http断点续传简单实现（java)

/* oore:`m;  
**SiteFileFetch.java k!T-X2L=  
*/ [,Y;#;   
package NetFox; 7CCSG{k  
import java.io.*; a *bc#!e  
import java.net.*; @7t*X-P.;-  
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public class SiteFileFetch extends Thread { s]HJc
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SiteInfoBean siteInfoBean = null; //文件信息Bean UZL-mF:)&  
long[] nStartPos; //开始位置 .G}$jO}  
long[] nEndPos; //结束位置 vos-[$  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ZSB;4 ?:h  
long nFileLength; //文件长度 fc<,
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boolean bFirst = true; //是否第一次取文件 #bb$Icmtk  
boolean bStop = false; //停止标志 rW)}$|-Z  
File tmpFile; //文件下载的临时信息 PKev)M;C+  
DataOutputStream output; //输出到文件的输出流 k#2b3}(,  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） #UnGU,J  
public SiteFileFetch(SiteInfoBean bean) throws IOException QZ5%nJme_  
{ FC4hvO(/m  
siteInfoBean = bean; qvs[Gkaa@  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >`n)-8  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); :UfaMe5  
if(tmpFile.exists ()) V.!z9AQ  
{ ioslarw1J  
bFirst = false; xw*/8.Md6f  
read_nPos(); 0Rn`63#  
} "VeNc,-nfQ  
else B~3qEdoK5`  
{ aSeh?
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nStartPos = new long[bean.getNSplitter()]; HmV JkkksJ  
nEndPos = new long[bean.getNSplitter()]; 1y7$"N8Xo  
} _Ry  
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} d 8z9_C-  
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public void run() UFE~6"t(  
{ ?osYs<k \  
//获得文件长度 'fIG$tr9X  
//分割文件 =/N0^  
//实例FileSplitterFetch =Q8$O 2TW  
//启动FileSplitterFetch线程 YY$O"!."
 
//等待子线程返回 hw&~OJeo  
try{ tY?evsVgz  
if(bFirst) 6}_J;g\|  
{ } ejc  
nFileLength = getFileSize(); af/;Dr@  
if(nFileLength == -1) >;X^+JH!)  
{ 7v(<<>  
System.err.println("File Length is not known!"); wHErF #xo  
} z6OJT6<'  
else if(nFileLength == -2) !Mk]%  
{ Z?'?+48xv4  
System.err.println("File is not access!"); Wp=:|J  
} 0urM@/j+  
else P'k`H  
{ +B O
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for(int i=0;i<nStartPos.length;i++) .:;#[Z{-  
{ kJ0otr2P  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Rx4O?7;  
} L;'v,s  
for(int i=0;i<nEndPos.length-1;i++) \fC}l Ll  
{ D]Gt=2\NG9  
nEndPos = nStartPos[i+1]; MLn?t^v-  
} G]I^zd&P  
nEndPos[nEndPos.length-1] = nFileLength; j"<F?k@`Q  
} ;4(FS  
} ACH!Gw~  
y
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//启动子线程 x;/%`gKn8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; r)Iq47Uiw  
for(int i=0;i<nStartPos.length;i++) ?E7.x%n7X5  
{  av!~B,  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), wEIAU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 7A>glZ/x  
nStartPos,nEndPos,i); _+nlm5  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); o n?8l?iQ  
fileSplitterFetch.start(); b
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} 9,Ug  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), j*1O(p+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?;Ge/~QU5  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", b%I2ig  
nEndPos = " + nFileLength); .sbV<ulbc  
// fileSplitterFetch[nPos.length-1].start(); M{~KT3c  
a.g:yWL\  
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//等待子线程结束 AlT04H
  
//int count = 0; rxAb]~MMp  
//是否结束while循环 n5 jzVv  
boolean breakWhile = false; y:8Oc?  
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while(!bStop) RLbxNn  
{ $.r:  
write_nPos(); .cm$*>LW:x  
Utility.sleep(500); #3Jn_Y%P.  
breakWhile = true; 4O3-PU>N  
V s1Z$HS`  
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for(int i=0;i<nStartPos.length;i++) n>I NJ  
{ xn4-^2
 
if(!fileSplitterFetch.bDownOver) hlTM<E  
{ _cH 7lO[  
breakWhile = false; c*x5t"{  
break; )~[hf,R5S  
} p'IF2e&z  
} <f`G@  
if(breakWhile) -AxO1 qO  
break; [O(8
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].<B:]:,  
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//count++; bT{iei]?  
//if(count>4) v}\Nx[}  
// siteStop(); ?)B\0` %*'  
} y2,M9  
{QTnVS't 0  
4&([<gyR<  
System.err.println("文件下载结束！"); !5K9L(gqb  
} 9;u&,R  
catch(Exception e){e.printStackTrace ();} }e*OprF  
} X,h"%S<c#H  
KPSHBv-#  
 ,L}  
//获得文件长度 pe$l'ur
 
