http断点续传简单实现（java)

/* xyJgHbml  
**SiteFileFetch.java $MVeMgPa  
*/ ,vY I O  
package NetFox; u #QSa$P  
import java.io.*; [?r\b  
import java.net.*; ?Kz` O>"6  
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public class SiteFileFetch extends Thread { -3XnK5  
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SiteInfoBean siteInfoBean = null; //文件信息Bean V9 t:JY  
long[] nStartPos; //开始位置 GH)+yD[o  
long[] nEndPos; //结束位置 ~|d?o5W  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [`nyq)  
long nFileLength; //文件长度 PL B=%[  
boolean bFirst = true; //是否第一次取文件 @md^
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boolean bStop = false; //停止标志 w\Eve:  
File tmpFile; //文件下载的临时信息 Erymx$@P  
DataOutputStream output; //输出到文件的输出流 C g,w6<7  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） BOcEL%+  
public SiteFileFetch(SiteInfoBean bean) throws IOException )UU6\2^  
{ &(U=O?r7  
siteInfoBean = bean; Ita!07  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); M(f*hOG{Y  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ha'm`LiX  
if(tmpFile.exists ()) tp3N5I  
{ $G([#N<  
bFirst = false; pDS4_u  
read_nPos(); Rn^N+3o'M  
} ,T>2zSk  
else y&|{x "  
{ '$nGtB5  
nStartPos = new long[bean.getNSplitter()]; hzVr3;3Zn  
nEndPos = new long[bean.getNSplitter()]; z>#$#:Z4  
} Ppn
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} m`6`a|Twp$  
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public void run() }{PtQc6RL!  
{ ~oyPmIcb  
//获得文件长度 W| eG}`  
//分割文件 Hd}t=6  
//实例FileSplitterFetch ^8t*WphZC  
//启动FileSplitterFetch线程 vx,6::%]  
//等待子线程返回 )CU(~s|s  
try{ ov}{UP]a?  
if(bFirst) l1j   
{
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nFileLength = getFileSize(); _$x *CP0(  
if(nFileLength == -1) C_&tOt  
{ NWcF9z%@  
System.err.println("File Length is not known!"); 4ov~y1Da)  
} Qx#)c%v\\  
else if(nFileLength == -2) wn.0U  
{ zXO.NSC[  
System.err.println("File is not access!"); +4RaN`I  
} F.w#AV  
else B9 {DO  
{ hj[g2S%X  
for(int i=0;i<nStartPos.length;i++) L3Iz]D3s  
{ ~~ w4854  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @J)vuGS  
} jP]'gQ!-w  
for(int i=0;i<nEndPos.length-1;i++) ~nlY8B(  
{ ,4UJ|D=J  
nEndPos = nStartPos[i+1]; -4a&R=%p  
} u-<s@^YG  
nEndPos[nEndPos.length-1] = nFileLength; ;bbEd'  
} s!
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} !r,drb  
3sNq3I  
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//启动子线程 n*uZ=M_/Q  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];  )BB a  
for(int i=0;i<nStartPos.length;i++) [J#(k`@  
{ yLX\pkAt4  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Fx\Re]~n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), LdL\B0^l  
nStartPos,nEndPos,i); b /ySt<  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u?i1n=Ne  
fileSplitterFetch.start(); 5sUnEHN  
} bL%)k61G_v  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V-|}.kOH2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); '`"&RuB  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", }mK_d9dx  
nEndPos = " + nFileLength); 4#uoPkLK  
// fileSplitterFetch[nPos.length-1].start(); o%iTYR:x  
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k[m-"I%ZFX  
//等待子线程结束 b/`'?| C  
//int count = 0; 3@JwL{C  
//是否结束while循环 3WHH3co[  
boolean breakWhile = false; G_@H:4$3  
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9|,AhyhO  
while(!bStop) C09@2M'  
{ 5=\b+<pE  
write_nPos(); R!ij CF\  
Utility.sleep(500); NgKNT}JDv  
breakWhile = true; o=}?aC3I  
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:csLZqn[  
for(int i=0;i<nStartPos.length;i++) {s]eXc]K}  
{ K9iR>put  
if(!fileSplitterFetch.bDownOver) ;8UHPDnst  
{ Yy]Henw;  
breakWhile = false; UWp(3FQ  
break; +$C5V,H~  
} H{If\B%1t  
} 3yDvr*8-@  
if(breakWhile) pe8MG(V  
break; GzX@Av$  
:1Ay_b_J  
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//count++; \}5\^&}_  
//if(count>4) IN"qJ3<k  
// siteStop(); ?p]w_l  
} (Y86q\DQ?|  
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System.err.println("文件下载结束！"); uzOZxW[e  
} ul E\>5O4h  
catch(Exception e){e.printStackTrace ();} 9ZwhCsO  
} Ru/3>n  
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//获得文件长度 YGB|6p(  
public long getFileSize() g"xZ{k_3  
{ ev`p!p  
int nFileLength = -1; rz(DZV  
try{ d{Z  
URL url = new URL(siteInfoBean.getSSiteURL()); 98l#+4+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '`n\YO.N  
httpConnection.setRequestProperty("User-Agent","NetFox"); ufmFeeg  
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int responseCode=httpConnection.getResponseCode(); Z=ho7i  
if(responseCode>=400) TAP/gN'  
{ Rh39x-`Z  
processErrorCode(responseCode); aX!J0
&3  
