http断点续传简单实现（java)

/* TyjZ  
**SiteFileFetch.java J.'%=q(Sb  
*/ ?T.=ym  
package NetFox; Oxa8ue?  
import java.io.*; ``eam8Az_U  
import java.net.*; <nb%$2r1  
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public class SiteFileFetch extends Thread { fERO(
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SiteInfoBean siteInfoBean = null; //文件信息Bean eWNg?*/  
long[] nStartPos; //开始位置 iPkCuLQ}  
long[] nEndPos; //结束位置 /&<V5?1|  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 rlGv6)vb  
long nFileLength; //文件长度 ];lZ:gT  
boolean bFirst = true; //是否第一次取文件 }i,r{Y]s]  
boolean bStop = false; //停止标志 N#ZWW6  
File tmpFile; //文件下载的临时信息 lx=tOfj8  
DataOutputStream output; //输出到文件的输出流 s2<[@@@q  
L
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Fe4>G8uuwn  
public SiteFileFetch(SiteInfoBean bean) throws IOException d,?Tq  
{ :o .+<_&  
siteInfoBean = bean; /Q3\6DCl  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Gw
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); fIl!{pv[  
if(tmpFile.exists ()) |35OA/O?X  
{ O$}.b=N9  
bFirst = false; /aMOZ=,q}  
read_nPos(); jz![#-G  
} dJ m9''T')  
else 3fp&iz  
{ } ck<R
  
nStartPos = new long[bean.getNSplitter()]; 8I*N  
nEndPos = new long[bean.getNSplitter()]; W7 dSx  
} huS*1xl  
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} [!yA#{xl,  
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public void run() Qj;{Z*l%+  
{ nvT@'y+  
//获得文件长度 E "}@SaB-  
//分割文件 
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//实例FileSplitterFetch xE w\'tH  
//启动FileSplitterFetch线程 <K`E*IaW  
//等待子线程返回 jT=|!,Pn  
try{ |Ia9bg'1U  
if(bFirst) UUlz3"`  
{ 1*Pxndt&  
nFileLength = getFileSize(); j&oRj6;Ha+  
if(nFileLength == -1) w\YS5!P,V  
{ P|bow+4  
System.err.println("File Length is not known!"); 3>-h- cpMX  
} (=Cb)/s0  
else if(nFileLength == -2)
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{ t+iHsCG)>  
System.err.println("File is not access!"); U`i5B;k}-  
} 26rg-?;V^  
else &<]f-  
{ fDf[:A,8  
for(int i=0;i<nStartPos.length;i++) v={{$=/t  
{ T5."3i  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); uW(-?  
} Rbf6/C  
for(int i=0;i<nEndPos.length-1;i++) v/q-{1  
{ X!ruQem /  
nEndPos = nStartPos[i+1]; hj9TiH/+  
} @%R4V[Lo.  
nEndPos[nEndPos.length-1] = nFileLength; `a4&_`E,p  
} )6C+0b*  
} > 0MP[  
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fw jo?  
//启动子线程 5'I+%66?h$  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ],pB:=  
for(int i=0;i<nStartPos.length;i++) 3- Kgz  
{ BsIF3sS#9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !%,7*F(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), UxTLr-db^  
nStartPos,nEndPos,i); FnA Kfh(  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :rVR{,pL  
fileSplitterFetch.start(); FOsd{Fw  
} -[L\:'Gp5  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7H  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); T,pr&1]Lw  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", e$Ds2%SaT  
nEndPos = " + nFileLength); UhDQl%&He  
// fileSplitterFetch[nPos.length-1].start();
n[iwi   
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(BVqm
i{  
//等待子线程结束 0Idek  
//int count = 0; m4hkV>$d  
//是否结束while循环 @-!P1]V|  
boolean breakWhile = false; +?{"Q#.>;  
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while(!bStop) lPR=C0h}@  
{ 0+FPAqX  
write_nPos(); ;{sZDjev>  
Utility.sleep(500); /grTOf&  
breakWhile = true; bkV<ZUW|;  
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for(int i=0;i<nStartPos.length;i++) 2X@9o4_4q  
{ 6VGY4j}:(  
if(!fileSplitterFetch.bDownOver) o72r `2  
{ h+Co:pr  
breakWhile = false; `MOw\Z)..  
break; o8g7wM]M  
} `q*[fd1u.  
} U6M~N0)Yr  
if(breakWhile) &jF'2D^_  
break; '? 5
-  
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//count++; pWV_KS  
//if(count>4) g-sNYd%?a  
// siteStop(); X9m^i2tk  
} ,_e[P  
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System.err.println("文件下载结束！"); |U|>YA1[b  
} u9hd%}9Qd?  
catch(Exception e){e.printStackTrace ();} eP-|3$  
} .Fo#Dmq3  
&>JP.//spi  
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//获得文件长度 6m:$mhA5  
public long getFileSize() Tx;a2:6\[  
{ }nd>SK4  
int nFileLength = -1; GTdoUSUq  
try{ r].n=455[  
URL url = new URL(siteInfoBean.getSSiteURL()); -l= 4{^pK  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [CJ<$R !  
httpConnection.setRequestProperty("User-Agent","NetFox"); JQ03om--(  
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int responseCode=httpConnection.getResponseCode(); o}rG:rhIh  
if(responseCode>=400) 2RkW/)A9  
{ Z2g'&,uc#  
processErrorCode(responseCode); e|]e\Or>  
return -2; //-2 represent access is error e(0OZ_w  
} \Bo%2O%4  
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String sHeader; I&1Lm)W&  
VQ9A/DH/  
28!C#.(h  
for(int i=1;;i++) lFzVd N  
{ {kpF etXt?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); d0(zB5'}  
//Utility.log(in.readLine()); E5ce=$o  
sHeader=httpConnection.getHeaderFieldKey(i); 2aYBcPFQh#  
if(sHeader!=null) = lo.LFV  
{ {MgRi7  
if(sHeader.equals("Content-Length")) 7ch9Pf  
{ P<PZ4hNx  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); f^F;`;z  
break; PgkU~68`  
} o2!738  
} N"70P/  
else =~1EpZ  
break; =[(34#  
} r: K1PO  
} ~5KcbGD~  
catch(IOException e){e.printStackTrace ();} [Hh-F#|R  
catch(Exception e){e.printStackTrace ();} 0kE[=#'.'  
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Utility.log(nFileLength); %qc_kQ5%  
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*  
return nFileLength; 'PF>#
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} Bj@>iw?g'  
*9'3 `^l  
h(
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//保存下载信息（文件指针位置） ,Z{\YAh1  
private void write_nPos() 0m_yW$w  
{ @DysM~I  
try{ RjWwsC~B  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2k.VTGak  
output.writeInt(nStartPos.length); NqD]p{>Y  
for(int i=0;i<nStartPos.length;i++) (nqry[g&  
{ eCGr_@1  
// output.writeLong(nPos); :;{M0  
output.writeLong(fileSplitterFetch.nStartPos); `zQuhD 8W  
output.writeLong(fileSplitterFetch.nEndPos); _p )NZ7yC  
} rW?WdEg  
output.close(); '`jGr+K,wU  
} 1:-'euA"  
catch(IOException e){e.printStackTrace ();} f.6>6%l  
catch(Exception e){e.printStackTrace ();} x%mRDm~-  
} Qq,2V
 
