http断点续传简单实现（java)

/* o<9yaQ;  
**SiteFileFetch.java *)2x&~T*|  
*/ "'Q$.sR  
package NetFox; })h'""i&xn  
import java.io.*; `<.
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import java.net.*; |E>v~qD8I  
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public class SiteFileFetch extends Thread { e<&_tx   
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SiteInfoBean siteInfoBean = null; //文件信息Bean 7R% PVgS4x  
long[] nStartPos; //开始位置 $sB48LJuU'  
long[] nEndPos; //结束位置 My`josJ`Pb  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 iPR!JX _  
long nFileLength; //文件长度 :Q0?ub]  
boolean bFirst = true; //是否第一次取文件 e)fJd*P  
boolean bStop = false; //停止标志 A?%XO %  
File tmpFile; //文件下载的临时信息 TW;|G'}$  
DataOutputStream output; //输出到文件的输出流 *rujdQ
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） I_R5\l}O+D  
public SiteFileFetch(SiteInfoBean bean) throws IOException TZvBcNi   
{ QH~8 aE_i  
siteInfoBean = bean; ~)oWSo5ll  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); BVwRP
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); d|D'&&
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if(tmpFile.exists ()) 3}.mp}K5  
{ 0`aHwt/F  
bFirst = false; >n@>h$]  
read_nPos(); 3M`hn4)K  
} uaZ"x&oZ#  
else *)}Ap4[  
{ =N[V{2}q  
nStartPos = new long[bean.getNSplitter()]; 8 RzF].)  
nEndPos = new long[bean.getNSplitter()]; k}+MvGq  
} |TNiKy  
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} .j+2x[`l  
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public void run() jSOa   
{ q_%w l5\F  
//获得文件长度 \6nQ-S_  
//分割文件 wnZ*k(  
//实例FileSplitterFetch Z]1z*dv  
//启动FileSplitterFetch线程 A1=$kzw{UH  
//等待子线程返回 [xp~@5r'  
try{ !$ J)  
if(bFirst) wAj(v6  
{ Y;%R/OyWY  
nFileLength = getFileSize(); ajcPt]f  
if(nFileLength == -1) OmoplJ+  
{ pE YrmC  
System.err.println("File Length is not known!"); qx#ghcU  
} 80R=r  
else if(nFileLength == -2) "
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{ <W^XSk  
System.err.println("File is not access!"); f(9$"Vi  
} gzJ{Gau{)  
else 0N} wD-  
{ hoSU`X  
for(int i=0;i<nStartPos.length;i++) f0fqDmn  
{ XyKKD&j  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); [4+a 1/^  
} xYzcV%-Pm  
for(int i=0;i<nEndPos.length-1;i++) t0AqGrn  
{ S3JygN*  
nEndPos = nStartPos[i+1]; dKN3ZCw*gF  
} =."WvBKg  
nEndPos[nEndPos.length-1] = nFileLength; 9b=^"
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} W0r5D9k  
} n<"a+TTU  
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//启动子线程 B2Awdw3=g  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; S|u1QGB  
for(int i=0;i<nStartPos.length;i++) 6r-<XNv)0  
{  zxynEdO  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), xVwi }jtG|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), j{Qbzczy,  
nStartPos,nEndPos,i); &&QDEDszp  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); hnfrnYH  
fileSplitterFetch.start(); QeOt;{_|  
} 3vvFF]D5k  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _`Yvfz3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #dn%KMo2r  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "l2N_xX;  
nEndPos = " + nFileLength); [7Kj$PB3  
// fileSplitterFetch[nPos.length-1].start(); gWU(uBS  
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//等待子线程结束 -^nQ^Td=j  
//int count = 0; /v5g;x
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//是否结束while循环 fU){]YP  
boolean breakWhile = false; ;H#R{uR_<  
]6c2[r?g{  
.AQ3zpy5B  
while(!bStop) y[7xK}`_  
{ `'k's]Y  
write_nPos(); Sr#fyr  
Utility.sleep(500); iJp!ROI  
breakWhile = true; Ul~}@^m]4}  
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for(int i=0;i<nStartPos.length;i++) =*)O80oaW  
{ P A+e= %  
if(!fileSplitterFetch.bDownOver) n*8RYm)?  
