http断点续传简单实现（java)

/* t]&n_]`{.  
**SiteFileFetch.java 6kDU}]c:H]  
*/ ihYfWG|  
package NetFox; 5N|77AAxK  
import java.io.*; [FCNW0NV  
import java.net.*; 5j}@Of1pd  
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public class SiteFileFetch extends Thread { Xs?>6i@$$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean hOC,Eo  
long[] nStartPos; //开始位置 <_Lo3WGwc  
long[] nEndPos; //结束位置 0WPxzmY  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 bQeYFY#^  
long nFileLength; //文件长度 eo,]b1C2n  
boolean bFirst = true; //是否第一次取文件 r-0 7!A  
boolean bStop = false; //停止标志 kN) pi "  
File tmpFile; //文件下载的临时信息 l3MH+o  
DataOutputStream output; //输出到文件的输出流 p,0 \NUC  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） hg&AQk  
public SiteFileFetch(SiteInfoBean bean) throws IOException D"WkD j"M  
{ tw(2V$J  
siteInfoBean = bean; VuR BJ2D  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @]7\.>)  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -Tt}M#W  
if(tmpFile.exists ()) 2#[Y/p  
{ QRjt.Ry|  
bFirst = false; LH8?0N[  
read_nPos(); pJ(l=a  
} O*PHo_&G  
else ;wF|.^_2  
{ 7wnzef?)  
nStartPos = new long[bean.getNSplitter()]; sDC RL%0QK  
nEndPos = new long[bean.getNSplitter()]; :Ry24X  
} X>4`{x`  
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} 5zGj,y>u  
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public void run() KWUz]>Z  
{ }M9al@"  
//获得文件长度 S#9SAX [  
//分割文件 `lhLIQ'j  
//实例FileSplitterFetch g2]-Q.  
//启动FileSplitterFetch线程 l.juys8s  
//等待子线程返回 a3 x~B=E  
try{ X A|`wAGP  
if(bFirst) C] w< &o  
{ ;cr6Xop#?  
nFileLength = getFileSize(); B`aAvD`7  
if(nFileLength == -1) WdAGZUp  
{ g@k9w{_  
System.err.println("File Length is not known!"); Uz|]}t5V  
} {p 0'Lc<3n  
else if(nFileLength == -2) L'Zud,JKg  
{ DO1{r/Ib.{  
System.err.println("File is not access!"); p#d UL9  
} 02[II_< 1  
else W6T
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{ ([*t.  
for(int i=0;i<nStartPos.length;i++) ea0tx3'  
{ T6$<o\g'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); P{eR
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} u2]g1XjeG  
for(int i=0;i<nEndPos.length-1;i++) %ZyPK,("  
{ !@{[I:5  
nEndPos = nStartPos[i+1]; 6sl<Z=
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} fm>K4\2  
nEndPos[nEndPos.length-1] = nFileLength; E{s|#  
} 7V (7JV<>  
} >` QX xTn  
:, [!8QP  
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//启动子线程 zI!R-Nb  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *hs<Ez.cC  
for(int i=0;i<nStartPos.length;i++) X.l"f'`l  
{ PV6*-[  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), P&0cF{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), lO> 7`2x=F  
nStartPos,nEndPos,i); N>%KV8>{L  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dY@Tt&k8E  
fileSplitterFetch.start(); Z4o
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} ,7jiHF  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [KI`e  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); h
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", H)T# R?  
nEndPos = " + nFileLength); s4`*0
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// fileSplitterFetch[nPos.length-1].start(); \Ntdl:fSw  
9c}]:3#XO  
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//等待子线程结束 8sF0]J[g{  
//int count = 0; 36WzFq#  
//是否结束while循环 zRo
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boolean breakWhile = false; *2 $m>N  
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while(!bStop) Y_3YO2K]  
{ .Xz"NyW  
write_nPos(); Doc'7P  
Utility.sleep(500); ]AA*f_!  
breakWhile = true; wQrPS  
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for(int i=0;i<nStartPos.length;i++) nBIv{  
{ UFAMbI  
if(!fileSplitterFetch.bDownOver) p9}c6{Wp  
{ X`v79`g_  
breakWhile = false; B0XBI0w^Y  
break; b, **$  
} p C2c(4  
} f+aS2k(e>  
if(breakWhile) ~v(M6dz~vk  
break; *ez~~ Y  
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//count++; sEJ;t0.LX  
//if(count>4) J(&M<<%  
// siteStop(); lp0T\ %  
} {p*hNi)0  
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System.err.println("文件下载结束！"); [FV=@NI  
} v6DxxE2n  
catch(Exception e){e.printStackTrace ();} k5%0wHpk=  
} +yP[(b/  
)bCG]OM7<  
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//获得文件长度 iI@Gyq=  
public long getFileSize() XG\a-dq[  
{ Vh.;p.!e  
int nFileLength = -1; OxHw1k  
try{ ;GgQ@s@  
URL url = new URL(siteInfoBean.getSSiteURL()); 2*FWIHyf  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D.&eM4MZ  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~SR(K{nf#.  