return -2; //-2 represent access is error a,X3=+_K  
} / wEr>[8S  
 )57OZ  
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String sHeader; `KZ}smMA  
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=
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for(int i=1;;i++) ]0o78(/w2  
{ T ^uBMDYe  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); *<KY^;  
//Utility.log(in.readLine()); 'n\ZmG{  
sHeader=httpConnection.getHeaderFieldKey(i); K/altyj`  
if(sHeader!=null) w!Z3EA;`  
{ A\:M}D-(  
if(sHeader.equals("Content-Length")) -k'=s{iy  
{ ;kdJxxUox  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Gz`Zp "i%0  
break; MYu-[Hg  
} ^#;2 Pd>  
} 8YCtU9D  
else kj>XKZL10  
break; *0Fn C2W1  
} <w[)T`4N  
} zg]9~i8  
catch(IOException e){e.printStackTrace ();} nfd^'}$]  
catch(Exception e){e.printStackTrace ();} 9+pnpaZB0  
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Utility.log(nFileLength); yQ\c<z^e  
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return nFileLength; N'IzHyo.  
} ugOcK Gf  
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;vuok]@  
//保存下载信息（文件指针位置） V;9.7v  
private void write_nPos() w<>B4m\  
{ IU&n!5d$)|  
try{ ~u.CY  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ~|riFp=J  
output.writeInt(nStartPos.length); iielAj*b  
for(int i=0;i<nStartPos.length;i++) TEv3;Z*N  
{ C&r&&Pw  
// output.writeLong(nPos); UkeX">  
output.writeLong(fileSplitterFetch.nStartPos); %-> X$,Q :  
output.writeLong(fileSplitterFetch.nEndPos); !Vy/-N  
} !M\8k$#"n  
output.close(); rqSeh/<iD  
} G8H=xr#  
catch(IOException e){e.printStackTrace ();} bvi Y.G3  
catch(Exception e){e.printStackTrace ();} Z sv(/>  
} p v%`aQ]o{  
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//读取保存的下载信息（文件指针位置） K '7M\:zy  
private void read_nPos() 5V8WSnO  
{ B/AS|i] sM  
try{ >,7-cm=.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,x&T8o/a  
int nCount = input.readInt(); _I+QInD;)  
nStartPos = new long[nCount]; [Q6PFdQ_JT  
nEndPos = new long[nCount]; VI/77  
for(int i=0;i<nStartPos.length;i++) K8daSvc  
{ qJj"WU5  
nStartPos = input.readLong(); 6;Wns'  
nEndPos = input.readLong(); b
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} =wtu  
input.close(); PF~w$ eeQ  
} w`x4i fZ0q  
catch(IOException e){e.printStackTrace ();} Gg$4O
8  
catch(Exception e){e.printStackTrace ();} 3vepJ)D (  
} J4"?D9T3G  
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private void processErrorCode(int nErrorCode) tFn_{fCc>  
{ M8(N9)N  
System.err.println("Error Code : " + nErrorCode); N"L@  
} #?u#=]  
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//停止文件下载 TuG%oV}   
public void siteStop() wN
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{ rrz^LD  
bStop = true; *5m4j=-  
for(int i=0;i<nStartPos.length;i++) 4z6kFQgu  
fileSplitterFetch.splitterStop(); 3e,"B S)+  
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x
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} djmd @{Djt  
}
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//负责部分文件的抓取 7G':h0i8  
**FileSplitterFetch.java {?X:?M_  
*/ uidoz f2}  
package NetFox; Xnc?o
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import java.io.*;
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import java.net.*; LiyR,e  
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public class FileSplitterFetch extends Thread { Fa0Fl}L  
,76Q*p  
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String sURL; //File URL Kt3T~k  
long nStartPos; //File Snippet Start Position P1_6:USBM  
long nEndPos; //File Snippet End Position PjE%_M<  
int nThreadID; //Thread's ID cB0"vbdO  
boolean bDownOver = false; //Downing is over XcFu:B  
boolean bStop = false; //Stop identical l3N '@GO  
FileAccessI fileAccessI = null; //File Access interface p54e'Zb  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException o)WzZ,\F^J  
{ p
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this.sURL = sURL; JuDadIrd{  
this.nStartPos = nStart; QCJf   
this.nEndPos = nEnd; X?7s  
nThreadID = id; w!r.MWE  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 II]-mb  
} Zx&=K"  
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public void run() af_bG;  
{ [{PmU~RMYf  
while(nStartPos < nEndPos && !bStop) J9&#);(  
{ ZMEYF!jN  
uQl=?085  
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try{ wV q4DE  
URL url = new URL(sURL); u}-)ywX  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); eB_ M *+^  
httpConnection.setRequestProperty("User-Agent","NetFox"); %'MR;hQsd8  
String sProperty = "bytes="+nStartPos+"-"; vMYEP_lhK,  
httpConnection.setRequestProperty("RANGE",sProperty); T,uJO<  
Utility.log(sProperty); DI\^&F)3T2  
rT'<6]`  

