http断点续传简单实现（java)

/* 6bt{j   
**SiteFileFetch.java )"y
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*/ Q9 RCN<!  
package NetFox; c]:@y"W5$  
import java.io.*; IeJ@G)  
import java.net.*; "
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public class SiteFileFetch extends Thread { "yxBD 7  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 
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long[] nStartPos; //开始位置 vX}mwK8  
long[] nEndPos; //结束位置 }i2dXC/  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 SlUt&+)  
long nFileLength; //文件长度 s&qr2'F+z  
boolean bFirst = true; //是否第一次取文件 &bS!>_9  
boolean bStop = false; //停止标志 TWTRMc;z+  
File tmpFile; //文件下载的临时信息 R$VeD1n@  
DataOutputStream output; //输出到文件的输出流 }F (lffb  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） \(xQ'AQ-  
public SiteFileFetch(SiteInfoBean bean) throws IOException v7- d+P=  
{ @EcY&mP)  
siteInfoBean = bean; c)=UX_S!  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [KwwhI@3  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); QjwCY=PK!  
if(tmpFile.exists ()) {m<!-B95  
{ @GE:<'_:{  
bFirst = false; l
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read_nPos(); \{`*`WQF  
} K?aUIkVs  
else 9:6d,^X  
{ *gXm&/2*  
nStartPos = new long[bean.getNSplitter()]; 7S9Q{
 
nEndPos = new long[bean.getNSplitter()]; XvW $B|  
} 7
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} ^o*$+DbC  
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public void run() yj{:%Km:`  
{ 98eS f  
//获得文件长度 MHKB:t]hA  
//分割文件 ._z[T@!9  
//实例FileSplitterFetch pvJPMx  
//启动FileSplitterFetch线程 S~DY1e54GF  
//等待子线程返回 6WnGP>tc.  
try{ 7 }sj&  
if(bFirst) 6KI< J*Wz`  
{ |1(9_=i'  
nFileLength = getFileSize(); m=2e1wc  
if(nFileLength == -1) /I&b5Vp  
{ =Z(#j5TGvH  
System.err.println("File Length is not known!"); ;]^JUmxU[d  
} ^@..\X9  
else if(nFileLength == -2) +,
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{ _Uz}z#jt  
System.err.println("File is not access!"); i<Be)Y-'  
} T"m(V/L$W  
else in6iJ*E@'  
{ L)ry!BuHI  
for(int i=0;i<nStartPos.length;i++) >ak53Ij$  
{ u +OfUBrf  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Ey"<hAF  
} lCyp&b#(L  
for(int i=0;i<nEndPos.length-1;i++) \W6|un  
{ "i_}\p.,X  
nEndPos = nStartPos[i+1]; 8h2!8'  
} I:aG(8Bi)H  
nEndPos[nEndPos.length-1] = nFileLength; wfrWpz=FO  
} ?RD)a`y51  
} )(pJ~"'L  
h&6x.ps@  
lEC58`Ws  
//启动子线程 P&Q 5ZQb  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3It'!R8$  
for(int i=0;i<nStartPos.length;i++) $0zH2W  
{ gZs8BKO  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (7rG~d1iS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), lFY;O !Y5\  
nStartPos,nEndPos,i); f V.(v&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); wFaWLC|&  
fileSplitterFetch.start(); N7xkkAS{  
} JZQ$*K  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Yg#)@L  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); s"?&`S  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", xf@D<}~1  
nEndPos = " + nFileLength); Pne[>}_l/  
// fileSplitterFetch[nPos.length-1].start(); rLcQG  
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//等待子线程结束 9D_4]'KG  
//int count = 0; !2N#H~{  
//是否结束while循环 +:d))r=n  
boolean breakWhile = false; G?/1 F1  
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while(!bStop) 4>^ %_Xj[  
{ n.y72-&v  
write_nPos(); AsM""x1Ix  
Utility.sleep(500); hGF(E*  
breakWhile = true; sh?Dxodp9  
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for(int i=0;i<nStartPos.length;i++) b`K~l'8  
{ T+2I
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if(!fileSplitterFetch.bDownOver) bct&ge7YX  
{ [M2,bc8SJV  
breakWhile = false; <..%@]+  
break; f|FQd3o)  
} 'F
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} /7h%sCX  
if(breakWhile) MT#9x>  
break; nZN]Q9  
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//count++; $(}kau  
//if(count>4) Y
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// siteStop(); (w% hz']  
} 9#6ilF:F  
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System.err.println("文件下载结束！"); cVn7
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} wR/i+,K  
catch(Exception e){e.printStackTrace ();} )11/B
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} ld[]f*RuW  
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//获得文件长度 <z)MV oa  
public long getFileSize() j&m<=-q  
{ xyz-T1ib  
int nFileLength = -1; L*h X_8J  
try{ 1xq1te)  
URL url = new URL(siteInfoBean.getSSiteURL()); Ok({Al1A,w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 60AX2-sdJ,  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~rY<y%K  
#>ci!4Gz=Z  
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int responseCode=httpConnection.getResponseCode(); ? *I9  
if(responseCode>=400) W.:kE|a.g  
{ hY'"^?OP  
processErrorCode(responseCode); dt3Vy*zL  
return -2; //-2 represent access is error 9i|6  
} .#WF'  
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String sHeader; NnHM$hEI"U  
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for(int i=1;;i++) n7<<}wcV  
{ "TjR]jnV(  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); _TQt!Re`,  
//Utility.log(in.readLine()); ~?b(2gn  
sHeader=httpConnection.getHeaderFieldKey(i); sQihyq6U;  
if(sHeader!=null) J;q3 fa  
{ ]P<&CEk  
if(sHeader.equals("Content-Length")) Cv$TNkP*  
{ cS ];?tqrA  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [S</QS!  
break; <!OP b(g2  
} p-KuCobz]  
} 29Q5s$YD@  
else R#\8jvv
 