K0DXOVT\  
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int responseCode=httpConnection.getResponseCode(); >]XaUQ-  
if(responseCode>=400) 71<PEawL  
{ cH*/zNp  
processErrorCode(responseCode); N4`
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return -2; //-2 represent access is error &(uF&-PwO4  
} o )nT   
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String sHeader; =y-!k)t  
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for(int i=1;;i++) 8T.5Mhx0jS  
{ #SihedWi  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 1l|A[G  
//Utility.log(in.readLine()); ;LF)u2x=  
sHeader=httpConnection.getHeaderFieldKey(i); F<ocY0=9p  
if(sHeader!=null) fCt\2);a  
{ dj
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if(sHeader.equals("Content-Length")) leb^,1/D6  
{ zmL~]!~&  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \BbOljM=  
break; bUAR<R'E  
} ?;r8SowZ7  
} X.T\=dm%v  
else =
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break; =S[FJaIu7  
} 6Er0o{iI  
} e2-70UvW^  
catch(IOException e){e.printStackTrace ();} (9YYv+GGd*  
catch(Exception e){e.printStackTrace ();} |<$<L`xoe  

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B )1<`nJA  
Utility.log(nFileLength); m
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return nFileLength; bDh:!M  
} 74}eF)(me  
8%2rgA  
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//保存下载信息（文件指针位置） -M>K4*%K  
private void write_nPos() SP D207  
{ &` 00/p  
try{ =_?pOq  
output = new DataOutputStream(new FileOutputStream(tmpFile)); |B1;l<|`  
output.writeInt(nStartPos.length); FQ_%)Ty2  
for(int i=0;i<nStartPos.length;i++) l#5~t|\  
{ :uIi ?  
// output.writeLong(nPos); ,.6J6{  
output.writeLong(fileSplitterFetch.nStartPos); P+;CE|J`X  
output.writeLong(fileSplitterFetch.nEndPos); =;k+g?.@I  
} +C'TW^  
output.close(); e$ XY\{  
} p29yaM  
catch(IOException e){e.printStackTrace ();} |Uy e>%*}4  
catch(Exception e){e.printStackTrace ();} m<FWv2)^  
} D8@nkSP  
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&sZ9$s:(^  
//读取保存的下载信息（文件指针位置） 8z
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private void read_nPos() jsNH`"  
{ ;LQ# *NjL\  
try{ DD/>{kff  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 68koQgI[^  
int nCount = input.readInt(); qLQ <1>u  
nStartPos = new long[nCount]; *]}CSZ[>  
nEndPos = new long[nCount]; V9fGVDl;  
for(int i=0;i<nStartPos.length;i++) n) _dH/"  
{ d}{LM!s  
nStartPos = input.readLong(); =9qGEkd3  
nEndPos = input.readLong(); jb|mip@` <  
} BR& Aq  
input.close(); b!'l\~`{i  
} 99l>CYXd  
catch(IOException e){e.printStackTrace ();} /~3N@J  
catch(Exception e){e.printStackTrace ();} 74@lo-/LY  
} e2]
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private void processErrorCode(int nErrorCode) G"o!}  
{ Usa+b A  
System.err.println("Error Code : " + nErrorCode); nS_Ta  
} 
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//停止文件下载 ?QCmSK=
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public void siteStop() V]I:2k5  
{ s kN9O"^A  
bStop = true; 0HGlf  
for(int i=0;i<nStartPos.length;i++) wP[xmO-%  
fileSplitterFetch.splitterStop(); /@ y;iJk;  
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} ,N53Iic  
} ' |&>/dyq  
//负责部分文件的抓取 ojHhT\M`  
**FileSplitterFetch.java 95=gY  
*/ 6iG(C.b  
package NetFox; YEzU{J  
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taweGc%~  
import java.io.*; Z&_y0W=t  
import java.net.*; MkwU<ae AB  
*HR+a#o  
et=7}K]l  
public class FileSplitterFetch extends Thread { > 2#%$lX6  
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String sURL; //File URL 3gAR4  
long nStartPos; //File Snippet Start Position 2 P=[  
long nEndPos; //File Snippet End Position |^R*4;Phe  
int nThreadID; //Thread's ID ]*qU+&  
boolean bDownOver = false; //Downing is over 74+A+SK[  
boolean bStop = false; //Stop identical k<H%vg>{~s  
FileAccessI fileAccessI = null; //File Access interface $B\ H  
*ZaaO^!  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException lwc5S`"  
{ .20V 3  
this.sURL = sURL; kY"KD22a  
this.nStartPos = nStart; K UKACUL  
this.nEndPos = nEnd; [E7MsX  
nThreadID = id; iK#/w1`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 afHaB/t{R  
} #EDEYEW7  
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public void run() y`yZR _  
{ aBhV3Fd[B  
while(nStartPos < nEndPos && !bStop) SRZL\m}  
{ WF2NG;f=  
