http断点续传简单实现（java)

/* ~p/1 9/  
**SiteFileFetch.java f,Dj@?3+  
*/ SxRa
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package NetFox; }W"/h)q  
import java.io.*; g"v-hTx  
import java.net.*; *p%=u>?&  
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public class SiteFileFetch extends Thread { $~.'Tnk)  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ~@Eu4ip)F  
long[] nStartPos; //开始位置 Zut"P3d=J  
long[] nEndPos; //结束位置 |`6*~ciUV  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 w97%5[-T  
long nFileLength; //文件长度 t2q{;d~.  
boolean bFirst = true; //是否第一次取文件 T|Fl$is  
boolean bStop = false; //停止标志 >a2i%j/T  
File tmpFile; //文件下载的临时信息 PzDekyl  
DataOutputStream output; //输出到文件的输出流 niJtgK:H^  
.~dNzonq  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） s8 0$   
public SiteFileFetch(SiteInfoBean bean) throws IOException UB1/0o  
{ =?gB@vS  
siteInfoBean = bean; 5QUL-*t  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); if
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); #Rcb iV*M  
if(tmpFile.exists ()) g O ;oM?|  
{ K.K=\ Y2  
bFirst = false; 6Z3L=j  
read_nPos(); 6#/v:;bF  
} h"DxgG  
else V t@
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{ `z{sDe;  
nStartPos = new long[bean.getNSplitter()]; '9d] B^)F  
nEndPos = new long[bean.getNSplitter()]; i@p0Jnh|  
} NvqIYW  
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} DqGm
 
