http断点续传简单实现（java)

/* 6N~q`;p0  
**SiteFileFetch.java 5Bjgr  
*/ S6xgiem  
package NetFox; 7 oQ[FdRn*  
import java.io.*; mi,&0xDea  
import java.net.*; 9\JQ7$B  
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public class SiteFileFetch extends Thread { d2N:^vvvR  
}TB(7bbd;  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 2;2}wM[  
long[] nStartPos; //开始位置 -e*ZCwQ  
long[] nEndPos; //结束位置 :E&g%'1  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 YXW%]Uy+  
long nFileLength; //文件长度 F$V/K&&W  
boolean bFirst = true; //是否第一次取文件 Y?d9l  
boolean bStop = false; //停止标志 hK|j6xf.o  
File tmpFile; //文件下载的临时信息 #%lo;W~IY  
DataOutputStream output; //输出到文件的输出流 YA:nOvd@O  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） BU|#e5  
public SiteFileFetch(SiteInfoBean bean) throws IOException HKDID[d0  
{ !RW `3  
siteInfoBean = bean; @? c2)0
 
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *L4`$@l8  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); )h{ ]k=  
if(tmpFile.exists ()) QDx$==Fo  
{ )e|=mtp  
bFirst = false; Q~{H@D`<  
read_nPos(); =u[k1s?  
} Wb}c=hZv  
else yQNV@T<o  
{ &;&ho+qD  
nStartPos = new long[bean.getNSplitter()]; n>>Qn&ym  
nEndPos = new long[bean.getNSplitter()]; k,yZ[n|`  
} 5=|hC3h  
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} yQ,{p@#X8  
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public void run() ?a(L.3E  
{ s$D ^>0  
//获得文件长度 EJ@p-}I!  
//分割文件 u&mS8i}  
//实例FileSplitterFetch @a:>
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//启动FileSplitterFetch线程 wMqX)}>  
//等待子线程返回 ?i
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try{ eqw0]U\pv  
if(bFirst) a`[uNgDO  
{ a2'^8;U*_  
nFileLength = getFileSize(); VXLT^iX  
if(nFileLength == -1) d?`ny#,GB  
{ aE;le{|!({  
System.err.println("File Length is not known!"); scLn=  
} fC
,:{}  
else if(nFileLength == -2) ojvj}ln  
{ '(bgs  
System.err.println("File is not access!"); ?T9(Vw  
} .sC?7O=  
else (8.Z..PH  
{ }J">}j]/  
for(int i=0;i<nStartPos.length;i++) TJ q~)Bm  
{ m< _S_c  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3 @ak<9&  
} (bsXo q  
for(int i=0;i<nEndPos.length-1;i++) %LVm3e9  
{ [W%$qZlP  
nEndPos = nStartPos[i+1]; )E@A0W  
} @=}YTtq  
nEndPos[nEndPos.length-1] = nFileLength; r\qj!  
} X/iT)R]b  
} EQ'V{PIfj  
?7<JQh)"e  
Zjbc3M5  
//启动子线程 3)\8%Ox  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; MrZh09y  
for(int i=0;i<nStartPos.length;i++) *%{gYpn  
{ P"B0_EuR<T  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ):i&`}SY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), CC#;c1t  
nStartPos,nEndPos,i); d ,4]VE  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &?mD$Eo  
fileSplitterFetch.start(); Tyvtmx M  
} ?c[*:N(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o.0ci+z@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); WI?oSE w  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", u%w`:v7Yo(  
nEndPos = " + nFileLength); {&jb5-*f  
// fileSplitterFetch[nPos.length-1].start(); ne4Q#P  
M$Zcn#A  
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//等待子线程结束 T:5fc2Ngv  
//int count = 0; Z.92y  
//是否结束while循环 UrqRx?#  
boolean breakWhile = false; +=O5YR!{  
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while(!bStop) T6 '`l?H`;  
{ bbrXgQ`s+w  
write_nPos(); c-B cA  
Utility.sleep(500); 9FB19  
breakWhile = true; =EHUR'  
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for(int i=0;i<nStartPos.length;i++) D#3\y*-y?  
{ rg^'S1x|  
if(!fileSplitterFetch.bDownOver)  -i0~]*  
{ :A/d to  
breakWhile = false; 5H*\t 7  
break; TWA-.>c  
} Z'"tB/=W  
} ILGMMA_2  
if(breakWhile) a(l29>  
break; _d5QbTe  
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9I}-[|`u  
//count++; Wf|Q$MHos  
//if(count>4) gIjh:_ Pz  
