = -1; Y[8GoqE|  
try{ L
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URL url = new URL(siteInfoBean.getSSiteURL()); 9(CY"Tc3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T+0Z2H  
httpConnection.setRequestProperty("User-Agent","NetFox"); "E6*.EtTN#  
fBi6% #  
X<j(AAHE  
int responseCode=httpConnection.getResponseCode(); $U]KIHb  
if(responseCode>=400) P>i!f!o*I  
{ nKO4o8js{{  
processErrorCode(responseCode); D=0^"7K  
return -2; //-2 represent access is error -VO&#Mt5u  
} ?_VoO  
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^`MGlI}  
String sHeader; 3G;#QK-c  
-%g$~MZ?'  
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for(int i=1;;i++) }%@q; "9`  
{ 8}^R jMgI  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); d hp-XI
A;  
//Utility.log(in.readLine()); 9Sy|:J0  
sHeader=httpConnection.getHeaderFieldKey(i); h3<L,Olp  
if(sHeader!=null) -!C9x?gNY  
{ V*C%r:5 ,v  
if(sHeader.equals("Content-Length")) 5N_w(B  
{ zD9gE  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); $r'PYGn  
break; <uYeev%  
} kw gsf5[  
} 0?{Y6:d+  
else C=sEgtEI  
break; k,kr7'Q  
} &Oxf^x["]  
} &Se!AcvKF  
catch(IOException e){e.printStackTrace ();} +IM:jrT(  
catch(Exception e){e.printStackTrace ();} C;EC4n+s  
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Utility.log(nFileLength); s[}4Q|s%  
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return nFileLength; V?0Yzg$sy  
} ]nM 2J}7  
NY,ZTl_  
d`g)(*  
//保存下载信息（文件指针位置） B}&9+2M  
private void write_nPos() v"K #  
{ q5UD!&W  
try{ L (#DVF  
output = new DataOutputStream(new FileOutputStream(tmpFile)); A'
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output.writeInt(nStartPos.length); h,(f3Ik0O  
for(int i=0;i<nStartPos.length;i++) (z:DT
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{ YWXY4*G  
// output.writeLong(nPos); AB1.l hR  
output.writeLong(fileSplitterFetch.nStartPos); *\M$pUS{  
output.writeLong(fileSplitterFetch.nEndPos); 
\uUd *  
} Q
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output.close(); K4[XP]\jr  
} >B~vE2^tQ~  
catch(IOException e){e.printStackTrace ();} ?: XY3!{  
catch(Exception e){e.printStackTrace ();} A@o:mZ+XN(  
} @7fx0I'n  
f-BEfC,}'  
UgBD|~zu  
//读取保存的下载信息（文件指针位置） \H-,^[G3  
private void read_nPos() q"uP%TN  
{ RY4b<i3  
try{ 6bacU#0o  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); g:yUZ;U
 
int nCount = input.readInt(); 5x}XiMM  
nStartPos = new long[nCount]; ))<1"7D^^  
nEndPos = new long[nCount]; E;>BcP
t5  
for(int i=0;i<nStartPos.length;i++) O9_S"\8]@  
{ 7F;dLd'  
nStartPos = input.readLong(); ~*-%tFSv  
nEndPos = input.readLong(); ' thEZ  
} "8%z,lHw  
input.close(); @8;0p  
} -UMPt"o  
catch(IOException e){e.printStackTrace ();} n_qDg  
catch(Exception e){e.printStackTrace ();} d${RZ}/  
} uh8+Y%V p  
|vI1C5e  
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private void processErrorCode(int nErrorCode) KBO{g:"  
{ =ll{M{0Q]!  
System.err.println("Error Code : " + nErrorCode); rRK^vfoJ`  
} +,H6)'#Z  
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wBbJ \  
//停止文件下载 rF*L@HI  
public void siteStop() D|lm,  
{ |rhCQ"H  
bStop = true; )=:gO`"D  
for(int i=0;i<nStartPos.length;i++) 8!!iwmH{  
fileSplitterFetch.splitterStop(); TSp;VrOP  
]\8
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} j0]|$p  
} `O'@T
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//负责部分文件的抓取 `n{yls7.  
