http断点续传简单实现（java)

/* #QS`_TlKk  
**SiteFileFetch.java IDad9 Bx  
*/ +=>,Pto<  
package NetFox; M=8.Bp|Ye  
import java.io.*; ZFiee|,q  
import java.net.*; ](Xb_xMf  
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public class SiteFileFetch extends Thread { pf]xqhL  
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SiteInfoBean siteInfoBean = null; //文件信息Bean %h hf
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long[] nStartPos; //开始位置 O;+ m
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long[] nEndPos; //结束位置 NyaQI<5D  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 n"h`5p5'  
long nFileLength; //文件长度 ]>W6 bTK  
boolean bFirst = true; //是否第一次取文件 C+*d8_L  
boolean bStop = false; //停止标志 B~?*?Z'  
File tmpFile; //文件下载的临时信息 kS%Ydy#:'  
DataOutputStream output; //输出到文件的输出流 6{@w="VT  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） aH yx_B  
public SiteFileFetch(SiteInfoBean bean) throws IOException Hf%@3X  
{ k)i3   
siteInfoBean = bean; W6^5YH%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); jqz ux[6{  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); pD8+ 4;A  
if(tmpFile.exists ()) ~jWn4 \  
{ 
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bFirst = false; #{6{TFx\  
read_nPos(); l?\jB\,  
} pg6cF  
else S~<$Hy*kh  
{ aJSO4W)P  
nStartPos = new long[bean.getNSplitter()];
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nEndPos = new long[bean.getNSplitter()]; \/
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} SDC4L <!  
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} 1]d!~  
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public void run() fIM,lt  
{ )n1_(;  
//获得文件长度 /~DI 6g  
//分割文件 fPU`/6  
//实例FileSplitterFetch O5!7'RZ  
//启动FileSplitterFetch线程 _;W.q7b]  
//等待子线程返回 {k(g]#pP  
try{ hMa]B*o/-  
if(bFirst) y>S.?H:P  
{ W}nlRbN?  
nFileLength = getFileSize();  nI[os  
if(nFileLength == -1) >R|/M`<ph  
{ n"$jG:AQJ  
System.err.println("File Length is not known!"); R%Hi+#/dr-  
} +[
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else if(nFileLength == -2) u:}%xD6  
{ Y`KqEjsC*  
System.err.println("File is not access!"); Q
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} ZVW'>M7.  
else @MoKWfc  
{ B[qzUD*P_n  
for(int i=0;i<nStartPos.length;i++) Ih@61>X.o*  
{ !d'GE`w T  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); D,FHZDt  
} [.K1iZyTi  
for(int i=0;i<nEndPos.length-1;i++) |O3q@  
{ []D&bYpv  
nEndPos = nStartPos[i+1]; t1]K<>g  
} md+nj{Ib  
nEndPos[nEndPos.length-1] = nFileLength; =-tw5], L  
} 3\AU 72-  
} '-wj9OU  
( B!uy`  
<xup'n^7C  
//启动子线程 "WlZ)wyF%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 6d:zb;Iz  
for(int i=0;i<nStartPos.length;i++) <<UB ^v m  
{ 6o^,@~:R  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `34zkPB??  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), j 'FVz&  
nStartPos,nEndPos,i); ?}qttj  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); '|ad_M  
fileSplitterFetch.start(); y~(h>gi,x  
} .nTwPrG  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \-L&5x"x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); u^&A W$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",  JR'  
nEndPos = " + nFileLength); q~ tz? T_  
// fileSplitterFetch[nPos.length-1].start(); Mc@
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//等待子线程结束 1f%1*L0>@  
//int count = 0; &)2i[X  
//是否结束while循环 0mpX)S  
boolean breakWhile = false; #akpXdXs  
-N6f1>}pE  
; a/X<  
while(!bStop) %) /s;Q,  
{ t9nqu!);  
write_nPos(); [v7F1@6b  
Utility.sleep(500); wrviR  
breakWhile = true;
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s:?

