http断点续传简单实现（java)

/* *,5V;7OR  
**SiteFileFetch.java N ncur]  
*/ ]+;1)  
package NetFox; cP%mkh_ri  
import java.io.*; vJVL%,7  
import java.net.*; a_XM2dc%  
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public class SiteFileFetch extends Thread { tp<uN~rTgh  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Y~EKMowI&e  
long[] nStartPos; //开始位置 ]C_g:|q  
long[] nEndPos; //结束位置 ?9xaBWf  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 8 P85qa@w  
long nFileLength; //文件长度 PhW<)B]  
boolean bFirst = true; //是否第一次取文件 ^IGutZov  
boolean bStop = false; //停止标志 *c4uCI:0t  
File tmpFile; //文件下载的临时信息 ..6 : _{wg  
DataOutputStream output; //输出到文件的输出流 w^Qb9vTa8  
|@?B%sY  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） xO)vn\uJ  
public SiteFileFetch(SiteInfoBean bean) throws IOException :W(3<D7\  
{ 0yr=$F(]s  
siteInfoBean = bean; O9*cV3}H  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /3->TS  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); //cj$}Rn!  
if(tmpFile.exists ()) g\;AU2?p7  
{ H~E(~fl  
bFirst = false; j_S///  
read_nPos(); B5h-JON]-  
} !c-Ie~GIT  
else jV Yt=j*"V  
{ =S/$h}Vi  
nStartPos = new long[bean.getNSplitter()]; RNGTSz  
nEndPos = new long[bean.getNSplitter()]; G6K;3B  
} ^{&Vv(~!Q  
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} j~,7JJ (y  
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public void run() 2GOQ|Z  
{ .|Y2'TWQ  
//获得文件长度 U ^1Xc#Ff  
//分割文件 -5,QrMM<  
//实例FileSplitterFetch eUlF4l<]  
//启动FileSplitterFetch线程 
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//等待子线程返回 ^|y6o
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try{ 2KVMQH`B9  
if(bFirst) bOjvrg;Sz\  
{ &.z: i5&o!  
nFileLength = getFileSize(); f`'?2  
if(nFileLength == -1) T|^rFaA  
{ %7=B?c|  
System.err.println("File Length is not known!"); >I
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} cF!ygz//  
else if(nFileLength == -2) .Tr!/mf_  
{ ~_ss[\N  
System.err.println("File is not access!"); taOD,}c|$  
} N*z_rZE  
else 9bvzt8pc  
{ 5W"&$6vj  
for(int i=0;i<nStartPos.length;i++) ({ 'I;]AQ  
{ :0G "EM4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ^@?-YWt   
} O8:$sei$  
for(int i=0;i<nEndPos.length-1;i++) SA_5..  
{ L,#ij!txS  
nEndPos = nStartPos[i+1]; =9$hZ c  
} OZ 4uk.)  
nEndPos[nEndPos.length-1] = nFileLength; I;iJa@HWQ  
} =" Q5Z6W  
} iu!j#VO  
/V@~Vlww  
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//启动子线程 8a{S*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; sLiKcR8^  
for(int i=0;i<nStartPos.length;i++) ELoE-b)Cb  
{ ZuZe8&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d*3;6ZLy  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), oc.H}Eb%Z  
nStartPos,nEndPos,i); Yw7+wc8R  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (iM*Y"Y  
fileSplitterFetch.start(); f9v%k'T[  
} 0}:- t^P  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), W*A-CkrO  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); t\LAotTF/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2<&lrsh  
nEndPos = " + nFileLength); g+>$_s  
// fileSplitterFetch[nPos.length-1].start(); `I*W}5  
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.b'o}DLa  
//等待子线程结束 ^6&?R?y  
//int count = 0; CBaU$`5  
//是否结束while循环 ?VC[%sjwn  
boolean breakWhile = false; ybWb'+x  
E`vCYhf{  
["4sCB@Tr  
while(!bStop) R.n:W;^`  
{ 9 Yv;Dom  
write_nPos(); tbz?th\#  
Utility.sleep(500); Y:|_M3&'o  
breakWhile = true; 6ww4ZH?j  
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for(int i=0;i<nStartPos.length;i++) O'tVZ!C#J  
{ CX](^yU_  
if(!fileSplitterFetch.bDownOver) V}?d ,.m`{  
{ &?~OV:r9  
breakWhile = false; C.SGm  
break; $dr=M(&  
} US8pT|/  
