http断点续传简单实现（java)

/* YGP.LR7  
**SiteFileFetch.java ]iewukB4  
*/ 5?+ECxPt  
package NetFox; /; ;_l2t  
import java.io.*; h:iK;  
import java.net.*; hn
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public class SiteFileFetch extends Thread { jm1f,=R  
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SiteInfoBean siteInfoBean = null; //文件信息Bean p\]Mf#B  
long[] nStartPos; //开始位置 *NdSL  
long[] nEndPos; //结束位置 `y5?lS*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Ca]+*Eb9z{  
long nFileLength; //文件长度 R[Q`2ggG  
boolean bFirst = true; //是否第一次取文件 LeBuPR$  
boolean bStop = false; //停止标志 413,O~^  
File tmpFile; //文件下载的临时信息 V!#+Ti/w4  
DataOutputStream output; //输出到文件的输出流 )UA$."~O  
1|)l6#hOL  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ig(a28%  
public SiteFileFetch(SiteInfoBean bean) throws IOException J<h^V+x  
{ o2e aSG  
siteInfoBean = bean; rQ -pD  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); (|DmYn!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); :_;9&[H9ha  
if(tmpFile.exists ()) kwRXNE(k]_  
{ tz&'!n}  
bFirst = false; h2g|D(u)  
read_nPos(); ">vxYi  
} !+tz<9BBY  
else m\>531&  
{ U)~?/s{v  
nStartPos = new long[bean.getNSplitter()]; zPWX%1Qr  
nEndPos = new long[bean.getNSplitter()]; C$o#zu q-  
} ydo"H9NOS  
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} 5$o]
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public void run() 2P9gS[Ub  
{ &WN#HI."]  
//获得文件长度 InDISl]  
//分割文件 qkB)CY7  
//实例FileSplitterFetch PjriAlxD  
//启动FileSplitterFetch线程 ea-NqdGs;m  
//等待子线程返回 .v<c_~y  
try{ asT:/z0  
if(bFirst) _" 0VM>  
{ 7'pCFeA>=T  
nFileLength = getFileSize(); &{${Fq
 
if(nFileLength == -1) LB}y,-vX>  
{ '<"eG!O  
System.err.println("File Length is not known!"); #g,JNJ}  
} `6:;*#jO,  
else if(nFileLength == -2) FSZQ2*n5  
{ 7Io]2)V  
System.err.println("File is not access!"); x ;V7D5 q  
} fx@Hd!nO~"  
else "L^Klk?Vn  
{ Ipo?>To  
for(int i=0;i<nStartPos.length;i++) V?U->0>Z4  
{ "Sp+Q&2U  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); | k"?I  
} d&K2\n  
for(int i=0;i<nEndPos.length-1;i++) )SG+9!AbMZ  
{ @
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nEndPos = nStartPos[i+1]; b~?FV>gl  
} u
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nEndPos[nEndPos.length-1] = nFileLength; KLv`Xg\  
} _,V 9^  
} B
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z(]14250  
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//启动子线程 A<ca9g3  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 6.? Ke8iC  
for(int i=0;i<nStartPos.length;i++) dKyJ.p
 
{ MONfA;64/  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4%wP}Zj#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), My'u('Q%  
nStartPos,nEndPos,i); ?c712a ?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); PM3kI\:)m  
fileSplitterFetch.start(); kL;sA'I:S  
} [4uTp[U!r  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <4,hr
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,4$ZB(\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",  9?c0cwP?  
nEndPos = " + nFileLength); tRU+6D <w  
// fileSplitterFetch[nPos.length-1].start(); _[|~(lDJl  
-V@vY42  
uM"G)$I\  
//等待子线程结束 f\+MnZ4[Qj  
//int count = 0; >r+Dl\R  
//是否结束while循环 dL%?k@R  
boolean breakWhile = false; R$
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o33wePx,  
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while(!bStop) J#DYZ>}Y  
{ 6XyhOs%/  
write_nPos(); }RX[J0Prq~  
Utility.sleep(500); L&3Ak}sh  
breakWhile = true; &Rw4ub3  
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for(int i=0;i<nStartPos.length;i++) 0ut/ ')[  
{ ;Awt:jF  
if(!fileSplitterFetch.bDownOver) 5B3S]@%  
{ 3@XkO  
breakWhile = false; !6yoD  
break; 6gz !K"S  
} .&O}/B  
} {+~}iF<%  
if(breakWhile) ;Z]i$Vi_r  
break; T
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//count++; ">='l9  
//if(count>4) /wplP+w2  
// siteStop(); G gmv(!  
