http断点续传简单实现（java)

/* b<]--\  
**SiteFileFetch.java sbWen?  
*/ UIhU[
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package NetFox; N>Dr z  
import java.io.*; 6EHYIN^D  
import java.net.*; <"Ox)XG3]W  
-\Y"MwIED  
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public class SiteFileFetch extends Thread { :>@6\  
W u4` 3  

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SiteInfoBean siteInfoBean = null; //文件信息Bean 2`D1cX  
long[] nStartPos; //开始位置 7d44i  
long[] nEndPos; //结束位置 Im7t8XCG  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 RyI(6TZl  
long nFileLength; //文件长度 Gp0B^^H$  
boolean bFirst = true; //是否第一次取文件 zQ;jaS3hf  
boolean bStop = false; //停止标志 qs96($  
File tmpFile; //文件下载的临时信息 .XD.'S  
DataOutputStream output; //输出到文件的输出流 u@(z(P  
s-\.j-Sa  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） (MI8Kkb1d  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3J^"$qfSn  
{ 'N-nFc^  
siteInfoBean = bean; i)vbmV  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); rQ_!/J[9  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); v[3QI7E3  
if(tmpFile.exists ()) 1qEpQ
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{ MfX1&/Z+  
bFirst = false; {8'f>YP  
read_nPos(); ; O6Ez-"  
} pZpAb+  
else ~EYsUC#B_  
{ yuTSzl25,/  
nStartPos = new long[bean.getNSplitter()]; br
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nEndPos = new long[bean.getNSplitter()]; ?Ek 3<7d  
} 3Kv~lo
^  
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} 3#=%2\  
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q
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public void run()
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{ @ m' zm:  
//获得文件长度 xJ2DkZ  
//分割文件 +#|| w9p  
//实例FileSplitterFetch  j-H2h  
//启动FileSplitterFetch线程 a&'!
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//等待子线程返回 q<5AB{Oj?  
try{ nnv&~
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if(bFirst) oxs0)B  
{ _$&C$q$1y  
nFileLength = getFileSize(); =)Aav!  
if(nFileLength == -1) +3;`4bW  
{ cip"
9|"  
System.err.println("File Length is not known!"); {LwV&u(  
} K *<+K<Tp  
else if(nFileLength == -2) *%[L @WF  
{ 2X:OS/  
System.err.println("File is not access!"); scXY~l]I*  
} TSgfIE|
 
else <BUKTRq  
{ j %3wD2 l  
for(int i=0;i<nStartPos.length;i++) s{"}!y=]  
{ td}%reH  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); LSX;|#AI  
} }^ g6Y3\  
for(int i=0;i<nEndPos.length-1;i++) #:UP'v=w  
{ n9PCSl j  
nEndPos = nStartPos[i+1]; OoG Nij  
} BZ'63  
nEndPos[nEndPos.length-1] = nFileLength; 6k1;62Ntk  
} kYwV
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} Hp#IOsP~  
T-;|E^  
_4Ciai2Ql  
//启动子线程  T:~c{S4&  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |8DMj s()*  
for(int i=0;i<nStartPos.length;i++) u\&F`esQ2  
{ ^lI>&I&1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &l&B[s6[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), R#K,/b%SV  
nStartPos,nEndPos,i); C0RnBu  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `$fKS24u  
fileSplitterFetch.start(); WbIf)\  
} ^]{)gk8P~2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), []\=(Uc;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); dKG2f  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", lR
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nEndPos = " + nFileLength); /=+y[y3`  
// fileSplitterFetch[nPos.length-1].start(); 53g(:
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`oPUf!  
vv 
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//等待子线程结束 d=*&=r0!C{  
//int count = 0; O/N Ed)H!  
//是否结束while循环 Q5kf-~Jx+  
boolean breakWhile = false; KtR*/<7IC  
<i!:{'%  
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while(!bStop) T@{}!  
