http断点续传简单实现（java)

/* I[}75:^Rt  
**SiteFileFetch.java 3^{8_^I  
*/ d)N^PJ/  
package NetFox; M2}np  
import java.io.*; ZTN(irK  
import java.net.*; ?Phk~ jE  
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public class SiteFileFetch extends Thread { Yl$X3wi  
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SiteInfoBean siteInfoBean = null; //文件信息Bean v2d<o[[C  
long[] nStartPos; //开始位置 9X(Sk%  
long[] nEndPos; //结束位置 YQ; cJ$  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 KE<kj$  
long nFileLength; //文件长度 #,G1R7  
boolean bFirst = true; //是否第一次取文件 S@x}QQ|.  
boolean bStop = false; //停止标志 m+?N7  
File tmpFile; //文件下载的临时信息 <j;]!qFR  
DataOutputStream output; //输出到文件的输出流 ?]^zD k@~  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） u#1%P5r&X  
public SiteFileFetch(SiteInfoBean bean) throws IOException W;4Lkk$  
{ ;+sl7qlA4  
siteInfoBean = bean; |XRI
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >-M ]:=L  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Y(_KizBY  
if(tmpFile.exists ()) 9e!vA6Fx  
{ KF+mZB  
bFirst = false; uVGa(4u}  
read_nPos(); uMvb-8  
} ,of]J|  
else 8'_ 0g[s  
{ t0q_>T-kt  
nStartPos = new long[bean.getNSplitter()]; e'34Pw!m  
nEndPos = new long[bean.getNSplitter()]; &iqw! ud  
} %t
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} ; DDe.f"  
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public void run() <*<U!J-i  
{ 6V1:qp/6  
//获得文件长度 )T1iN(Z  
//分割文件 yS!(Ap  
//实例FileSplitterFetch v*z(@<Y  
//启动FileSplitterFetch线程 px=]bALU  
//等待子线程返回 RF?DtNuq  
try{ T  p<s1'"  
if(bFirst) d]SYP  
{ Z(e^iH  
nFileLength = getFileSize(); hi|!  
if(nFileLength == -1) -:<lkq&/  
{
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System.err.println("File Length is not known!"); E7nFb:zlV  
} 8AL\ST51x"  
else if(nFileLength == -2) }Cj8  
{ bcH_V|5
}  
System.err.println("File is not access!"); [&#/|zH'j:  
} |quij0_'e  
else `)Ky0&?  
{  &;c>O  
for(int i=0;i<nStartPos.length;i++) L(G92,.  
{ `s"d]/85VW  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); <jA105U"m>  
} -Q"hZ9  
for(int i=0;i<nEndPos.length-1;i++) G$bJ+  
{ C&<~f#lB  
nEndPos = nStartPos[i+1]; ZVih=Y-w  
} +v7) 1y  
nEndPos[nEndPos.length-1] = nFileLength; Z[?mc|*x  
} V
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} @S^ASDuQU7  
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' cIEc1y  
//启动子线程 rD &D)w  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8b(!k FxD  
for(int i=0;i<nStartPos.length;i++) (xpn`NA  
{ k N7Bd}  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )[Z!*am  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), iE].&>w  
nStartPos,nEndPos,i); !t#F/C  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (?0`d  
fileSplitterFetch.start(); 12UD19!  
