http断点续传简单实现（java)

/* /DyeMCY-  
**SiteFileFetch.java B:0oT  
*/ jpS$5Ct  
package NetFox; ]];pWlo!  
import java.io.*; {:VK}w  
import java.net.*; JC-> eY"O2  
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public class SiteFileFetch extends Thread {  qsXkm4  
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={ -kQq  
SiteInfoBean siteInfoBean = null; //文件信息Bean 44B D2`nF  
long[] nStartPos; //开始位置 XqUQ{^;aI  
long[] nEndPos; //结束位置 XksI.]tfj  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 v_pe=LC{-e  
long nFileLength; //文件长度 n}e%c B  
boolean bFirst = true; //是否第一次取文件 Im!b-1  
boolean bStop = false; //停止标志 @>.aQE  
File tmpFile; //文件下载的临时信息 8 l)K3;q_  
DataOutputStream output; //输出到文件的输出流 JhwHsx/  
V_D wHq2  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） DTM(SN8R+n  
public SiteFileFetch(SiteInfoBean bean) throws IOException Lk@+iHf  
{ frW\!r{LT  
siteInfoBean = bean; :A!EjIL`#  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 83 R_8  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~<O.Gu&"R  
if(tmpFile.exists ()) m.`I}  
{ y6-P6T  
bFirst = false; K5T1dBl,0  
read_nPos(); X=Ar"Dx}}s  
} U
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else '[%Pdd]! E  
{ 3`{;E{  
nStartPos = new long[bean.getNSplitter()]; DEhR\
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nEndPos = new long[bean.getNSplitter()]; Ta/zDc"e  
} 2|i
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} .d[^&<^  
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public void run() bma.RCyY<  
{ 3+d^Bpp4  
//获得文件长度 P]y{3y:XxM  
//分割文件 <YEKbnw$o  
//实例FileSplitterFetch O-)[!8r  
//启动FileSplitterFetch线程 wb(S7OsMO  
//等待子线程返回 s_RK x)w@  
try{ dhxzW@'nIL  
if(bFirst) }fkdv6mz  
{ ,Nhv#U<$  
nFileLength = getFileSize(); E3[9!L8gb  
if(nFileLength == -1) &\~*%:C  
{ D]aQt%TL  
System.err.println("File Length is not known!"); ~"vS$>+  
} 'nh2}  
else if(nFileLength == -2) "(p/3qFY  
{ 7kA+F+f  
System.err.println("File is not access!"); ~vA8I#.  
} KU{zzn;g  
else sb3z8:r  
{ `MCtm(<  
for(int i=0;i<nStartPos.length;i++) 3fpaTue|x  
{ ]+a~/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); I3r")}P  
} O;V^Fk(  
for(int i=0;i<nEndPos.length-1;i++) ~xc/Dsb$  
{ &[j9Up'   
nEndPos = nStartPos[i+1]; ')yYpWO  
} xr@;w8X`^  
nEndPos[nEndPos.length-1] = nFileLength; V_m!<sr(  
} 60nP'xfR  
} Opg_-Bf  
iHc(e(CB<  
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//启动子线程 QJVB:>A  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; oMLs22Do?  
for(int i=0;i<nStartPos.length;i++) p^q/u  
{ +cYDz#3%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V4}jv7>A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2ib,33 Z  
nStartPos,nEndPos,i); &s}sA+w  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OgQ8yKfDB  
fileSplitterFetch.start(); i%<NKE;v7m  
} z)v o  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), nHDKe)V  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ~8(Xn2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 40`Qsv0#  
nEndPos = " + nFileLength); [bX^_ Y  
// fileSplitterFetch[nPos.length-1].start(); dyf>T}Iy  
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>
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//等待子线程结束  q"T?  