{ y)Y0SY1\j  
write_nPos(); q'% cVM  
Utility.sleep(500); 8<2 [ F  
breakWhile = true; $G,#nh2 oD  
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for(int i=0;i<nStartPos.length;i++) 4^OPzg6Z%p  
{ bvR0?xnq  
if(!fileSplitterFetch.bDownOver) {&I3qk2(  
{ 6 _Cc+}W  
breakWhile = false; `S&.gPE2  
break; UA%tI2  
} [f8mh88r  
} )C1ihm!7\  
if(breakWhile) UHaY|I${U  
break; 20NotCM  
<$:Hf@tpMo  
*# 7 1aZ  
//count++; n0T>sE-9  
//if(count>4) D.ajO^[  
// siteStop(); ?gGmJl  
} HW"';M%  
>3,t`Z:  
9 M<3m  
System.err.println("文件下载结束！"); _d J"2rx  
} ;oT!\$Mu  
catch(Exception e){e.printStackTrace ();} +eIX{J\s  
} $Fr>'H+i  
sX,."@[  
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//获得文件长度 kJfMTfl,  
public long getFileSize() Jh6 z5xUV  
{ 1>"Yw|F-|3  
int nFileLength = -1; ]Av)N6$&-Z  
try{ C8oAl3d+h  
URL url = new URL(siteInfoBean.getSSiteURL()); 5(qc_~p^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B=,j$uH  
httpConnection.setRequestProperty("User-Agent","NetFox"); .!><qVg  
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=D}]
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int responseCode=httpConnection.getResponseCode(); (&=gM  
if(responseCode>=400) =0" Zse,  
{ 6M)4v{F  
processErrorCode(responseCode); 1|Q-|jq`  
return -2; //-2 represent access is error $!m (S&f  
} wpW3
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String sHeader; Q"Ur*/-U  
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for(int i=1;;i++) -h|YS/$f  
{ RY\[[eG  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ! ,v!7I  
//Utility.log(in.readLine()); zmEg4v'I  
sHeader=httpConnection.getHeaderFieldKey(i); FKVf_Ncf%
 
if(sHeader!=null) A2xfNY<  
{ 1#OM~v6B  
if(sHeader.equals("Content-Length")) 7hLdCSX  
{ &.4m(ZX  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); iAd3w6  
break; ^~65M/  
} S(Ej: H  
} ,!{/Y7PmJ  
else $Lf-Gi  
break; rT}k[  
} '4x uH3  
} &|j^?ro6  
catch(IOException e){e.printStackTrace ();} tXu_o6]  
catch(Exception e){e.printStackTrace ();} -sqoE*K[8  
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Utility.log(nFileLength); 8t$w/#'@  
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return nFileLength; E5EA
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} q n2X._`  
^CtA@4  
6%8,OOS  
//保存下载信息（文件指针位置） `&rt>Bk /  
private void write_nPos() b+DBz}L4  
{ }@'Zt6+tS  
try{ zK@DQ5  
output = new DataOutputStream(new FileOutputStream(tmpFile)); s+jL BY  
output.writeInt(nStartPos.length); -NgL4?p=  
for(int i=0;i<nStartPos.length;i++) <:gNx%R  
{ m-h+UKt  
// output.writeLong(nPos); }X;LR\^u[f  
output.writeLong(fileSplitterFetch.nStartPos); YlP8fxS  
output.writeLong(fileSplitterFetch.nEndPos); <6(&w9WY  
} Co%EJb"tk  
output.close(); 8G6[\P3fQ  
} 2TxHY|4  
catch(IOException e){e.printStackTrace ();} }-8ZSWog6f  
catch(Exception e){e.printStackTrace ();} WXgGB[x  
} bf2B  
O*%@(w6  
',g'Tl^E  
//读取保存的下载信息（文件指针位置） <8_~60  
private void read_nPos() j1Q"s(  
{ ^]A,Q%1q^  
try{ $^XCI%DH  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); {G^f/%  
int nCount = input.readInt(); 3%'Y):  
nStartPos = new long[nCount]; &|8R4l
C|  