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InputStream input = httpConnection.getInputStream(); `aL4YH-v  
//logResponseHead(httpConnection); 8Yw V"+Fu/  
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byte[] b = new byte[1024]; :@,UPc-+  
int nRead; b`^mpB*6R  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 72sBx3 ;  
{ <-xu
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nStartPos += fileAccessI.write(b,0,nRead); "v+%F  
//if(nThreadID == 1) yb-/_{Y  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
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} y*j8OA.S  
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Utility.log("Thread " + nThreadID + " is over!"); t_iZ\_8
  
bDownOver = true; W4S]2P>T  
//nPos = fileAccessI.write (b,0,nRead); +zzS  
} K@@Jt  
catch(Exception e){e.printStackTrace ();} O;RNmiVoq  
} fVxRK\a\\  
} {ud^+I&  
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//打印回应的头信息 0u8(*?  
public void logResponseHead(HttpURLConnection con) nXxSv
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{ ;aUI3n%  
for(int i=1;;i++) vQ
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{ #mbl4a  
String header=con.getHeaderFieldKey(i); ?r}!d2:dX  
if(header!=null) Ge4tc  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); o/p'eY:)  
Utility.log(header+" : "+con.getHeaderField(header)); }$1Aw%p^  
else Gq^#.o]  
break; ai~JY
[  
} !GBGC|avE  
} b6gD*w<  
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public void splitterStop() M^~  
{ 2`w\<h  
bStop = true; -g)*v<Fb5  
} 1@A*Jj[R%  
4r>buEU  
?u8vK<2h  
} 1Qgd^o:d  
 
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/* M)!:o/!cS  
**FileAccess.java s\i.pd:Q  
*//文件访问(定位，写) Gq
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package NetFox; Y/w) V
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import java.io.*; 9 ulr6  
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public class FileAccessI implements Serializable{ )SYZ*=ezl.  
mLn =SU{#  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 CQNt  
RandomAccessFile oSavedFile; u3H2\<  
long nPos; ]]Da/^K=Z  
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public FileAccessI() throws IOException _A.?:'-  
{ nNff~u)I  
this("",0); ^ok;<fJ  
} hOx">yki  
U;:,$]+  
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public FileAccessI(String sName,long nPos) throws IOException 9{bzxM  
{ ]4>[y?k34  
oSavedFile = new RandomAccessFile(sName,"rw"); ]Zim8^n?`.  
this.nPos = nPos; 41TB  
oSavedFile.seek(nPos); 5yQv(<~*G
 