break; n{'
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} -U/&3  
} J;T_9  
catch(IOException e){e.printStackTrace ();} 6lWO8j^BN  
catch(Exception e){e.printStackTrace ();} 5K6_#g4"  
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Utility.log(nFileLength); ,$;CII v  
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return nFileLength; eIqj7UY_  
} DD3J2J  
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//保存下载信息（文件指针位置） 5E!|-xD  
private void write_nPos() ^jmnE.8R  
{ ~C!vfPC  
try{ B|GJboQ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); :Dr& {3>  
output.writeInt(nStartPos.length); HZK0Ldf  
for(int i=0;i<nStartPos.length;i++) Bxa],inuZ  
{ ?4lAL  
// output.writeLong(nPos); *10e)rzM  
output.writeLong(fileSplitterFetch.nStartPos); SV\x2^Ea0  
output.writeLong(fileSplitterFetch.nEndPos); J0=`n(48B  
} HWefuj  
output.close(); WVNQ}KY  
} }=GyBnXu  
catch(IOException e){e.printStackTrace ();} [#9ij3vxd  
catch(Exception e){e.printStackTrace ();} BEI/OGp  
} #JLDj(a?  
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//读取保存的下载信息（文件指针位置） ^c(PZ,/#JB  
private void read_nPos() BklB3*n  
{ E$ngmm[  
try{ O5=ggG  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Y\%}VD2k  
int nCount = input.readInt(); M3t_!HP}!  
nStartPos = new long[nCount]; f`IgfJN  
nEndPos = new long[nCount]; o"]eAQ  
for(int i=0;i<nStartPos.length;i++) $&e(
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{ ^g[])2",  
nStartPos = input.readLong(); ,^<+5TYM7
 