nEndPos = new long[nCount]; XzH"dDAVE  
for(int i=0;i<nStartPos.length;i++) c|,6(4j>$  
{ rgOc+[X  
nStartPos = input.readLong(); [fjP.kw;J  
nEndPos = input.readLong(); ( ;(DI^Un8  
} dRXEF6G  
input.close(); FWJhi$\:D]  
} .dvOUt I[  
catch(IOException e){e.printStackTrace ();} -%g&O-i\  
catch(Exception e){e.printStackTrace ();} L=1~)>mP  
} |
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?-HLP%C('  
private void processErrorCode(int nErrorCode) $QB~ x{v@n  
{  `[=3_  
System.err.println("Error Code : " + nErrorCode); ]3/_?n-"`  
} {0t-Q k  
&P,z$H{o@  
ZNX=]]HM<n  
//停止文件下载 6k@(7Mw8A  
public void siteStop() e71dNL'$  
{ bWe_<'N  
bStop = true; m\];.Da  
for(int i=0;i<nStartPos.length;i++) ~t` uq  
fileSplitterFetch.splitterStop(); -T0@b8  
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9BA*e-[  
} [IgB78_$  
} ^ rB7&96C,  
//负责部分文件的抓取 2[;4D/`*  
**FileSplitterFetch.java GqT0SP  
*/ jLy3c@Dp  
package NetFox; Y>l92=G  
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import java.io.*; {@7{!I|eD  
import java.net.*; s,*kWy"jp  

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public class FileSplitterFetch extends Thread { tU :,s^E"#  
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String sURL; //File URL ZI0C%c.~  
long nStartPos; //File Snippet Start Position t;?TXAA  
long nEndPos; //File Snippet End Position f L}3I(VK  
int nThreadID; //Thread's ID IB sQaxt.  
boolean bDownOver = false; //Downing is over <:tD m  
boolean bStop = false; //Stop identical e/{1u$  
FileAccessI fileAccessI = null; //File Access interface ^q$m>|KI  
qyx  '  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException zv%9?:  
{ p903*F^[,  
this.sURL = sURL; e7cqm*Qi  
this.nStartPos = nStart; Gd]!D~[1  
this.nEndPos = nEnd; x^J}]5{0  
nThreadID = id; |1@/gqa  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 l?AWG&  
} 1$]hyC/f  
Cqy)+x_OQ,  
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public void run() T,sArKBI  
{ A{3?G-]*  
while(nStartPos < nEndPos && !bStop) juAUeGT  
{ _W3>Km-A=/  
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try{ c~0hu*&  
URL url = new URL(sURL); r/32pY  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #RG/B2  
httpConnection.setRequestProperty("User-Agent","NetFox"); Rpi@^~aPE  
String sProperty = "bytes="+nStartPos+"-"; *_aeK~du.  
httpConnection.setRequestProperty("RANGE",sProperty); x2KIGG^  
Utility.log(sProperty); ;Rz+4<  
Y@+e)p{  
YXdd=F  
InputStream input = httpConnection.getInputStream(); w[A$bqz  
//logResponseHead(httpConnection); `h:$3a:5  
:JEzfI1  
b&i0)/;  
byte[] b = new byte[1024]; nVp*u9]  
int nRead; ')8c  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ir-= @@  
{ Rqk;!N  
nStartPos += fileAccessI.write(b,0,nRead); SS/9fT"[  
//if(nThreadID == 1) )Hp{
8c  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6^Q Bol  
} k
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SR4cR)Iz
 
Utility.log("Thread " + nThreadID + " is over!"); "K7{y4  
bDownOver = true; 4]VoIUIuN  
//nPos = fileAccessI.write (b,0,nRead); mo$`a6[h<  
} |BO!q9633V  
catch(Exception e){e.printStackTrace ();} ]4$t'wI.  