} f.=4p^  
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public synchronized int write(byte[] b,int nStart,int nLen) $E4W{ad2jW  
{ p\8
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int n = -1; va8V{q@t'  
try{ VmkYl$WZo  
oSavedFile.write(b,nStart,nLen); BifA&o%  
n = nLen; d/(=q  
} :u{0M&  
catch(IOException e) 7`tnoTUv  
{ =3oz74O[  
e.printStackTrace (); UUY-EC7X  
} EBM\p+x&  
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return n; Q jBCkx]g  
} $1?X%8V  
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} KB"iF}\P0  
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/* Nb#7&_f=  
**SiteInfoBean.java WsV3>=@f  
*/ ) ,hj7  
package NetFox; \Zv =?\  
,\M_q">npc  
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public class SiteInfoBean { # 0!IUSa  
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private String sSiteURL; //Site's URL U]D.z}0  
private String sFilePath; //Saved File's Path if}]8
  
private String sFileName; //Saved File's Name rl^LSz  
private int nSplitter; //Count of Splited Downloading File -7O/ed+  
^<VE5OM  
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public SiteInfoBean() cA%U  
{//nSplitter的缺省值为5 3kQ^f=Wd  
//default value of nSplitter is 5 >slN:dr0:  
this("","","",5); (RmED\.]4  
} :(b3)K  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 3rY /6{  
{ Mak9qaWqF>  
sSiteURL= sURL; BZ<z@DJp  
sFilePath = sPath; k@aP&Z~  
sFileName = sName; 8@aS9th$  
this.nSplitter = nSpiltter; Rdg0WT*;j  
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} V 3]p3  
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^.CX6%  
public String getSSiteURL() 'r n;|K  
{ "
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return sSiteURL; tTFoS[V  
} Hm*vKFhz  
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ZY!pw6R1>*  
public void setSSiteURL(String value) 02^(z6K'&?  
{ qX'a&~s)n  
sSiteURL = value; :UcS$M1LE  
} #@6L|$iX  
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)Zf}V0!?+  
public String getSFilePath() N
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{ G`#
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return sFilePath; 4_%FSW8-  
} CDYx/yO  
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public void setSFilePath(String value) ~fp+@j-A  
{ 3t8H?B12ow  
sFilePath = value; '<=MhNh\  
} gqD^Bs'VF  
JGDUCb~  
m90R8 V  
public String getSFileName() .XKvk(9  
{ V&oT':%q  
return sFileName; TcLaWf!c5  
} J8v:a`bX&  
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8}oDRN!
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public void setSFileName(String value) f5GR#3-h(  
{ x0A%kp&w  
sFileName = value; #KNq:@wp6  
} gZEA;N:H%<  
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public int getNSplitter() CotMV^   
{ Z)O>h^0  
return nSplitter; @!a]qAt  
} T7,Gf({  
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public void setNSplitter(int nCount) Px7g\[]  
{
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nSplitter = nCount; +Q!xEfpO;  
} (bFWT_CChz  
} ,c7u  

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/* ]AC!R{H  
**Utility.java u1|P'>;lF  
*/ e=]oh$]  
package NetFox; h NOYFH  
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ck
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public class Utility { %M)oHX1p  
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public Utility() v*'iW
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{ ioY\8i  
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9 QCpXy  
} Kpp*^  
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//线程睡眠 \eMYw7y5M  
public static void sleep(int nSecond) J]Gc  
{ E2h;hr;W  
try{ WQLHjGehe  
Thread.sleep(nSecond); t2-nCRXEP  
} k`7.p,;}U  
catch(Exception e) zUEfa!#?  
{ 4=F]`Lql  
e.printStackTrace ();  `\|3 ~_v  
} _/]:=_bf_z  
} G\:psx/  
M*~v'L_sI  
//日志 H8<7#
 
public static void log(String sMsg) :&1=8^BY  
{ nA_ zP4  
System.err.println(sMsg); A D}}>v  
} `m@]  

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SCh7O}  
public static void log(int sMsg) 61+pryW%g  
{ K*_{Rs0P  
System.err.println(sMsg); _> |R-vQ8  
} V:F+HM
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} Ef_F#X0#  
L=$?q/=-  
-M1~iOb  
/* c6Yf"~TD0  
**TestMethod.java csFJ5  
*/ n<%=~1iY+  
package NetFox; *t?~)o7  
J+cAS/MYX  
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public class TestMethod { LG Y!j_bD  
v/aPiFlw  
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public TestMethod() R
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{ ///xx/weblogic60b2_win.exe |?2 hml  
try{ N[a ljC-R  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); BS-:dyBw  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); w]W`R.  
SiteFileFetch fileFetch = new SiteFileFetch(bean); r(,= uLc  
fileFetch.start();
2Z/][?Jj{  
} W?"2;](  
catch(Exception e){e.printStackTrace ();} ]{Mci]H6T  
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} TXd5v#_vo  
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public static void main(String[] args) |8DH4*y!  
{ )KaLSL>  
new TestMethod(); ;gxN@%}@  
} H9Y2n 0  
} 9S:
{  
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