} HGqT"NJr  
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System.err.println("文件下载结束！"); $'D|}=h<Y  
} ut8v&i1?  
catch(Exception e){e.printStackTrace ();} ;&B;RUUnTO  
} 3F fS2we  
V8`o71p  
eZes) &4  
//获得文件长度 m
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public long getFileSize() J^tLKTB  
{ )}QtK+Rq  
int nFileLength = -1;
``*iK  
try{ O_%X>Q9  
URL url = new URL(siteInfoBean.getSSiteURL()); Jq0aDf f  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); H4C]%Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); +]I7]  
;&mefaFlWp  
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int responseCode=httpConnection.getResponseCode(); d{^9` J'  
if(responseCode>=400) UIS\t^pJD  
{ fFu+P<?"  
processErrorCode(responseCode); w1q-bIU  
return -2; //-2 represent access is error VJW%y)_[  
} ug]WIG7 S  
]%Am
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String sHeader; t[HfaW1W  
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for(int i=1;;i++) G 3))3]  
{ )l 0\TF  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Nl~'W  
//Utility.log(in.readLine()); $07;gpZt  
sHeader=httpConnection.getHeaderFieldKey(i); HRX}r$  
if(sHeader!=null) X>}-UHKV+  
{ 9FB k|g"U)  
if(sHeader.equals("Content-Length")) +OSF0#bj  
{ #.1+-^TQk  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {8b6M  
break; V~nqPh!Jc  
} ^{f^%)X  
} 3d<Z##`{4  
else *F:f\9  
break; SUv(MA&  
} XcN"orAo  
} tzH~[n,  
catch(IOException e){e.printStackTrace ();} pC=kvve  
catch(Exception e){e.printStackTrace ();} WC2sRv4]3  
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Utility.log(nFileLength); 1 Hw%DJ  
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return nFileLength;
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} 2
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//保存下载信息（文件指针位置） "d1~(0=6<m  
private void write_nPos() Cp!bsasj  
{ e`]x?t<U4/  
try{ k*xMe-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); d v8q&_  
output.writeInt(nStartPos.length); 2
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for(int i=0;i<nStartPos.length;i++) JDbRv'F:(  
{ P*=M?:Jb,  
// output.writeLong(nPos); fXo$1!  
output.writeLong(fileSplitterFetch.nStartPos); pi?$h"y7Q  
output.writeLong(fileSplitterFetch.nEndPos); CEQs}bz  
} JU>F&g/|  
output.close(); 'YFy6rds  
} +!"GYPUXy  
catch(IOException e){e.printStackTrace ();} 0oT~6BGm  
catch(Exception e){e.printStackTrace ();} a!?JVhD&  
} 0Y|"Bo9
k  
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//读取保存的下载信息（文件指针位置） _
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private void read_nPos() :v$][jZ2  
{ nF"NXYa  
try{ 5t
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); msf%i!  
int nCount = input.readInt(); t%S2D  
nStartPos = new long[nCount]; 7XM:4whw  
nEndPos = new long[nCount]; ;W~H|M  
for(int i=0;i<nStartPos.length;i++) luvxwved  
{ "`6pF8k  
nStartPos = input.readLong(); uV=ZGr#o  
nEndPos = input.readLong(); C-
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} YY4XCkt  
input.close(); k-CW?=  
} lE=&hba  
catch(IOException e){e.printStackTrace ();} dbe\ YE  
catch(Exception e){e.printStackTrace ();} f;{K+\T  
} Z;'5A2  
{TOz}=R"3h  
@~ 6,8nQ  
private void processErrorCode(int nErrorCode) 
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{ T<ka4  
System.err.println("Error Code : " + nErrorCode); x<Ac\Cx  
} ]H {g/C{j  
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//停止文件下载 b)(si/]\  
public void siteStop() >~}}*yp  
{ u2o196,Ut  
bStop = true; SJ7-lben3  
for(int i=0;i<nStartPos.length;i++) +,q#'wSQG  
fileSplitterFetch.splitterStop(); ~rfUqM]I   
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} |U:VkiKt  
} { POfT m}  
//负责部分文件的抓取 Y@l>4q")  
**FileSplitterFetch.java '/U%-/@  
*/ VX6M4<8  
package NetFox; 'hNRIM1  
V*,6_-^l  
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import java.io.*; uY;7&Lw y1  
import java.net.*; )u?^w  
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public class FileSplitterFetch extends Thread { -IE=?23Do?  
"2_nN]%u-  
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String sURL; //File URL =38
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long nStartPos; //File Snippet Start Position p!/ *(TT  
long nEndPos; //File Snippet End Position a/Ik^:>m  
int nThreadID; //Thread's ID Nm{J=`  
boolean bDownOver = false; //Downing is over -Pp =)_O  
boolean bStop = false; //Stop identical :"Gd;~p.  