} !@r1B`]j+"  
} 2}ttCm  
cr&sI=i  
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//打印回应的头信息 AaVj^iy/X  
public void logResponseHead(HttpURLConnection con) /hojm6MM  
{ >sUavvJ~x  
for(int i=1;;i++) +~E;x1&'  
{ p\7(`0?8VN  
String header=con.getHeaderFieldKey(i); *G<K@k  
if(header!=null) S:*.,zC  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); AWY#t&
 
Utility.log(header+" : "+con.getHeaderField(header)); Gs2|#*6  
else nO'lN<L  
break; s Y^#I  
} f:=y)+@1My  
} 6eUM[C.  
{GTOHJ2  
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public void splitterStop() bpQ5B'9  
{ .??[qBOTE  
bStop = true; KKPQ[3g  
} Y6>@zznk  
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} (zVT{!z  
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* mzJ)4A  
/* &L88e\ c+  
**FileAccess.java zNu>25/)(  
*//文件访问(定位，写) 0#gu7n|J  
package NetFox; KfSI6 Y_  
import java.io.*; ,-C%+S
C  
y@5{.jsr_  
th$?#4SbR  
public class FileAccessI implements Serializable{ }67lL~L  
0 e}N{,&Y  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {hS9FdWA;  
RandomAccessFile oSavedFile; -2{NIF^H  
long nPos; ^1#"FU2cP  
Qh4<HQ<9  
<"93  
public FileAccessI() throws IOException MDHTZ94\Q  
{ xJQ-k/`  
this("",0); &2~c,] 9C  
} O?6ph4'  
8"fZ>XQ  
7Vn;LW  
public FileAccessI(String sName,long nPos) throws IOException 'zEmg}  
{ !)Y T_ib  
oSavedFile = new RandomAccessFile(sName,"rw"); 5gdsV4DH$  
this.nPos = nPos; ~^<ju6O'  
oSavedFile.seek(nPos); 9^DXw!  
} J=%(f1X<W  
20Umjw.D  
b5-WK;  
public synchronized int write(byte[] b,int nStart,int nLen) -^Pn4
y]A)  
{ k>2tC<  
int n = -1; =JqKdLH
 
try{ z'FpP  
oSavedFile.write(b,nStart,nLen); E{Tvjh+  
n = nLen; _{eH" ,(  
} >uu]
K  
catch(IOException e) zA~aiX  
{ %\if
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e.printStackTrace (); l,I[r$TCf  
} 8&g`Uy/b  
lg9
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return n; ;tBc&LJ?  
} Lrr1) h  
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} 'Ti7}K  
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/* 4iDlBs+  
**SiteInfoBean.java >~nc7j u  
*/ d0b`qk @4  
package NetFox; gcaXN6C  
ckglDhC  
)L
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public class SiteInfoBean { ?`,Rkg0fe  
rZ|!y ~S|  
.4t-5,7s%  
private String sSiteURL; //Site's URL dbmty|d  
private String sFilePath; //Saved File's Path Y&G]M  
private String sFileName; //Saved File's Name \Q CH.~]  
private int nSplitter; //Count of Splited Downloading File SR+<v=i  
5kRP Sfh  
n1"QHA  
public SiteInfoBean() yV'<l .N  
{//nSplitter的缺省值为5 hC nqe  
//default value of nSplitter is 5 lZt{L0  
this("","","",5); Y$@?Y/rhR  
} mYE8]4  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) I^CKq?V?:  
{ 0~)_/yx?S  
sSiteURL= sURL; +&U{>?.u  
sFilePath = sPath; |JR;E
$  
sFileName = sName; 2tEA8F~k  
this.nSplitter = nSpiltter; #dd-rooQuD  
Ykt{]#  
5S;|U&f|  
} H.n+CR  
O%$XgEJ8p  
{<p-/|Z52  
public String getSSiteURL() A.5N<$l  
{ :~% zX*  
return sSiteURL; cNd;qO0$  
} ]tu:V,q  
Ja*k|Rz~  
m^9[k,;K  
public void setSSiteURL(String value) 5UTIGla  
{ A3!xYG=+  
sSiteURL = value; ZjOUk;H
?  
