http断点续传简单实现（java)

/* np9dM  
**SiteFileFetch.java *[}^[J x  
*/ vScjq5"p  
package NetFox; r!GW=u'  
import java.io.*; 8b(!k FxD  
import java.net.*; 7DD&~ZcD  
#7G*GbKY  
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public class SiteFileFetch extends Thread { =9wy/c$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean F3Maqr y  
long[] nStartPos; //开始位置 "i^ GmVn  
long[] nEndPos; //结束位置 ravyiOL  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 >''U  
long nFileLength; //文件长度 A8r^)QJP{  
boolean bFirst = true; //是否第一次取文件 /F)H\*  
boolean bStop = false; //停止标志 :-T*gqj|  
File tmpFile; //文件下载的临时信息 -NJ!g/ >mM  
DataOutputStream output; //输出到文件的输出流 7[pBUDA  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） u]*0;-tz  
public SiteFileFetch(SiteInfoBean bean) throws IOException % Zjdl  
{ <0P5 o|  
siteInfoBean = bean; 8\.b4FNJ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Yk!/ow@.  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 0RFRbi@n(  
if(tmpFile.exists ()) nh+l78  
{ Z4b||  
bFirst = false; }<a^</s  
read_nPos(); >l']H*&B<  
} 80OtO#1y  
else I:98$r$  
{ 64>krmVIe  
nStartPos = new long[bean.getNSplitter()]; Z<?OwAWz  
nEndPos = new long[bean.getNSplitter()]; @(g_<@Jz  
} baV>N[F&  
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} w"Y` ]2  
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public void run() e'%v1-&sP  
{ "qz3u`[o  
//获得文件长度 rwLAW"0Qz  
//分割文件 B;>{0 s  
//实例FileSplitterFetch K<`osdp=&  
//启动FileSplitterFetch线程 `F YjQe"p  
//等待子线程返回 =@&cHY  
try{ s$ENFp7P  
if(bFirst) EOj"V'!  
{ b?X.U}62_  
nFileLength = getFileSize(); l e4?jQQ@L  
if(nFileLength == -1) +ZMls [  
{ @mP]*$00  
System.err.println("File Length is not known!"); RGKYW>$0RR  
} )Z 9E=%  
else if(nFileLength == -2) 8Me:Yp_Xt  
{ [epi#]m  
System.err.println("File is not access!"); *a;@*  
} % 2$/JZ  
else >{gPN"S"a  
{ S8[=S  
for(int i=0;i<nStartPos.length;i++) Dl(3wgA  
{ K_)eWf0a  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); i':ydDOOHA  
} fWfk[(M'9  
for(int i=0;i<nEndPos.length-1;i++) 2WX7nK;I  
{ TxjYrzC  
nEndPos = nStartPos[i+1]; nRL. ppUI  
} x+ncc_2n&D  
nEndPos[nEndPos.length-1] = nFileLength; _.IxRk)T  
} gI^oU4mq  
} BS Iy+  
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3s\.cG?`r  
//启动子线程 3$.deYa$R  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0R{dNyh{  
for(int i=0;i<nStartPos.length;i++) ('wY9kvL&  
{ &qpr*17T  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1tTgP+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), (~CLn;'  
nStartPos,nEndPos,i); AjcX  N  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); MYJg8 '[j  
fileSplitterFetch.start(); _vSn`  
} drzL.@h|  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :I -V_4b  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .+7;)K
  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 7S/G B  
nEndPos = " + nFileLength); HEA#bd\  
// fileSplitterFetch[nPos.length-1].start(); ,@1p$n  

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//等待子线程结束 (py]LBZ  
//int count = 0; w0w G-R ?  
//是否结束while循环 G'3qzBJ#  
boolean breakWhile = false; G9g1hie@%  
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while(!bStop)
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{ =mA: ctu~v  
write_nPos(); }ci#>  
Utility.sleep(500); 3"o"fl  
breakWhile = true; s!n<}C  
(WJ${OW  
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for(int i=0;i<nStartPos.length;i++) xX*H7#  
{ wP[t0/dl  
if(!fileSplitterFetch.bDownOver) GpZc5c  
{ !Mi;*ZR  
breakWhile = false; 64hk2a8  
break; o-}R?>  
} b Q]/?cCYV  
} 2M#r]  
if(breakWhile) 3nZo{p:E  
break; ,%\o4Rc'o  
\ [a%('}  
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//count++; O
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//if(count>4) W6On93sa  
// siteStop(); 9Xx's%U  
} m(pE5
B(  
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System.err.println("文件下载结束！"); K|dso]b/  
} w@
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catch(Exception e){e.printStackTrace ();} h;6lK$!c  
} y|'SXM  
}CeCc0M  
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//获得文件长度 u_ABt?'  