//int count = 0; )F&.0 '  
//是否结束while循环 |@1(^GX  
boolean breakWhile = false; 0g=vMLi  
5Uy*^C7M^  
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while(!bStop) <"`f!k#[  
{ Ci4c8  
write_nPos(); J@<f*  
Utility.sleep(500); 5%
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breakWhile = true; 2^Im~p~ByE  
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for(int i=0;i<nStartPos.length;i++) Ah@e9`_r  
{ [Y.JC'F#  
if(!fileSplitterFetch.bDownOver) g$"x,:2x{  
{ )=#Js<&3:  
breakWhile = false; xZ%3e sp  
break; K8-1?-W  
} R1Q,
m  
} U
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if(breakWhile) iR{@~JN=)  
break; 4G;KT~Cgb  
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+/[Rvh5WZ  
//count++; 5W|wDy  
//if(count>4) FYE(lEjxi  
// siteStop(); \r{wNqyv  
} ThW9=kzQW  
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lf KV%  
System.err.println("文件下载结束！"); XVfUr\=,T  
} 9 ;uw3vI%  
catch(Exception e){e.printStackTrace ();} BdU .;_K  
} ?G~rYETvw  
bf1$:09  
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//获得文件长度 $RF.L
Vc  
public long getFileSize() ^qBm%R(  
{ @cxM
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int nFileLength = -1; ,\3Cq2h  
try{ Z[Iej:o5  
URL url = new URL(siteInfoBean.getSSiteURL()); HfP<hQmN'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l?m 3*  
httpConnection.setRequestProperty("User-Agent","NetFox"); roG<2i F  
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| a i#rU  
int responseCode=httpConnection.getResponseCode(); >QN-K]YLL  
if(responseCode>=400) 1>OU~A"  
{ U61 LMH  
processErrorCode(responseCode); 3xP<J)S0  
return -2; //-2 represent access is error #n.v#FyNx  
} IQ~Anp^R  
8::y5Yv]  
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String sHeader; D,FgX/&i/  
.-MJ5d:  
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for(int i=1;;i++) BonjK#  
{ =x(k)RTDu  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^c.pvC"4j
 
//Utility.log(in.readLine()); rP"Y.;s  
sHeader=httpConnection.getHeaderFieldKey(i); y/_=  
if(sHeader!=null) }7{(o-  
{ ##F$8d)q  
if(sHeader.equals("Content-Length")) mAIl)mq|g  
{ 2Z<S^9O9  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); S7cD}yx*[  
break; +:70vZc:V@  
} A>S7Ap4z>  
} 1
7;9>*O'  
else 7T!t*sSO'  
break; eW3?3l`fvt  
} 48J{Y3F  
} F2<Q~gQ;  
catch(IOException e){e.printStackTrace ();} 4
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catch(Exception e){e.printStackTrace ();} j1K~zG  
SLNOOEN  
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Utility.log(nFileLength); 3&c'3y:b  
^:f)XZ  
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return nFileLength; K~^o06 Y  
} LSXsq}  
5OOXCtIKf  
,?%Y*?v  
//保存下载信息（文件指针位置） )ytP$,r![S  
private void write_nPos() :AuKQ`c  
{ 1{cF/ :o  
try{ lSd tw b  
output = new DataOutputStream(new FileOutputStream(tmpFile)); j 7O!uUQQ  
output.writeInt(nStartPos.length); fffWvf  
for(int i=0;i<nStartPos.length;i++) 9M|#X1r{%{  
{ VRY@}>W'  
// output.writeLong(nPos); f1o^:}5x  
output.writeLong(fileSplitterFetch.nStartPos); SjJ$Oinc  
output.writeLong(fileSplitterFetch.nEndPos); *(i%\  
} r
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output.close(); &js$qgY  
} |6Iw\YU  
catch(IOException e){e.printStackTrace ();} G2c\"[N1/  
catch(Exception e){e.printStackTrace ();} L-q)48+^k  
} hA&m G33  
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t
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//读取保存的下载信息（文件指针位置） NP~3!b  
private void read_nPos() ^$oEM0h  
{ fG.6S"|M  
try{ +>a(9r|:  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); es+ZPX>Y  
int nCount = input.readInt(); L!ms{0rJ  
nStartPos = new long[nCount]; * "
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nEndPos = new long[nCount]; OMYbCy^  
for(int i=0;i<nStartPos.length;i++) NW21{}=4  
{ m,w^,)  
nStartPos = input.readLong(); }>YEtA  
nEndPos = input.readLong(); ^QHgc_oDm  
} pMUUF5  
input.close(); y=SpIbn{  
} pm=s  
catch(IOException e){e.printStackTrace ();} UK@hnQU8`  
catch(Exception e){e.printStackTrace ();} EW]8k@&g  
} 6Ol)SQE,  
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private void processErrorCode(int nErrorCode) {K/xI  
{ =1O;,8`
 
System.err.println("Error Code : " + nErrorCode); ;1TQr3w  
} O4a~(*f  
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0? KvR``Aj  