public long getFileSize() |\MgE.N  
{ mdTCe HX  
int nFileLength = -1; vMV}M%~  
try{ 2bk~6Osp  
URL url = new URL(siteInfoBean.getSSiteURL()); pT`oC&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [q{[Avqf  
httpConnection.setRequestProperty("User-Agent","NetFox"); S( r Fa  
L)
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int responseCode=httpConnection.getResponseCode(); qE&R.I!o  
if(responseCode>=400) 4R/cN'-  
{ "?UBW5nM#  
processErrorCode(responseCode); fSFb)+  
return -2; //-2 represent access is error g",htYoEnj  
} [~<X|_LG  
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String sHeader; 8vLaSZ="[  
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for(int i=1;;i++) zg2}R4h  
{ ?@i_\<A2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ]FNqNZ  
//Utility.log(in.readLine()); sox0:9Oqnf  
sHeader=httpConnection.getHeaderFieldKey(i); $Dm2>:D
mt  
if(sHeader!=null) j!:^+F/  
{ &6`h%;a/&  
if(sHeader.equals("Content-Length")) 58@YWvAk  
{ R6A{u(  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =k\V~8XZ  
break; fGtUr_D  
} j:;[Y`2  
} #DI%l`B  
else B~RVFc +  
break; jLRh/pbz4  
} :d ts>  
} 8(Ab NQ  
catch(IOException e){e.printStackTrace ();} +I {ZW}rA  
catch(Exception e){e.printStackTrace ();} D 1Q@4 g  
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Utility.log(nFileLength); uoM;p'  
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return nFileLength; *?a rEYc8  
} b!7*bFTt  
69{BJ]q  
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//保存下载信息（文件指针位置） oK5"RW  
private void write_nPos()
([r4N#lx  
{ oWu2}#~z_  
try{ T5g}z5~"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); x9s7:F  
output.writeInt(nStartPos.length); =skw@c^  
for(int i=0;i<nStartPos.length;i++) ur
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{ 2|KgRk|!  
// output.writeLong(nPos); V kA$T8  
output.writeLong(fileSplitterFetch.nStartPos); [!ghI%VK  
output.writeLong(fileSplitterFetch.nEndPos); LK}Ih@f  
} &G)I|mv  
output.close(); h2SVDKj  
} Y%FQ
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catch(IOException e){e.printStackTrace ();} 
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catch(Exception e){e.printStackTrace ();} ZPieL&uV`  
} zF9SZ#{a  
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//读取保存的下载信息（文件指针位置）  jIMT&5k  
private void read_nPos() K/,y"DUN&  
{ s\k4<d5  
try{ H6Mqy}4W  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); E,S[3+  
int nCount = input.readInt(); LijisE  
nStartPos = new long[nCount]; QgZwU$`p0  
nEndPos = new long[nCount]; o"te7nBI  
for(int i=0;i<nStartPos.length;i++) "%o,P/<X  
{ :ub 4p4h*  
nStartPos = input.readLong(); OD*\<Sc  
nEndPos = input.readLong(); csceu+IA  
} lTe7n'y^^  
input.close(); KxZO.>,  
} `K,{Y_  
catch(IOException e){e.printStackTrace ();} 8 z) K  
catch(Exception e){e.printStackTrace ();} ~$GRgOn  
} PJq;OM|  
b) k\?'j  
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private void processErrorCode(int nErrorCode) Z`UwXp_s  
{ |\?mX=a.y  
System.err.println("Error Code : " + nErrorCode); s#%$aQ|Fp  
} yJCqP=  
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//停止文件下载 S_E-H.d"  
public void siteStop() 0Jz5i4B  
{ *Kpk1  
bStop = true; KW* 2'C&  
for(int i=0;i<nStartPos.length;i++) [g bYIwL.  
fileSplitterFetch.splitterStop(); 0zQ^ 6@  
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} >MuI-^3  
} fgiOYvIS2m  
//负责部分文件的抓取 
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**FileSplitterFetch.java RZ(*%b<C  
*/ \3
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package NetFox; ,buSU~c_Q  
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import java.io.*; ae1?8man  
import java.net.*; zn,y'},  
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public class FileSplitterFetch extends Thread { R&>G6jZ?8  
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String sURL; //File URL #.<Uy."z2  
long nStartPos; //File Snippet Start Position ~  4v  
long nEndPos; //File Snippet End Position WpPm|h  
int nThreadID; //Thread's ID 4LEWOWF}  
boolean bDownOver = false; //Downing is over r8.`
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boolean bStop = false; //Stop identical }ZQ)]Mr  
FileAccessI fileAccessI = null; //File Access interface 9H~2 iW,Q;  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException HE;}B!>  
{ iyA=d{S;V  
this.sURL = sURL; ~XzT~WxW  
this.nStartPos = nStart; ;PS V3Zh  
this.nEndPos = nEnd; v qt#JdPp9  
nThreadID = id; 'n:|D7t  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Vu0d\l^$  
} zBQV2.@  
wMW."gM|  
