http断点续传简单实现（java)

/* "Y@q?ey[1  
**SiteFileFetch.java 59i2*<k  
*/ PcI~,e%  
package NetFox; V Ds0+RC  
import java.io.*; Q\N
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import java.net.*; 4*HBCzr7[  
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public class SiteFileFetch extends Thread { u=Xpu,q  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 8U}+9  
long[] nStartPos; //开始位置 I'[;E.KU  
long[] nEndPos; //结束位置 6OqF-nso[E  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 umCmxmr&  
long nFileLength; //文件长度 D !{e  
boolean bFirst = true; //是否第一次取文件 \fp'=&tp~a  
boolean bStop = false; //停止标志
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File tmpFile; //文件下载的临时信息 ~(B%E'  
DataOutputStream output; //输出到文件的输出流 "=LeHY=9  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） c'mg=jH  
public SiteFileFetch(SiteInfoBean bean) throws IOException \:+ NVIN  
{ zGy+jeH:.  
siteInfoBean = bean; <p-@XzyE  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); :jC$$oC].  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); e X6o7a  
if(tmpFile.exists ()) Q<KF<K'0hg  
{ GMB3`&qh  
bFirst = false; sL;;'S&  
read_nPos(); <[u(il  
} ?cn`N|   
else \U##b~Z,g  
{ h B_p  
nStartPos = new long[bean.getNSplitter()]; _>;{+XRX[  
nEndPos = new long[bean.getNSplitter()]; XVb9)a  
} ;Sg,$`]  
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} 6ND*L
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public void run() Y*{5'q+2  
{ c *<m.  
//获得文件长度 btC6R>0   
//分割文件 p.b#RY  
//实例FileSplitterFetch 2 /*z5  
//启动FileSplitterFetch线程 H!Dj.]T  
//等待子线程返回 _!Pi+l4p/}  
try{ D7muf  
if(bFirst) sH'0utD#Y  
{ IiJ$Ng  
nFileLength = getFileSize(); '=xO?2U-Z  
if(nFileLength == -1) 72_+ b  
{ Jd',
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System.err.println("File Length is not known!");
}EP}D?Mmu  
} ii>^]iT  
else if(nFileLength == -2) /I{K_G@  
{ 8&3&^!I  
System.err.println("File is not access!"); p"- %~%J=  
} a .?AniB0  
else BOP7@D  
{ RLzqpE<rJ  
for(int i=0;i<nStartPos.length;i++) $!TMS&Wk  
{ j5A>aj  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); (44L8)I.D  
} )>U"WZ'<  
for(int i=0;i<nEndPos.length-1;i++) 3Bvz& `\  
{ K9yZG
  
nEndPos = nStartPos[i+1]; J<4_<.o(a  
} qg|ark*1u  
nEndPos[nEndPos.length-1] = nFileLength; Gm\)1b  
} Z'l!/l!  
} >AY9F|:  
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>< P<k&  
//启动子线程 7=Pj}x)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; j>l  
for(int i=0;i<nStartPos.length;i++) Bjj=UtI  
{ ~)[pL(4  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2J%L%6z8~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), IXlk1tHN4I  
nStartPos,nEndPos,i); BE],PCpPr  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0c1=M|2  
fileSplitterFetch.start(); l!W!Gz0to  
} (I(U23A~  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _a|g >  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ^)a:DKL  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -B! a O65^  
nEndPos = " + nFileLength); ;uv$>Fauk  
// fileSplitterFetch[nPos.length-1].start(); !VsdKG)  
>[wB|V5  
,?IXfJ`c  
//等待子线程结束 G2 V$8lh  
//int count = 0; p#-=mXE/2  
//是否结束while循环 mAY/J0_  
boolean breakWhile = false; qh&q<
M  
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while(!bStop) &;p}HL,  
{ g1_z=(i`Z  
write_nPos(); ?^MH:o  
Utility.sleep(500); .Cs'@[Ciy  
breakWhile = true; .I
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for(int i=0;i<nStartPos.length;i++) vu}U2 0@  
{ !0UfX{.  