} SplEY!.k  
if(breakWhile) 7;cb^fi/  
break; V6)e Jy  
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8Ar5^.k  
//count++; rn1^6qy)  
//if(count>4) B>kx$_~  
// siteStop(); ?m&?BsW$)  
} XXbAn-J  
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6=V&3|"  
System.err.println("文件下载结束！"); _N`:NOM  
} nAc02lJh|  
catch(Exception e){e.printStackTrace ();} S+c)  
} 5LVhq[}mP  
_D%aT6,G+(  
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//获得文件长度 @ 2r9JqR[=  
public long getFileSize() |eD$eZ=m  
{ D&5>Op4U  
int nFileLength = -1; H{*~d+:ol  
try{ IooAXwOF  
URL url = new URL(siteInfoBean.getSSiteURL()); Uloa]X=Im8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0fgt2gA33  
httpConnection.setRequestProperty("User-Agent","NetFox"); #R_IF&7  
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int responseCode=httpConnection.getResponseCode(); \A gPkW  
if(responseCode>=400) R~40,$e{  
{ O 0Fw!IQk  
processErrorCode(responseCode); W5a)`
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return -2; //-2 represent access is error xf1@mi[a  
} rUC@Bf  
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@^47Qgj8U  
String sHeader; v-`RX;8  
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for(int i=1;;i++) %T:~N<8)  
{ _c*0Rr  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); $~M#msK9  
//Utility.log(in.readLine()); /15e-(Zz/  
sHeader=httpConnection.getHeaderFieldKey(i); g_z%L?N  
if(sHeader!=null) n W2[x;  
{ u<`CkYT  
if(sHeader.equals("Content-Length"))
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{ Q v/}WnBk  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 8 VMe#41  
break; d!0p^!3  
} Xy{\>}i]N  
} ;m/%g{oV  
else #R&Dgt  
break; Hm=!;xAFX  
} VEAf,{)Q  
} eNN)2-96  
catch(IOException e){e.printStackTrace ();} ?+Sjt  
catch(Exception e){e.printStackTrace ();} D[) Z$+D4f  
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{Lj]++`fB]  
Utility.log(nFileLength); k@1\ULo  
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return nFileLength; %%["&  
} #K1VPezN  
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//保存下载信息（文件指针位置） AH$D./a  
private void write_nPos() [d="94Ab  
{ FX QUj&9  
try{ _~f&
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output = new DataOutputStream(new FileOutputStream(tmpFile));  uY]nqb  
output.writeInt(nStartPos.length); hr9[$4'H  
for(int i=0;i<nStartPos.length;i++) ` <+MR6M  
{ mfHZGk[[  
// output.writeLong(nPos); 3DH} YAUU  
output.writeLong(fileSplitterFetch.nStartPos); Q[t|+RNKv2  
output.writeLong(fileSplitterFetch.nEndPos); Bny3j~*U  
} ZTV|rzE   
output.close(); ,k}-I65M*t  
} {[V<mT2/  
catch(IOException e){e.printStackTrace ();} /]~Oa#SQ:  
catch(Exception e){e.printStackTrace ();} 0zD[mt  
} RY=B>398:  
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//读取保存的下载信息（文件指针位置） w0n.Y-v4i  
private void read_nPos()  b,]QfC  
{ 2y/|/IW=  
try{ eh=.Q<N  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); HyKvDJ 3_  
int nCount = input.readInt(); "F nH>g-  
nStartPos = new long[nCount]; qV^Z@N+,  
nEndPos = new long[nCount]; E/MD]ox  
for(int i=0;i<nStartPos.length;i++) w'NL\>  
{ Opc, {,z6  
nStartPos = input.readLong(); .t\#>Fe  
nEndPos = input.readLong(); }Gmwm|`*  
} |E/r64T  
input.close(); `w@8i[2J  
} &)4#0L4  
catch(IOException e){e.printStackTrace ();} E! '|FJ  
catch(Exception e){e.printStackTrace ();} X 4\  
} 1"pvrX}  
3o=R_%r  
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private void processErrorCode(int nErrorCode) 9os>k*  
{ !]1'?
8  
System.err.println("Error Code : " + nErrorCode); 9$)I=Rpk=  
} :\I88 -N@'  
|G^w2"D_Z  
@edx]H1~^  
//停止文件下载 k/MrNiC  
public void siteStop() =+{SZh@  
{ X6lkz*M.  