// siteStop(); 7@D@ucL  
} #"@|f  
*MKO I'  
OCNQvF~  
System.err.println("文件下载结束！"); L7dd(^  
} o,_?^'@  
catch(Exception e){e.printStackTrace ();} < jJ  
} OX\A|$GS  
hDF@'G8F  
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//获得文件长度 wB.&}p9p  
public long getFileSize() C{U?0!^  
{ k?+?v?I =  
int nFileLength = -1; .yz}ROmN^  
try{ E=nIRG|g  
URL url = new URL(siteInfoBean.getSSiteURL()); vSEuk}pk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &L=suDe  
httpConnection.setRequestProperty("User-Agent","NetFox"); As'=tIro  
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int responseCode=httpConnection.getResponseCode(); \W~N  
if(responseCode>=400) =vX/{C  
{ gEy?s8_,  
processErrorCode(responseCode); [CQ+p!QZ  
return -2; //-2 represent access is error h2G$@8t}I  
} Q+[n91ey**  
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String sHeader; 8Vr%n2M  
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for(int i=1;;i++) fdFo#P  
{ `sn^ysp  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 4h|c<-`>t  
//Utility.log(in.readLine()); k>;`FFQU>  
sHeader=httpConnection.getHeaderFieldKey(i); HiZ*+T.B  
if(sHeader!=null) R!}H;[c  
{ 6^]+[q}3  
if(sHeader.equals("Content-Length")) IG2r#N|C#  
{ os=e|vkB*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); u_oaebOrpP  
break; k\5c|Wq|g  
} ~%&LTX0s|  
} 9jM}~XvV  
else H\ F:95  
break; Lt64JH^lz  
} (A9Fhun  
} 0X6YdW_2X  
catch(IOException e){e.printStackTrace ();} +^60T$  
catch(Exception e){e.printStackTrace ();} TM%|'^)  
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Utility.log(nFileLength); 9X}10u:  
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return nFileLength; D4eDHq  
} Q /U2^  
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gb[5&>(#  
//保存下载信息（文件指针位置） M?1Y,5  
private void write_nPos() =^M/{51j  
{ J,'M4O\S  
try{ 'j#*6x
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output = new DataOutputStream(new FileOutputStream(tmpFile)); C0T;![/4A  
output.writeInt(nStartPos.length); (KjoSN( K  
for(int i=0;i<nStartPos.length;i++) igCZ|Ru\  
{ W=N+V
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// output.writeLong(nPos); 5-:?&|JK;  
output.writeLong(fileSplitterFetch.nStartPos); rBQ_iB_  
output.writeLong(fileSplitterFetch.nEndPos); 3dg1DR;  
} G#ZH.24Y  
output.close(); \V;F/Zy(  
} jys:5P  
catch(IOException e){e.printStackTrace ();} 8{^kQ/]'|  
catch(Exception e){e.printStackTrace ();}  dm\F  
} $*^7iT4q_t  
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//读取保存的下载信息（文件指针位置） BX`{73sw  
private void read_nPos() 03$mYS_?  
{ R`NYEptJ  
try{ t%d Z-Ym  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0yk]o5a++  
int nCount = input.readInt(); rD*jp6Cl  
nStartPos = new long[nCount]; cN/6SGHK  
nEndPos = new long[nCount]; W=~~5jFX  
for(int i=0;i<nStartPos.length;i++) ;AG8C#_  
{ .]8ZwAs=&  
nStartPos = input.readLong(); l{*@v=b(  
nEndPos = input.readLong(); c[0}AGJ  
} wON!MhA;  
input.close(); /C
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} uy>q7C  
catch(IOException e){e.printStackTrace ();} p*XANGA  
catch(Exception e){e.printStackTrace ();} T$8)u'-pa  
} (~
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; 5*&xz  
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private void processErrorCode(int nErrorCode) j\eI0b @*  
{ ">\?&0  
System.err.println("Error Code : " + nErrorCode); 'g}
!  
} <$D`Z-6  
sA+ }TNhq  
/:cd\A}  
//停止文件下载 g@d*\ P)  
public void siteStop() ]%;:7?5l  
{ 9)l$ aBa  
bStop = true; #|uCgdi  
for(int i=0;i<nStartPos.length;i++) )HEa<P^kJl  
fileSplitterFetch.splitterStop(); [:7'?$  
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} )*u8/U  
} `}p0VmD{NE  
//负责部分文件的抓取 7y.kQI?3  
**FileSplitterFetch.java /T"+KU*
 
