http断点续传简单实现（java)

/* c~+l|r=u?  
**SiteFileFetch.java n~k9Z^ $  
*/ q#N8IUN}4  
package NetFox; ro4 XA1  
import java.io.*; 3?GEXO&,E  
import java.net.*; -kd_gbnr3  
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public class SiteFileFetch extends Thread { ~?n)1Vr|  
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<ib#PLRM  
SiteInfoBean siteInfoBean = null; //文件信息Bean Ym*Ed[S  
long[] nStartPos; //开始位置 u%=M
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long[] nEndPos; //结束位置 rTj
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 G#;$;  
long nFileLength; //文件长度 u;*Wc9>sU  
boolean bFirst = true; //是否第一次取文件 &Rx-zp&dJ  
boolean bStop = false; //停止标志 ISuye2tExq  
File tmpFile; //文件下载的临时信息 +9mnxU>  
DataOutputStream output; //输出到文件的输出流 OQON~&~  
85 tQHm6j  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类）  D=nuK25  
public SiteFileFetch(SiteInfoBean bean) throws IOException 'WG%O7s.  
{ 4X2/n  
siteInfoBean = bean; ~Xg@,?Zr  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Yg6 f  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); g2WDa'{L  
if(tmpFile.exists ()) ggUJ -M'2h  
{ VL/%D*  
bFirst = false; 0g@ 8x_3  
read_nPos(); 4W9#z~'  
} "7pd(p *C  
else #Xc6
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{ 'i|z>si[*  
nStartPos = new long[bean.getNSplitter()]; iVt*N$iZ  
nEndPos = new long[bean.getNSplitter()]; 7usf^g[dh  
} +SSF=]4+  
}pa@qZXh  
tF<|Eja*  
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} e8@@Pi<sB  
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public void run() do9@6[{Sv  
{ {%5tqF  
//获得文件长度 Fss7xP'  
//分割文件 u"\HBbBx  
//实例FileSplitterFetch S/|'ggC  
//启动FileSplitterFetch线程 +_HPZo  
//等待子线程返回  zF2GW  
try{ joh=0nk;D  
if(bFirst) HUtuUX  
{ q*oUd/F8  
nFileLength = getFileSize(); >g@;`l.Z#  
if(nFileLength == -1) \*s'S*~  
{ ~/6m|k  
System.err.println("File Length is not known!");  Yq.Cz:>b  
} 8#w}wGV*  
else if(nFileLength == -2) )} y1  
{ eXI^9u
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System.err.println("File is not access!"); 2c.~cNx`q[  
} /u }AgIb  
else E3\O?+h#  
{ A`4j=OF\  
for(int i=0;i<nStartPos.length;i++) :mU,g|~55  
{ 9i8D_[  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Pgs^#(^>  
} O>zM(I+p  
for(int i=0;i<nEndPos.length-1;i++) 95,y@~*]  
{ >`a)gky%~  
nEndPos = nStartPos[i+1]; 2bS)|#v<_t  
} fo$iV;x`  
nEndPos[nEndPos.length-1] = nFileLength; ,o}!pQ  
} 8V
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} h*f=  
@O<kjR<b  
xr)Rx{)3h  
//启动子线程 K4i#:7r'b  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; zlmb_akJ  
for(int i=0;i<nStartPos.length;i++) 2yhtJ9/  
{ >WMH.5p  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kEtYuf^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), |*0oz=  
nStartPos,nEndPos,i); 5rqjqfFa  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yG5T;O&  
fileSplitterFetch.start(); ~l%Dcp  
} t+k"$zR  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #~54t0|Cd>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); s%Q pb{  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^IuHc_  
nEndPos = " + nFileLength); xNTO59Y-s  
// fileSplitterFetch[nPos.length-1].start(); \eE0Rnaf-  
2+Z2`k]AC  
M=$y_9#  
//等待子线程结束 Cd.pMoS  
//int count = 0; O^I~d{M 5I  
//是否结束while循环