{ Dm`U|<o  
breakWhile = false; %w|3:  
break; bU +eJU_%  
} J;]@?(  
} NB6h/0*v  
if(breakWhile) YI(OrR;V  
break; H fmMf^c  
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//count++; .^+$w$  
//if(count>4) r3bvuq,6$  
// siteStop(); ^}pREe c=  
} EpS8,[w  
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System.err.println("文件下载结束！"); ST[1'T+L  
} #,9TJ:~N  
catch(Exception e){e.printStackTrace ();} o4 OEA)k)=  
} Y Z2VP  
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//获得文件长度 u2x=YUWb]  
public long getFileSize() !{ )AV/\D  
{ k^%ec3l  
int nFileLength = -1; ZCF-*nm  
try{ W2LblZE!  
URL url = new URL(siteInfoBean.getSSiteURL()); IF?B`TmZ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3*23+}^G  
httpConnection.setRequestProperty("User-Agent","NetFox"); V$F.`O!hfi  
*gpD4c7A\  
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int responseCode=httpConnection.getResponseCode(); !5 :[XvI#  
if(responseCode>=400) EF^=3  
{ #3[b|cL  
processErrorCode(responseCode); 7;-i_&vws  
return -2; //-2 represent access is error qN,FX#DP  
} r0uXMr=Z96  
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String sHeader; ^{+:w:g  
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for(int i=1;;i++) 4g^+y.,r_f  
{ DT]p14@t9  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); :mHtK)z~  
//Utility.log(in.readLine()); S7>gNE;%]u  
sHeader=httpConnection.getHeaderFieldKey(i); [k{iN1n  
if(sHeader!=null) Q>c6ouuJ  
{ '9Odw@tp  
if(sHeader.equals("Content-Length")) .`#R%4Xl  
{ `-YSFQ~O,  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); DN{G$$or  
break; x{o5Ha{  
} [j
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} 54DR.>O  
else X',0MBQ0  
break; yQ&%* ?J  
} wupD  
} R'HA>?D  
catch(IOException e){e.printStackTrace ();} \ OINzfbr  
catch(Exception e){e.printStackTrace ();} Afl'-  
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Utility.log(nFileLength); MFsy`aiS  
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return nFileLength; :R\v# )C  
} 
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//保存下载信息（文件指针位置） t? Ja q  
private void write_nPos() %Z0S"B 3  
{ "(VcYQ+  
try{ =}lA|S  
output = new DataOutputStream(new FileOutputStream(tmpFile)); eE_X
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output.writeInt(nStartPos.length); 7f,WzvV  
for(int i=0;i<nStartPos.length;i++) C2i..iD  
{ ~y^lNgujO  
// output.writeLong(nPos); s""8V_,;  
output.writeLong(fileSplitterFetch.nStartPos); ~o5iCt;w  
output.writeLong(fileSplitterFetch.nEndPos); PzkXrDlB7  
} fsuvg jlE  
output.close(); m6<0 hP  
} ZU'^%)6~o~  
catch(IOException e){e.printStackTrace ();} fOervo  
catch(Exception e){e.printStackTrace ();} K8c#/o  
} ,X6j$YLWp  
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' uw&f;/E  
//读取保存的下载信息（文件指针位置） ;CBdp-BUj  
private void read_nPos() `I{Q,HQ7  
{ c)fp;^  
try{ vBnHG-5;P  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6u;(R0n  
int nCount = input.readInt(); umn^QZ,  
nStartPos = new long[nCount]; V3UGx'@^y  
nEndPos = new long[nCount]; B`EgL/Wg[  
for(int i=0;i<nStartPos.length;i++) 0lN8#k>H  
{ :[03upyS  
nStartPos = input.readLong(); |:[vpJFK  
nEndPos = input.readLong(); P?7b,
a95O  
} >AFpO*q"  
input.close(); f`rz)C03  
} U# B  
catch(IOException e){e.printStackTrace ();} R/|{?:r?:x  
catch(Exception e){e.printStackTrace ();} AE _~DZ:%c  
} HE'8  
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private void processErrorCode(int nErrorCode) 1]`HX=cl  
{ /MtacR  
System.err.println("Error Code : " + nErrorCode); ^SCWT\E  
} )zV5KC{{  
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X jN.X  
//停止文件下载 $c47cJO)W  
public void siteStop() Or>[_3  
{ zxdO3I  
bStop = true; Jl ?Q}SB  
for(int i=0;i<nStartPos.length;i++) KL`>mJo$  
fileSplitterFetch.splitterStop(); v}D!  