} A7Po 3n%Q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kz}R[7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); jgv`>o%<W  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", u]*0;-tz  
nEndPos = " + nFileLength); YJeyIYCs<  
// fileSplitterFetch[nPos.length-1].start(); C[sh,  
dT|vYK}\  
Z4b||  
//等待子线程结束 3SttHu0X  
//int count = 0; 4T6 {Y  
//是否结束while循环 cVnJ^*Z  
boolean breakWhile = false; <ABX0U[*  
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!]yO^Ob.E  
while(!bStop) zi9[)YqxPH  
{ =q7Z qP  
write_nPos(); SRIA*M.B}  
Utility.sleep(500); 2_^aw[-  
breakWhile = true; "Jq8?FoT  
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for(int i=0;i<nStartPos.length;i++) m0n)dje  
{ fxaJZz$o  
if(!fileSplitterFetch.bDownOver) l e4?jQQ@L  
{ q[q?hQ/b  
breakWhile = false; x!LQxoNF  
break; )SF}2?7e  
} :}8Z@H!KkY  
} yZr M.%V  
if(breakWhile) Mips.Bx  
break; i<kD  
#'D" 'B  
g- AHdYJ  
//count++; J]lrS  
//if(count>4) gxz-R?.  
// siteStop(); fZ04!R  
} ^bg2[FV  
#} ~qqJ G2  
y&}E~5O  
System.err.println("文件下载结束！"); ^k5ll=}  
} *_a@z1  
catch(Exception e){e.printStackTrace ();} %~L>1ShtU  
} Nkxmm/Z  
S#)Eom?V  
{^(ACS9mL  
//获得文件长度 *f&EoUk}F  
public long getFileSize() B`*ZsS=R-  
{ +zXEYc  
int nFileLength = -1; Tc8un.  
try{ /|#&px)G  
URL url = new URL(siteInfoBean.getSSiteURL()); p' M%XBu  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <N\v)Ug`  
httpConnection.setRequestProperty("User-Agent","NetFox"); il|1a8M2~  
ee%fqVQ8P  
06$!R/K  
int responseCode=httpConnection.getResponseCode(); IDnC<MO>  
if(responseCode>=400) 6q
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{ %K(<$!  
processErrorCode(responseCode); xX*H7#  
return -2; //-2 represent access is error ;"(foY"L  
} =t6z \WB  
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i4^o59}8  
String sHeader; K>*a*[t0Sy  
:Ad&$eg+  
sR/b$j>i3  
for(int i=1;;i++) .e=C{  
{ `PY>Hgb  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); nstUMr6  
//Utility.log(in.readLine()); 8\{^|y9-  
sHeader=httpConnection.getHeaderFieldKey(i); .e_cga
d :  
if(sHeader!=null) z dO#0tN  
{ }CeCc0M  
if(sHeader.equals("Content-Length")) @|Rrf*J?%  
{ rn<PR*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [IK  )  
break; ]T%rjsN  
} bV ZMW/w  
} _YF%V;X  
else 0v9rv.Y"  
break; (V4 ~`i4V  
} y@\V+  
} :=J,z,H_U  
catch(IOException e){e.printStackTrace ();} ULQMG'P^D  
catch(Exception e){e.printStackTrace ();} (\SA*.)  
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9<KAXr#  
Utility.log(nFileLength); _cXqAo  
0qX3v<+[6  
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return nFileLength; L'u\w  
} qAw x2fPu  
mauI42  
?Wz8[u  
//保存下载信息（文件指针位置） |+T1XYG5  
private void write_nPos() {?yr'*  
{ u9N 1pZ~  
try{ :s4p/*f  
output = new DataOutputStream(new FileOutputStream(tmpFile)); U~p
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output.writeInt(nStartPos.length); 2$Tj84'X  
for(int i=0;i<nStartPos.length;i++) 3`k;a1Z#O'  
{ ayiu,DXx  
// output.writeLong(nPos); |`cKD >  
output.writeLong(fileSplitterFetch.nStartPos); Nqu>6^-z0  
output.writeLong(fileSplitterFetch.nEndPos); 0(S"{Ov
 
} ;aw=MV  
output.close(); }I :OsAw  
} 92 [;Y  
catch(IOException e){e.printStackTrace ();} nJo`B4'U  