*/ `aOFs+<)  
package NetFox; * `JYC  
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import java.io.*; &)Q
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import java.net.*; Na<pwC  
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public class FileSplitterFetch extends Thread { GV1pn) 4  
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String sURL; //File URL  {y)=eX9  
long nStartPos; //File Snippet Start Position 5tl< 3g`  
long nEndPos; //File Snippet End Position -M\<nx  
int nThreadID; //Thread's ID 4j-Xi  
boolean bDownOver = false; //Downing is over x[cL Bc<  
boolean bStop = false; //Stop identical n'"/KS+_  
FileAccessI fileAccessI = null; //File Access interface zrvF]|1UP  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException rjK%t|aV^  
{ hqD*z6aH  
this.sURL = sURL; irZ]
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this.nStartPos = nStart; 49eD1h3'X[  
this.nEndPos = nEnd; |44Ploz2b  
nThreadID = id; M$wC=b  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 R7%#U`Q^A  
} 91/Q
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public void run() C2!|OQ9A2  
{ n3WlZ!$  
while(nStartPos < nEndPos && !bStop) aHD]k8m z  
{ pd?Mf=>#  
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try{ &s(^@Oa
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URL url = new URL(sURL); P1!qbFDv8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )705V|v  
httpConnection.setRequestProperty("User-Agent","NetFox"); Zj(AJ*r  
String sProperty = "bytes="+nStartPos+"-"; X;$+,&M"  
httpConnection.setRequestProperty("RANGE",sProperty); _YRFet[,m  
Utility.log(sProperty); z'Hw  
;[ZEDF5H  
j;zM{qu_  
InputStream input = httpConnection.getInputStream(); /l3V3B7  
//logResponseHead(httpConnection); 7^avpf)>  
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byte[] b = new byte[1024]; dRYqr}!%n  
int nRead; Zpt\p7WQ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *VCXihgo  
{ $t+,Tav  
nStartPos += fileAccessI.write(b,0,nRead); Dm981t>wL  
//if(nThreadID == 1) 10Q ]67  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !aUs>1i  
} l]5KN  
@FAA2d  
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Utility.log("Thread " + nThreadID + " is over!"); -OV&Md:~  
bDownOver = true; gb1V~  
//nPos = fileAccessI.write (b,0,nRead); L;z?aZ7n  
} rSY!vkLE\  
catch(Exception e){e.printStackTrace ();} 9 ql~q  
} RHW]Z Pr<  
} AI2)g1m  
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//打印回应的头信息 h4gXvPS&r  
public void logResponseHead(HttpURLConnection con) h
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{ =IZT(8  
for(int i=1;;i++) '@v\{ l  
{ SO/c}vnBB  
String header=con.getHeaderFieldKey(i); AYBns]!  
if(header!=null) #^0R&) T
 
//responseHeaders.put(header,httpConnection.getHeaderField(header)); VD*6g%p  
Utility.log(header+" : "+con.getHeaderField(header)); x8 2cT21b  
else h'llK6_)  
break; 9cbd~mM{  
} h,:m~0gmj  
} ]h`&&Bqt  
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public void splitterStop() P}}* Q7P  
{ l:~/<`o  
bStop = true; J3V= 46Yc  
} fUWG*o9  
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} dl
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/* Qp5VP@t  
**FileAccess.java ;+R&}[9,A)  
*//文件访问(定位，写) ma]F7dZ5  
package NetFox; ZDJ`qJ8V  
import java.io.*; ,Fl)^Gl8?  
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public class FileAccessI implements Serializable{ 1ba~SHi  
5DU6rks%
 