nEndPos = input.readLong(); HRb_ZJz  
} Txfb-f!mv\  
input.close(); a<Ns C1  
} FQ-(#[  
catch(IOException e){e.printStackTrace ();} ]nQ$:%HP  
catch(Exception e){e.printStackTrace ();} rL,)Tc|"  
} YwF6/JA0^  
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private void processErrorCode(int nErrorCode) H_AV3 ;  
{ VG8rd'Z  
System.err.println("Error Code : " + nErrorCode); O\D({>  
} no/]Me!j=  
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//停止文件下载 
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public void siteStop() =:g^_Hy  
{ hx2C<;s4  
bStop = true; .gPsJ?b  
for(int i=0;i<nStartPos.length;i++) gOWyV@  
fileSplitterFetch.splitterStop(); R_1C+  
| 5L1\O8#  
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} Q./lX:  
} $@Ay0GEI"  
//负责部分文件的抓取 `-/l$A} U  
**FileSplitterFetch.java qA~D*=  
*/ 1tr>D:c\  
package NetFox; kCC9U_dj,  
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import java.io.*; EIYM0vls(  
import java.net.*; U.)G#B  
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public class FileSplitterFetch extends Thread { Zn/9BO5  
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String sURL; //File URL I|j
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long nStartPos; //File Snippet Start Position R^2Uh$kk{A  
long nEndPos; //File Snippet End Position (O-)uC  
int nThreadID; //Thread's ID ~c="<xBE  
boolean bDownOver = false; //Downing is over 2 Lamvf  
boolean bStop = false; //Stop identical .3U[@*b(  
FileAccessI fileAccessI = null; //File Access interface |O)deiJRy  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException :HE]P)wz-  
{ wqwJpWIe  
this.sURL = sURL; t@u\ 4bv  
this.nStartPos = nStart; cV{ZDq  
this.nEndPos = nEnd; y{{EC#  
nThreadID = id; 9kF#*  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 eb/V}%  
} fD~!t 8J  
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public void run() a`-hLX)~Z  
{ ];I|_fXo%  
while(nStartPos < nEndPos && !bStop) &V?q d{39  
{ Ij#a  
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try{ S[a5k;8GL  
URL url = new URL(sURL); O|>1~^w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); da2[   
httpConnection.setRequestProperty("User-Agent","NetFox"); ILi5WuOYX  
String sProperty = "bytes="+nStartPos+"-"; 0`!Q-G7  
httpConnection.setRequestProperty("RANGE",sProperty); sv;zvEn;-L  
Utility.log(sProperty); ZW?7g+P  
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InputStream input = httpConnection.getInputStream(); F3Y>hs):7  
//logResponseHead(httpConnection); & .?HuK  
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byte[] b = new byte[1024]; )KqR8UO
  
int nRead; X}*o[;2G  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5|R
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{ |\a:]SlH  
nStartPos += fileAccessI.write(b,0,nRead); Ib2@Wi   
//if(nThreadID == 1) KCk?)Qv  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); S(J\<)b  
} x ctU.)p  
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Utility.log("Thread " + nThreadID + " is over!"); A(n=k
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bDownOver = true; m"G N^V7  
//nPos = fileAccessI.write (b,0,nRead); "k-ov9yK  
} \B2d(=~4  
catch(Exception e){e.printStackTrace ();} z}1xy+  
} }o^A^
 
} g&4~nEp  
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//打印回应的头信息 kP)o=\|W{z  
public void logResponseHead(HttpURLConnection con) -L9R&r#_e  
{ DLY
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for(int i=1;;i++) nr>{ uTa  
{ @LKG\zYBu  
String header=con.getHeaderFieldKey(i); _g 4/%  
if(header!=null) (L5'rNk  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); eFSC^  
Utility.log(header+" : "+con.getHeaderField(header)); AD@PNM  
else u7"Ve
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break; M%{?\)s  
} g`OOVaB  
} -(w~LT$ "  
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public void splitterStop() L)lQ&z?  
{ }[z<iij4  
bStop = true; v1r_Z($  
} )_v\{N  
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} fcICFReyV  
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/* ChTXvk
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**FileAccess.java ,iVPcza  
*//文件访问(定位，写) ]&:b<]K3  
package NetFox; nnE_OK!}T  
import java.io.*; FxfL+}?Q  
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public class FileAccessI implements Serializable{ C,r`I/;  

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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 EF=dXm/\  
RandomAccessFile oSavedFile; NGD*ce"w  
long nPos; Q0cY/'>4  
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public FileAccessI() throws IOException `4%;qLxngP  
{ `\jTpDV_W  
this("",0); h.V]fS
 