+`B'r '  
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try{ oKA&An  
URL url = new URL(sURL); i^)WPP>4Aw  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]N^*tO  
httpConnection.setRequestProperty("User-Agent","NetFox"); j(eFoZz,  
String sProperty = "bytes="+nStartPos+"-"; Ye5jB2Z  
httpConnection.setRequestProperty("RANGE",sProperty); <xo-Fv  
Utility.log(sProperty); .m;G$X|3U  
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InputStream input = httpConnection.getInputStream(); #DFV=:|~  
//logResponseHead(httpConnection);  Ow:1?Z{4  
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byte[] b = new byte[1024]; t9^A(Vh"-  
int nRead; uLQ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) cK@jmGj+  
{ xyA-P& N  
nStartPos += fileAccessI.write(b,0,nRead); /6KIl  
//if(nThreadID == 1) l>6@:nq|R  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9MY7a=5E~  
} ]ikomCg   
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Utility.log("Thread " + nThreadID + " is over!"); N@xg:xr  
bDownOver = true; -.IEgggf  
//nPos = fileAccessI.write (b,0,nRead); 6/Fz
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} R"AUSO|{  
catch(Exception e){e.printStackTrace ();} 52d^K0STC  
} C[uOReo  
} ua5?(,E`']  
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//打印回应的头信息 R@iUCT^$  
public void logResponseHead(HttpURLConnection con) XL$* _c <)  
{ O(z}H}Fv  
for(int i=1;;i++) 5D Y
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{ W_`A"WdT.  
String header=con.getHeaderFieldKey(i); l@JSK;  
if(header!=null) lFSe
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); 1LnyWZ  
Utility.log(header+" : "+con.getHeaderField(header)); dRi5hC$  
else B@y(.  
break; <7_KeOLJ  
} ::5E8919  
} &?,6~qm[  
6
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public void splitterStop() G:W>I=^DaR  
{ 'heJ"k?  
bStop = true; `J0i.0p  
} ^|!I+  
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} I1Sa^7  
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/* ->^~KVh&  
**FileAccess.java .7NNT18  
*//文件访问(定位，写) o Y}]UB>  
package NetFox; DZS]AC*  
import java.io.*; BYrZEVM9  
:1ecx$  
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public class FileAccessI implements Serializable{ JAjmrX  
'XrRhF (  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 4+;$7"fJ  
RandomAccessFile oSavedFile; :O<bA&:d  
long nPos; 4Y> Yi*n  
(-77[+2  
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public FileAccessI() throws IOException YevyN\,}V!  
{ M:KbD|  
this("",0); g7V8D  
} l_'[27
 
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7dG79H  
public FileAccessI(String sName,long nPos) throws IOException *OJ/V O  
{ -|k)tvAm  
oSavedFile = new RandomAccessFile(sName,"rw"); LQ11ba  
this.nPos = nPos; qBV x6MI  
oSavedFile.seek(nPos); YTQt3=1ii  
} "@A![iP  
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s=6}%%q6  
public synchronized int write(byte[] b,int nStart,int nLen) B(?Yw>Xd[  
{ =]`lN-rYw  
int n = -1; IQ<MyB(  
try{ F~:O.$f]G  
oSavedFile.write(b,nStart,nLen); ?3ig)J,e[  
n = nLen;
}?F`t[+  
} $ ,SF@BhO  
catch(IOException e) {GDmVWG0q  
{ ~\)qi=  
e.printStackTrace (); 4/kv3rv  
} `1*nL,i  
oI:o"T77sA  
2~[@_  
return n; Pi,QHb`>  
} 2kAx>R  
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} >d"3<S ;b  
n\Fp[9+Z\  
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/* {t"+ 3zy'  
**SiteInfoBean.java d)cOhZy  
*/ f4-a?bp  
package NetFox; XC 7?VE  
;*ix~taL%  
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public class SiteInfoBean { 9)xUA;Qw?z  
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private String sSiteURL; //Site's URL Uoya3#4 G  
private String sFilePath; //Saved File's Path [ EFMu;q  
private String sFileName; //Saved File's Name iovfo2!hD  
private int nSplitter; //Count of Splited Downloading File 09A X-JP  
"mL++>ZSQ  
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public SiteInfoBean() 73{'kK  
{//nSplitter的缺省值为5 Q9}dHIe1E  
//default value of nSplitter is 5 DRqZ,[!+
 
this("","","",5); o1&:r
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} I;5R2" 3  
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1O].v&{  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }X GEX:1K  
{ L %ip>  
sSiteURL= sURL; u2oKH{/z  
sFilePath = sPath; #HS]NA|e@  
sFileName = sName; D=:04V}2+  
this.nSplitter = nSpiltter; !D!~^\  
hA\K</h.  
