http断点续传简单实现（java)

/* ZRK1UpP
 
**SiteFileFetch.java H.n+CR  
*/ O%$XgEJ8p  
package NetFox; {<p-/|Z52  
import java.io.*; SWrt4G  
import java.net.*; 7AOjlC9R}  
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public class SiteFileFetch extends Thread { o#X=1us  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Z7Y+rP[l  
long[] nStartPos; //开始位置 U#7moS'r  
long[] nEndPos; //结束位置 hDP&~Mk  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 M_ GN3  
long nFileLength; //文件长度 Buv4&.Z}  
boolean bFirst = true; //是否第一次取文件 ZjOUk;H
?  
boolean bStop = false; //停止标志 `;:zZ8*  
File tmpFile; //文件下载的临时信息 B?-~f^*,jG  
DataOutputStream output; //输出到文件的输出流 a2z1/Nh  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ",pN.<F9O  
public SiteFileFetch(SiteInfoBean bean) throws IOException +FYQ7UE  
{ ^T{ww=/v  
siteInfoBean = bean; =LUDg7P  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); U,Duq^l~s  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -t5DcEAb$  
if(tmpFile.exists ()) Mzbbr57n  
{ B <CK~ybY  
bFirst = false; WX2w7O'R  
read_nPos(); J[?7`6\M  
} ](z?zDk  
else bSKe@4C  
{ ]xYm@%>6  
nStartPos = new long[bean.getNSplitter()]; X-Q;4M-CJ  
nEndPos = new long[bean.getNSplitter()]; /.[;u1z"^  
} 1Ar6hA  
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} fG^#G/n2  
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public void run() }+" N '  
{ ?11\@d  
//获得文件长度 gOE3x^X*{  
//分割文件 CQ(;L{}  
//实例FileSplitterFetch xIrRFK9[Q  
//启动FileSplitterFetch线程 8%Wg;:DZx  
//等待子线程返回 ;`TSu5/  
try{ ,J(+%#$UT  
if(bFirst) cl4Vi%  
{ VgoN=S  
nFileLength = getFileSize(); TsX(=N_  
if(nFileLength == -1) o C5}[cYD`  
{ R>3a?.X  
System.err.println("File Length is not known!"); "]"!"#aMv  
} !GNLq.rQ  
else if(nFileLength == -2) neHozmm|  
{ ub#>kCL9  
System.err.println("File is not access!"); il)LkZ@  
} .\W6XRw  
else `!K!+`Z9  
{ #4iiY6  
for(int i=0;i<nStartPos.length;i++) #]BpTpRAe<  
{ c T[.T#I  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); yD0,q%B`}  
} 8" x+^  
for(int i=0;i<nEndPos.length-1;i++) HifU65"8  
{ =36e&z-#  
nEndPos = nStartPos[i+1]; upJ|`,G{  
} :N3'$M"  
nEndPos[nEndPos.length-1] = nFileLength; /!u#S9_B  
} Q]?Lg  
} vbZGs7%  
5_d=~whO&2  
F$;vPAxbK"  
//启动子线程 uMB|x,X I  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; T.=du$  
for(int i=0;i<nStartPos.length;i++) 8olR#>  
{ }iK_7g`yKa  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), pxF<L\L?:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), E8:4Z$|c  
nStartPos,nEndPos,i); *@C4~Zo  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); N1O& fMz  
fileSplitterFetch.start(); s`bC?wr5h  
} A(xCW+h@)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (4U59<ie  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Ix"hl0Kh  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Rj/9\F3H  
nEndPos = " + nFileLength); T}?vp~./   
// fileSplitterFetch[nPos.length-1].start(); V?k"BU  
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//等待子线程结束 l<](8oc. w  
//int count = 0; WF6'mg^^?  
//是否结束while循环 I& `>6=)  
boolean breakWhile = false; V!'N:je  
xTnd9'Pk`:  
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while(!bStop) j'?^<4i  
{ NjTVinz  
write_nPos(); .CrrjS w  
Utility.sleep(500); %Jrdr`<  
breakWhile = true; yrDWIU(8;6  
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for(int i=0;i<nStartPos.length;i++) {
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{ [n`SXBi+n  
if(!fileSplitterFetch.bDownOver) S;o U'KOY  
{ E0nR Vg  
breakWhile = false; gc'C"(TO(  
break; 4{'0-7}  
} 3^LSK7.:  
} AUloP?24  
if(breakWhile) '~-Lxvf'  
break; imx/hz!  
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//count++; ZCQ7xQD  
//if(count>4) qAH@)}  
// siteStop(); 4>4*4!KR}  
} ~P*t_cpZ  
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System.err.println("文件下载结束！"); B|IQ/g?  