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//读取保存的下载信息（文件指针位置） zdYH9d>D  
private void read_nPos() }*:3]  
{ b| L;*<KU  
try{ F-m%d@P&X  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); DDrR9}k  
int nCount = input.readInt(); 3aqH!?rVU  
nStartPos = new long[nCount]; ]1 f^ SxSI  
nEndPos = new long[nCount];
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for(int i=0;i<nStartPos.length;i++) digc7;8L  
{ YC6T0m  
nStartPos = input.readLong(); MPB[~#:  
nEndPos = input.readLong(); |*bUcS<S  
} i2<z"v63  
input.close(); o}AXp@cqi  
} CNNqS^ct  
catch(IOException e){e.printStackTrace ();} Y
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catch(Exception e){e.printStackTrace ();} =KPmZ,/w  
} {ZeY:\G~  
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private void processErrorCode(int nErrorCode) [:X@|,1V!L  
{ j yHa}OT  
System.err.println("Error Code : " + nErrorCode); DGvuo 8  
} #T)Gkc"{  
?|M-0{  
!f~a3 {;j  
//停止文件下载 k~[jk5te  
public void siteStop() KXt8IMP_"y  
{ $?GggP d  
bStop = true; XM
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for(int i=0;i<nStartPos.length;i++) m212 gc0u  
fileSplitterFetch.splitterStop(); MzvhE0ab  
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} SdH=1zBc  
} //@6w;P  
//负责部分文件的抓取 FvsVfV U  
**FileSplitterFetch.java H!;N0",]N  
*/ do" m=y  
package NetFox; l,@>J9}Se  
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import java.io.*; P'~`2W0sz  
import java.net.*; r5j$FwY  
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public class FileSplitterFetch extends Thread { WuK<?1meN  
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String sURL; //File URL 24wDnDyh  
long nStartPos; //File Snippet Start Position 2s}S9  
long nEndPos; //File Snippet End Position HlE8AbEg  
int nThreadID; //Thread's ID #S7oW@  
boolean bDownOver = false; //Downing is over I_1?J* b4k  
boolean bStop = false; //Stop identical S*l/ Sa@  
FileAccessI fileAccessI = null; //File Access interface !8@yi"n  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException S?v/diK ]J  
{ R>c>wYt
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this.sURL = sURL; czRBuo+k+  
this.nStartPos = nStart; ;lmg0dtJ  
this.nEndPos = nEnd; rmg\Pa8W>  
nThreadID = id; 67EGkW?hbt  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "kApGNB  
} -VohU-6 |  
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public void run() 5AT^puL]]  
{ +?\JQ|  
while(nStartPos < nEndPos && !bStop)  kF1$  
{ }8#olZ/(q  
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try{ *<\`"C;  
URL url = new URL(sURL); WsbVO|C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); QGNKQ`~  
httpConnection.setRequestProperty("User-Agent","NetFox"); wH"9N+82M  
String sProperty = "bytes="+nStartPos+"-"; |5flvkid  
httpConnection.setRequestProperty("RANGE",sProperty); &S="]
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Utility.log(sProperty); ;Am3eJa*-  
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| V(sCF  
InputStream input = httpConnection.getInputStream(); Mnranhe>G  
//logResponseHead(httpConnection); bg~CV&]M  
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/3)\^Pof  
byte[] b = new byte[1024]; {/noYB<;  
int nRead; J@>|`9T9$  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) (H:c80/V  
{ %Za}q]?  
nStartPos += fileAccessI.write(b,0,nRead); {^oohW -  
//if(nThreadID == 1) 7c_2.T@4  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); co,0@.i  
} 10Eun }  
]fb@>1 jp  
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Utility.log("Thread " + nThreadID + " is over!"); ]2u   
bDownOver = true; 0=,Nz  
//nPos = fileAccessI.write (b,0,nRead); }/J"/
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} e\~nqKCb  
catch(Exception e){e.printStackTrace ();} N:|``n>  
} ^.J_w  
} h`U-{VIrqi  
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//打印回应的头信息 0$Tb5+H5  
public void logResponseHead(HttpURLConnection con) i>S@C@~  
{ DWtITO>  
for(int i=1;;i++) E$lbm>jsb$  
{ n\;;T1rM  
String header=con.getHeaderFieldKey(i); I{w(`[Nxw*  
if(header!=null) zsQ]U!*rD  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); p+b/k2Q  
Utility.log(header+" : "+con.getHeaderField(header)); hV $Zr4'  
else cKYvNM  
break;
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} l!gX-U%-  
} $mK;{9Z  
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[!U%''  
public void splitterStop() :PV3J0pB~  
{ iUz?mt;k  
bStop = true; ]ovtH