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boolean breakWhile = false; inavi5.  
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7*xg{  
while(!bStop) LMWcF'l  
{ 9}Tf9>qP>M  
write_nPos(); kDJ5x8Q#  
Utility.sleep(500); t$8f:*6(*  
breakWhile = true; HHD4#XcU  
'+NmHu:q  
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for(int i=0;i<nStartPos.length;i++) VY$hg  
{ m,v"N%k,  
if(!fileSplitterFetch.bDownOver) G6xdGUM  
{ EN()dCQHr  
breakWhile = false; eP-q[U?$n  
break; -c!{'
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} Y'-BKZv!  
} ^:K"Tv.=  
if(breakWhile) Z mF}pa,gd  
break; ="RDcf/  
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//count++; Deq
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//if(count>4) A?q[C4-BO,  
// siteStop(); A0yRA+  
} u#?K/sU  
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^  
3@?#4]D{'  
System.err.println("文件下载结束！"); Ob?>zsx  
} Y:]~~-f\~  
catch(Exception e){e.printStackTrace ();} I@a7AuOw  
} ZPn`.Qc  
]v@#3,BV  
q(e&{pbM)  
//获得文件长度 C<2vuZD  
public long getFileSize() |x2>F   
{ 0]{h,W3]@[  
int nFileLength = -1; @"-<m|lM  
try{ a_m P$4T  
URL url = new URL(siteInfoBean.getSSiteURL()); FZz\zp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |uQJMf[L)  
httpConnection.setRequestProperty("User-Agent","NetFox"); -*k%'Gr  
#Oz<<G<  
g/W<;o<v(I  
int responseCode=httpConnection.getResponseCode(); s<|.vVi"  
if(responseCode>=400) O82T|0uw  
{ eCMcr !.  
processErrorCode(responseCode); ?UoA'~=  
return -2; //-2 represent access is error 1?`,h6d*=  
} /}r%DND'  
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s%>>E!Qi_  
String sHeader; T.GY
  
:^71,An >E  
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for(int i=1;;i++) b{s_cOr/  
{ P*T'R  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Q1IN@Db}y  
//Utility.log(in.readLine()); z)=D&\HX  
sHeader=httpConnection.getHeaderFieldKey(i); /OK.n3Tt  
if(sHeader!=null) R:x4j#(  
{ (ta!4h,  
if(sHeader.equals("Content-Length")) `&b8wF  
{ V"*|`z)  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 1[C,*\X8v  
break; j./3)  
} ~K
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} .JZoZ.FAb  
else 3_
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break; n`? j. s  
} sAfSI<L_  
} l.\Fr+*ej  
catch(IOException e){e.printStackTrace ();} Cq?l>  
catch(Exception e){e.printStackTrace ();} wy<m&M<Gr  
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Utility.log(nFileLength); w#U3h]>,  
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return nFileLength; muo(bR8  
} bdk"7N  
m.EI("n"J  
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//保存下载信息（文件指针位置） 5Az=)q4Q  
private void write_nPos() 7gfNe kr~W  
{ q-eC=!#}  
try{ a9mLPP  
output = new DataOutputStream(new FileOutputStream(tmpFile));  &Hb6  
output.writeInt(nStartPos.length); NZ/gp"D?  
for(int i=0;i<nStartPos.length;i++) YTpSR~!Rj  
{ G$}\~dD  
// output.writeLong(nPos); DGj:qd(  
output.writeLong(fileSplitterFetch.nStartPos); _W/s=pCh  
output.writeLong(fileSplitterFetch.nEndPos); fySzZ  
} hf^,  
output.close(); Y[i>  
} m,,-rC  
catch(IOException e){e.printStackTrace ();} |3/=dG  
catch(Exception e){e.printStackTrace ();} YH&`+ +  
} .slA}  
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//读取保存的下载信息（文件指针位置） )9 5&-Hs  
private void read_nPos() {'E%SIRZ)  
{ 1T!b#x4  
try{ "n,">  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); xmb]L:4F  
int nCount = input.readInt(); eZIqyw  
nStartPos = new long[nCount]; "yXKu)_  
nEndPos = new long[nCount]; ^](sCE7  
for(int i=0;i<nStartPos.length;i++) Zk__CgS#  
{ n'9Wl'  
nStartPos = input.readLong(); d^mw&F)S  
nEndPos = input.readLong(); /@X!  
} GL_YT.(!  
input.close(); B^P)(Nu+  
} UX;?~X  
catch(IOException e){e.printStackTrace ();} VUxuX5B3M  
catch(Exception e){e.printStackTrace ();} Xa=oryDt  
} tq H7M0Ry  
8{#WF#  
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private void processErrorCode(int nErrorCode) <iuESeDG  
{ #wK {G)J  
System.err.println("Error Code : " + nErrorCode); vP`Sz}FU  
} ST5L O#5  
5,}
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Fm_^7|  
//停止文件下载 u\ro9l  
public void siteStop() G|Rsj{2'  
{ a\ fG)Fqp  
bStop = true; C$(US8:{  
for(int i=0;i<nStartPos.length;i++) #3>o^cN~8k  
fileSplitterFetch.splitterStop(); KV9'ew+M  
,
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} ztTj2M"  
} ]W~\%`#8?  
//负责部分文件的抓取 :JH#*5%gQ:  
**FileSplitterFetch.java de1cl<  
*/ Ckd@
|  
package NetFox; 7DDd1"jE  
?;zu>4f|  
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import java.io.*; GPz0qK  
import java.net.*; _v bCC7Bf8  
Y<-h#_  
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public class FileSplitterFetch extends Thread { c[J?`8  
OB`(,m#  
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String sURL; //File URL ^ gM
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long nStartPos; //File Snippet Start Position #%O|P&rA  
long nEndPos; //File Snippet End Position h/5|3  
int nThreadID; //Thread's ID Z<L}ur  
boolean bDownOver = false; //Downing is over `-fWN
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boolean bStop = false; //Stop identical Y[)b".K  
FileAccessI fileAccessI = null; //File Access interface [~*5uSG  
1AQVj]#S  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException k>E^FB=  
{ fb-Lp#!T39  
this.sURL = sURL; q
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this.nStartPos = nStart; WD#
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this.nEndPos = nEnd; +Ac.@!X}%  
nThreadID = id; ~k\Dde  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 }A jE- K{  
}
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vF@hg)A  
Q
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public void run() (VDY]Q)  
{ SW5V:|/  
while(nStartPos < nEndPos && !bStop) NIgqdEu1
 