bStop = true; (* WO<V  
for(int i=0;i<nStartPos.length;i++) ~ ;CnwG
  
fileSplitterFetch.splitterStop(); B(+J?0Dj  
N"A863>  
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} X?PcEAi;w  
} 6M({T2e  
//负责部分文件的抓取 x<_uwL2a  
**FileSplitterFetch.java 0q6$KP}q  
*/ l423+vo  
package NetFox; 5Oh>rK(  
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import java.io.*; ~?l>QP|o  
import java.net.*; v<+5B5"1  
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public class FileSplitterFetch extends Thread { =1qM`M   
2$G,pT1J  
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String sURL; //File URL NGsG4y^g?z  
long nStartPos; //File Snippet Start Position ;Mzy>*#$Q  
long nEndPos; //File Snippet End Position tGq0f"}'J  
int nThreadID; //Thread's ID W!@*3U]2R  
boolean bDownOver = false; //Downing is over 3zdm-5R.b  
boolean bStop = false; //Stop identical :Kc9k(3&r  
FileAccessI fileAccessI = null; //File Access interface 8RGU^&  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Y 6B7qp  
{ QU&LC  
this.sURL = sURL; >"}z % #  
this.nStartPos = nStart; i@Vi.oc4[  
this.nEndPos = nEnd; QfHJZ7K.4  
nThreadID = id; uvbXsO"z]]  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 <d&9`e1Hc  
} puE!7:X7  
{3s=U"\  
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public void run() .(D,CGtYb  
{ S3cV^CzNg  
while(nStartPos < nEndPos && !bStop) HN7C+e4U~  
{ X:3W9`s)*  
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try{ ;gE]*Y.Z.p  
URL url = new URL(sURL); ak_&\'P  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); S.^/Cl;aj  
httpConnection.setRequestProperty("User-Agent","NetFox"); El9D1],  
String sProperty = "bytes="+nStartPos+"-";  ' ];|  
httpConnection.setRequestProperty("RANGE",sProperty);
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Utility.log(sProperty); vz{Z tE"  
m :M=De  
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InputStream input = httpConnection.getInputStream(); w-2?|XvDmf  
//logResponseHead(httpConnection); ;:)1:Dy5  
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byte[] b = new byte[1024]; (fSpY\JPI  
int nRead; -UTTJnu^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) h_xHQf&#  
{ xna4W|-  
nStartPos += fileAccessI.write(b,0,nRead); 6qAs$[  
//if(nThreadID == 1) SuorCp
]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Vdpvo;4uy  
} `Z)]mH\X  
*=b#>//  
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Utility.log("Thread " + nThreadID + " is over!"); &_1Ivaen6  
bDownOver = true; c)5d-3"  
//nPos = fileAccessI.write (b,0,nRead); T/9`VB%N  
} "
}91wfG9  
catch(Exception e){e.printStackTrace ();} :h(r2?=7  
} :3oLGiL  
} =Su~iOa  
#RN"Ul-B|  
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//打印回应的头信息 Ei$@)qS/  
public void logResponseHead(HttpURLConnection con) 
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{ pz uR H1[  
for(int i=1;;i++) j$%uip{  
{ 3M@!?=|U  
String header=con.getHeaderFieldKey(i); \H6[6*JuB  
if(header!=null) h3udS{9'8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ,sk0){rW  
Utility.log(header+" : "+con.getHeaderField(header)); <"}Gvi  
else (hb\1wZ  
break; FxK2 1  
} 4I
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} s\Zp/-Q  
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public void splitterStop() |o5F%1o  
{ ~"IjT'W3  
bStop = true; xklXV  
} P.j0Xlof  
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} )"]Nf6  
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/* qad`muAd  
**FileAccess.java ophQdJM  
*//文件访问(定位，写) DXH"`1[-  
package NetFox; Y*KHr`\C4  
import java.io.*; !.^%*6f  
faqh }4
 
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public class FileAccessI implements Serializable{ j,%<16f^A  
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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 =Eimbk  
RandomAccessFile oSavedFile; SFaG`T=  
long nPos; %YhM?jMW  
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public FileAccessI() throws IOException tsqk
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{ eX1<zzd  
this("",0);  q\xT  
} 0~;Owu  
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public FileAccessI(String sName,long nPos) throws IOException S.Z2gFE&tu  
{ ar#Xe;T!  