catch(Exception e){e.printStackTrace ();} hRCed4qA  
} 5F~'gLH/F-  
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3? HhG  
//读取保存的下载信息（文件指针位置） Z:*76PP,  
private void read_nPos() `DC2gJKk%  
{ ?:)
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try{ ~P@Q7T*  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9T1Z
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int nCount = input.readInt(); 6b:tyQ  
nStartPos = new long[nCount]; ;dJ1  
nEndPos = new long[nCount]; /K(o]J0F  
for(int i=0;i<nStartPos.length;i++) #E&80#Z5  
{ mVy|{O
h  
nStartPos = input.readLong(); (_"*NY0  
nEndPos = input.readLong(); 8p:j&F  
} t{.8|d@  
input.close(); Ba!J"b]  
} PBp^|t]E>  
catch(IOException e){e.printStackTrace ();} 7:2WgLo  
catch(Exception e){e.printStackTrace ();} )/wk( O+  
} ?W)A  
hK_LEwd;  
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private void processErrorCode(int nErrorCode) 6#HK'7ClL  
{
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System.err.println("Error Code : " + nErrorCode); yI"6Da6|y  
} _iir<}  
N9v1[~ bv_  
7BJzMlJ1Y  
//停止文件下载 pNKhc#-w  
public void siteStop() ?]}8o}G  
{ <x<"n t  
bStop = true; vuoQz\  
for(int i=0;i<nStartPos.length;i++) =Xqc]5[i  
fileSplitterFetch.splitterStop(); e=+?K5q{P(  
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} '7iSp=  
} P7{gfiB  
//负责部分文件的抓取 c1E'$- K@  
**FileSplitterFetch.java LyAn&h
}  
*/ /!3@]xz*  
package NetFox; t({W [JL  
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import java.io.*; BS:+~|3w  
import java.net.*; n:{qC{D-qS  
u
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public class FileSplitterFetch extends Thread { s]f6/x/~  
-(~!Jo_*'  
 ~Hr}]  
String sURL; //File URL oz}+T(@O  
long nStartPos; //File Snippet Start Position _N{RVeO  
long nEndPos; //File Snippet End Position sXD1C2o  
int nThreadID; //Thread's ID d'G0m9u2  
boolean bDownOver = false; //Downing is over *1fb
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boolean bStop = false; //Stop identical IrqZi1  
FileAccessI fileAccessI = null; //File Access interface '.81zpff  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException .O0+H+  
{ MP4z-4Y  
this.sURL = sURL; XYZ4TeW\1  
this.nStartPos = nStart; @CZT  
this.nEndPos = nEnd; 3%(N[&LU  
nThreadID = id; TjwBv6h  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 F)'.g d  
} z$?~Y(EY  
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&GB:|I'%7  
public void run() d ysC4DS  
{ ucG@?@JENm  
while(nStartPos < nEndPos && !bStop) YTexv;VNb|  
{ mg$]QnbAnH  
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try{ wv\w;'  
URL url = new URL(sURL); (K)]qNH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !AKg m'Nw  
httpConnection.setRequestProperty("User-Agent","NetFox"); \<y#R~7s  
String sProperty = "bytes="+nStartPos+"-"; :uK?4  
httpConnection.setRequestProperty("RANGE",sProperty); ZI
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Utility.log(sProperty); A8oo@z68n>  
"3)4vuX@;c  
/#VhkC _  
InputStream input = httpConnection.getInputStream(); O4^8jK}  
//logResponseHead(httpConnection); +KvU$9Ad>  
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byte[] b = new byte[1024]; qT`k*i?  
