http断点续传简单实现（java)

/* dlU=k9N-  
**SiteFileFetch.java \kRBJ1)|f  
*/ gK>Vm9rO  
package NetFox; /x-t-}  
import java.io.*; (lm/S_U$  
import java.net.*; L{=z}QO  
P~#jvm!  
#K[ @$BY:  
public class SiteFileFetch extends Thread { qq/Cn4fN8  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 4>|5B:  
long[] nStartPos; //开始位置 4[#.N 3Y4*  
long[] nEndPos; //结束位置 ,^[s4 =3X?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Qw^tzP8  
long nFileLength; //文件长度 SX4p(t  
boolean bFirst = true; //是否第一次取文件 k.0C*3'  
boolean bStop = false; //停止标志 (u_sz  
File tmpFile; //文件下载的临时信息 3o?Lz7L  
DataOutputStream output; //输出到文件的输出流 "6}+|!"$  
>5j/4Ly  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） (-#{qkA  
public SiteFileFetch(SiteInfoBean bean) throws IOException 0TNzVsu7  
{ p$V+IJtO(  
siteInfoBean = bean; aT0 y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ff0B*0  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");
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if(tmpFile.exists ()) 4rx|6NV6  
{ l>]M^=,&7  
bFirst = false; tY#^3ac  
read_nPos(); xq{4i|d)  
} '=2t(@aC  
else U".-C`4v  
{ c;e,)$)-|  
nStartPos = new long[bean.getNSplitter()]; ?BRL;(x  
nEndPos = new long[bean.getNSplitter()]; u>eu47"n!  
} ?R+$4;iy  
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} Ju\"l8[f  
p
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public void run() w7C=R8^  
{ o#Y1Uamkf  
//获得文件长度 1
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//分割文件 Ob+&!XTp?0  
//实例FileSplitterFetch 9f@)
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//启动FileSplitterFetch线程 vuAjAeKm  
//等待子线程返回 +u#x[xO  
try{ vZxy9Wmc
 
if(bFirst) 0jmlsC>  
{ ?m!F
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nFileLength = getFileSize(); .jKO 6f  
if(nFileLength == -1) 1-n
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{ +~@Y#>+./l  
System.err.println("File Length is not known!"); l\5NuCgRY  
} usA!MMH4  
else if(nFileLength == -2) L_~G`Rb3  
{ "&%Hb's  
System.err.println("File is not access!"); N7_Co;#(zK  
} Xx^c?6YM  
else jDnh/k0{d  
{ kel {9b=i  
for(int i=0;i<nStartPos.length;i++) PEWzqZ|!;  
{ $Yka\tS'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 87Kx7CKF"  
}
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for(int i=0;i<nEndPos.length-1;i++) wnX6XyUH  
{ _e'mG'P(  
nEndPos = nStartPos[i+1]; ^#o.WL%4/B  
} u *< (B  
nEndPos[nEndPos.length-1] = nFileLength; ke0W?  
} D8ly8]H  
} .EdV36$n  
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H,}?YW  
//启动子线程 wB^a1=C  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; PjHm#a3zg%  
for(int i=0;i<nStartPos.length;i++) e#('`vGB  
{ { \ePJG#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4Bn+L,}.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), *.RVH<W=8  
nStartPos,nEndPos,i); UXP;
'  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2KEww3.