//停止文件下载 YQO9$g0% ~  
public void siteStop() \[B#dw#  
{ HXqG;Fds(  
bStop = true; b|@f!lA  
for(int i=0;i<nStartPos.length;i++) 6gq`V,  
fileSplitterFetch.splitterStop(); nK]L0*s  
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} L9z5o(Aa  
}
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//负责部分文件的抓取 i^}DIx{  
**FileSplitterFetch.java :pP l|"
 
*/ $f6wmI;<y  
package NetFox; VK}H;  
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import java.io.*; a)/ }T  
import java.net.*; _uk
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public class FileSplitterFetch extends Thread { "j}fcrlG9  
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String sURL; //File URL gvxOo#8]  
long nStartPos; //File Snippet Start Position QWwEfL  
long nEndPos; //File Snippet End Position P;p20+  
int nThreadID; //Thread's ID a ,
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boolean bDownOver = false; //Downing is over 2wYY0=k2  
boolean bStop = false; //Stop identical MrS~u  
FileAccessI fileAccessI = null; //File Access interface l;;"v) C8  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException KMV&c  
{ j"P}W
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this.sURL = sURL; 4Mjcx.21  
this.nStartPos = nStart; _^]:tL6  
this.nEndPos = nEnd; +H3;{ h9,  
nThreadID = id; !O/(._YB`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9,AHC2kn%  
} <
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public void run() { Em fw9L  
{ rqi|8gKY  
while(nStartPos < nEndPos && !bStop) 9$N~OZ;-*x  
{ ?_G?SQ  
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try{ l Gy`{E|  
URL url = new URL(sURL); 7E)*]7B%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); { daEKac5  
httpConnection.setRequestProperty("User-Agent","NetFox"); +"SYG  
String sProperty = "bytes="+nStartPos+"-"; fBt`D !Z8  
httpConnection.setRequestProperty("RANGE",sProperty); $3:O}X>  
Utility.log(sProperty); >^+c s^jCM  
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InputStream input = httpConnection.getInputStream(); sQr |3}I(  
//logResponseHead(httpConnection); 4.i< `'  
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byte[] b = new byte[1024]; *bTR0U  
int nRead; `1U?^9Nf  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) rtgu{m02  
{ /-&a]PJ  
nStartPos += fileAccessI.write(b,0,nRead); 1 c4I`#_v  
//if(nThreadID == 1) ~z*A%vp6ER  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); orr6._xw  
} 8>~\R=SC  
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Utility.log("Thread " + nThreadID + " is over!"); |H@1g=q  
bDownOver = true; YWUCrnr  
//nPos = fileAccessI.write (b,0,nRead); hG%J:}  
} }SF<. A  
catch(Exception e){e.printStackTrace ();} I?IAZa)  
} uMM?s?q  
} !TdbD56  
a
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//打印回应的头信息 t"L-9kCM  
public void logResponseHead(HttpURLConnection con) e8ZMB$byP  
{ *u`[2xmuYf  
for(int i=1;;i++) o+.LG($+U  
{ v6_fF5N/  
String header=con.getHeaderFieldKey(i); 9)]asY  
if(header!=null) Y1h)0_0  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); x9B{|+tIoc  
Utility.log(header+" : "+con.getHeaderField(header)); dw e$, 9  
else \4pWHE/  
break; W_P&;)E  
} Z4'8x h)-  
} O&De!Gx  
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public void splitterStop() G^=C#9c.m  
{ q+/7v9  
bStop = true; [qGj*`@C  
} lZ` CFZR0
 
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} 57eA(uI  
5 U{}A\q  
#:n:3]t  
/* BK16~Wl  
**FileAccess.java [N4#R  
*//文件访问(定位，写) ^;]Q,*Q  
package NetFox; ct#3*]  
import java.io.*; 8KrqJN0\  
\9GJa"xA`  
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public class FileAccessI implements Serializable{ )cd5iE:FO  
%uWq)D4r  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !uJDhC  
RandomAccessFile oSavedFile; Q(J6;s#b  
long nPos; 8KU5x#  
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%  
 !xz0zT.  
public FileAccessI() throws IOException ]NrA2i?  
{ u=u#6%  
this("",0); _9Zwg+oO[  
} +vh 4I  
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public FileAccessI(String sName,long nPos) throws IOException Z}Ld!Byz  
{ 9e*v&A2Y'  
oSavedFile = new RandomAccessFile(sName,"rw"); p%
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this.nPos = nPos; `swf~  
oSavedFile.seek(nPos); ui\yY3?  