} YN@6}B#1  
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%)axGbZG;  
public FileAccessI(String sName,long nPos) throws IOException OB6J.dF[%  
{ G*\abL  
oSavedFile = new RandomAccessFile(sName,"rw"); ZCQ<%f  
this.nPos = nPos; 90s;/y(  
oSavedFile.seek(nPos); "#twY|wW  
} Cqgk  
%f(S'<DhC  
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public synchronized int write(byte[] b,int nStart,int nLen) 5r4gmy>  
{ lRDxIuTK  
int n = -1; YZGS-+  
try{ w(/DTQc~d  
oSavedFile.write(b,nStart,nLen); 1n'$Ji7  
n = nLen; #SQvXMT  
} {y-2  
catch(IOException e) 1TNz&=e  
{ ;cI#S%uvpn  
e.printStackTrace (); i-,D_   
} /2e%s:")h  
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return n; *KK[(o}^J-  
} / Mod=/e  
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} q_T]9d  
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/*
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**SiteInfoBean.java '@TI48 J+  
*/ 9?;@*x  
package NetFox; 5VR.o!h3I  
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~uI**{  
public class SiteInfoBean { s=d+GMa  
yGiP[d|tRc  
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private String sSiteURL; //Site's URL (=1q!c`  
private String sFilePath; //Saved File's Path $n= O  
private String sFileName; //Saved File's Name 84
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private int nSplitter; //Count of Splited Downloading File yo'9x s  
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s`hav  
public SiteInfoBean() J&eAL3"GF  
{//nSplitter的缺省值为5 bD35JG^&i  
//default value of nSplitter is 5 RF_[?O)Q  
this("","","",5); W+gpr|R2  
} ^qxdmMp)l  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &%^K,Q"  
{ k-"<{V  
sSiteURL= sURL; ]9jZndgC  
sFilePath = sPath; __!m*!sd  
sFileName = sName; Y@Y`gF6F  
this.nSplitter = nSpiltter; $$JIBf8  
ll^DY hx}  
[O2h-`  
} P##Z[$IJ3  
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}A|))Ao
|  
public String getSSiteURL() Wo{K}  
{ 0G5'Y;8  
return sSiteURL; :pwa{P  
} |;P^clS3  
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public void setSSiteURL(String value) 9
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{ x;u~NKy  
sSiteURL = value; &Yp+k}XU  
} Xo Y7/&&  
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public String getSFilePath() td >,TW=A*  
{ .Gh%p`<  
return sFilePath; lop uf/U0  
} B{p4G`$i1  
Fn!SGX~kx$  
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public void setSFilePath(String value) 7JI:=yY!>:  
{ !z MDP/V  
sFilePath = value; <Nex8fiJ9  
} pI>*u ]x  
"u;YI=+  
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public String getSFileName() HA!t$[_Ve  
{
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return sFileName; WSLy}@`Vx  
} !hCS#'  
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public void setSFileName(String value) MiJ6n[iv
 
{ K\P!a@>1  
sFileName = value; [ ?iqqG.  
} ^av6HFQ  
:
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es  
$
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public int getNSplitter() @9 )}cg  
{ mb\
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return nSplitter; ]#zZWg zv  
} e.l!3xY2'  
L/?]^!.  
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public void setNSplitter(int nCount) <Ct_d Cc  
{  (
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nSplitter = nCount; !v9lk9SV  
} O8lFx_N7Q  
} )iU^&@[S  
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/* =i>\2J%'R  
**Utility.java _s+c+]bO  
*/ ;cKH1  
package NetFox; @2 =z}S3O  
\9)#l#m  
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public class Utility { CISO<z0  
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public Utility() XP-C  
{ q8xd*--#  
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} \a))  
uZIJoT  
//线程睡眠 8>NwCjN  
public static void sleep(int nSecond) !msNEE@[  
{ {%b }Z2  
try{ ?n]FNjd  
Thread.sleep(nSecond); |~K(F<;j  
} oM,- VUr  
catch(Exception e) iW;i
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{ 5~+XZA#2  
e.printStackTrace (); cin2>3Z$  
} |g-b8+.=]  
} \Q&,ISO\  
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//日志 +E5=
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public static void log(String sMsg) h*w6/ZL1  
{ T3N"CUk  
System.err.println(sMsg); zO~9zlik  
} >7b)y  
por/^=e{Y  
qX#MV>1  
public static void log(int sMsg) 9+qOP>m  
{ dqc1q:k?$  
System.err.println(sMsg); *:hyY!x  
} mfom=-q3k  
} )TJS4?  
UE :HMn6  
[}2Z/   
/* 2.lgT|p  
**TestMethod.java 5`-UMz<
]  
*/ PaO-J&<  
package NetFox; ]@ M5_%p  
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public class TestMethod { #X`8dnQZ  
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q  
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public TestMethod() S%mfs!E>  
{ ///xx/weblogic60b2_win.exe Ug%_@t/?  
try{ jQh^WmN  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {Wv%zA*8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >v+jh(^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Y`G
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fileFetch.start(); d=3'?l`  
} _yH`t[  
catch(Exception e){e.printStackTrace ();} T!2=*~A  
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} C~4PE>YtTv  

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public static void main(String[] args) #8h;Bj  
{ p(JlvJjo  
new TestMethod(); c EnkU]  
} FjFMR 63  
} Di5(9]o2  
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