{  
fileSplitterFetch.start(); `FwAlYJK  
} 4!jHZ<2Z  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ($s{em4L  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); }dz(DPd  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", R32d(2%5K  
nEndPos = " + nFileLength); z-DpLV  
// fileSplitterFetch[nPos.length-1].start(); dUZ&Ty^{  
55,-1tWs  
X&IY(CX  
//等待子线程结束 Q?@G>uz  
//int count = 0; tTgW^&B  
//是否结束while循环 if'4MDl  
boolean breakWhile = false; H/$q]i*#K  
*"ShE=\p  
0u_'(Z-^2  
while(!bStop) gUp0RPs  
{ `Nn?G  
write_nPos(); gm DC,"Y<  
Utility.sleep(500); wu')Q/v  
breakWhile = true; d%hA~E1rR  
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for(int i=0;i<nStartPos.length;i++) MF`'r#@:wa  
{ yKJ^hv"#  
if(!fileSplitterFetch.bDownOver) YLGLr@:q  
{ Q)>'fZ)  
breakWhile = false; EMG*8HRI>r  
break; ;j=1 oW  
} -
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} u
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if(breakWhile) jq)|Uq'6  
break; bed+Ur&  
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#pfosC[  
//count++; LnGSYrx1  
//if(count>4) OT i3T1&  
// siteStop(); BP$#a
#  
} "+&<Qd2  
;>N ~,Q  
z3]U%y(,  
System.err.println("文件下载结束！"); 639k&"V  
} V{{x~Q9  
catch(Exception e){e.printStackTrace ();} _3a 5/IZ  
} 3iw9jhK!W  
j&.BbcE45  
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//获得文件长度 <Tf;p8#  
public long getFileSize() z7C1&bGe  
{ =*jcO119L  
int nFileLength = -1; x3|'jmg  
try{ DlI5} Jh  
URL url = new URL(siteInfoBean.getSSiteURL()); mI#; pO2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]6 wi  
httpConnection.setRequestProperty("User-Agent","NetFox"); !`lqWO_/ :  
;kBies>V  
Kf#!IY][  
int responseCode=httpConnection.getResponseCode(); 'Aj>+H<B  
if(responseCode>=400) 99K+7G\{  
{ n~j[Pw  
processErrorCode(responseCode); Sj?sw]3  
return -2; //-2 represent access is error R:?vY!  
} `x)bw  
|m- `, we  
g/p }r.  
String sHeader; VWt'Kx"  
(+dRD]|T  
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for(int i=1;;i++) ,np`:fBMy  
{ ;0}2@Q2@ZK  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +_
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//Utility.log(in.readLine()); :g#it@  
sHeader=httpConnection.getHeaderFieldKey(i); E e>j7k.G.  
if(sHeader!=null) S8m&Rj3O&  
{ "~C#DZwt{  
if(sHeader.equals("Content-Length")) D5u"4\g<&  
{ y>|XpImZ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *(B[J  
break; 3:lp"C51  
} nX%'o`f  
} g/p9"eBpq  
else [t{#@X  
break; %PbqASm  
} \[1CDz=}1  
} r:4IKuTR  
catch(IOException e){e.printStackTrace ();} E2'e}RQ  
catch(Exception e){e.printStackTrace ();} ZGhoV#T@  
%+a@|Z  
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Utility.log(nFileLength); y51D-vj
 
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return nFileLength; 9t.yP;j\Y  
} jSp&mD*xv  
+|)1_NK  
x=Jn&4q  
//保存下载信息（文件指针位置） 6xh#;+e}  
private void write_nPos() _PUm Pom.  
{ Gj`Y2X2r  
try{ cE5Zxcn  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?^ezEpW  
output.writeInt(nStartPos.length); `sy &dyM  
for(int i=0;i<nStartPos.length;i++) 3,I >.3  
{ b.q"
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// output.writeLong(nPos); A>%UYA  
output.writeLong(fileSplitterFetch.nStartPos); h^kNM8  
output.writeLong(fileSplitterFetch.nEndPos); GY]6#
>D#7  
} }, &,Dt  
output.close();
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} Gj8[*3d  
catch(IOException e){e.printStackTrace ();} 8:?Q(M7  
catch(Exception e){e.printStackTrace ();} sJK:xk.6!  