public long getFileSize() H54R8O$  
{ &|/| ''A)  
int nFileLength = -1; 0
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try{ 3B1cb[2y  
URL url = new URL(siteInfoBean.getSSiteURL()); ^^5&QSB:'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8Y5  
httpConnection.setRequestProperty("User-Agent","NetFox"); **}h&k&%2  
,3@#F/c3i~  
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int responseCode=httpConnection.getResponseCode(); FJasS8  
if(responseCode>=400) *Z|y'<s  
{ NH+(?TN  
processErrorCode(responseCode); 27;ci:5  
return -2; //-2 represent access is error J~#;<e{\"  
} OE}*2P/M>  
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String sHeader; P*cNh43U  
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for(int i=1;;i++) rF]h$Z8o  
{ qh`t-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); XLH0 ;+CL{  
//Utility.log(in.readLine()); ]CoeSA`j  
sHeader=httpConnection.getHeaderFieldKey(i); &L^+BQ`O?  
if(sHeader!=null) 9uGrk^<t  
{ qAw x2fPu  
if(sHeader.equals("Content-Length")) 'nF2a
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{ ?Wz8[u  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9/nn)soC3  
break; 0:+WO%z  
} y-1 pR  
} j$+nKc$  
else TA{\PKA)  
break; g1jTy7g?  
} ~Q\3pI. |  
} 8 XU1/i7N  
catch(IOException e){e.printStackTrace ();} 1Z9qjV%^  
catch(Exception e){e.printStackTrace ();} >yULC|'F&~  
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Utility.log(nFileLength); B[KJR?>  
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return nFileLength; l,kUhZ@W  
} #FNcF>3>  
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//保存下载信息（文件指针位置） Y./2Ely  
private void write_nPos() JfR%L q~  
{ 92 [;Y  
try{ 3\B>lKhQ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2RX!V@z.G  
output.writeInt(nStartPos.length); sQ fFu  
for(int i=0;i<nStartPos.length;i++) L31HGH2l  
{ 8?%-'z.  
// output.writeLong(nPos); 7x@A%2J  
output.writeLong(fileSplitterFetch.nStartPos); YxP&7oq  
output.writeLong(fileSplitterFetch.nEndPos); Vv ?-"\Z>  
} Ry'= ke  
output.close(); _A=$oVe  
} 1&-
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catch(IOException e){e.printStackTrace ();} )'~6HO8Z  
catch(Exception e){e.printStackTrace ();} ={z*akn,  
} RRI"d~~F6  
-:na:Vsi  
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//读取保存的下载信息（文件指针位置） S;)w.  
private void read_nPos() 6Aku1h  
{ tQjLOv+?=  
try{ @~%r5pz6  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); kOed ]>H  
int nCount = input.readInt(); "T|PS6R~  
nStartPos = new long[nCount]; A -b [>}_  
nEndPos = new long[nCount]; *m#Za<_Gv  
for(int i=0;i<nStartPos.length;i++) yrlf+tl  
{ Y 1t\iU  
nStartPos = input.readLong(); Wr( y)D<y}  
nEndPos = input.readLong(); =17t- [  
} D}mjN=Y  
input.close(); "OdXY"G  
} WS`qVL]^&  
catch(IOException e){e.printStackTrace ();} 'L8' '(eZ^  
catch(Exception e){e.printStackTrace ();} R.yC(r  
} i{`;R  
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private void processErrorCode(int nErrorCode) xLC3>>P  
{ 6E^.7%3  
System.err.println("Error Code : " + nErrorCode); |fHV2Y`:g  
} ;NHt7p8SE  
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//停止文件下载 !s&NT @ S  
public void siteStop() yI"6Da6|y  
{ 1#ft#-g}
 
bStop = true; @9lUSk^9  
for(int i=0;i<nStartPos.length;i++) P9vA7[  
fileSplitterFetch.splitterStop(); /%;mqrdk  
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} cj1cZ-  
} ekWePL;rR2  
//负责部分文件的抓取 f>N!wgo[  
**FileSplitterFetch.java wwyPl  
*/ ~W{2Jd  
package NetFox; hBBUw0"  
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import java.io.*; L{8xlx`  
import java.net.*; E6pMT^{K  
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public class FileSplitterFetch extends Thread { '7iSp=  
)3>hhuaa  
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String sURL; //File URL c1E'$- K@  
long nStartPos; //File Snippet Start Position 6x%h6<#xh*  
long nEndPos; //File Snippet End Position |\7 ET[Xq  
int nThreadID; //Thread's ID :>Ay^{vf=  
boolean bDownOver = false; //Downing is over L2[f]J%  
boolean bStop = false; //Stop identical %@6}GmK^  
FileAccessI fileAccessI = null; //File Access interface jW  3c"  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException /\4'ddGU  
{ C,v(:ZE$J7  
this.sURL = sURL; vy\RcP  
this.nStartPos = nStart; .8by"?**  
this.nEndPos = nEnd; *tK\R&4,4s  
nThreadID = id; 5) pj]S!]-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _t^{a]/H  
} j4cwI90=  
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public void run() Yi$vg  
{ BZ?