} i
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catch(Exception e){e.printStackTrace ();} O&#bC  
} <v?9:}  
>4:W:;R  
_tR%7%3*  
//获得文件长度 U.oxLbJ`  
public long getFileSize() (~oUd4  
{ ]fXMp*LvY  
int nFileLength = -1; rK*s/mX <  
try{ +#5nk,1c>  
URL url = new URL(siteInfoBean.getSSiteURL()); j+3~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]JX0:'x^  
httpConnection.setRequestProperty("User-Agent","NetFox"); s,TKC67.%+  
5/Ng!bW  
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int responseCode=httpConnection.getResponseCode(); ]McLace&  
if(responseCode>=400) ]1 #&J(  
{ gmfux b/  
processErrorCode(responseCode); \s2hep  
return -2; //-2 represent access is error -ob_]CKtJ~  
} i0uBb%GMT  
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TB] %?L:  
String sHeader; lrjlkgSN  
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 Z*d8b  
for(int i=1;;i++) #&.&Uu$  
{ d:0
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); AElx #`T  
//Utility.log(in.readLine()); [L1pDICoy  
sHeader=httpConnection.getHeaderFieldKey(i); >n@?F[Y  
if(sHeader!=null) oK h#th  
{ lgZ3=h  
if(sHeader.equals("Content-Length")) yhe$A<Rl=  
{ m?-3j65z  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ze Qgg|;  
break; 3Ak,M-Jp  
} L0SeG:  
} U">D_ 8  
else (US]e un  
break; "U34D1I)#  
} 9+.0ZP?  
} "GP!]3t  
catch(IOException e){e.printStackTrace ();} GZ\;M6{oh  
catch(Exception e){e.printStackTrace ();} R2Fh WiL  
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Utility.log(nFileLength); 22|eiW/a  
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return nFileLength; h&J6  
} n6;jIf|  
i TY4X:x  
SF61rm  
//保存下载信息（文件指针位置） .ag4i;hS8  
private void write_nPos() i8I%}8  
{ ;HM& ":7  
try{ IC+Z C   
output = new DataOutputStream(new FileOutputStream(tmpFile)); l?~SH[V  
output.writeInt(nStartPos.length); D;)Tm|XizW  
for(int i=0;i<nStartPos.length;i++) ^~(vP:  
{ K1Nhz'^=D  
// output.writeLong(nPos); .]%PnJM9K  
output.writeLong(fileSplitterFetch.nStartPos); qIK"@i[ uq  
output.writeLong(fileSplitterFetch.nEndPos); cD^n}'ej  
} I,vy__sZ  
output.close(); 7/NXb  
} [P2$[|IM  
catch(IOException e){e.printStackTrace ();} xBd#  
catch(Exception e){e.printStackTrace ();} oD_je~b)  
} F"j0;}+N  
bp2l%A;  
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//读取保存的下载信息（文件指针位置） Nh~ Hh(  
private void read_nPos() "<0BCJJ  
{ -;'8#"{`^  
try{ QJp _>K  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .pQH>;k]K  
int nCount = input.readInt(); ?:Y{c#w>  
nStartPos = new long[nCount]; =?T\zLN=  
nEndPos = new long[nCount]; ?"PUw3V3lB  
for(int i=0;i<nStartPos.length;i++) 8 s!0Z1Roc  
{ ]y@8mb&  
nStartPos = input.readLong(); K8doYN  
nEndPos = input.readLong(); n'0^l?V  
} 4)+MvKxjS  
input.close(); c|u{(E58  
} xf<D5 olZ  
catch(IOException e){e.printStackTrace ();} aM?Xi6 U5  
catch(Exception e){e.printStackTrace ();} g5R2a7  
} "JAYTatO7H  
/HgdTyR)  
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private void processErrorCode(int nErrorCode) 33|>u+  
{ OBi9aFoQ  
System.err.println("Error Code : " + nErrorCode); _)Q)tOW  
} ed4:r/Dpo  
ji<b#YO4  
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//停止文件下载 U.hV1  
public void siteStop() NY\q  
{ p!>FPS  
bStop = true; =2pGbD;*  
for(int i=0;i<nStartPos.length;i++) R_\{a*lV0  
fileSplitterFetch.splitterStop(); vb)
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} Bp6jF2  
} v9INZ1# v  
//负责部分文件的抓取 9=pG$+01OR  
**FileSplitterFetch.java ! lgsV..R  
*/ x;S v&  
package NetFox; 5j
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import java.io.*; Q+)fI  
import java.net.*; rA&|!1q"B  
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public class FileSplitterFetch extends Thread { MFcN.M  
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String sURL; //File URL T[B@7$Dp*  
long nStartPos; //File Snippet Start Position aiGT!2  
long nEndPos; //File Snippet End Position [c]X) @#S  
int nThreadID; //Thread's ID #o_`$'>  
boolean bDownOver = false; //Downing is over 12DMb9_rp  
boolean bStop = false; //Stop identical [t5:4 Iq  
FileAccessI fileAccessI = null; //File Access interface 1@RctI_}  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _,_>B8  
{ o0&jel1a  
this.sURL = sURL; |Y|{9Osus  
this.nStartPos = nStart; B;Ab`UX#t  
this.nEndPos = nEnd; 5WgdgDb@L  
nThreadID = id; DtG><g}[]  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Fh9`8  
} .,(bDXl?  