} (Zg'pSs)  
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//读取保存的下载信息（文件指针位置） I S8nvx\  
private void read_nPos() kjC{Zr  
{ Q;ZHx.ye{  
try{ \}QuNwc  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));
2$zq (  
int nCount = input.readInt(); a& aPBv1  
nStartPos = new long[nCount]; >"g<-!p@  
nEndPos = new long[nCount]; 8~(+[[TQ@  
for(int i=0;i<nStartPos.length;i++) >ydb?
 
{ [=ak>>8  
nStartPos = input.readLong(); 'ag6B(0Z  
nEndPos = input.readLong(); dIa(</ }  
} m4U+,|Fa  
input.close(); WfT)CIKs  
} iSz@E&[X  
catch(IOException e){e.printStackTrace ();} m2q;^o:J  
catch(Exception e){e.printStackTrace ();} o/ g+Z  
} D4O5@KfL  
%iL@:'?K  
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|  
private void processErrorCode(int nErrorCode) gq_7_Y/  
{ j /dE6d  
System.err.println("Error Code : " + nErrorCode); p$1Rgm\  
} ?Ga2K  
#C;zS9(]B  
]n]uN~)9  
//停止文件下载 dFP-(dX#  
public void siteStop() |k
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{ @W\4UX3dK  
bStop = true; ddq 1NW  
for(int i=0;i<nStartPos.length;i++) 1;:t~Y  
fileSplitterFetch.splitterStop(); @23R
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} ?I2k6%a  
} ?WQd  
//负责部分文件的抓取 Fr3d#kVR  
**FileSplitterFetch.java pG F5aF7T  
*/ CziaxJ  
package NetFox; x"llX  
g[wP!y%V  
*JY`.t  
import java.io.*; O})u'  
import java.net.*; 
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public class FileSplitterFetch extends Thread { .W@4vrp
@  
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q"LJwV}W  
String sURL; //File URL y }&4HrT&  
long nStartPos; //File Snippet Start Position <% 7P  
long nEndPos; //File Snippet End Position }y-;>i#m=g  
int nThreadID; //Thread's ID ^0x.'G?  
boolean bDownOver = false; //Downing is over &!DZW5  
boolean bStop = false; //Stop identical F;Q_*0mIQ  
FileAccessI fileAccessI = null; //File Access interface MX`Wg  
`mKlv~$1^  
> 0Twr  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException BsK|:MM]  
{ aFr!PQp4{  
this.sURL = sURL; k99gjL`  
this.nStartPos = nStart; b1+hr(kMRM  
this.nEndPos = nEnd; -_EY$?4  
nThreadID = id; )`s;~_ZZ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 I*:qGr+ WJ  
} TvWU[=4Yk  
+\k9w.[:/  
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public void run() _<%\h?W$  
{ )+w/\~@  
while(nStartPos < nEndPos && !bStop) WpJD=C%  
{ +Y5(
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t(j_eq}J  
try{ ,a9D~i 9R  
URL url = new URL(sURL); *dG}R#9Nv  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B%eDBu ")  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^Cc8F3os=  
String sProperty = "bytes="+nStartPos+"-"; YHO;IQ5  
httpConnection.setRequestProperty("RANGE",sProperty); +U+aWk  
Utility.log(sProperty); j(Fa=pi  
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)RA\kZ"  
InputStream input = httpConnection.getInputStream(); 2Ft8dfdm`  
//logResponseHead(httpConnection); k(-Z@  
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byte[] b = new byte[1024]; `i t+D  
int nRead; 6^]`-4*W  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @Xq&t}*8  
{ "M9TB. O  
nStartPos += fileAccessI.write(b,0,nRead); V~J*49t&2J  
//if(nThreadID == 1) l$qStL*8O  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YeRcf`  
} }>{ L#JW  
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` $.X[\*U  
Utility.log("Thread " + nThreadID + " is over!"); `z3|M#r\;  
bDownOver = true; $ DDSN  
//nPos = fileAccessI.write (b,0,nRead); } g3HoFC  
} QmH/yy3.%  
catch(Exception e){e.printStackTrace ();} qE#&)  
} qPXANx<^  
} &*(n<5wt  
2I]]WBW#:  
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//打印回应的头信息 |'U,/
 
public void logResponseHead(HttpURLConnection con) 9E
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{ m\*&2Na  
for(int i=1;;i++) ~:/%/-^  
{ j<l#qho{h  
String header=con.getHeaderFieldKey(i); 8qFUYZtY  
if(header!=null) 69[V <1  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); -O~C m}e  
Utility.log(header+" : "+con.getHeaderField(header)); Yl)eh(\&J  
else ERp:EZ'  
break; %rM-"6Q  
} gB/;clCdX)  
}  &7L~PZ  
lSn5=^]q  
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public void splitterStop() lq>*x=<  
{ eZ@Gu  
bStop = true; 9nng}em>.  