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while(nStartPos < nEndPos && !bStop) #?/<  
{ ' <@3i[M  
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try{ |bO"_U  
URL url = new URL(sURL); f)^_|8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5 4L\Jx  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]zWon~  
String sProperty = "bytes="+nStartPos+"-"; 4X+ifZO  
httpConnection.setRequestProperty("RANGE",sProperty); Y07ZB'K  
Utility.log(sProperty); '.81zpff  
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InputStream input = httpConnection.getInputStream(); 5Hw~2 ?a,  
//logResponseHead(httpConnection); F*3j.lI  
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byte[] b = new byte[1024]; G}ob<`o|"  
int nRead; H\0~#(z?.  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) f7X6fr<  
{ K otrX  
nStartPos += fileAccessI.write(b,0,nRead); N<IT w/@^  
//if(nThreadID == 1) $Z\.-QE\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); FXi{87F2  
} Jc|6&  
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Utility.log("Thread " + nThreadID + " is over!"); 8j=}u/T@F  
bDownOver = true; x6e}( &p*  
//nPos = fileAccessI.write (b,0,nRead); tX> G,hw  
} 9*{[buZX  
catch(Exception e){e.printStackTrace ();} )~HUo9K9  
}
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} >o7n+Rb:  
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//打印回应的头信息 U8LtG/  
public void logResponseHead(HttpURLConnection con) 
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{ VrxQc qPr`  
for(int i=1;;i++) 2-C!jAfd  
{ wv\w;'  
String header=con.getHeaderFieldKey(i); C'o64+W^  
if(header!=null) !3 f?:M  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); =[@zF9  
Utility.log(header+" : "+con.getHeaderField(header)); oaoU _V  
else z6w3"9Um  
break; ).sRv6/c  
} a{qM2P(S  
} ZI
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#nK>Z[  
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public void splitterStop() '~&9D:(  
{ #py[  
bStop = true; |ayVjqJ*  
} }l],.J\BGX  
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} RHO(?8"_  
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/* 9+{G8$Ai  
**FileAccess.java .7.b:Dn0  
*//文件访问(定位，写) q(.:9A*0  
package NetFox; 9&_<f}ou  
import java.io.*; (<}
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/q5v"iX]T  
3 %|86:*  
public class FileAccessI implements Serializable{ V9dF1Hj  
R)RG[F#  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 }5}.lJ:  
RandomAccessFile oSavedFile; =W BTm  
long nPos; 6u7?dG'4  
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public FileAccessI() throws IOException sU@nc!&Y@  
{ Ux}(?Z  
this("",0); ]2\VweV  
} 79xx2  
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public FileAccessI(String sName,long nPos) throws IOException ?Vf o+a,  
{ N=QfP  
oSavedFile = new RandomAccessFile(sName,"rw"); Y!gCMLL  
this.nPos = nPos; -U/c\-~fU  
oSavedFile.seek(nPos); tjluk  
} A#95&kJpy  
i*NH'o/  
Y[K*57fs  
public synchronized int write(byte[] b,int nStart,int nLen) 8=Z9T<K  
{ "vyNxZE  
int n = -1; 3T!lA  
try{ 0QOBL'{7)  
oSavedFile.write(b,nStart,nLen); W^]3XJP  
n = nLen; 'zGo?a  
} 8@2OJ=`[  
catch(IOException e) p~,]*y:XT  
{ kAC&S!n  
e.printStackTrace (); (r D_(%o  
} @>)r}b  
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return n; R]btAu;Z  
} a8 mVFm  
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} "G@g" gP  
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/* @p NNq
  
**SiteInfoBean.java WUsKnf  
*/ 371 TvZ4  
package NetFox; HO}Hh[{V9  
2g>SHS@1>  
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public class SiteInfoBean { jr!?v<NoX  
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>=  
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private String sSiteURL; //Site's URL X6mqi;+  
private String sFilePath; //Saved File's Path qQsku;C?i  
private String sFileName; //Saved File's Name 4@ML3d/  
private int nSplitter; //Count of Splited Downloading File frT]5?{  
S&\L-@  
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public SiteInfoBean() 2m35R&  
{//nSplitter的缺省值为5 g;8jK8Kh  
//default value of nSplitter is 5 }woo%N P  
this("","","",5);
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} /i-J&*6_  
,
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) `P8Vh+7u  
{ B&.FOO  
sSiteURL= sURL; u(wGl_  
sFilePath = sPath; }c}| $h^Y  
sFileName = sName; [h34d5'w  
this.nSplitter = nSpiltter; d~:!#uWyFk  
J<dVTxK12  
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} '=G|Sq^aO  
f/Hm{<BY  
]b%Hy  
public String getSSiteURL() ?$6Y2  
{ q&/Yg,p\  
return sSiteURL; NNE<L;u  
} V%YiAr>  
IS#FiH  
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public void setSSiteURL(String value) !>e5z|1   
{ }c`fW&  
sSiteURL = value; _;~,Cgfi  
} I]&#Dl/  
F;l$.9?.s  
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public String getSFilePath() xgNJeQ  
{ K,boVFs  
return sFilePath; |&[L?  