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} Gt{%O>P8t  
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} 'g<"@SS+  
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/* Lp%J:ogV`  
**FileAccess.java 8nZ_.  
*//文件访问(定位，写) }\m.~$|[  
package NetFox; PkFG0  
import java.io.*; AxEdQRGk  
K!AA4!eUzM  
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public class FileAccessI implements Serializable{ 5OPvy,e6  
}#tbK 2[  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 xjD$i'V+  
RandomAccessFile oSavedFile; BNk>D|D;  
long nPos; pzt<[;  
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public FileAccessI() throws IOException kXdXyq  
{ VN09g&  
this("",0); ,2
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} t"9r`0>  
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u  
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public FileAccessI(String sName,long nPos) throws IOException Mq\?J{E  
{ kbvF 9#  
oSavedFile = new RandomAccessFile(sName,"rw"); ;>/Mal  
this.nPos = nPos; ^7Z?}tgU  
oSavedFile.seek(nPos); G/~b(V;>  
} $ r-rIW5\  
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public synchronized int write(byte[] b,int nStart,int nLen) OI0@lSAo<  
{ %qqCpg4  
int n = -1; ;dfIzi  
try{ mz x$
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oSavedFile.write(b,nStart,nLen); yD
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n = nLen; ^N^s|c'  
} %p7onwKq0  
catch(IOException e) *yHz#u'  
{ ?ec
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e.printStackTrace (); $mf O:%  
} B^]Gv7-  
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J
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return n; N/
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} KbciRRf!k  
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} } gwfe H
 