if(!fileSplitterFetch.bDownOver) ;l<Hen*  
{ 49O_A[(d  
breakWhile = false; =<)/lz] H  
break; (l9jczi  
} /u`Opv&I
 
} <P&X0S`O  
if(breakWhile) Vpzjh,r-j  
break; YC<FKWc  
xj&~>&U){;  
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//count++; 2PUB@B
' +  
//if(count>4) wZbT*rU  
// siteStop(); $sZ4r>-  
} SG&H^V8  
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System.err.println("文件下载结束！"); AE`UnlUSF  
} e%4vvP
p  
catch(Exception e){e.printStackTrace ();} {f*{dSm9b  
} |2=w":2#  
(~! @Uz5  
*CAz_s<  
//获得文件长度 .y_~mr&d  
public long getFileSize() _3O*"S=1  
{ nD>X?yz2  
int nFileLength = -1; :_2:Fh.}3~  
try{ oL }d=x/  
URL url = new URL(siteInfoBean.getSSiteURL()); HU|qeSyel  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); N~or
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httpConnection.setRequestProperty("User-Agent","NetFox"); odJE~\\hw  
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int responseCode=httpConnection.getResponseCode(); !vc5NKv#n  
if(responseCode>=400) DYC2bs>  
{ UEm4):/}  
processErrorCode(responseCode); 3-n&&<  
return -2; //-2 represent access is error @{Fa=".Ch  
} l&"bm C:xr  
v&%W*M0q@  
[nX{sM%  
String sHeader; -;RAW1]}Y$  
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for(int i=1;;i++) ^h#A7 g  
{ +iQ~ Y2Gh  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &hi
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//Utility.log(in.readLine()); IM[=]j.?  
sHeader=httpConnection.getHeaderFieldKey(i); wN6sica|  
if(sHeader!=null) rq1~%S  
{ EG8z&^O x  
if(sHeader.equals("Content-Length")) A)d0Z6G`  
{ E5c)\ D  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); <5CQ#^cK  
break; Ae2Y\sAV  
} @Eh(GZN  
} XRyeEwA;pp  
else m9jjKu]|  
break; ;i+(Q%LO  
} Z3ODZfu>  
} W=|'&UU Ul  
catch(IOException e){e.printStackTrace ();} ]^{5`  
catch(Exception e){e.printStackTrace ();} 0tMzVxS  
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Utility.log(nFileLength); (4`Tf*5hHa  
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return nFileLength; !y!s/i&P%  
} @cm[]]f'l  
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2!{_x8,n  
//保存下载信息（文件指针位置） ,5K&f\  
private void write_nPos() ?6I`$ &OA  
{ A^0-%Ygl  
try{ ?o/p}6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ilQ\
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output.writeInt(nStartPos.length); a"1LF`  
for(int i=0;i<nStartPos.length;i++) to#2.  
{ F0r5$Pl*  
// output.writeLong(nPos); HBk5p>&  
output.writeLong(fileSplitterFetch.nStartPos); R\$6_  
output.writeLong(fileSplitterFetch.nEndPos); 40-/t*2Ly  
} ]Rp<64I o  
output.close(); %V
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} ~wGjr7Wt  
catch(IOException e){e.printStackTrace ();} /\1Q :B3W  
catch(Exception e){e.printStackTrace ();} SxC(:k2b;  
} MzlE  
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S%7bM~J@  
//读取保存的下载信息（文件指针位置） AJRiwP|H+  
private void read_nPos() }2Im?Q  
{ *t={9h  
try{ >Wpdq(o  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); R9+f^o`W  
int nCount = input.readInt(); +ZBj_Vw*|  
nStartPos = new long[nCount]; R~N%sn  
nEndPos = new long[nCount]; K:pG<oV|}  
for(int i=0;i<nStartPos.length;i++) 1'B=JyR~K  
{ :n x;~f  
nStartPos = input.readLong(); SBw'z(U  
nEndPos = input.readLong(); _,-\;  
} )S_%Ip  
input.close(); )MX%DQw  
} x}reeqn  
catch(IOException e){e.printStackTrace ();} Ja@?.gW  
catch(Exception e){e.printStackTrace ();} T16B2|C"Y  
} `X`|]mWj  
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private void processErrorCode(int nErrorCode) `WQpGBS_z_  
{ lw4#C`bx  
System.err.println("Error Code : " + nErrorCode); ({!*&DVu  
} |txzIc.#  
}yCgd 5+_  
uuCVI2|  
//停止文件下载 _b=})**  
public void siteStop() o%Qn%gaX  
{ wo^1%:@/2  
bStop = true; F#efs6{  
for(int i=0;i<nStartPos.length;i++) !}xRwkN  
fileSplitterFetch.splitterStop(); CR|>?9V  
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} \l 3M\$oS>  
} |e3YTLsI  