{ 2t 6m#  
DmU,}]#:  
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try{ 7irpD7P>  
URL url = new URL(sURL); -f
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); H3-(.l[!b)  
httpConnection.setRequestProperty("User-Agent","NetFox"); -]el_:H  
String sProperty = "bytes="+nStartPos+"-"; E|{(O
  
httpConnection.setRequestProperty("RANGE",sProperty); %"-bG'Yc  
Utility.log(sProperty); <G|i!Pm  
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InputStream input = httpConnection.getInputStream(); ]QKo>7%[  
//logResponseHead(httpConnection); p3r("\Za,  
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byte[] b = new byte[1024]; z^lcc7  
int nRead; `#HtVI  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) +t*V7nW  
{ j9gn7LS  
nStartPos += fileAccessI.write(b,0,nRead); i(T[   
//if(nThreadID == 1) `-t8ag3  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <*JFY%y"  
} F+o4f3N  
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i>z_6Gax*[  
Utility.log("Thread " + nThreadID + " is over!"); Kb
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bDownOver = true; -t]3 gCLb  
//nPos = fileAccessI.write (b,0,nRead); m`i_O0T  
} 88Nx/:#Y*  
catch(Exception e){e.printStackTrace ();} @)#EZQix  
} 5aj%<r  
} .~$!BWP  
) >;7"v  
 I~T   
//打印回应的头信息 IiU\}<O  
public void logResponseHead(HttpURLConnection con) EfX\"y  
{ e!W U
 
for(int i=1;;i++) "C0?s7Y  
{ wZ4w`|'  
String header=con.getHeaderFieldKey(i); WwsH7X)  
if(header!=null) >$$z6A[  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9?X8H1  
Utility.log(header+" : "+con.getHeaderField(header)); FKZ'6KM&A  
else yPrF2@#XZ/  
break; 9xi nX-x;n  
} J':X$>
E|  
} r[?GO"ej5  
K;z$~;F  
_(zZrUHB  
public void splitterStop() YMN=1Zuj?  
{ fj|b;8_}l  
bStop = true; uMx6:  
} ?(Se$iTZ  
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}y%c.  
} 8)lrQvZ  
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/* arIEd VfNa  
**FileAccess.java Um}f7^fp^l  
*//文件访问(定位，写) eFh7#~m  
package NetFox; 6Hbu7r*tm  
import java.io.*; g,9&@g/  
3 ,zW6-}  
4#CHX^De  
public class FileAccessI implements Serializable{ "(r%`.l=I  
y2W|,=Vd  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 VwudNjL  
RandomAccessFile oSavedFile; 5?MaKNm}  
long nPos; T;G<62`
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public FileAccessI() throws IOException Ul_5"3ze  
{ #M
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this("",0); TZ63=m  
} JM1O7I  
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public FileAccessI(String sName,long nPos) throws IOException PYBE?td  
{ Fc#Sn2p*  
oSavedFile = new RandomAccessFile(sName,"rw"); A XhP3B]  
this.nPos = nPos; @9eN\b%I^H  
oSavedFile.seek(nPos); N4#D&5I",  
} Ngj&1Ta&[  
yR?./M!  
fy]c=:EmD  
public synchronized int write(byte[] b,int nStart,int nLen) UX+vU@Co[  
{ $xT9e  
int n = -1; `OfD^Q=  
try{ SJ91(K  
oSavedFile.write(b,nStart,nLen); Q^;:
Kl.b  
n = nLen; ua"2nVxK_K  
} s+~GQcj<T  
catch(IOException e) )=#e*1!b  
{ LSo*JO6  
e.printStackTrace (); tLi91)oG  
} g<@Q)p*ow  
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? cXW\A(  
return n; pdB\D  
} I_5/e>9  
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} 76bMy4re  
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/* /vq$/  
**SiteInfoBean.java 9
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*/ X;H\u6-|>6  
package NetFox; "={*0P  
F^$;hMh%  
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public class SiteInfoBean { {nXygg J  
}K8e(i6z  
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private String sSiteURL; //Site's URL Ui!l3_O  
private String sFilePath; //Saved File's Path d)S`.Q  
private String sFileName; //Saved File's Name 5JhvYsf3_  
private int nSplitter; //Count of Splited Downloading File !ej]'>V,X  
O2\(:tvw  
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public SiteInfoBean() mogmr  
{//nSplitter的缺省值为5 lP*n%Pn)  
//default value of nSplitter is 5 e'>q( B  
this("","","",5); :_y!p  
} N2k<W?wQ  