FileAccessI fileAccessI = null; //File Access interface Sp-M:,H3H  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException `st^i$A  
{ %) /Bl.{}<  
this.sURL = sURL; 70F(`;  
this.nStartPos = nStart; W<\*5oB%H  
this.nEndPos = nEnd; X,`^z,M%I  
nThreadID = id; mV;)V8'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 GhC%32F  
} ;s^F:O  
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public void run() lPA:ho/`:  
{ 3J}/<
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while(nStartPos < nEndPos && !bStop) zgPUW z X=  
{ }JM02R~I  
e
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try{ jRBKy8?[C  
URL url = new URL(sURL); S<o\.&J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2>F`H7W  
httpConnection.setRequestProperty("User-Agent","NetFox"); [&5%$ T  
String sProperty = "bytes="+nStartPos+"-"; -~TgA*_5]  
httpConnection.setRequestProperty("RANGE",sProperty); rPx:o}&<  
Utility.log(sProperty); oV;I8;#\J  
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InputStream input = httpConnection.getInputStream(); '/GZ/$a_l  
//logResponseHead(httpConnection); 0czEA  
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byte[] b = new byte[1024]; +kM*BCPYE  
int nRead; OE(!^"5?[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ."h>I @MH  
{ `{+aJ0<S  
nStartPos += fileAccessI.write(b,0,nRead); >U62vX"  
//if(nThreadID == 1) qlg?'l$03)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,3bAlc8D7  
} qwvch^?>FQ  
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pKhV<MFB  
Utility.log("Thread " + nThreadID + " is over!"); 9;L50q>s  
bDownOver = true; ~PA6e+gmL  
//nPos = fileAccessI.write (b,0,nRead); *3h!&.zm  
} .]LP327u  
catch(Exception e){e.printStackTrace ();} 9V?:!%J  
} ,K8(D<{  
} =P`l+k3  
yr q){W  
+<7a$/L?4  
//打印回应的头信息 lQt* LWd[  
public void logResponseHead(HttpURLConnection con) _<7e5VR  
{ ;#n+$Q#:  
for(int i=1;;i++) KBa   
{ ~Aoo\fN_U  
String header=con.getHeaderFieldKey(i); Ji;R{tZ.R  
if(header!=null) 8+8P{_  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); D`@*udn=  
Utility.log(header+" : "+con.getHeaderField(header)); ,7^,\ ,-m  
else !A#(bC  
break; jB0ED0)wX  
} +*Pj,+;W  
} ?T7ndXX  
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*K=Yrisz  
public void splitterStop() S)z5=N(Xz  
{ g6(u6%MD  
bStop = true; zf?U q  
} hC2_Yr>N%  
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} }NF7"tOL  
#RVN7-x  
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/* A
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**FileAccess.java #]e](j>]  
*//文件访问(定位，写) ;`}b .S=n  
package NetFox; 0|OmQ\SQ  
import java.io.*; {on+ ;,  
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public class FileAccessI implements Serializable{ |<w Z;d  
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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 f}?q  
RandomAccessFile oSavedFile; A"no!AN  
long nPos; JTfG^Nv>K  
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public FileAccessI() throws IOException >n6yKcjY]  
{ WG(%Pkowv
 
this("",0); u{(-`Al}L  
} "bk'#?9  
(VH0+  
93fClF|@  
public FileAccessI(String sName,long nPos) throws IOException V8IEfU  
{ Q0-}!5`E1$  
oSavedFile = new RandomAccessFile(sName,"rw"); [y1 x`WOk9  
this.nPos = nPos; [cvtF(,  
oSavedFile.seek(nPos); &+-]!^2o  
} @DK;i_i  
0OPpALl  
[XDr-5Dm  
public synchronized int write(byte[] b,int nStart,int nLen) #`b5kqQm  
{ h0n,WU/Kw  
int n = -1; )Qixde>]p  
try{ [;8vO=Z  
oSavedFile.write(b,nStart,nLen); D_-<V,3t  
n = nLen; AZ& ]@Ao  
} 5Q.z#]Lg  
catch(IOException e) K!onV3mR  
{ h;`]rK;g  
e.printStackTrace (); ZX03FJL7u  
} }5a$Ka-  
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return n; 3m59EI-p  
} -3eHJccB  
)kuw&SH,  
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} (#%R'9Rv  
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A3c&VT6Q  
/* ;,Q6AS!