**FileSplitterFetch.java [tP6FdS/M=  
*/ \`MX\OR  
package NetFox; f5droys9  
Og8'K=O#  
|fd}B5!c  
import java.io.*; 2^TJ_xG~  
import java.net.*; =64%eF  
0nDlqy6b1b  
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public class FileSplitterFetch extends Thread { Bp.z6x4  
:AzP3~BI  
F:P&hK  
String sURL; //File URL ndY1j5  
long nStartPos; //File Snippet Start Position ' >
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long nEndPos; //File Snippet End Position 82q_"y>6  
int nThreadID; //Thread's ID F[65)"^  
boolean bDownOver = false; //Downing is over }$zJdf,\  
boolean bStop = false; //Stop identical [HV9KAoA  
FileAccessI fileAccessI = null; //File Access interface a BHV  
j+E[[  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException pH'1be{K  
{ -H;%1y$A-  
this.sURL = sURL; !FhiTh:GCh  
this.nStartPos = nStart; G|"`kAa  
this.nEndPos = nEnd; 'B$bGQ  
nThreadID = id; vcsMU|GGh  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 @6~OQN  
} 8r 4 L4  
%L^S;v3  
/JOEnQ5X\!  
public void run() @Qa)@'u  
{ unUCn5hJ=  
while(nStartPos < nEndPos && !bStop) 2qY+-yOEt  
{ \qU.?V[2  
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try{ Ju~8C\Dd  
URL url = new URL(sURL); 9m:qQ1[\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3}}#'5D  
httpConnection.setRequestProperty("User-Agent","NetFox"); F%v?,`_&I  
String sProperty = "bytes="+nStartPos+"-"; OFtAT@=O  
httpConnection.setRequestProperty("RANGE",sProperty); 'za4c4b*u  
Utility.log(sProperty); :<`hsKy&  
sT^^#$ub  
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InputStream input = httpConnection.getInputStream(); nvyyV\w  
//logResponseHead(httpConnection); #$qhxYy
d  
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byte[] b = new byte[1024]; fR4O^6c:  
int nRead; <^Hh5kfS'  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >#MGGCGL  
{ -/s2'  
nStartPos += fileAccessI.write(b,0,nRead); L'>t:^QTh  
//if(nThreadID == 1) p4|Zz:f  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |c]Y1WwDx  
} /y\KLa  
F
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Utility.log("Thread " + nThreadID + " is over!"); mxpncM=q  
bDownOver = true; ZA
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//nPos = fileAccessI.write (b,0,nRead); f"0{e9O]2  
} o~I
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catch(Exception e){e.printStackTrace ();}
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} #hBDOXHPf  
} qP"<vZ  
*+E9@r=HF  
D\:~G}M  
//打印回应的头信息 CPI7&jqu  
public void logResponseHead(HttpURLConnection con) hE-u9i  
{ N o}Ly{  
for(int i=1;;i++) @nJ#kd[  
{ e3L<;MAt  
String header=con.getHeaderFieldKey(i); _~M*XJ] `  
if(header!=null) olC@nQ1c*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >D';i\2j&  
Utility.log(header+" : "+con.getHeaderField(header)); jocu=Se@  
else wHQyMq^  
break; |7jUf$Q\p  
} l6X\.oI  
} !5~{?sr>  
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public void splitterStop() o <lS90J  
{ k++Os'hSEY  
bStop = true; (wNL,<%~  
} N[~"X**x  
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} m|O7@N  
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/* a9ab>2G?FR  
**FileAccess.java i%+p\eeq*  
*//文件访问(定位，写) y@|gG&f T  
package NetFox; NhxTSyT"t  
import java.io.*; -P09
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=NH p%|  
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public class FileAccessI implements Serializable{ Ksq{=q-T  
dpO ZqhRs.  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 io]e]m%  
RandomAccessFile oSavedFile; -vXX u;frt  
long nPos; F3\'WQh  
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*8zn\No<,  
public FileAccessI() throws IOException 7W[}7Y  
{ oEE*H2l\  
this("",0); ^/wvHu[#  
} 1{oq8LB  
p;dH[NW  
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public FileAccessI(String sName,long nPos) throws IOException TR8
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{ @<ba+z>"~4  
oSavedFile = new RandomAccessFile(sName,"rw"); @)>9l&  
this.nPos = nPos; m<>3GF,5bP  
oSavedFile.seek(nPos); 2$^n@<uZ@  
} s%nx8"  
).TQYrs  
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public synchronized int write(byte[] b,int nStart,int nLen) 7m6@]S6  
{ 'AX/?Srd  
int n = -1; -hf)%o$  
try{ !"2nL%PW~  
oSavedFile.write(b,nStart,nLen); #h@/~xr  
n = nLen; R 2uo ZA,  
} !3{> F"  
catch(IOException e) C>q,c3s5  
{ V:rq}F}  
e.printStackTrace (); **V^8'W<  
} ">}l8MA  
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return n; dnVl;L8L3  
} @,D 3$P8}  
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} EKsL0;FV  
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/* 66x>*  
**SiteInfoBean.java +A 6xY  
*/ =PiDZS^"  
package NetFox; >-YP

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public class SiteInfoBean { q;a`*gX^  
"8wRxDr+  
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private String sSiteURL; //Site's URL D!kv+<+  
private String sFilePath; //Saved File's Path 8BC F.y  
private String sFileName; //Saved File's Name T8
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private int nSplitter; //Count of Splited Downloading File q1sK:)Hu+  
.%7#o
 
. KJEA#  
public SiteInfoBean() r3oAP[+n  
{//nSplitter的缺省值为5 Qi',[Xmf  
//default value of nSplitter is 5 9"g=it2Rh6  
this("","","",5); ,vEwck#  
} &B\tcF  
F gM<2$h  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) wkK61ah6  
{ /238pg~Cw5  
sSiteURL= sURL; RKsr}-18  
sFilePath = sPath; $:kG>R@\t  
sFileName = sName; \TSt  
this.nSplitter = nSpiltter; eOa:%{Kj  
:B?X
No  
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} ;/#E!Ja/u  
nj99!"_  
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public String getSSiteURL() kVk^?F  
{ 5K13   
return sSiteURL; 8Czy<}S<G  
} gNJ,Bj Pd  
jA R@?X  
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public void setSSiteURL(String value) DQM\Y{y|3  
{ d:C-   
sSiteURL = value; <:)T7yVq  
} S8mqz.  