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public void run() RO+N>Wkt  
{ Y(3X5v?[  
//获得文件长度 8\/$cP"<^  
//分割文件 QlCs,bT  
//实例FileSplitterFetch hYS}PE  
//启动FileSplitterFetch线程 HXp$\%A)  
//等待子线程返回 B LI 9(@  
try{ 1Vy8TV3D  
if(bFirst) Q=~*oYR  
{ [Y_CRxa\u  
nFileLength = getFileSize(); Tt
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if(nFileLength == -1) T>2_r6;  
{ \x9.[?;=e  
System.err.println("File Length is not known!"); 'Wz`P#/  
} nA?Ks!9T  
else if(nFileLength == -2) oW \k%Vj  
{ kzuI<DW  
System.err.println("File is not access!"); 3BzC'nplm  
} A5[iFT
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else P/XCaj3a[  
{ iVe"iH  
for(int i=0;i<nStartPos.length;i++) U1^3 &N8  
{ J':x]_;  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); v%$c_'d  
} _(%;O:i  
for(int i=0;i<nEndPos.length-1;i++) I->BDNk  
{ xg8$ <Ut  
nEndPos = nStartPos[i+1]; x^]J^L45  
} ?hh#@61  
nEndPos[nEndPos.length-1] = nFileLength; _ ,~D]JYE  
} b[s=FH]#N  
} !}pvrBS  
&6q67  
fDD^?/^  
//启动子线程 h51)kN:  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; thK4@C|X4  
for(int i=0;i<nStartPos.length;i++) (R|Ftjs .  
{ H05xt
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #)b0&wyW6i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), DICS6VG}  
nStartPos,nEndPos,i); e61e|hoX\  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); GA+#'R  
fileSplitterFetch.start(); fZka$ 4  
} Bb9/nsbE  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l:- <CbG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); q'1 86L87  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", dk>qTY+j5  
nEndPos = " + nFileLength); s)9d\{  
// fileSplitterFetch[nPos.length-1].start(); YG K7b6  
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//等待子线程结束 Bm4fdf#A]  
//int count = 0; ![Ll$Lr  
//是否结束while循环 !>,XK!)  
boolean breakWhile = false; y^[?F>wB  
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while(!bStop) |!hN!j*)  
{ &MJcLM]  
write_nPos(); _MxKfah'  
Utility.sleep(500); B x-"<^<  
breakWhile = true; }!*CyO*  
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for(int i=0;i<nStartPos.length;i++) JDP/vNq  
{ |] cFsB#G  
if(!fileSplitterFetch.bDownOver) n@_aTY  
{ K'U8ft*_  
breakWhile = false; kO/]mNLG  
break; 8Os: SC@Q  
} O/Mx$Q3re  
} " 3tk"#.#  
if(breakWhile) ^E]y >Y  
break; IutU~%wv  
 1 .Nfl@]  
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//count++; 0HPqoen$  
//if(count>4) lQKq{WLFx.  
// siteStop(); %_. fEFy07  
} cxz\1Vphd  
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;!pSYcT,  
System.err.println("文件下载结束！"); |mF=X*  
} ?!a8'jfs  
catch(Exception e){e.printStackTrace ();}
_
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} ^SWV!rrg  
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CfEACH4_  
//获得文件长度 H:]'r5sw  
public long getFileSize() '#NDR:J"  
{ 9}$'q$0R]  
int nFileLength = -1; ]/[$3rPwZ  
try{ |Ng}ZLBM  
URL url = new URL(siteInfoBean.getSSiteURL()); bBY7^k  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2Dw}o;1'  
httpConnection.setRequestProperty("User-Agent","NetFox"); G'{*guYU  
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int responseCode=httpConnection.getResponseCode(); COH9E
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if(responseCode>=400) a[ yyEgm2  
{ h ;1D T  
processErrorCode(responseCode); @cB6,iUr  
return -2; //-2 represent access is error E_-
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} ",pd 9  
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String sHeader; `M!'PMX  
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for(int i=1;;i++) r1[#_A`Yn  
{ Bk@&k}0  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); l,ic-Y1  
//Utility.log(in.readLine()); .TO#\!KBv  
sHeader=httpConnection.getHeaderFieldKey(i); GP0}I@>?  
if(sHeader!=null) O #5`mo  
{ +[7 DRT:  
if(sHeader.equals("Content-Length")) `>u^Pm  
{ ?*:BgaR_  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); -u~AY#*  
break; V|)nUsU  
} >6gduD!6I  
} (97&mhs3  
else 8=-#LVo~c  
break; o3Z<tI8-V  
} WO=P~F<  
} +pxt
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catch(IOException e){e.printStackTrace ();} LF ;gdF%@  
catch(Exception e){e.printStackTrace ();} !SThK8j$7  
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Utility.log(nFileLength); mw*KLMo42  
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return nFileLength; VLC=>w\,  
} Dv}VmC""  
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//保存下载信息（文件指针位置） K_-S`-eH  
private void write_nPos() ~vKDB$2  
{ +kx#"L:  
try{ 6 -IThC  
output = new DataOutputStream(new FileOutputStream(tmpFile)); OySn[4`(i  
output.writeInt(nStartPos.length); LRPdA "Z
 
for(int i=0;i<nStartPos.length;i++) lh-zE5;  
{ rQ)I  
// output.writeLong(nPos); PDb7h  
output.writeLong(fileSplitterFetch.nStartPos); e/zz.cd){  
output.writeLong(fileSplitterFetch.nEndPos); KP CZiu7  
} ,EH^3ODD  
output.close(); Ur(< ]  
} }8Nr.gY  
catch(IOException e){e.printStackTrace ();} "LM[WcDX  
catch(Exception e){e.printStackTrace ();} vlPViHF.  
} oT9qd@uQ0:  
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 ?S'Wd=  
//读取保存的下载信息（文件指针位置） y|(?>\jBl  
private void read_nPos() j=Z;M1  
{ V-lp';bD  
try{ wcL|{rUXba  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); r^`~GG!,Q  
int nCount = input.readInt(); /e7BW0$1  
nStartPos = new long[nCount]; ' [%?j?2r  
nEndPos = new long[nCount]; ?{r-z3@ N  
for(int i=0;i<nStartPos.length;i++) 1(qL),F;  
{ *_eY +\j  
nStartPos = input.readLong(); JxQGL{) >  
nEndPos = input.readLong(); R@2*Lgxz~  
} tw&biLM5T  
input.close(); ?:#$btmn?  
} DS=Dg@y  
catch(IOException e){e.printStackTrace ();} #4F0o@Z  
catch(Exception e){e.printStackTrace ();} -qpe;=g&f  
} ,Ofou8C6  
+,J!xy+~,  
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private void processErrorCode(int nErrorCode) =/bC0bb{i  
{ URMxCL^"  
System.err.println("Error Code : " + nErrorCode); Gy!bPVe
 