oSavedFile = new RandomAccessFile(sName,"rw"); $
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this.nPos = nPos; o/6'g)r*  
oSavedFile.seek(nPos); 7/:C[J4GTN  
} C@$!'^ 61  
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public synchronized int write(byte[] b,int nStart,int nLen) a7_&;  
{ Fhr5)Z  
int n = -1; FK2* O  
try{ <%~`!n,t0  
oSavedFile.write(b,nStart,nLen); 7[)IP:I>  
n = nLen; ap7Z
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} "B^c  
catch(IOException e) i- v PJg1  
{ e=yQFzQT)  
e.printStackTrace (); [ BpZ{Ql  
} Ns*&;x9  
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return n; v_7?Zik8E  
} X:ck  
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} =gYKAr^p5  
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/* _$oN"pj  
**SiteInfoBean.java V2&O]bR  
*/ t04_~e  
package NetFox; bu j}pEI  
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?aMV{H*Q*  
public class SiteInfoBean { 2Gw2k8g&  
f <,E  
S>! YBzm&X  
private String sSiteURL; //Site's URL WaaF;|,(  
private String sFilePath; //Saved File's Path AxsTB9/  
private String sFileName; //Saved File's Name )C@O7m*.4  
private int nSplitter; //Count of Splited Downloading File nNN~Z'bG  
jIzkI)WC|  
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public SiteInfoBean() u@"nVHgMJ  
{//nSplitter的缺省值为5 D<DSK~  
//default value of nSplitter is 5 _yu d  
this("","","",5); yq
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} s"7$SxMT  
323zR*\m  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) !ULU#2'1  
{ >Z\{P8@k
0  
sSiteURL= sURL; pKnM=N1f  
sFilePath = sPath; 3>+9Rru  
sFileName = sName; @lYm2l^  
this.nSplitter = nSpiltter; -$; h+9BO  
 3Y L  
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} T[z}^"  
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public String getSSiteURL() X:un4B}O  
{ aT]G&bR?  
return sSiteURL; sp2"c"_+  
} 5*q!:$ W  
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public void setSSiteURL(String value) %y{
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{ cEP
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sSiteURL = value; 'R{X
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} L,m'/}$  
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public String getSFilePath() tU5Z?QS  
{ 7jj
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return sFilePath; ,vxxp]#5  
} TIs~?wb$  
3!&PI  
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public void setSFilePath(String value) "&_$%#HUv  
{ xD:t$~  
sFilePath = value; P ,%IZ.  
} 4P>[]~S  
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public String getSFileName() vxey$Ir  
{ ZQ%4]=w  
return sFileName; up# R9 d|  
} 4*)a3jI?  
j,]KidDWm  
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public void setSFileName(String value) Gr&)5hm$  
{ NSsLuM=.  
sFileName = value; z'W8t|m}Pb  
} EJ%Kr$51K  
cl`!A2F1G#  
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public int getNSplitter() 65P*Gu?  
{ $jc&Tk#  
return nSplitter; o_(@v2G`  
} (i 3=XfZ!C  
V5.=08L  
 MeP,8,n'  
public void setNSplitter(int nCount) ]]EOCGZ"  
{ T3JM8  
nSplitter = nCount; C:?mOM#_  
} <
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} "%mu~&Ga  
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cLZaQsS%  
/* ,>AA2@6zMT  
**Utility.java 6JCq?:#ab  
*/ [!<W{ ($5  
package NetFox; MnQ4,+ji-  
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public class Utility { `veq/!  
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public Utility() [s}nv]  
{ wqZ*$M  
.!B>pp(9  
Y*KP1=Md  
}
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>k)zd-  
//线程睡眠 HQ7  
public static void sleep(int nSecond) ZQVr]/W^r  
{ ){sn!5=  
try{ /Cl=;^)  
Thread.sleep(nSecond); FUD M]:XQ  
} ZJod=^T  
catch(Exception e) WlF}R\N!  
{ "Q[rM1R  
e.printStackTrace (); JDI1l_Ga  
} ,l
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} g?mfpw
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w]& o]VP  
//日志 Mqk[+n  
public static void log(String sMsg) F4#^jat{  
{ $
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System.err.println(sMsg); Tp.t.Qic  
} MIn6p  
'A#bBn,|  
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public static void log(int sMsg) jx?"m=`s:  
{ "fq8)  
System.err.println(sMsg); T 8. to
 
} rDEdMT  
} 7/UdE:~]*=  
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#% 1|$V*:  
/* ,iy;L_N  
**TestMethod.java S*D Bzl  
*/ $.g)%#h:  
package NetFox; sT;:V  
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w%NT 0J  
public class TestMethod { Ia'm9Z*  
0\X'a}8Bu  
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public TestMethod() N+V_[qr#  
{ ///xx/weblogic60b2_win.exe -IP
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try{ H+O^el  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -:jC.} Y  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 8K;wX%_,  
SiteFileFetch fileFetch = new SiteFileFetch(bean); h88IP:bo  
fileFetch.start(); _]/&NSk  
} M6MtE_E  
catch(Exception e){e.printStackTrace ();} f:K3 P[|  
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aP}%&{iC*  
} h]w5N2$}?  
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public static void main(String[] args) flr&+=1?D  
{ '-?t^@  
new TestMethod(); !vQDPLBL  
} 4or8fG  
} uTq)Ets3  
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