//负责部分文件的抓取 ,z0E2  
**FileSplitterFetch.java U(:t$SBKy  
*/ eA/}$.R  
package NetFox; |'#uV)b0@  
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import java.io.*; 6AmFl<  
import java.net.*; l02aXxT)]  
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public class FileSplitterFetch extends Thread { Z?w=-  
+T7FG_  
89A04HX  
String sURL; //File URL E95VR?nUg  
long nStartPos; //File Snippet Start Position ]m^ECA$  
long nEndPos; //File Snippet End Position .MRLAG  
int nThreadID; //Thread's ID sF#t{x/sW  
boolean bDownOver = false; //Downing is over It^_?oiK  
boolean bStop = false; //Stop identical /3~}=b  
FileAccessI fileAccessI = null; //File Access interface sZU Ao&  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException v8A{q  
{ DAd$u1  
this.sURL = sURL; 9, 792b  
this.nStartPos = nStart; 11yS2D   
this.nEndPos = nEnd; u+8?'ZT,  
nThreadID = id; 2l4`h)_q  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Al]z=  
} k:zGv  
:.\h.H;  
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public void run() {*4Z9.2c*  
{ \V.U8asfI  
while(nStartPos < nEndPos && !bStop) s-
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{ VnMiZAHR  
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try{ &oiBMk`*  
URL url = new URL(sURL); z[_Gg8e  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O<w7PS  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,[Z;"wE  
String sProperty = "bytes="+nStartPos+"-"; `#N7ym;s@  
httpConnection.setRequestProperty("RANGE",sProperty); 1uhSP!b  
Utility.log(sProperty); i'vjvc~   
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InputStream input = httpConnection.getInputStream(); 1Aa=&B2  
//logResponseHead(httpConnection); 8f|+045E@  
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byte[] b = new byte[1024]; '~'3x4B
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int nRead; @BXV>U2B{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) %|3UWN  
{ Ehf{Kl  
nStartPos += fileAccessI.write(b,0,nRead); V?cUQghHg  
//if(nThreadID == 1) aD3Q-a[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5($ '@u  
} pG:)u cj  
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Utility.log("Thread " + nThreadID + " is over!"); zL3'',Ha  
bDownOver = true; doaqHri\,  
//nPos = fileAccessI.write (b,0,nRead); S-+^L|  
} meV RdQ  
catch(Exception e){e.printStackTrace ();} 1YMu\(  
} x;*KRO  
} bwh.ekf8  
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!b+Kasss9  
//打印回应的头信息 D<cHa |  
public void logResponseHead(HttpURLConnection con) V]9?9-r  
{ 3bPvL/\Lb  
for(int i=1;;i++) ~UJ_Rr54  
{ KcjP39@I  
String header=con.getHeaderFieldKey(i); I*K~GXWs#  
if(header!=null) DavG=kvd  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `_v|O{DC{  
Utility.log(header+" : "+con.getHeaderField(header)); ^UK6q2[  
else x_5H_! \#  
break; sxLq'3(  
} !P0
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} ?wx|n_3<:  
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public void splitterStop() etH%E aF[  
{ dGz
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bStop = true; *l^%7Wrk  
} 4<&`\<jZ  
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_#+~#U%5n  
} Kq';[Yc  
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/* &u_f:Pog  
**FileAccess.java 6]^}GyM!  
*//文件访问(定位，写) l8hOryB&  
package NetFox; [?hc.COE  
import java.io.*; o3l_&?^  
/^\6q"'  
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public class FileAccessI implements Serializable{ Y75,{1\l0  
RW|3d<Fj  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Y m|zM1qc  
RandomAccessFile oSavedFile; Ro?aDrQ  
long nPos; S:Ne g!`  
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public FileAccessI() throws IOException fNx3\<~V=  
{ X] &Q^  
this("",0); @DrMaTr  
} /E@|  
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public FileAccessI(String sName,long nPos) throws IOException n
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{ DEL#MD!  