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public void run() /C[Q?  
{ O$qxo &  
while(nStartPos < nEndPos && !bStop) C+0MzfLgf  
{ KKBrw+)AJ  
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try{ ,4Q1[K35B  
URL url = new URL(sURL); 3WVH8Sb  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Fy; sVB  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,Y:ET1:  
String sProperty = "bytes="+nStartPos+"-"; ty"|yA  
httpConnection.setRequestProperty("RANGE",sProperty); r}**^"mFy  
Utility.log(sProperty); Qe[ejj1o:  
&RJ*DAmL  
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InputStream input = httpConnection.getInputStream(); i,H(6NL.  
//logResponseHead(httpConnection); i/C`]1R/  
V< Ib#rd'  
*:5S*E&}V  
byte[] b = new byte[1024]; K2XRKoG  
int nRead; :17Pc\:DS  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ~WjK'N4n5  
{ AV>_bw.  
nStartPos += fileAccessI.write(b,0,nRead); bu?4$O  
//if(nThreadID == 1) L">\c5ca  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); rD\)ndPv  
} fT2F$U  
\,AE5hnO  
3 T1,:r  
Utility.log("Thread " + nThreadID + " is over!"); V0l"tr@  
bDownOver = true; AMw#_8Y  
//nPos = fileAccessI.write (b,0,nRead); K7 J RCLA  
} 5K:'VX  
catch(Exception e){e.printStackTrace ();} .E:3I!dH7  
} gW5yLb_Vz$  
} u|mTF>L  
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t]CA!i`  
//打印回应的头信息  [HEljEv  
public void logResponseHead(HttpURLConnection con) /E39Z*  
{ y}F;~H~P  
for(int i=1;;i++) th1;Ym+Ze  
{ z/I\hC9i  
String header=con.getHeaderFieldKey(i); H|IG"JB  
if(header!=null) b9xvLR8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); l(y,lK=YP1  
Utility.log(header+" : "+con.getHeaderField(header)); 1KUM!DUD  
else V0<g$,W=  
break; ~.<QC<dN  
} `0
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} g5C$#<28  
5|jsv)M+  
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public void splitterStop() /V{1Zw=  
{ bess b>=  
bStop = true; -d.i4X3j  
} O**
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}G)2HTaZ  
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} oj(st{,  
;u-[%(00S  
2<T/N  
/* !(F?Np Am  
**FileAccess.java 9Tg k=  
*//文件访问(定位，写) l;SXR <EU  
package NetFox; I7#^'/  
import java.io.*; 3xz|d`A  
*EwDwS$$  
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public class FileAccessI implements Serializable{ iYf)FPET  
8og8;#mnyr  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 `Frr?.3&-  
RandomAccessFile oSavedFile; +lXIv  
long nPos; TVM19
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n
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public FileAccessI() throws IOException I 6'!b/  
{ p/qu4[Mm  
this("",0); P6I<M}p  
} 4?fpk9c{2  
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public FileAccessI(String sName,long nPos) throws IOException !Ln 'Mi_B  
{ hD[r6c  
oSavedFile = new RandomAccessFile(sName,"rw"); y`i?Qo3  
this.nPos = nPos; D<`M<:nq  
oSavedFile.seek(nPos); m1e Sn |)7  
} )<f4F!?,A  
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@uz(h'~  
public synchronized int write(byte[] b,int nStart,int nLen) s f.z(o  
{ #~m8zG  
int n = -1; |)C #  
try{ H_JE)a:+  
oSavedFile.write(b,nStart,nLen); !' 0PM[  
n = nLen; [C/{ru&E  
} gt9(5p  
catch(IOException e) #+N_wIP4  
{ Ifokg~X~G  
e.printStackTrace (); ify48]  
} }[=)sb_  
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return n; Fi'ZId  
} ilXKJJda  
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} psse^rFg  
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\*&?o51!e  
/* $) M2  
**SiteInfoBean.java ff7#LeB9  
*/ !Eg2#a?  
package NetFox; &8pGq./lr=  
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public class SiteInfoBean { ~;z] _`_Va  
M~7Cb>%<  
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private String sSiteURL; //Site's URL w?zy/+N~  
private String sFilePath; //Saved File's Path p>i8aN  
private String sFileName; //Saved File's Name $)nP
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private int nSplitter; //Count of Splited Downloading File +V(^"Z~  
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public SiteInfoBean() =1k%T{>  
{//nSplitter的缺省值为5 gKcBx6G Q  
//default value of nSplitter is 5 lXF7)H&T  
this("","","",5); rT=C/SKP  
} lo1bj*Y2  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) YR? E z<p  
{ |h%HUau  
sSiteURL= sURL; eXD~L&s[  
sFilePath = sPath;
7W*a+^   
sFileName = sName; z]SEPYq:  
this.nSplitter = nSpiltter; *>"NUHq  
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nW*cqM%+  
} $)$r  
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/qJCp![X  
public String getSSiteURL() oc]:Ty  
{ ul~6zBKO
 