} `;:zZ8*  
_:0)uR LS  
aCwb[7N  
public String getSFilePath() hv6w=?7  
{ 8.g(&F  
return sFilePath; +FYQ7UE  
} ;)SWUXa;{  
U,Duq^l~s  
-t5DcEAb$  
public void setSFilePath(String value) /IkSgKJiz\  
{ %.zcE@7*  
sFilePath = value; ^<}>]F_  
} RH"
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.;:jGe(  
OE"r=is  
public String getSFileName() =VctG>ct|  
{ \0^ZNa?  
return sFileName; =s\RK   
} :J'ibb1  
,)CRozC\}K  
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public void setSFileName(String value) +pq/:h  
{ 2f=7`1RCD  
sFileName = value; uqN:I)>[P  
} s-z*Lq*  
QIcg4\d%s  
9T#JlV  
public int getNSplitter() ?9?eA^X%  
{ R24ZjbKL  
return nSplitter; 8%Wg;:DZx  
} ;`TSu5/  
,J(+%#$UT  
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public void setNSplitter(int nCount) 4ZRE3^y\"  
{ .&Vyo<9Ck  
nSplitter = nCount; Wb|xEwqd`  
} p{sbf;-x}  
} 5GwXZ;(G  
N?7vcN+-t)  
X53TFRxnT  
/* $_5@NOZ,M  
**Utility.java HLPnbI-+  
*/ @ZD/y%e  
package NetFox; T9c=As_EM  
n1Y3b~E?E  
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public class Utility { AIx,c1G]K  
bay7%[BLB  
f\Fk+)e@  
public Utility() :=<0Z1S  
{ e2onR~Cf  
1VH$l(7IQ  
mJ>@Dh3>G  
} bhIyq4N  
r%QnV0L^  
//线程睡眠 oQkY@)3.w  
public static void sleep(int nSecond) g.cD3N  
{ #ilU(39e  
try{ _QhB0/C  
Thread.sleep(nSecond); xEA%UFB.!G  
} ]{[8$|Mg  
catch(Exception e) ?^# h|aUp.  
{ dZ kr#>  
e.printStackTrace (); }-e  
} ~[|zf*ZISG  
} jv"^_1  
A(xCW+h@)  
//日志 (4U59<ie  
public static void log(String sMsg) Ix"hl0Kh  
{ )ZU=`!4  
System.err.println(sMsg); T}?vp~./   
} w'Kc#2  
ddR_+B*H  
w84 ]s%y  
public static void log(int sMsg) OfR\8hAY  
{ ""dX4^gtU  
System.err.println(sMsg); ~+y0UEtq7  
} l<](8oc. w  
} R/yOy^<  
t;Rdrk  
Tz=YSQy$9  
/* }x[d]fcC  
**TestMethod.java Dm3/i|Y  
*/ 3,snx4q (  
package NetFox; pY3N7&m\:  
Y'.WO[dgf  
K{ s=k/h  
public class TestMethod { yxECK&&P0#  
U2tsHm.O  
x bG'![OX  
public TestMethod() ~/@5&ajz  
{ ///xx/weblogic60b2_win.exe "!yKX(aTX  
try{  9"@P.8_  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 4b"%171  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); n&. bs7N2  
SiteFileFetch fileFetch = new SiteFileFetch(bean); T4W"!4[  
fileFetch.start(); 3wS{@'  
} !  Z e  
catch(Exception e){e.printStackTrace ();} S;o U'KOY  
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} OFJ T  
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public static void main(String[] args) }T?MWcG4  
{ c=YJ:&/5&  
new TestMethod(); b&$ ?.z  
} =A6/D    
} ,_66U;T  
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