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for(int i=0;i<nStartPos.length;i++) Y)1PB+  
{ lvdf^b/ j  
if(!fileSplitterFetch.bDownOver) A8x
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{ P|^f0Rw3.  
breakWhile = false; f< ia(
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break; >q#rw  
} _uWpJhCT  
} B3:ez jj  
if(breakWhile) B#exHf8  
break; w2;eh]k  
]5mnew  
Jlri*q"hE  
//count++; x`U^OLV  
//if(count>4) d+<G1w&z  
// siteStop(); %fc!2E9|  
} ng[Ar`  
8G9s<N}5&u  
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System.err.println("文件下载结束！"); [I0:=yJ+  
} C'G/AU  
catch(Exception e){e.printStackTrace ();} \<.+rqa!  
} 63^O|y\W8  
>l]Xz*HE  
\jh'9\  
//获得文件长度 >/g#lS 5  
public long getFileSize() %!]@J[*1  
{ wHzEMwY_  
int nFileLength = -1; !-ok"k0,u  
try{ 6rh5h:  
URL url = new URL(siteInfoBean.getSSiteURL()); W~6
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A]<y:^2])C  
httpConnection.setRequestProperty("User-Agent","NetFox"); f}aL-N~  
]-PH^H  
{^ qcx8  
int responseCode=httpConnection.getResponseCode(); .O74V~T  
if(responseCode>=400) pqk?|BvpK_  
{ H0:E(}@  
processErrorCode(responseCode); gGvz(R:
y  
return -2; //-2 represent access is error c*(bO3
b  
} J\/cCW-rF  
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c
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String sHeader; *,3SGcYdJj  
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for(int i=1;;i++) pN!}UqfI-  
{ 'ZT^PV\  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 1Y/s%L  
//Utility.log(in.readLine());
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sHeader=httpConnection.getHeaderFieldKey(i); ;QWIsVz  
if(sHeader!=null) V\t.3vT  
{ }]e-{C}  
if(sHeader.equals("Content-Length")) ?Fi=P#  
{ ]
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); F{Z~ R  
break; }
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} N+++4;  
} ! _f9NK  
else YT8vP~  
break; 5}:-h>  
} ?u-|>N>  
} PbW(%7o(t  
catch(IOException e){e.printStackTrace ();} =V-A@_^!c  
catch(Exception e){e.printStackTrace ();} a,xycX:U  
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Utility.log(nFileLength); %kv0Wefs  
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return nFileLength; mIurA?&7!  
} 3cFf#a#  
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//保存下载信息（文件指针位置） ,X#2\r<|  
private void write_nPos() 9G9fDG#F\I  
{ N8k00*p65  
try{ w0ht  
output = new DataOutputStream(new FileOutputStream(tmpFile)); S)lkz'tdk  
output.writeInt(nStartPos.length); #EO9UW5  
for(int i=0;i<nStartPos.length;i++) t=|evOz]  
{ (gy#js#  
// output.writeLong(nPos); &{ay=Mj  
output.writeLong(fileSplitterFetch.nStartPos); 5XO;
N s  
output.writeLong(fileSplitterFetch.nEndPos); Q7*SE%H  
} JF # # [O  
output.close(); mZk]l5Lc  
} ,ek_R)&[o  
catch(IOException e){e.printStackTrace ();} 4~y(`\0?4  
catch(Exception e){e.printStackTrace ();} tro7Di2Q  
} ?h.wK  
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//读取保存的下载信息（文件指针位置） GYJ80k|  
private void read_nPos() MJOz.=CbhR  
{ ;hYS6  
try{ 6;u$&&c(  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3 N.~mR  
int nCount = input.readInt();
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nStartPos = new long[nCount]; /h+8A',  
nEndPos = new long[nCount]; s1=X>'q  
for(int i=0;i<nStartPos.length;i++) :QpuO1Gu  
{ ^?U!pq-`  
nStartPos = input.readLong(); q ]M+/sl  
nEndPos = input.readLong(); i'4B3  
} w,w{/T+B  
input.close(); j:5=s%S  
} }3o|EXx=  
catch(IOException e){e.printStackTrace ();} ~R_ztD+C(  
catch(Exception e){e.printStackTrace ();} ;-9=RI0  
} $eD.W
 
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private void processErrorCode(int nErrorCode) cVubb}ou  
{ ,u!*2cWN  
System.err.println("Error Code : " + nErrorCode); G;&-\0>W  
} DBPRGQ  
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>_e]C}QUr  
//停止文件下载 K&nE_.kbl  
public void siteStop() v 0 }
@  
{ n1JRDw"e$$  
bStop = true; Ey_" ~OB  
for(int i=0;i<nStartPos.length;i++) ZYI{i?Te#  
fileSplitterFetch.splitterStop(); /]=C{)8  
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9S-Z&2L  
} PUF/#ck  
} _&N2'hG=sn  
//负责部分文件的抓取 L$9.8W  
**FileSplitterFetch.java =4[v3Qx  
*/ \n{qsf:  
package NetFox; {. 2k6_1[  
<Fi%iA  
@W vatD V  
import java.io.*; MNC*Glj=  
import java.net.*; CsTF  
9;_sC  
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public class FileSplitterFetch extends Thread { \Kl+ 5%L  
%ZNI:Uh  
z54EG:x.7^  
String sURL; //File URL ]%|GmtqZs,  
long nStartPos; //File Snippet Start Position ~Q?a|mV,  
long nEndPos; //File Snippet End Position 7[I}*3Q'  
int nThreadID; //Thread's ID 4kG,*3&2  
boolean bDownOver = false; //Downing is over S/^"@?z,vE  
boolean bStop = false; //Stop identical X}tVmO?  
FileAccessI fileAccessI = null; //File Access interface N$h{Yvbn  
&0NFb^8+  