} TchByN6oN<  
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//停止文件下载 c4M]q4]F  
public void siteStop() TJs~}&L  
{ I~25}(IDZ"  
bStop = true; goc"+K  
for(int i=0;i<nStartPos.length;i++) m>+e;5  
fileSplitterFetch.splitterStop(); I GB)  
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Q=#Wk$1.  
} 1_z~<d @?;  
} o.])5i_HV  
//负责部分文件的抓取 :@J.!dokF  
**FileSplitterFetch.java eKL3Y_5p@  
*/ D>K=D"  
package NetFox; /086qB|  
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import java.io.*; 47^
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import java.net.*; nh>lDfJV<  
xN44>3#  
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public class FileSplitterFetch extends Thread { mxl"Y&l2<  
2,G9~<t  
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String sURL; //File URL YT)@&HaF  
long nStartPos; //File Snippet Start Position K"VRHIhfg  
long nEndPos; //File Snippet End Position 7DIFJJE'  
int nThreadID; //Thread's ID wE#z)2?`\  
boolean bDownOver = false; //Downing is over sF p% T4j  
boolean bStop = false; //Stop identical {@>6E8)H5  
FileAccessI fileAccessI = null; //File Access interface D@yu2}F{IY  
_[S<Cb*1  
bw OG|\  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <@+{EK'`q  
{ 7aeyddpM  
this.sURL = sURL; >e QFY^d5  
this.nStartPos = nStart; fk(h*L|sI  
this.nEndPos = nEnd; <xr\1VjA  
nThreadID = id; WS1#i\0  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 zN,2 (v"  
} ^MUvd  
FuFA/R=x/  
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public void run() `_>44!M  
{ oPR?Ar  
while(nStartPos < nEndPos && !bStop) \mDBOC0eK  
{ g)^g_4  
i" >kF@]c8  
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try{ ,=`iQl3(y/  
URL url = new URL(sURL); %lSjC%Z'd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *[b2
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httpConnection.setRequestProperty("User-Agent","NetFox"); vABUUAo!Jr  
String sProperty = "bytes="+nStartPos+"-"; wZKEUJpQ  
httpConnection.setRequestProperty("RANGE",sProperty); ?m dGMf)  
Utility.log(sProperty); (zIIC"~5  
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InputStream input = httpConnection.getInputStream(); lIgA
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//logResponseHead(httpConnection); vs(x;zpJ  
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byte[] b = new byte[1024]; i|QL6e*0  
int nRead; u]s}@(+.  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &T\,kq>)  
{ 7r wNjY#  
nStartPos += fileAccessI.write(b,0,nRead); xaW9Sj0ZM  
//if(nThreadID == 1) Fm
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]$i~;f 8I  
} n$y@a?al  
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Utility.log("Thread " + nThreadID + " is over!"); @&GfCg5Cb  
bDownOver = true; Wt
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//nPos = fileAccessI.write (b,0,nRead); (v1~p3H  
} _e94  
catch(Exception e){e.printStackTrace ();} (K3eb  
} n0tVAH'>  
} ]c\d][R N  
*1CZRfWI  
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//打印回应的头信息 +'!Y[7|9iv  
public void logResponseHead(HttpURLConnection con) R&9Q#n-  
{ j|2s./!Qg  
for(int i=1;;i++) @szr '&\%A  
{ 1 JB~G7  
String header=con.getHeaderFieldKey(i); $W0O
  