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} 0yNlf-O  
} 0n=E.qZ9c  
//负责部分文件的抓取 Gzt5efygKt  
**FileSplitterFetch.java oFp&j@`k8j  
*/ sAlgp2-  
package NetFox;
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import java.io.*; ,cEcMaJ  
import java.net.*; gK#w$s50  
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public class FileSplitterFetch extends Thread { Pme?`YO$x  
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String sURL; //File URL )`-]nMc  
long nStartPos; //File Snippet Start Position $)V4Eu;  
long nEndPos; //File Snippet End Position -2_$zk*n  
int nThreadID; //Thread's ID zPYa@0I  
boolean bDownOver = false; //Downing is over ?2;G_P+  
boolean bStop = false; //Stop identical )I4t
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FileAccessI fileAccessI = null; //File Access interface Efl+`6`J  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6 -}gqkR  
{ p3'+"sFU  
this.sURL = sURL; 3>6o=7/PU  
this.nStartPos = nStart; -C+vmY*@  
this.nEndPos = nEnd; ~T~v*'_h  
nThreadID = id; KK6YA  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?da3Azp  
} kn\>ZgU  
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public void run() !w Bmf&=  
{ |*$_eb  
while(nStartPos < nEndPos && !bStop) 9@06]EI_  
{ 9':$!Eoq  
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try{ '\Ub*m((1O  
URL url = new URL(sURL); hj4Rr(T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); y(
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httpConnection.setRequestProperty("User-Agent","NetFox"); 5hAg*zJb5o  
String sProperty = "bytes="+nStartPos+"-"; %}[??R0  
httpConnection.setRequestProperty("RANGE",sProperty); l;uEw  
Utility.log(sProperty); d9(FwmE  
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InputStream input = httpConnection.getInputStream(); A?/?9Gr  
//logResponseHead(httpConnection); rxARJso  
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byte[] b = new byte[1024]; ; F=_ozWV*  
int nRead; @4i DN  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) j4h 7q<  
{ MYDSkW  
nStartPos += fileAccessI.write(b,0,nRead); Y"@kvd  
//if(nThreadID == 1) !NCT) #G`  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); M<"D!h9YP  
} DKZ69^  
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Utility.log("Thread " + nThreadID + " is over!"); TI332,eL  
bDownOver = true; nCrNZ&P  
//nPos = fileAccessI.write (b,0,nRead); Mw~?@Sq  
} AZa3!e/1  
catch(Exception e){e.printStackTrace ();} <Yc:,CU  
} zP9!fA  
} zkMQ=,[  
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//打印回应的头信息 oZ}e w!V
 
public void logResponseHead(HttpURLConnection con) g:Dg
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{ D&shrKFx  
for(int i=1;;i++) m{*l6`dF  
{ VxCH}&!  
String header=con.getHeaderFieldKey(i); 9c6=[3)V  
if(header!=null) ,J|};s+  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); AOe~VW  
Utility.log(header+" : "+con.getHeaderField(header)); .\VjS^o&Z&  
else  51j  
break; bbJa,}R  
} (;"ICk&  
} <LJ$GiU  
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public void splitterStop() >HFJm&lQ  
{ 3{ci]h`:y8  
bStop = true; G 1$l%B  
} g_=Q=y@,  
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} 073(xAkL{  
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[V2l&ZUni  
/* H)S3/%.|  
**FileAccess.java gDsZb
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*//文件访问(定位，写) ^Z*_@A_v  
package NetFox; rnr7t \a~]  
import java.io.*; v%1#y5  
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public class FileAccessI implements Serializable{
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%VMazlM
15  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 rdb%/@.-  
RandomAccessFile oSavedFile; |3i~?] A  
long nPos; R9W(MLe58  
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public FileAccessI() throws IOException 4Mprc~ 7vr  
{ 3!,%;Vz=  
this("",0); #_E8>;)k  
} x!< C0N>?z  
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, ?%`Ky/  
public FileAccessI(String sName,long nPos) throws IOException TX>;2S3q  
{ B0Z@ Cf  
oSavedFile = new RandomAccessFile(sName,"rw"); #U1soZ7  
this.nPos = nPos; VYF4q9  
oSavedFile.seek(nPos); \R<yja  
} j.z#fU  
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public synchronized int write(byte[] b,int nStart,int nLen) g9gyWz  
{ @ +7'0[y?  
int n = -1; |!}$V  
try{ 78X;ZMY  
oSavedFile.write(b,nStart,nLen); &EQov9P7  
n = nLen; _uBf.Qfs  
} !yxb<  
catch(IOException e) E`i;9e'S  
{ "-hgeQX  
e.printStackTrace (); tly:$;K  
} PH]q#/'  
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return n; /`1zkBj<&  
} 3{%/1>+x5  
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} 0trFLX  
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/* YFW+l~[#  
**SiteInfoBean.java n\ IVpgP  
*/ g~cWBr%>  
package NetFox; %|;^[^7+}t  
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public class SiteInfoBean { 6G(k{S  
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7 724,+2N  
private String sSiteURL; //Site's URL |BXq8Erh  
private String sFilePath; //Saved File's Path 0{
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private String sFileName; //Saved File's Name b*bR<|dTj  
private int nSplitter; //Count of Splited Downloading File -du+iOe?  