} ?vZWUWa  
vQ:x%=]  
ELN|;^-/|Q  
} ^H5w41  
V.K70)]  
ZhGh{D[,  
/* P<>[e9|  
**FileAccess.java %'{V%I
XQ  
*//文件访问(定位，写) ,pDp>-vI%  
package NetFox; gf:vb*#Wa  
import java.io.*; ?gd'M_-J,  
z6p#fsD  
5*JV )[  
public class FileAccessI implements Serializable{ 5"1!p3`\D{  
/yx=7<  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 CCuxC9i7  
RandomAccessFile oSavedFile; JZ %`%rA  
long nPos; W.yV/fu  
vx04h~  
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public FileAccessI() throws IOException |9+bSH9  
{ _n< LVdE  
this("",0); >lA7*nn  
} ?D1x;i9<  
+DicP"~*  
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public FileAccessI(String sName,long nPos) throws IOException xh{mca>?
G  
{ aN>U. SB  
oSavedFile = new RandomAccessFile(sName,"rw"); $|Q".dD  
this.nPos = nPos; S#P+B*v  
oSavedFile.seek(nPos); ~J%R-{U9  
} |tG05+M  
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IgLVn<5n  
public synchronized int write(byte[] b,int nStart,int nLen) nped  
{ lN);~|IOv7  
int n = -1; jz %;4e
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try{ p9/bzT34.  
oSavedFile.write(b,nStart,nLen); BD hLz  
n = nLen; !$D&6M|C8l  
} w|&,I4["  
catch(IOException e) :0B |<~lX  
{ J=@hk@Nq#  
e.printStackTrace (); 1T!cc%ah  
} Lqg]Fd  
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63.( j P1;  
return n; gB>(xY>LrA  
} )qbI{^_g  
~af8p {  
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} qO7fbql_  
+VwV5iy[`  
h{\t*U54'  
/*  W|lH  
**SiteInfoBean.java )i&%cyZw  
*/ \'[3^/('  
package NetFox; s;s0}Td_1  
)r=9]0=  
"PMO  
public class SiteInfoBean { '-`O. 4u  
v,n);  
S<V-ZV&_:U  
private String sSiteURL; //Site's URL <BZ_ (H  
private String sFilePath; //Saved File's Path 1d`cTaQ-  
private String sFileName; //Saved File's Name Ny[QT*nV  
private int nSplitter; //Count of Splited Downloading File (viWY  
=ntftSH  
j(&GVy^;?  
public SiteInfoBean() HB%K|&!+  
{//nSplitter的缺省值为5 7@JjjV  
//default value of nSplitter is 5 vxb@9eb!H  
this("","","",5); B i'd5B5  
} {&E?<D2_&  
wc"9A~  
 "";=DH  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Z?-;.G*  
{ [9LxhPi  
sSiteURL= sURL; 8IeI0f"l)  
sFilePath = sPath; '[%jjUU  
sFileName = sName; 1bd$XnU  
this.nSplitter = nSpiltter; qbH%
Hx  
U4]30B{;H  
X)8e4~(?  