#;n+YM">:  
} G?f\>QSZ  
q$1PG+-  
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public String getSSiteURL() ^c~)/F/cF  
{ LjL[V'JL  
return sSiteURL; f.24:Dw,  
} ~GE$myUT\p  
bjAnaya  
=%
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public void setSSiteURL(String value) 6wco&7   
{ $$:ZX  
sSiteURL = value; gP+fN$5'd  
} *[=bR>  
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public String getSFilePath() G=;k=oX(  
{ LZM
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return sFilePath; hhoEb(B
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} f+rz|(6vs{  
GGhM;%H_99  
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public void setSFilePath(String value) Hw#d_P:  
{ Sa19q.~%  
sFilePath = value; olLfko4$*V  
} qY\f'K}Q*  
b64 @s2]  
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public String getSFileName() 5*[2yKsTi  
{ :4v3\+T  
return sFileName; 7d92Pe  
} [{C )LDN  
s=?g\oR  
8kP3+  
public void setSFileName(String value) 1-.~7yC  
{ rJ KZ)N{  
sFileName = value; 5NJ4  
} s1?[7yC  
wP,JjPUt  
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public int getNSplitter() !n6wWl  
{ #+$Q+Z|6k  
return nSplitter; v&Kqq!DE  
} S*AERm  
"`6n6r42  
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public void setNSplitter(int nCount) 5BBD.!  
{ /%lZu^  
nSplitter = nCount; a<]B B$~  
} 3> /K0N|$  
} Xl74@wq   
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/* 
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**Utility.java Fs[aa#v4B  
*/ )E+'*e{cK  
package NetFox; Q]p(u\*  
a1Qv@p^._b  
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public class Utility { {nU=%w"\  
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O{ /q-~_  
public Utility() JI vo_7{  
{ H4]Ul eU  
zSb PW6U  
:kfp_o+J  
} B:7mpSnEQ  
BL&LeSa  
//线程睡眠 q\H[am  
public static void sleep(int nSecond) iX3HtIBj'  
{ N>>uCkC  
try{ ?)e37  
Thread.sleep(nSecond); oPPX&e@=s]  
} =_0UD{"_0  
catch(Exception e) 8b0d]*q  
{ S;]*)i,v  
e.printStackTrace (); Pb*5eXk  
} GKcv<G208  
} a'\o7_  
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//日志 41SGWAd#:  
public static void log(String sMsg) GRY2?'`  
{ >ooZj9:'  
System.err.println(sMsg); ul*Q
t}  
} `O'`eY1f  
;j2vHU#q-  
aN(|'uO@  
public static void log(int sMsg) @gG<le6  
{ 6]-SK$  
System.err.println(sMsg); \(%Y%?dy  
} m>SErxU(z  
} H<1WbM:w  
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/* xCtmXo  
**TestMethod.java Qqlup  
*/
R i^[i}  
package NetFox; +k`!QM>e-  
O eL}EVs8=  
o;?/HE%,[  
public class TestMethod { <mAhr  
\m1~jMz*>k  
'e6WDC1Am(  
public TestMethod() !>1@HH?I\/  
{ ///xx/weblogic60b2_win.exe HF(KN{0.B  
try{ l<N}!lG|  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 4rrSb*
  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 0tU.(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); H<3I 5Kgt  
fileFetch.start(); NQ6sGL  
} oJfr +3I  
catch(Exception e){e.printStackTrace ();} db6mfxi  
f;b[w

 
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pA)  
} +>PX&F  
r-<F5<H+K@  
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public static void main(String[] args) Ng_!zrx04  
{ /3{b%0Aa  
new TestMethod(); 0L/n?bf  
} @mfEKU!  
} #{\%rWnCm  
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