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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException GqWB{$J;"  
{ ZT,B(#m  
this.sURL = sURL; T?
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this.nStartPos = nStart; ])L A42|  
this.nEndPos = nEnd;  '`eO\huf  
nThreadID = id; KMU4n-s"o  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 I2 j}Am  
} "ul {d(K3  
]3VI|f$$  
-M[$Zy^  
public void run() D$bIo"  
{ CPP` qt%f  
while(nStartPos < nEndPos && !bStop) nyBJb(5"B  
{ c/zJv*}x?  
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try{ c%&:6QniZ  
URL url = new URL(sURL); (>VX-Y/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); u#Z#)3P  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0Uz\H0T1  
String sProperty = "bytes="+nStartPos+"-"; )+}]+xRWGj  
httpConnection.setRequestProperty("RANGE",sProperty); ROk5]b.  
Utility.log(sProperty); ?\$#L^;b}  
XLAN Np%E  
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InputStream input = httpConnection.getInputStream(); s0DGC  
//logResponseHead(httpConnection); .Jt[(;  
$/.zm;D  
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byte[] b = new byte[1024]; sYjpU  
int nRead; O>^C4c!  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {) Q@c)'  
{ R,F[XI+=N  
nStartPos += fileAccessI.write(b,0,nRead); q>mE< (-M  
//if(nThreadID == 1) 0BH_'ZW  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); t*>R`,j  
} enp)-nS0  
} w 5l  
?RK]FP"A  
Utility.log("Thread " + nThreadID + " is over!"); '[C.|)"  
bDownOver = true; H2um|6>  
//nPos = fileAccessI.write (b,0,nRead); 7Garnd b  
} G`\f  
catch(Exception e){e.printStackTrace ();} Xb{ [c+.  
} (xVsDAp=@  
} |P -8HlOr  

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%kB8'a3  
//打印回应的头信息 1E73i_L  
public void logResponseHead(HttpURLConnection con) 9[m6Li  
{ 8"dv_`ym  
for(int i=1;;i++) q~3,yyu  
{ |4T!&[r  
String header=con.getHeaderFieldKey(i); E-I-0h2  
if(header!=null) 0%m)@ukb  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); xKQ+{"?-^g  
Utility.log(header+" : "+con.getHeaderField(header)); vgUb{D  
else 5m9*85Ib  
break; =dII- L=`  
} )yTm.F  
} QNARkYY~|  
,Fi>p0bz  
HYD"#m'TkB  
public void splitterStop() >B2:kY F  
{ WDg+J  
bStop = true; $OP7l>KZY  
} >2,Gy-&"0  
}; f#^gz'  
!<SA6m#  
} 0&/b42W  
9'{}!-(xR  
l2l(_$@3  
/* q|8{@EMT  
**FileAccess.java M-[$L XR  
*//文件访问(定位，写) Zf'TJ`S  
package NetFox; o>7ts&rk  
import java.io.*; Q5FM8Q
 
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z.Y$7bf)  
public class FileAccessI implements Serializable{ *,Za6.=  
w
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 e_/b2"{  
RandomAccessFile oSavedFile; j{NNSi3  
long nPos; /Wy.>YC|  
u%/goxA  
#*TEq
 
public FileAccessI() throws IOException `;>= '"O!\  
{ s1e:v+B]  
this("",0); RLSc+kDH_  
} BRk0CLr5  
!OT-b>*w  
:dLAs@z  
public FileAccessI(String sName,long nPos) throws IOException cIp D~0\  
{ wlEdt1G  
oSavedFile = new RandomAccessFile(sName,"rw"); * 1Od-3  
this.nPos = nPos; uPRQU+  
oSavedFile.seek(nPos); 4"xPr[=iG  
} cCa|YW^j  
NcP.;u;`  
gS:A'@&  
public synchronized int write(byte[] b,int nStart,int nLen) Oi:<~E[kz.  
{ ?c7*_<W5  
int n = -1; A?`jnRo=\  
try{ M?[h0{^K  
oSavedFile.write(b,nStart,nLen); ^b7GH9<&  
n = nLen; rtL}W__  
} .N*Pl(<[  
catch(IOException e) VMCLHpSfW  
{ Gkp<o  
e.printStackTrace (); dlG=Vq&Y  
} jS]><rm  
=IUUeFv +r  
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return n; fgBM_c&9T  
} 1&P<  
cKn`/\.H  
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} 1*dRK6  
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#?XQ7Im  
/* l2&`J_"  
**SiteInfoBean.java #hlCs  
*/ ^k Cn*&  
package NetFox; |QMhMGjV  
V=lfl1Ev0J  
*bxzCI7b  
public class SiteInfoBean { l983vKr  
%/>Y/!;  
9JWa$iBH@  
private String sSiteURL; //Site's URL Rcawc Y  
private String sFilePath; //Saved File's Path JXw^/Y$  
private String sFileName; //Saved File's Name ~j-cS J3  
private int nSplitter; //Count of Splited Downloading File #Jna6  
HmZ{L +"  
yB3;  
public SiteInfoBean() l/Vo-#  
{//nSplitter的缺省值为5 @]![o %  
//default value of nSplitter is 5 bcAvM;  
this("","","",5); \'M3|w`f  
} ~u.T-0F  
11,!XD*"  
efD)S92  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) %%Qo2^-  
{ rYp3(k3  
sSiteURL= sURL; }=v)Js
 