} -'iV-]<  
- P$mN6h  
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public synchronized int write(byte[] b,int nStart,int nLen) Dy[_Ix/Y,  
{ Anu`F%OzB  
int n = -1; ;m[-yqX  
try{ vdLBf+Zi  
oSavedFile.write(b,nStart,nLen); o2C{V1nB  
n = nLen; sAG#M\A6  
} w`")^KXi  
catch(IOException e) e MT5bn  
{ @!UuK;  
e.printStackTrace (); ]a}K%D)H  
} ,XJ Xw(LM  
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return n; oju}0h'1  
} RZ#~^5DiO  
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} quPNwNy  
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+hJ@w-u,G  
/* MvLmEmKb}\  
**SiteInfoBean.java 6pHn%yE*  
*/ ~RRp5x _  
package NetFox; ca},tov&  
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XDWR]  
public class SiteInfoBean { >*A"tk#oR  
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,  
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private String sSiteURL; //Site's URL G2A^+R0\  
private String sFilePath; //Saved File's Path 5#|f:M]Bo|  
private String sFileName; //Saved File's Name ]N\J~Gm  
private int nSplitter; //Count of Splited Downloading File -9Ll'fbq  
#@#/M)  
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public SiteInfoBean() v7ShXX:  
{//nSplitter的缺省值为5 OcBKn=8  
//default value of nSplitter is 5 |H LU5=Y  
this("","","",5); xKl!{A9$w  
} YF]W<ZpY  
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7vRFF@eq}  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) t3dvHU&Z:  
{ !G0O
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sSiteURL= sURL; rk$$gXg9/  
sFilePath = sPath; z ]@ Q  
sFileName = sName; bh9!OqK9K  
this.nSplitter = nSpiltter; Ch~2w)HAA  
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9HjtWQn  
} Z+qTMm  
+~6Nq(kV  
1m52vQSo3l  
public String getSSiteURL() 2,nVo^13}  
{ ;U02VguC  
return sSiteURL; 1${lHVx]  
} _.ny<r:g  
xzqgem`[\  
\,b@^W6e>  
public void setSSiteURL(String value) @.PVUP  
{ lBbUA)z6  
sSiteURL = value; Z;nbnRz  
} 'DB4po.   
Xlw8>.\  
6WN1DW  
public String getSFilePath() LZ97nvK  
{ uEK9  
return sFilePath; eq|G\XJ  
} }3"FQ/6C  
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public void setSFilePath(String value) -27uh  
{ Dd(#
  
sFilePath = value; B_^ ~5_0:  
} %(
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@bc=O1vX~;  
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public String getSFileName() xS4
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{ A
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return sFileName; &s +DK`  
} px!
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@dy<=bh~  
public void setSFileName(String value) _*xjG \!  
{ A[/_}bI|  
sFileName = value; 9{{|P=  
} J73B$0FP  
[_jd  
8f^QO:  
public int getNSplitter() (dL;A0L  
{ u9t@%H)lZ  
return nSplitter; `*A!vO8  
} 5B
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public void setNSplitter(int nCount) S690Y]:h$v  
{ h\jV@g$  
nSplitter = nCount; wTpjM@F?J|  
} RjII(4Et  
} j2UiZLuV  
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iK#5nY].  
/* Q\P?[i]  
**Utility.java @E(_H$|E  
*/ (5^bU<  
package NetFox; 6vx0F?>_  
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public class Utility { A,tmy',d"  
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public Utility() k *a?Ey$  
{ e~Oge  
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} X&
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$_j\b4]%  
//线程睡眠 qdlz#-B  
public static void sleep(int nSecond) .,)C^hs@  
{ Dlc=[kf9  
try{ z!z+E%H^  
Thread.sleep(nSecond); (&25 8i,  
} sHk,#EsKH  
catch(Exception e) 'nK(cKDIG  
{ WBo|0(#  
e.printStackTrace (); .>5KwEK~  
} 7*!h:rg  
} x
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_I("k:E7  
//日志 52*9q!  
public static void log(String sMsg) EJdl%j  
{ e?Pzhha  
System.err.println(sMsg); 5 A/[x$q  
} ,rvw E  
S%h[e[[fST  
>)/,5VSE  
public static void log(int sMsg) /rKdxsI*  
{ 2wHvHH!  
System.err.println(sMsg); J>I.|@W4  
} j}0W|*  
} SR,id B&i  
X*Ibk-PUM  
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/* a/9R~DwN  
**TestMethod.java ?w{lC,  
*/  aOS:rC  
package NetFox; + _=&7  
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Lo'P;Sb4<}  
public class TestMethod { EcBJ-j6d  
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public TestMethod() r
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{ ///xx/weblogic60b2_win.exe we6kV-L.  
try{ n=HId:XT  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6x1!!X+)+  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); y^7ol;t  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Z9:erKT   
fileFetch.start(); )2@_V %  
} x%acWeV5  
catch(Exception e){e.printStackTrace ();} *Q?
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y*
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} #6XN_<  
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public static void main(String[] args) 2>l =oXq  
{ ~$#"'Tl4J  
new TestMethod(); (dOC ^i  
} 1_D|;/aI  
} QZcdfJck=+  
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