int nRead; w6{TE(]zp  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *U]V@;XF  
{ !,Va(E|=  
nStartPos += fileAccessI.write(b,0,nRead); ysQ,)QoiR{  
//if(nThreadID == 1) ak |WW]R  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }DK7'K  
} =W BTm  
:]^P1sH[  
LS88.w\=S@  
Utility.log("Thread " + nThreadID + " is over!"); /eOzXCSws  
bDownOver = true; \0vr>C  
//nPos = fileAccessI.write (b,0,nRead); )Ccq4i  
} f'VX Y-  
catch(Exception e){e.printStackTrace ();} !VI]oRgP  
} qpE&go=k'  
} fH>NJK;  
)XzI #iQ  
` M3w]qJ<}  
//打印回应的头信息 ( 8c9 /7h  
public void logResponseHead(HttpURLConnection con) .[JYj(p  
{ Ooq! 0g  
for(int i=1;;i++) 'zGo?a  
{ HFaj-~b  
String header=con.getHeaderFieldKey(i); kAC&S!n  
if(header!=null)
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); m/y2WlcRx  
Utility.log(header+" : "+con.getHeaderField(header)); "0cID3A$  
else 86mp=6@  
break; x*nSHb  
} )Hk3A$6(  
} J1:1B,^y  
<c,u3cp  
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public void splitterStop() @Q/-s9b  
{ thvYL.U:  
bStop = true; Jh?dw3Ai^  
} (;57Vw  
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} fmiz,$O4?  
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/* m:WyuU<  
**FileAccess.java ,
;Hu=;  
*//文件访问(定位，写) ]5$eAYq  
package NetFox; PUBWZ^63  
import java.io.*; 846$x$G4  
Qe}`~a9P  
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public class FileAccessI implements Serializable{ f/Hm{<BY  
$d)ca9  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 N.]qU d  
RandomAccessFile oSavedFile; "gne_Ye.  
long nPos; mqAWL:VvQ7  
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public FileAccessI() throws IOException i]|Yg$  
{ r]l!WRn  
this("",0); jp"JafS/E  
} nZ@&2YPlem  
l-s!A(l  
n;$5Cq!v=  
public FileAccessI(String sName,long nPos) throws IOException IuOgxm~Y  
{ 8-_QFgY  
oSavedFile = new RandomAccessFile(sName,"rw"); :)_~w4&  
this.nPos = nPos; ALNc'MW!  
oSavedFile.seek(nPos); bD[!/'4eJ  
} 9v}G{mQ#  
ni6{pK4Wqm  
3'c0#h@VD  
public synchronized int write(byte[] b,int nStart,int nLen) 0em#-*|2"  
{ +S R+x/?z  
int n = -1; :w<V  
try{ v}tag#f5>?  
oSavedFile.write(b,nStart,nLen); %ix)8+Eb  
n = nLen; B|4X}*@SX  
} 5fm?Lxr&?  
catch(IOException e) |pmZ.r  
{ >OG:vw)E  
e.printStackTrace (); `S2[5i  
} &p}$J)q  
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L. EiO({W  
return n; GF>'\@Th  
} i%g#+Gw  
r; xLP  
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} u6MzRC  
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2A\,-*pc  
/* `X`2:@gQ  
**SiteInfoBean.java Ty<L8+B|  
*/ qWx][D"  
package NetFox; sz)oZPu|  
7\9>a  
C%U`"-%n@7  
public class SiteInfoBean { GD:4"$)[o  
Uv?|G%cD-  
a9T@$:  
private String sSiteURL; //Site's URL !O#dV1wAa  
private String sFilePath; //Saved File's Path 0%Z]h?EYy|  
private String sFileName; //Saved File's Name .%^]9/4  
private int nSplitter; //Count of Splited Downloading File #~=
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N @#c,,  
9!Ar`Io2@  
public SiteInfoBean() g"L|n7_b  
{//nSplitter的缺省值为5 *JaqTI,e  
//default value of nSplitter is 5 h^*4}GU  
this("","","",5); c1_5, 1U'  
} b L]erYm  
\|Ul]1pO8  
)6w}<W*1E  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) oh KCdT~  
{ ^m/oDB-  
sSiteURL= sURL; \oEo~  
sFilePath = sPath; p<&Xd}]"^W  
sFileName = sName; C:uz6i1  
this.nSplitter = nSpiltter; PI~1GyJr@;  
p?2Y }9  
]/!<PF  
} .!6>oL/iF  
cwuO[^S}  
0UH*\<R  
public String getSSiteURL() $rhgzpZ!X_  
{ >rP#ukr5  
return sSiteURL; 5|I[>Su  
} s (0*  
!{82D[5  
`-\/$M9s=  
public void setSSiteURL(String value) N~?{UOZd  
{ Qf|U0  
sSiteURL = value; "ywh9cp  
} p)=~% 7DV  
1N\D5g3  
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public String getSFilePath() .p ls!  