sFilePath = sPath; f}L*uw  
sFileName = sName; 0jzbG]pc:E  
this.nSplitter = nSpiltter; kEO7PK/  
*c)uGz'cD  
@m?QR(LJ  
} x)UwV  
!J=sk4T  
cv(PP-'\  
public String getSSiteURL() g!i45-n3gt  
{ *FfMI  
return sSiteURL; up2+s#  
} (Z}>1WRju  
U#n#7G6fRp  
KK,Z"){  
public void setSSiteURL(String value) QaGlR`Y  
{ 9 C{;h  
sSiteURL = value; 4G@nZn  
} \j2;4O?`  
zd_HxYrN  

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public String getSFilePath() |ea~'N1  
{ }dxDtqb  
return sFilePath; Bk}><H  
} dtPoo\@  
IG?'zppjd6  
m'-|{c  
public void setSFilePath(String value) `funE:>,  
{ `]v[5E  
sFilePath = value; )>7%pz  
} 5[{*{^F4  
 h C=:q  
9]'($:LF08  
public String getSFileName() >\ u<&>i  
{ }YOL"<,:o  
return sFileName; S?{/hy  
} .d?%;2*{q  
`mH %!{P  
f(D_FTTO  
public void setSFileName(String value) l/
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{ IZ3{>NV  
sFileName = value; 3u>8\|8wz  
} h7X_S4p/Mg  
1ZJQs6  
|xoF49
 
public int getNSplitter() XCsiEKZ_i  
{ IkzTJ%>  
return nSplitter; OquAql:   
} 3K@@D
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O9(r{Vu7u  
`Y40w#?uW  
public void setNSplitter(int nCount) 0)m8)!gj  
{ LwuF0\  
nSplitter = nCount; .bD_R7Bi6  
} U Q@7n1  
} YHV-|UNF  
)R_E|@"  

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/* 7:NmCpgL!  
**Utility.java RQW6N??C  
*/ 5~XN>>hp  
package NetFox; ":Edu,6O  
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~Z$bf>[(R7  
public class Utility { rSP_:}  
?RFg$Z'^  
02AI%OOH  
public Utility() :RxHw;!  
{ s,*c@1f?  
w'7R4  
+~sd"v6  
} I-NN29Sk  
V+wH?H=  
//线程睡眠 E{Pgf8
 
public static void sleep(int nSecond) !.5),2  
{ !SHj$Jwa'  
try{ 7@%'wy&A  
Thread.sleep(nSecond); _L.n,  
} vOI[Z0Lq9h  
catch(Exception e) w-N1.^  
{ io4A>>W==/  
e.printStackTrace (); \'?#i@O  
} oh#N 0 0X  
} &ogt2<1W  
]"fsW 9s  
//日志 &B{8uge1
 
public static void log(String sMsg) |-2}j2'  
{ IF k  
System.err.println(sMsg); &217l2X /  
} `BZ&~vJ_  
|I[7,`C~  
'3l$al:H^  
public static void log(int sMsg) $<?X7n^  
{ @=]8^?$t 0  
System.err.println(sMsg); KT*:F(4`  
} ZX`J8lZP  
} M"^K0 .  
QYE7p\  
WNa0,  
/* ek-!b!iI  
**TestMethod.java U!q[e`B  
*/ eQ
X`,9:5  
package NetFox; ,35&G"JK5  
@y~P&HUN  
eTE2J~\  
public class TestMethod { P]<= ! F  
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public TestMethod() [!*xO?yCJ  
{ ///xx/weblogic60b2_win.exe EH9Hpo  
try{ ,qFA\cO*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ~0tdfK0c  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); yDd[e]zS`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8LM#WIm?  
fileFetch.start(); !)OB@F%U  
} h#f&|*Q5m  
catch(Exception e){e.printStackTrace ();} 4B O %{  
@6xGJ,s  
d;suACW  
} 0my9l;X   
~\_T5/I%  
2g`[u|  
public static void main(String[] args) ~5#)N{GbY  
{ ?s{C//  
new TestMethod(); X}JWf<=q  
} 9k2,3It  
} KXBL eR&^  
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