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rmC7!^/  
/* #y"LFoJn  
**SiteInfoBean.java GBBp1i  
*/ xY.?OHgG/  
package NetFox; M@G\b^"  
v=dK2FaY  
 6cjCn  
public class SiteInfoBean { xFIzq  
pI.8Ip_r  
RkTYvAk|kY  
private String sSiteURL; //Site's URL > Xij+tt{  
private String sFilePath; //Saved File's Path uT=5zu  
private String sFileName; //Saved File's Name A"qDc  
private int nSplitter; //Count of Splited Downloading File "1>w\21  
ttB>PTg#  
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public SiteInfoBean() ;gAL_/_  
{//nSplitter的缺省值为5 WAtv4  
//default value of nSplitter is 5 wi%ls8
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this("","","",5); Gr}NgyT<!D  
} -2u)orWP  
* RX^ z6  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \J#&]o)Y  
{ p/l">d]+  
sSiteURL= sURL; P;K3T![  
sFilePath = sPath; UxF9Ko( ]d  
sFileName = sName; 0N]\f.=`  
this.nSplitter = nSpiltter; N9*QQ0  
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} dK8dC1@,X;  
2 p}I  
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public String getSSiteURL() fo~*Bp()-E  
{ =w:)AWZ  
return sSiteURL; .r-Zz3  
} amX1idHo^  
.kkhW8:  
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public void setSSiteURL(String value) i6P$>8jBQ-  
{ Wl+spWqW  
sSiteURL = value; M '%zA;Wl  
} @Jqo'\~&  

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%] :ZAmN  
public String getSFilePath() [}l 90
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{ s +qodb+  
return sFilePath; 35x]'  
} MZWv#;.]  
Bva2f:)K|  
/?b{*<TK  
public void setSFilePath(String value) C9""sVs  
{ }L%2K"8?}  
sFilePath = value; [~G1Rz\h  
} .LnknjC  
0ZLLbEfnPB  
<Ter\o5%  
public String getSFileName() u~JR]T  
{ ?<\2}1  
return sFileName; Bga4kjfmk  
} })?-)fFD  
i\DU<lD5VN  
Lp4F1H2t-  
public void setSFileName(String value) gNDMJ^`  
{ lF40n4}  
sFileName = value; ^j10 f$B  
} vCK+v r!  
nZ#u#V  
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public int getNSplitter() *DZ7,$LQ~D  
{ (#)XRm{t  
return nSplitter; $A/?evJi8R  
} Gxxz4   
-yBj7F|  
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public void setNSplitter(int nCount) G+k wG)K  
{ _ yDDPuAi  
nSplitter = nCount; 28c6~*Te#  
} /;[x3}[  
} $"MVr5q6  
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BgDWl{pm  
/* :V@)A/}uk  
**Utility.java ?Pf#~U_  
*/ ty4R2LnC  
package NetFox; TiG?r$6v%  
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public class Utility { D/;[x{;E  
:("@U,  
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public Utility() l%?4L/J)#  
{ >ZeARCf"f  
WiQVZ{  
]:'

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} .c@Y?..+  
gX(Xj@=(&  
//线程睡眠 /eXiWasQ  
public static void sleep(int nSecond) $d4&H/u^  
{ ^Oeixi@f  
try{ %W=BdGr[8z  
Thread.sleep(nSecond); Hi/[  
} rl$"~/ oz  
catch(Exception e) ,S<) )  
{ bKzG5|Qu  
e.printStackTrace (); G)M! , Q  
} h+Yd \k  
} oR,zr  
piuM#+Y\'S  
//日志 :*DWL!a  
public static void log(String sMsg) njO~^Hl7  
{ L%<]gJtrO  
System.err.println(sMsg); 261? 8&c  
} "M\rO!f:  
;cPPx`0$9  
BIew\N  
public static void log(int sMsg) BSB&zp  
{ P{:Zxli0  
System.err.println(sMsg); R?/xH=u>  
} >}2 ,2  
} 0E,QOF{o  
so/0f1R?~  
4GG>n  
/* D]rYg'  
**TestMethod.java u2`j\ Vu  
*/ 3^-R_  
package NetFox; }[drR(]`dO  
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public class TestMethod { j
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~x+'-2A46  
public TestMethod() v6[VdWOx5  
{ ///xx/weblogic60b2_win.exe \.p; 4V&  
try{ U
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); pFZ$z?lI  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ],~[^0  
SiteFileFetch fileFetch = new SiteFileFetch(bean); J=(i0A  
fileFetch.start(); [wiB1{/Ls.  
} [Ob'E!;<  
catch(Exception e){e.printStackTrace ();} *A8Et5HAv  
\/gf_R_GN  
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} }u$c*}  
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MLM/!N 7  
public static void main(String[] args) /0Qo(  
{ &(l.jgqg&  
new TestMethod(); vWrTB   
} NjA[(8\:  
} K ;]dZ8  
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