oSavedFile = new RandomAccessFile(sName,"rw"); *#,wV  
this.nPos = nPos; Jx@3zl  
oSavedFile.seek(nPos); .4~n|d>z  
} n||/3-HDj  
_}7N,Cx   
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public synchronized int write(byte[] b,int nStart,int nLen) +)FB[/pXk  
{ W9?Vh{w  
int n = -1; nj~1y')  
try{ C_Y^
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oSavedFile.write(b,nStart,nLen); ^~2GhveBV  
n = nLen; 0t1WvW  
} )sVz;rF<  
catch(IOException e) <w.W[ak  
{ V3-5:z  
e.printStackTrace (); b$+.}&M  
}
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[  
w Maib3Q  
return n; fNc3&=]]  
} LzS@@']  
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} \&J7>vu^y  
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v3Y/D1jd"  
/* *.AokY)_a  
**SiteInfoBean.java 4QZ -
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*/ k#%BxT  
package NetFox; &'UYV>  
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e/EfWwqt  
public class SiteInfoBean { B]q &?~  
~&=-*  
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private String sSiteURL; //Site's URL jx&pRjP  
private String sFilePath; //Saved File's Path ]C-hl}iq  
private String sFileName; //Saved File's Name ]%3o"|  
private int nSplitter; //Count of Splited Downloading File g6k@E,cI_  
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public SiteInfoBean() ]n0kO&  
{//nSplitter的缺省值为5 vW 0m%  
//default value of nSplitter is 5 yK<%AV@v  
this("","","",5); utC]GiR  
} ;-47d ^  
69 R
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im
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) c.Pyt  
{ Q d]5e  
sSiteURL= sURL; ;$=`BI)  
sFilePath = sPath; 0}k[s+^  
sFileName = sName; ig]*Z  
this.nSplitter = nSpiltter; P'GX-H  
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} 9. Q;J#;1  
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1"009/|  
public String getSSiteURL() |r!G(an1x4  
{ *?7Ie;)  
return sSiteURL; DF/p{s1Y3  
} l.?R
7f  
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public void setSSiteURL(String value) <P7f\$o~  
{ &C<B=
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sSiteURL = value; |_8-3  
} ,2/qQD n/  
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y iE[^2Pv  
public String getSFilePath() FJgr=9>  
{ &Jv j@,>$d  
return sFilePath; |f&)
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} .R;HH_  
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public void setSFilePath(String value) ?h"+q8&  
{ Xz&Hfs"/J  
sFilePath = value;
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} kN>%y&cK  
c%
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}kdYR#{s  
public String getSFileName() V}=9S@$o  
{ +.&#whEw(i  
return sFileName; 8E"Ik~  
} UMuqdLaT9  
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public void setSFileName(String value) 7OG=LF*V-  
{ aR ao\Wp|  
sFileName = value; p#)u2^  
} P Ig)h-w?  
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public int getNSplitter()  ;?1H&  
{ 2Otd  
return nSplitter; W)ihk\E  
} sH(4.36+  
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public void setNSplitter(int nCount) }BS.OK?  
{ iXK.QktHw  
nSplitter = nCount; ilEWxr;,  
} 3:7J@>  
} -z./6dQ  
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/* {$)zC*l  
**Utility.java r5> FU>7'  
*/ _?kjIF  
package NetFox; p<*3mbgGO  
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F]\(p=U.  
public class Utility { jt?4raNW  
!*ct3{m  
> $DMVtE0  
public Utility() wd2GKq!  
{ 3r!6Z5P7{'  
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} AHc:6v^  
:oYu+cQ  
//线程睡眠
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public static void sleep(int nSecond) q%%8oaEI  
{ NypM+y  
try{ @&t';"AE  
Thread.sleep(nSecond); hJ\IE?+  
} 1r;]==  
catch(Exception e) VliX'.-  
{ 0B#9CxU%  
e.printStackTrace (); Y 
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} O|=5+X  
} x1</%y5ev  
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//日志 6z=h0,Y}  
public static void log(String sMsg) c[J(H,mt/  
{ A}pmr  
System.err.println(sMsg); zgRZgVj  
} =B<>H$  
r:lv[/D  
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public static void log(int sMsg) ~=91Kxf  
{ A&X(\c M  
System.err.println(sMsg); EjW3_ %  
} sS(t }$  
} &NZl_7PL  
=(:{>tO_"  
0YK`wuZGS  
/* =NLsT.aa  
**TestMethod.java gcDo o2RE  
*/ ms2y[b  
package NetFox; =&G<^7  

/RU'~(  
vaN}M)W/  
public class TestMethod { u UXj  
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1.*VliY  
public TestMethod() &<hDl<E  
{ ///xx/weblogic60b2_win.exe ,(&jG^IpVJ  
try{ )@+lfIE(l  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); IlQNo 1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); X^;[X~
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SiteFileFetch fileFetch = new SiteFileFetch(bean); %;ZWYj`]n  
fileFetch.start(); w/_n$hX  
} FN jT?*  
catch(Exception e){e.printStackTrace ();} Cq\1t  
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=OY&;d!C  
} z{XN1'/V  
&c!d}pU}  
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public static void main(String[] args) aK>5r^7S  
{ !kCMw%[  
new TestMethod(); b-4gHW
 
} ZslH2#  
} k\->uSU9  
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