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public SiteInfoBean() )ow3Bl8w  
{//nSplitter的缺省值为5 ULoTPx@N  
//default value of nSplitter is 5 .z
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this("","","",5); 2/;
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} vj#gY2qZ  
4 Hu+ljdjB  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) (Q@m;i>  
{ o]]Q7S=  
sSiteURL= sURL; M0^r!f>O  
sFilePath = sPath; 0]"j,  
sFileName = sName; ,@P3!|  
this.nSplitter = nSpiltter; ]03!KE  
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_ p?q/-[4  
} {}>"f]3  
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public String getSSiteURL() *fjarZu  
{ xd>2TW l#  
return sSiteURL; '8}\! i&  
} < *XC`Ii  
|5O%@  
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public void setSSiteURL(String value) &AoWT:Ea  
{ TzIgEn~  
sSiteURL = value; $mpfr#!&3o  
} mX<D]Z<
k  
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public String getSFilePath() n
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{ AKS(WNGEp  
return sFilePath; -5E<BmM  
} FMR0?\jnT  
E P<U:F  
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public void setSFilePath(String value) `_f3o,5  
{ MM^tk{2?.  
sFilePath = value; .d.7D ]Yn  
} Wve ^2lkoK  
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public String getSFileName() 
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{ ,x_g|J _Y  
return sFileName; <q_H 3|  
} ^6Xio6W  
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public void setSFileName(String value) 0ai4%=d-  
{ {(t (}-:Z  
sFileName = value; )`g[k"yB3  
} +|o-lb  
Ir]b.6B  
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public int getNSplitter() /0(4wZe~?  
{ XbHcd8N T  
return nSplitter; Bw{W-&$o  
} &qo'ge8p  
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V,2O`D%  
public void setNSplitter(int nCount) }
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{ 8^M5u>=t;  
nSplitter = nCount; ?p$WqVN}  
} R/P.m~?  
} 8fdOV&&D~i  
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/*  gs9f2t  
**Utility.java {0e5<"i  
*/ gAR];(*  
package NetFox; +L_.XToq-  
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public class Utility { ph69u #Og  
S>**hMU%  
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public Utility() sX@e1*YE_  
{ dLj
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+LrW#K;  
} h#;yA"j1&  
}P^n /  
//线程睡眠
/oWB7l&  
public static void sleep(int nSecond) %zY3,4~  
{ ]Q^oc  
try{ GTLlQy)'=  
Thread.sleep(nSecond); )TXn7{M:  
} x!G\-
2#  
catch(Exception e) #+r-$N.7  
{ GhQ.}@*  
e.printStackTrace (); k 9s3@S  
} Xst&QKU  
} 4CNK ]2  
.p0;y3so4  
//日志 Ws(BouJ  
public static void log(String sMsg) qo'pU/@  
{ 23Eg|Xk  
System.err.println(sMsg); >O~xu^N?  
} -[+FVvS  
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p%j@2U  
public static void log(int sMsg) _gU[FUBtJ  
{ Ih"f98lV  
System.err.println(sMsg); =niU6Q}  
} D b(a;o   
} 8whjPn0  
7_A(1Lx/l7  
t6LTGWs/_o  
/* v3`J~,V<  
**TestMethod.java "zm.jNn  
*/ 6"gncB.  
package NetFox; rJZ-/]Xf!6  
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|n]^gTJt  
public class TestMethod { oq;}q  
z#O{rwnl  
8B\,*JGY2  
public TestMethod() 3):7mE(  
{ ///xx/weblogic60b2_win.exe I8?egDkk  
try{ 6:QJ@j\  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); GY0<\-  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); mb?yG:L=0b  
SiteFileFetch fileFetch = new SiteFileFetch(bean); HaLEQ73  
fileFetch.start(); S0kH/A  
} [_b10Z'{  
catch(Exception e){e.printStackTrace ();} SkN^ytKE  
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} !$Mv)c/_u  
R'&^)_  
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public static void main(String[] args) @-Gf+*GZys  
{ a#KxjVM  
new TestMethod(); nj)M$'  
} k98-
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} +]UPY5:F  
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