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public void run() YUJlQ2e(  
{ {co(w 7  
while(nStartPos < nEndPos && !bStop) x0@J~ _0  
{ ZdeRLX  
j':Ybr>BR  
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try{
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URL url = new URL(sURL); D{I^_~-\5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lidzs<W-fW  
httpConnection.setRequestProperty("User-Agent","NetFox"); RxU6.5N  
String sProperty = "bytes="+nStartPos+"-"; YFOSv]w  
httpConnection.setRequestProperty("RANGE",sProperty); iJIPH>UMX  
Utility.log(sProperty); !/ TeTmo  
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InputStream input = httpConnection.getInputStream(); /vS!9f${  
//logResponseHead(httpConnection); Y>geP+-  
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byte[] b = new byte[1024]; wQWokpP;T7  
int nRead; hNmC(saMGm  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) '
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{ <iunDL0  
nStartPos += fileAccessI.write(b,0,nRead); i%+cPQ^o  
//if(nThreadID == 1) 9V`/zq?  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); SLpB$puS  
} $r*7)/  
st P~/}  
csz/[*  
Utility.log("Thread " + nThreadID + " is over!"); HGfV2FtTz  
bDownOver = true; 0RAmwfXm  
//nPos = fileAccessI.write (b,0,nRead); 2MQgTFM9  
} &Z/aM?  
catch(Exception e){e.printStackTrace ();} !}|n3wQ  
} xCFk1%qf  
} )Q9m,/F  
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//打印回应的头信息 _O2},9L n  
public void logResponseHead(HttpURLConnection con) =($RT  
{ ~4y&]:I  
for(int i=1;;i++) F&.iY0Pt  
{ I=6\z^:  
String header=con.getHeaderFieldKey(i); $cEl6(66iX  
if(header!=null) \{@s@VBx[  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); o0^..f  
Utility.log(header+" : "+con.getHeaderField(header)); ,$EM3   
else >[B}eS>  
break; ZQ9!k* ^  
} V|KYkEl r1  
} e  p~3e5  
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public void splitterStop() _fha9`  
{ "_]n_[t2C  
bStop = true; Gf\Dc  
} LvgNdVJDP|  
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} !c[(#g  
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}UJS*mR  
/* p0~=
 
**FileAccess.java 9YRoWb{y  
*//文件访问(定位，写) ]J+}WR  
package NetFox; YMOy
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import java.io.*; #-dfG
.*  
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7yo/sb9h  
public class FileAccessI implements Serializable{ S/G6NBnbS  
EM!#FJh  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 h~haA8i?{  
RandomAccessFile oSavedFile; ?rID fEvV  
long nPos; cZI )lX  
{E1g+><  
opxVxjTT#  
public FileAccessI() throws IOException S%gb1's  
{ Qg;A (\z  
this("",0); O^ZOc0<  
} 4of3#M  
Ac;rMwXk#  
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public FileAccessI(String sName,long nPos) throws IOException <jE6ye(R  
{ Ab`mID:  
oSavedFile = new RandomAccessFile(sName,"rw"); P/snzm|@  
this.nPos = nPos; ,g2|8>sJP  
oSavedFile.seek(nPos); Z3?,r[   
} V{@ xhW0  
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=xcA4"k  
public synchronized int write(byte[] b,int nStart,int nLen) im{'PgiR  
{ ON#\W>MK?  
int n = -1; z1[2.&9D-  
try{ z
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oSavedFile.write(b,nStart,nLen); \U;4\  
n = nLen; 1
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} 7^,C=2  
catch(IOException e) D|m6gP;P  
{ hV|pH)Nu{  
e.printStackTrace (); Bv_C *vW  
} Q<W9<&VZe  
}YJ(|z""  
3"=%[  
return n; 0jCYOl  
} N|hNh$J[  
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} _h>S7-X  
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n^P=a'+  
/* \hN\px  
**SiteInfoBean.java dK'?<w$  
*/ {o"X8  
package NetFox; IPmSkK  
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public class SiteInfoBean { #~?Q?"  