/Fej)WQp  
w}VS mt$F  
public String getSFilePath() R4G$!6Ld  
{ 'NF_!D  
return sFilePath; Z,/BPK
<e  
} EotZ$O=  
(#FWA<o  
n.]K"$230  
public void setSFilePath(String value) 2'_xg~  
{ 57e'a&}e  
sFilePath = value; uj|{TV>v9  
} !={Z]J  
WJBi#(SY  
BX&bhWYGFX  
public String getSFileName() rD)yEuYX  
{ xg %EQ  
return sFileName; ;u!qu$O  
} ;:Q 5?zM  
PLR[nB7K  
E+Z//)1Z  
public void setSFileName(String value) v# ab2  
{ i8pM,Ppi~  
sFileName = value; O1IR+"0  
} =M^4T?{T  
BuMBnbT  
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public int getNSplitter() zK
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{ R'f|1mt  
return nSplitter; |>a sGP  
} $wUFHEl  
(yWU9q)5  
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public void setNSplitter(int nCount) b[,J-/;JNL  
{ y&Sl#IQ L  
nSplitter = nCount; mDz{8N9<FG  
} mw%do&e  
} e`ti*1]q  
4]O{Nko)  
f
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/* P.
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**Utility.java -o*IJQ_  
*/ T8E=}!68w}  
package NetFox; uTGd{w@]0|  
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public class Utility { wjW>#DE  
so}(*E&(a  
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public Utility() tr0P;}=  
{ {vh}f+2  
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} ?{l}35Q.@  
 {h/[!I`  
//线程睡眠 ?.E6Ube  
public static void sleep(int nSecond) ^6s<  
{ (&R/ns~  
try{ HbQ `b  
Thread.sleep(nSecond); 'PRsZ`x.  
} R=P=?U.  
catch(Exception e) Y`jvza%  
{ $j*%}x~[  
e.printStackTrace (); %Cbqi.iuQ  
} OW1i{  
} I\E`xkbBu  
!Kr|04Qp#x  
//日志 <6g{vNA  
public static void log(String sMsg) NNSHA'F,.\  
{ U 2am1}  
System.err.println(sMsg); @qk$ 6X  
} <?'d\B  
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%LeG.~?  
public static void log(int sMsg) Yy`\??,  
{ gV@FT|j!i  
System.err.println(sMsg); - &u]B$  
} Jm&7&si7  
} GJN"43  
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/* KdIX`  
**TestMethod.java %PozxF:  
*/ N>##}i  
package NetFox; 9}^nozR,I  
y}5V3)P  
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public class TestMethod { eMyh&@7(F  
.lnyn|MVb  
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public TestMethod() sy`@q<h(  
{ ///xx/weblogic60b2_win.exe
$sK8l=#  
try{ 5
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); HwTb753  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); P{j2'gg3  
SiteFileFetch fileFetch = new SiteFileFetch(bean); g&eIfm  
fileFetch.start(); i]&C=X  
} `|?K4<5
|  
catch(Exception e){e.printStackTrace ();} )
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3)\jUVuj  
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} dbM~41C6  
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\6o%gpUkD  
public static void main(String[] args) =@(&xfTC  
{ kt?G\H!}  
new TestMethod(); V45A>#?U  
} ;NNYJqWd^]  
} FOJ-?s(  
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