 
**SiteInfoBean.java /;\{zA$uC=  
*/ Y
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package NetFox; { 0vHgi  
eE-c40Bae  
0Rze9od]$  
public class SiteInfoBean { l1wYN,rv  
:c^9\8S  
#E#.`/4  
private String sSiteURL; //Site's URL GPVqt"TY  
private String sFilePath; //Saved File's Path PTFe>~vr*  
private String sFileName; //Saved File's Name ~lB:xVzn  
private int nSplitter; //Count of Splited Downloading File R6/vhze4L2  
'q9='TOk  
990sE t?  
public SiteInfoBean() X'KkIo :  
{//nSplitter的缺省值为5 9;k!dM  
//default value of nSplitter is 5 ^lCQHz  
this("","","",5); F^)SQ%xx  
} t ]yD95|  
o,;Hb4Eu  
y&8kORz;?  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) (XJ0?;js=  
{ [!CIBK99  
sSiteURL= sURL; ZJeTx.Gi6  
sFilePath = sPath;
T%p/(  
sFileName = sName; )i{B:w\ ^  
this.nSplitter = nSpiltter; =(U&?1R4  
c<J/I_!  
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} GVt}\e~"  
S|HnmkV66  
j,BiWgj$8  
public String getSSiteURL() !;ipLC;e}  
{ "8|a4Y+F  
return sSiteURL; P-~kxb9aa  
} Lm}J&^>  
eFiUB  
&T)h9fyc  
public void setSSiteURL(String value) 0zvA>4cq)  
{  }FoO  
sSiteURL = value; 84uHK)h<%  
} pHkhs{/X  
39zwPoN>  
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public String getSFilePath() Rh.CnCbM  
{ 5,n{-V  
return sFilePath; m:A1wL4c6  
} GI40Ztms  
y8QJ=v* B  
n'-?CMH`  
public void setSFilePath(String value) =TzmhX5  
{ }|Wn6X  
sFilePath = value; I||4.YT  
} )^'g2gVK+p  
Z(=UZI?  
t@1bu$y  
public String getSFileName() nC>'kgRt  
{ #lHA<jI  
return sFileName; b\^q9fy  
} s wIJmA  
0~0OQ/>7  
Ws>2S  
public void setSFileName(String value) nD8CP[bRo  
{ ca{u"n  
sFileName = value; 'eRJQ*0F  
} 0Zq jq0O#  
#=* y7w  
JM?X]l  
public int getNSplitter() K V-}:u(  
{ >TqMb8e_  
return nSplitter; mm,be.  
} It .`  
;[~:Y[N  

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public void setNSplitter(int nCount) g)@d(EYY  
{ QIg.r\>o  
nSplitter = nCount; ;}BDEBl  
} NLLLt  
} O5:2B\B  
=Hs[peO*  
s/"?P/R  
/* X>`5YdT~+  
**Utility.java Bh\>2]~@a  
*/ ;HPQhN_  
package NetFox; :jc ?T  
+9[/> JM  
f;w7YO+$p9  
public class Utility { ^*fZ  
:GaK.W q  
iO,_0Y4  
public Utility() D@cv{ _M/  
{ X/D^?BKC  
]U8VU  
b+g(=z+  
} a9=pZ1QAG  
:{ }]$+|)\  
//线程睡眠 S|pMX87R  
public static void sleep(int nSecond) \~:Uj~  
{ c-ah
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try{ A"`^Abrm  
Thread.sleep(nSecond); |QIFtdU5T  
} 3bGJ?hpp  
catch(Exception e) mx'!I7b(L/  
{ Qmk}smvH  
e.printStackTrace (); W=9Zl(2C  
} ]^j'2nJv0  
} \ tK{!v+  
V*bX>D/  
//日志 Hik :Sqpox  
public static void log(String sMsg) 7 q%|-`#  
{ Z?#_3h$"T  
System.err.println(sMsg); 1gTW*vLM\  
} ,>^6ztM  
p? dXs^ c  
&%ZiI@O-  
public static void log(int sMsg) *XCid_{(  
{ 3kMf!VL  
System.err.println(sMsg); Hg$lXtn]  
} 0=E]cQwh  
} s}% M4  
X*Prll(  
p"ZG%Ow5Q]  
/* Fun^B;GA:  
**TestMethod.java +&2%+[nBZ  
*/ ?m?::R
H  
package NetFox; q
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;x@~A^<el  
u^qT2Ss0  
public class TestMethod { ah+iZ}E%  
5S--'=fu+  
 O+Y6N  
public TestMethod() EA]U50L(  
{ ///xx/weblogic60b2_win.exe 1Z~FCJz  
try{ lv+TD!b   
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [e}]}t8m  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Y\?"WGL)p  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >e[i5  
fileFetch.start(); @wNG{Stj  
} 6MMOf\   
catch(Exception e){e.printStackTrace ();} 9e,0\J  
JB[~;nLlC  
)C]gld;8  
} W+ko
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oEKvl3Hz_  
4 VW[E1
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public static void main(String[] args) #KexvP&*  
{ o
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new TestMethod(); 6.nCV0xA  
} FSW_<%  
} <+vw@M  
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