} 5c^Z/ Jl$c  
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L.2/*H#  
public void setSFilePath(String value) QzzW x2  
{ "9^j.  
sFilePath = value; )6Ny1x+  
} 00SbH$SU  
1}:bqI.<W  
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public String getSFileName() LX@/RAd vz  
{ '`XX "_k3  
return sFileName; PG_0\'X)/w  
} 9v}G{mQ#  
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public void setSFileName(String value) M\Z6$<H?U  
{ bV8!"{  
sFileName = value; z6?)3'  
} lmxr oHE  
-t2+|J*  
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public int getNSplitter() @:U+9[  
{ YE=q:Bv  
return nSplitter; +AHUp)  
} W0k0$\i
X  
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=ZDAeVz3w  
public void setNSplitter(int nCount) sm\f0P!rv  
{ F^5?\  
nSplitter = nCount; sp5eVAd  
} Tjl:|F8  
} 8&Oa_{1+Q  
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/* zD(`B+  
**Utility.java H~+l7OhV  
*/ awOd_![c'  
package NetFox; mFSw@CC  
7G\\{  
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public class Utility { >layJt
  
+> WM[o^I  
AwTJJ0>  
public Utility() \uXcLhXN  
{ j~+>o[c  
g-e#!(  
A
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f  
} >j'ZPwj^  
QR Ei7@t  
//线程睡眠 5Pd"h S  
public static void sleep(int nSecond) .9"Y_/0   
{ V\{tmDE  
try{ h-m\%|D  
Thread.sleep(nSecond); )*Q-.Je/U  
} KM!k$;my  
catch(Exception e) Fb4`|  
{ UY<e&Npo  
e.printStackTrace (); ObE,$_
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} ;+tpvnV;]  
} GD:4"$)[o  
>9f%@uSM$3  
//日志 }j^\(2  
public static void log(String sMsg) >TP7 }u|  
{ CXO2N1~(J  
System.err.println(sMsg); S=nP[s  
} ecgtUb8K  
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.%^]9/4  
public static void log(int sMsg) ]miy/V }5  
{ 2OwV^-OG  
System.err.println(sMsg); N @#c,,  
} EM/@T}  
} Cz W:L&t  
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GQl$yZaK{  
/* +8#_59;x  
**TestMethod.java ;?6No(/  
*/ r} P<iX
 
package NetFox; c1_5, 1U'  
;]w<&C!=  
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public class TestMethod { oXDN+4ge  
Rt{B(L.?<  
IZm(`b;t^  
public TestMethod() ,i0b)=!o  
{ ///xx/weblogic60b2_win.exe aj"M>zd*}  
try{ E^rbcGJ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); A)
~X
,  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); LS5vW|]w  
SiteFileFetch fileFetch = new SiteFileFetch(bean); tBm_YP[  
fileFetch.start(); `D":Q=:  
} fsEzpUY:{W  
catch(Exception e){e.printStackTrace ();} M#4QQ} F.  
8NU`^L:1  
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} I0'[!kBF|  
q\q=PB6r  
v"MX>^/<  
public static void main(String[] args) dDD<E?TjD  
{ &%2*Wu;  
new TestMethod(); qU,c~C=Qf  
} $%%os6y2v  
} /Ux*u#  
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