g+Vfd(e  
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private String sSiteURL; //Site's URL 9Axk-c  
private String sFilePath; //Saved File's Path (+7gS_c  
private String sFileName; //Saved File's Name wP28IB:^  
private int nSplitter; //Count of Splited Downloading File Y: &?xR  
[^xLK  
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public SiteInfoBean() bK;I:JK3  
{//nSplitter的缺省值为5 ^|y6o
j  
//default value of nSplitter is 5 JwWW w1  
this("","","",5); *Wk y#  
} ,9<}V;(  
*KNj5>6=  
 o`S|  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) UwOZBF<  
{ owL>w  
sSiteURL= sURL; ry9%Y3  
sFilePath = sPath; ~qQSt%  
sFileName = sName; #mg6F$E  
this.nSplitter = nSpiltter; tiG=KHK%o  
*A C){M  
dr0<K[S_  
} kbzzage6L  
z=1 J{]  
2[f8"'lUQ  
public String getSSiteURL() USfpCRj9  
{ :l>&5w;  
return sSiteURL; %UZ_wsY\  
}
z}\TS.  
9bvzt8pc  
#<df!)  
public void setSSiteURL(String value) 2RXU75VY  
{ =H&{*Ja  
sSiteURL = value; 8 tMfh  
} r&sm&4)p-5  
1A\Jh3;Q  
i zJa`K  
public String getSFilePath() mh`~1aEr  
{ SA_5..  
return sFilePath; =au7'i|6  
} kBolDPvBG  
0'y9HE'e  
,E,oz{,i(  
public void setSFilePath(String value) OZ 4uk.)  
{ xGsg'  
sFilePath = value; -oc@$*t  
} U-/-aNJ]U  
@+II@[_lT  
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public String getSFileName() &}}
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{ gN#&Ag<?  
return sFileName; w$I<WS{J:Z  
} *Pj[r  
F<SMU4]YdG  
d|5V"U]W;  
public void setSFileName(String value) j8WMGSrrF  
{ "@: b'm  
sFileName = value; r.1/*i  
} $s$j
</.q  
h+EG) <  
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public int getNSplitter() 4oW6&1  
{ Y1RiuJtL  
return nSplitter; ?EP>yCR9  
} BR\3ij  
dx['7l;I  
<Stfqa6FJ  
public void setNSplitter(int nCount) dIk/vg  
{ sOzmw^7   
nSplitter = nCount; r;:5P%:  
} !DsKa6Zj  
} }^r=(  
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/* r[; .1,(  
**Utility.java F-i`GMWC  
*/ 8W' ,T  
package NetFox; 9_yO6)`  
pw
;  
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public class Utility { `I*W}5  
r|!w,>.  
9MfBsp}c  
public Utility() E?%SOU<  
{ .xJW=G{/  
wX(h]X"q  
@0}Q"15,I  
} &8VB{S>r  
(`S32,=TS  
//线程睡眠 2c?-_OCy;  
public static void sleep(int nSecond) O
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{ J:6wFmU  
try{ 6J
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Thread.sleep(nSecond); 3GMRH;/w  
} -$Y@]uf^  
catch(Exception e) ?^TjG)e7  
{ l :sZ  
e.printStackTrace (); ^kg[n908Nw  
} tK9_]663  
} FPM@%U  
);4lM%]eb  
//日志 *#ccz  
public static void log(String sMsg) o`B,Pt5vu  
{ w!$|IC  
System.err.println(sMsg); `[T|Ck5  
} lMpjE  
_Wcr'*7  
]Z/<HP$#  
public static void log(int sMsg) WzM9{c  
{
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System.err.println(sMsg); HsA4NRF'7  
} J*)Vpk  
} 1.7tXjRd+  
q}-q[p? 5  
T /iKz  
/* p
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**TestMethod.java S+c)  
*/ 5LVhq[}mP  
package NetFox; _g+^jR4  
D ff0$06Nq  
@ 2r9JqR[=  
public class TestMethod { >T*/[{L8;  
D&5>Op4U  
H{*~d+:ol  
public TestMethod() U1pL `P1  
{ ///xx/weblogic60b2_win.exe }?f%cRT$  
try{ [kf$82  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); $[zy|Y(  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ka_]s:>+  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Q+e|;Mj  
fileFetch.start(); -phwzR\(t  
}
.PyPU]w  
catch(Exception e){e.printStackTrace ();} =
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uH"W07  
rV *`0hA1  
} Z4@%0mFll  
B)^uGSW  
m+Um^:\jX  
public static void main(String[] args) TOH!vQP  
{ 8ux?K5_  
new TestMethod(); 3W<_J_[  
} VB(S]N)F^  
} ^seb8o7  
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