} |ribWCv0  
L,#^&9bHa#  
en%J!<&W{K  
public String getSSiteURL() >#INEO  
{ 5~QhX22  
return sSiteURL; tbg*_ZQO u  
} 3eWJt\}?B  
2H6:np|O  
\/
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public void setSSiteURL(String value) 7vw;Egd@@-  
{ ~)_K"h.DY  
sSiteURL = value; 2.ew^D#
 
} w"1x=+  
7aV$YuL)X~  
$_wo6/J5+D  
public String getSFilePath() {aoMJJq  
{ 0fA=_=A,  
return sFilePath; B& "RS  
} 04~}IbeJ  
u >4ArtF  
#vtN+E  
public void setSFilePath(String value) >G&^?5  
{ ;ed#+$Na  
sFilePath = value; w;~>k%}j  
} r|<6Aae&  
r5[4h'f  
6s5yyy=L%~  
public String getSFileName() pp<E))&R  
{ o OQ'*7_  
return sFileName; ewpig4  
} @cPflb  
Vu%n&uF  
YKY2Cw  
public void setSFileName(String value) z"EWj73  
{ Oo1ecbY  
sFileName = value; (#If1[L  
} z{=v)F5y  
[z2eCH  
S!`:E  
public int getNSplitter() 07FT)Q
TE  
{ fCg@FHS&^  
return nSplitter; V3Yd&HVWNQ  
} G0Hs,B@5?  

1 =^  
sCkO0dl8  
public void setNSplitter(int nCount) (vnoP< 0  
{ b4)k&*dfR  
nSplitter = nCount; O:._
W<  
} 2$tQ @r  
} yyjw?#\8  
|kseKZ3  
*,&S',S-  
/* 9n"V\e_R  
**Utility.java s%O Y<B@V2  
*/ 4vLw?_".  
package NetFox; >L=;"+B0U&  
z+ ZG1\  
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public class Utility { e^8BV;+c  
*7Xzht&f  
gHZqA_*T8U  
public Utility() -=a[J;'q  
{ \E77SO,$  
Mb.4J2F?  
H{%H^t>  
} T pD;  
*{|$FQnR>(  
//线程睡眠 5{X*a  
public static void sleep(int nSecond) IJ_ m  
{ m]P/if7  
try{ d8o ewkiR  
Thread.sleep(nSecond); b
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} vY_eDJ~'  
catch(Exception e) 1O0X-C,wo$  
{ 8#l+{`$z  
e.printStackTrace (); /?P!.!W&  
} K{2h9 ]VF  
} 0m A(:"  
, D"]y~~I5  
//日志 (:n|v%  
public static void log(String sMsg) (v^Z BM_  
{ "mA1H]r3  
System.err.println(sMsg); +>}o;`
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} R$d7\nBG  
P#;Th8k{K2  
kC`Rd:5  
public static void log(int sMsg) ({ k7#1 h8  
{ jkt6/H  
System.err.println(sMsg); (A4&k{C_  
} i?-Y  
} =?/&u<  
ISBF\ wQY  
(:7a&2/M  
/*
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**TestMethod.java RG1\=J$:E  
*/ X!c?CL  
package NetFox; w.^yP7:  
+?AW>&68y  
``4?a7!!  
public class TestMethod { d}+W"j;  
QNpuTZn#Q  
bLlH//ZRH  
public TestMethod() WFDCPQ@  
{ ///xx/weblogic60b2_win.exe 7&|6KN}c  
try{ <u0,Fp  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); n[Co
S  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); M*`hDdS  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 6 64q~_@B1  
fileFetch.start(); 7n&yv
9"  
} p+Lv=e)0u  
catch(Exception e){e.printStackTrace ();} 2*'ciH37  
]0-<>  
vQHpf>o  
} {SdO9Yy?@7  
b#='^W3  
EO:avH.*0  
public static void main(String[] args) H,K`6HH  
{ ?1w"IjUS  
new TestMethod(); ag;dc  
} FN\GE\H  
} =:~(m  
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