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7  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;@T0wd_i|  
{ DI8<0.L  
sSiteURL= sURL; `3i<jZMG  
sFilePath = sPath; PxgJ7d  
sFileName = sName; a_+?#m  
this.nSplitter = nSpiltter; ]+46r!r|  
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9@ YKx0  
} zBlv?JwG  
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public String getSSiteURL() (M"rpG>L  
{ ~5`oNa  
return sSiteURL; 5?F5xiW  
} t[J=8rhER  
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public void setSSiteURL(String value) $%q=tn'EX  
{ nX 9]dz
 
sSiteURL = value; HO['o{>BL  
} hO&b\#@
~  
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:^WF%X  
public String getSFilePath() G~o!u8^;  
{ 71\53Qr#U  
return sFilePath; 3ZI7;Gw  
} &}[P{53sr  
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&n )MGg1%  
public void setSFilePath(String value) &:g:7l]g  
{ (z>t4(%\  
sFilePath = value; i
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} ^l|b>z"0ao  
C=V2Y_j  
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public String getSFileName() F'b%D  
{ y7M{L8{0  
return sFileName; z,4mg6gt  
} '{UKO7  
] re=8s6  
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public void setSFileName(String value) $GFR7YC 7  
{ fE+zA)KX  
sFileName = value; 7n6g;8xE  
} z,G_&5|f%  
hp)^s7H  
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public int getNSplitter() _yv#v_Z  
{ c%C6d97q  
return nSplitter; .Zczya  
} RC/ 3\'  
4_kN';a4Q  
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public void setNSplitter(int nCount) Bj1%}B  
{ R ,qQC<  
nSplitter = nCount; ];LFv5"  
} GeTk/tU  
} nFNRiDx  
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/* )rK2%\Z  
**Utility.java \~ChbPnc  
*/ s:}?rSI  
package NetFox; 'ZW(Hjrd  
}I&.xzJ  
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public class Utility { X+aQ 7^"s  
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public Utility() m4 (pMrJ  
{ n?.;*:  
W~/d2_|/  
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} aX^T[  
mkn1LzE|F  
//线程睡眠 j4?Qd0z  
public static void sleep(int nSecond) Bz/Vzc(  
{ y
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try{ &.,K@OFE}  
Thread.sleep(nSecond); zHb[.ry~  
} t1adS:)s  
catch(Exception e) e4tIO   
{ Mq
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e.printStackTrace (); fz=?QEG  
} {siOa%;*  
} G kjfDY:  
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//日志 +7H)s  
public static void log(String sMsg) qh~bX i!  
{ 1IA1
;  
System.err.println(sMsg); ?eIb7O  
} vd4@jZ5  
,Y/B49  
AU$~Ap*rsa  
public static void log(int sMsg) [yXmnrxA  
{ f1MRmp-f'  
System.err.println(sMsg); TVD~Ix  
} sllT1%?  
} "l56?@-x  
'dwT&v]@  
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/* 0N,<v7PX  
**TestMethod.java s1D<R,J|H  
*/ ={O ~  
package NetFox; :Z//  
 vmqa_gU\  
@'R)$:I%L  
public class TestMethod { {Yj5Mj|#  
OoSk^U)  
&u.{]Yjx  
public TestMethod() \)6glAtN  
{ ///xx/weblogic60b2_win.exe x%}D+2ro-t  
try{ 8}B  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); W%!(kN&d  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 8wsU`40=Q  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0>sa
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fileFetch.start(); 9GD0jJEu  
} {cm?Q\DT  
catch(Exception e){e.printStackTrace ();} _RbfyyaN  
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} t1FtYXv`/  
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public static void main(String[] args) LTWkHyx  
{ V)^Xz8H_  
new TestMethod(); ,MCTb'=G  
} +`HMl;0m  
} E=s,-  
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