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 QO:!p5^:  
RandomAccessFile oSavedFile; lN)C2
2  
long nPos; ) w5SUb  
g}oi!f$|  
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public FileAccessI() throws IOException /U*C\ xMm  
{ J1U/.`Oy  
this("",0); !?jrf] A@  
} M] %?>G  
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public FileAccessI(String sName,long nPos) throws IOException \.{$11P#  
{ _Ay9p[l  
oSavedFile = new RandomAccessFile(sName,"rw"); |3b^~?S  
this.nPos = nPos; r|8d 4  
oSavedFile.seek(nPos); k .;j  
} xIW3={b3  
i^&~?2  
Vm(y7}Aq{  
public synchronized int write(byte[] b,int nStart,int nLen) Ml{,  
{ O:R*rJ  
int n = -1; ,8uqdk-D  
try{ s\(k<Ks  
oSavedFile.write(b,nStart,nLen); |^I0dR/w:  
n = nLen; gs[uD5oo<  
} 2jItq2.>  
catch(IOException e) 7F7{)L  
{ J4C.+![!Ah  
e.printStackTrace (); W(Fv l  
} ^)S;xb9  
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return n; O63<AY@  
}
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} ua$GNm  
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/* {4}yKjW%z  
**SiteInfoBean.java pj{`'; :g  
*/ XEp{VC@=  
package NetFox; [!uG1GJ>  
U$.@]F4&  
oulVg];  
public class SiteInfoBean { gCS<iBT(7  
DJ k/{Z:  
P )"m0Lu<  
private String sSiteURL; //Site's URL 2;`1h[,-^  
private String sFilePath; //Saved File's Path #Y`~(K47  
private String sFileName; //Saved File's Name ? (Oy\  
private int nSplitter; //Count of Splited Downloading File %N6A+5H  
2#]#sZmk  
~$cV:O7  
public SiteInfoBean() Lx1FpHo  
{//nSplitter的缺省值为5 ,kGc]{'W  
//default value of nSplitter is 5 `2WFk8) F  
this("","","",5); "Yv_B3p   
} .V/Rfq  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) a2O75 kWnm  
{ zT.7  
sSiteURL= sURL; LgU_LcoM*  
sFilePath = sPath; 6 7.+ .2  
sFileName = sName; (zYtNLoFx  
this.nSplitter = nSpiltter; {X+3;&@  
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%P/Jq#FE.  
} S(lO(gY  
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public String getSSiteURL() +F` S>U  
{ 'Cfl*iNb  
return sSiteURL; . B9iLI  
} Oh`69 k  
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public void setSSiteURL(String value) gQg"j)  
{ py!|\00}  
sSiteURL = value; t;Sb/3  
} NjScc%@y  
e7Z32P0ls  
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public String getSFilePath() [< ?s?Ci
 
{ _$YkM,  
return sFilePath; }Yzco52  
} I\{ 1u  
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public void setSFilePath(String value) /QWvW=F2<  
{ ay ;S4c/_  
sFilePath = value; u@UMP@"#  
} =,=A,kI[;  
/GN<\_o=q  

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public String getSFileName() _x'6]f{n  
{ ,X-bJA@(  
return sFileName; F=e8IUr  
} \BTODZ:h  
zuad~%D<I  
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public void setSFileName(String value) XbKYiy  
{ 3>AMII  
sFileName = value; /{aj}M0kN  
} `l ^9/_g'6  
L-WT]&n_  
)._;~z!  
public int getNSplitter() z6=Z\P+  
{ Oi'5ytsES  
return nSplitter; _[c0)2h  
} Nho>f  
L^2%1GfE{  
#ym'AN  
public void setNSplitter(int nCount) >V?eog%~  
{ -`kW&I0  
nSplitter = nCount; iDp)FQ$  
} D9
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} +T1pJ 89P  
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/* x.!V^HQSN  
**Utility.java ZF9z~9  
*/ v\gLWq'  
package NetFox; Bi3<7  
rNWw?_H-H(  
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public class Utility { |`2RShu  
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public Utility() kWMl  
{ p Z|V 3  
x_N'TjS^{  
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} .\ULbN3Z  
2ozax)GY  
//线程睡眠 XFHYQ2ME2  
public static void sleep(int nSecond) yiXSYD  
{ fP 1[[3i  
try{ }(J}f)  
Thread.sleep(nSecond); ;;OAQ`  
} eC
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catch(Exception e) "Y =;.:qe  
{ .PIL +x*]N  
e.printStackTrace (); BDW^7[n  
} X8a/ `Y,  
} s^G.]%iU  
A@!qv#'  
//日志 45@ I*`  
public static void log(String sMsg) SuJ aL-;  
{ u^+7hkk  
System.err.println(sMsg); VGy<")8D/  
} {0Yf]FQb-a  
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public static void log(int sMsg) m<
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{ PB\(=
 
System.err.println(sMsg); B[Ku\A6&  
} )1J R#  
} n`B:;2X,
 
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/* FF`T\&u  
**TestMethod.java by1<[$8r  
*/ Olt?~}  
package NetFox; #?U}&Bd  
,*TmIPNK  
wY{-BuXv  
public class TestMethod { .=7vI$ujd  
Mlg0WrJ|2  
L2[($l  
public TestMethod() hc(#{]].  
{ ///xx/weblogic60b2_win.exe KEo,m  
try{ T"}5}6rSG  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); g#pr yYz  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); W dK #ZOR  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?DS@e@lx  
fileFetch.start();
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} T?CdZc.
 
catch(Exception e){e.printStackTrace ();} F`9xVnK=  
x*\Y)9Vgy  
{=9,n\85#  
} zOAd~E  
%8B}Cb&2c  
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public static void main(String[] args) kYP#SH/  
{ CAig]=2'  
new TestMethod(); Wq D4YGN  
} 2G& a{  
} 9rA0lqr]5  
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