{ (Si=m;g  
return sFilePath; Y];Y
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} o%4G
d~
  
y?)}8T^  
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public void setSFilePath(String value) Ka|eFprS  
{ pCu!l#J  
sFilePath = value; Ln.ZVMZ;  
} @<@SMK)  
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J@L9p46,  
public String getSFileName() /?6gdN  
{ ;+I/I9~  
return sFileName; : 5U"XY x@  
} ]}mxY vu_i  
vNW jH!'  
@f!AkzI  
public void setSFileName(String value) (5<^p&  
{ o]LRzI  
sFileName = value; SMf+qiM-E  
} G2#d$  
tQ~WEC  
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public int getNSplitter() hKlZi!4J  
{ e.o;eD}"  
return nSplitter; }#v{`Sn%^C  
} ir:d'g1k  
@4!x>q$3  
FZH\Q~IUV  
public void setNSplitter(int nCount) Z?^"\u-  
{ 8z<r.joxC  
nSplitter = nCount; eV6o3u:9  
} (X6sSO  
} n^hocGH*  
#)`A7 $/,  
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/* L7mz#CMWf
 
**Utility.java -Y:ROoFOZ  
*/ Iia.k'N  
package NetFox; np WEop>  
(D{Ys'{q  
bO<0qM~  
public class Utility { PK&2h,Cu+  
2N~E' 25  
{BO
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public Utility() GI
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{ 2 [!Mx&^  
sF
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} >sj bK%  
^GYq#q9Q  
//线程睡眠 E/za@W  
public static void sleep(int nSecond) >]}yXg=QK+  
{ .dI)R40L/\  
try{ ~2/{3m{3A  
Thread.sleep(nSecond); }#=Od e  
} I}v]Zm9  
catch(Exception e) ^C9x.4I$)  
{ =M
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e.printStackTrace (); dALK0U  
} &.*uc|{  
} 4R+P  
98*x 'Wp  
//日志 wq4nMY:#  
public static void log(String sMsg) ]0D9N"  
{ hXX1<~k  
System.err.println(sMsg); bZ#X9fT  
} vSM_]fn  
=ef1XQ{i*  
h39e)%x1  
public static void log(int sMsg)  q{X T  
{ W@B7yP7Rz  
System.err.println(sMsg); j 0 Y  
} 3C"_$?y"  
} Bp0bY9xLg_  
#'>?:k  
4uX(_5#j  
/* m4gU*?  
**TestMethod.java j,t~  
*/ nC~fvyd<P  
package NetFox; +5*vABvCu  
p^8JLC  
C6)R#  
public class TestMethod { ,#aS/+;[)  
B~_Spp  
uMDtdC8  
public TestMethod() baIbf@t/  
{ ///xx/weblogic60b2_win.exe !BRcq~-.  
try{ /Ri,>}n  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); sPpS~wk*  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); )nnCCRS6  
SiteFileFetch fileFetch = new SiteFileFetch(bean); -]QguZE  
fileFetch.start(); jm>U6  
} 
OMd# ^z  
catch(Exception e){e.printStackTrace ();} cDO:'-  
`Z8^+AMc  
.Qfnd#  
} WFj*nS^~l  
O3+)qb!X  
=z-5  
public static void main(String[] args) )]A9~H  
{ *')Q {8`  
new TestMethod(); <N5rv3 s  
} ;[caiMA-  
} "<*nZ~nE)  
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