return sSiteURL; =|``d-  
} d=meh4Y  
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ke!  
public void setSSiteURL(String value) S~ Z<-@S  
{ )/vom6y*   
sSiteURL = value; iqdU?&.;  
} hJ]Oa7r  
|/H?\]7  
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public String getSFilePath() MUsF  
{ 9a=>gEF],@  
return sFilePath; f^*Yqa  
} NtM ?Jh  
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public void setSFilePath(String value) 7V8k =  
{ ZgG~xl\My  
sFilePath = value; 9) ,|h  
} ~c<8;,cjYR  
.)$MZyo  
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public String getSFileName() EPH n"YK  
{ +or<(%o @  
return sFileName; OJ"./*H  
} e ><0crb  
J _dgP[  
{J izCUo_'  
public void setSFileName(String value) 3N-pND0>p  
{ $[Z~BfSQ  
sFileName = value; 2"?DaX  
} SepwMB4@  
bEj}J_#  
\?R#ZxP@  
public int getNSplitter() EnlAgL']|  
{ :H3/+/x  
return nSplitter; qzJ<9H  
} ZLxa|R7  
.MG83Si  
KUYwc@si\  
public void setNSplitter(int nCount) =f y|Dm74  
{ &PRoT#,  
nSplitter = nCount; J,)ytw]  
} [|1I.AZ{  
} aQ$sn<-l  
xSd&xwP  
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/* ^Z#G_%\Y:  
**Utility.java \u{4=-C.  
*/ u>.a;BO  
package NetFox; G 3,v'D5  
#"KC29!Yj  
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public class Utility { \Z3K ~  
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e
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public Utility() 3m!tb)  
{ 5v)bs\x6  
/ @"{u0  
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} &l7E|.JE  
0y,w\'j  
//线程睡眠 5 | ,b  
public static void sleep(int nSecond) I/tMFg  
{ ap )B%9  
try{ Uzzm2OS`  
Thread.sleep(nSecond); s$>n U  
} M Zz21H  
catch(Exception e) YIg43Av  
{
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e.printStackTrace (); PBb&.<  
} 9/29>K_  
} PjEJC@n  
1J"9Y81  
//日志 g assOd  
public static void log(String sMsg) b{ xlW }S  
{ clV^Xg8D  
System.err.println(sMsg); g?v
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} >":xnX#  
X2Z)> 10  
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public static void log(int sMsg)
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{ 2=NaqHt(  
System.err.println(sMsg); ) yMrET m  
} iO
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} aim\3y~  
8]&:'  
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/* }Cu[x'
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**TestMethod.java $xZ ~bE9  
*/ Cn3_D  
package NetFox;  SW#/;|m  
f; |fS~  
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public class TestMethod { (?\+
  
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g) oOravV  
public TestMethod() Mz6(M,hkq  
{ ///xx/weblogic60b2_win.exe 6EyPZ{  
try{ ZK^cG'^2|  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); rl%,9JD!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); PmE)FthdP(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); rvd$4l^  
fileFetch.start(); WqNXE)'  
} %/y=_G  
catch(Exception e){e.printStackTrace ();} #mu L-V  
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} W[O
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$C\ETQ@  
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public static void main(String[] args) dz9U.:C  
{ Z{0BH{23  
new TestMethod(); f+ceL'
fr  
} 8-nf4=ll  
} ~%/Rc`  
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