if(header!=null) ^{l$>e]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ,8Q&X~$rY  
Utility.log(header+" : "+con.getHeaderField(header)); g0>Q* x  
else V
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break; <_~e/+_.  
} %)p?&_  
} :FX|9h  
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public void splitterStop() MyaJhA6c  
{ 6gTc)rhRT  
bStop = true; nD\H$5>5  
} ky=h7#wdv-  
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} }B@44HdY  
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/* !"<~n-$B  
**FileAccess.java E8"$
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*//文件访问(定位，写) L=wpZ`@ y  
package NetFox; ?z0N-A2C2  
import java.io.*; HMq
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public class FileAccessI implements Serializable{ =SVb k  
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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 )>I-j$%=2  
RandomAccessFile oSavedFile; r>cN,C
 
long nPos; &l?AC%a5  
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public FileAccessI() throws IOException i6)HC  
{ >p 9~'
 
this("",0); B/Z-Cpz]  
} D-4{9[  
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public FileAccessI(String sName,long nPos) throws IOException VMH
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{ 20c
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oSavedFile = new RandomAccessFile(sName,"rw"); 4Be\5Byr  
this.nPos = nPos; do:IkjU~  
oSavedFile.seek(nPos); ^]MLEr!S  
} ~DP_1V?  
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public synchronized int write(byte[] b,int nStart,int nLen) y3OF+;E  
{ #*X\pjZ  
int n = -1; Eo>EK>  
try{ 
v-DZW,  
oSavedFile.write(b,nStart,nLen); 58P[EMhL  
n = nLen; il% u)NN  
} |H.ARLS  
catch(IOException e) CN:z *g  
{ ;@xlrj+  
e.printStackTrace (); B}0!b7!  
} q5{h@}|M  
+ f,Kt9Cy  
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return n; lRR A2Kql  
} <nc6&+  
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} w|c200Is}e  
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/* X}H?*'-  
**SiteInfoBean.java LB`{35b-  
*/ oL@K{dk  
package NetFox; (dT
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!cW!zP-B*p  
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public class SiteInfoBean { bE?X?[K  
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private String sSiteURL; //Site's URL &%m%b5  
private String sFilePath; //Saved File's Path es<8"CcP  
private String sFileName; //Saved File's Name :l&Yq!5  
private int nSplitter; //Count of Splited Downloading File SG]Sx4fg,Y  
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public SiteInfoBean() sLUOs]cj  
{//nSplitter的缺省值为5 9}5o> iR  
//default value of nSplitter is 5 VS>xvF  
this("","","",5); nJ h)iQu  
} 3S" /l
  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]kd:p*U6P  
{ N(V_P[]"*,  
sSiteURL= sURL; inh J|pe"  
sFilePath = sPath; GSW%~9WBa  
sFileName = sName; K&eT*JW>  
this.nSplitter = nSpiltter; aYn5AP'PH  
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AEkjyh\  
} EjMVlZC>  
m`}mbm^  
5Dzf[V^]`  
public String getSSiteURL() $ ^@fV=e  
{ S=\cF,Zs  
return sSiteURL; Y&H<8ez  
} +lb&_eD  
"c\WZB`|  
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public void setSSiteURL(String value) @)U;hk)j;  
{ d0-4
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sSiteURL = value; *2pf>UzL  
} 4:-x!lt  
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public String getSFilePath() -K3d u&j  
{ "$pbK:  
return sFilePath; u`D _  
} 4}s'xMT!  
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S`$%C=a.  
public void setSFilePath(String value) x-]:g&5T  
{ t+_\^Oa)  
sFilePath = value; <ZheWl  
} hz*T"HJ]t  
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public String getSFileName() e9HL)=YP  
{ [$;cjys  
return sFileName; 1\~I "$}  
} ,H%[R+)  
{2YqEX-I*  
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public void setSFileName(String value) HNCu:$Wr@  
{ k%X $@NP  
sFileName = value; xy b=7  
} mPHto-=fB  
c@Br_-  
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public int getNSplitter() ]YtN6Rq/  
{ ;0Q" [[J  
return nSplitter; ,n[<[tkCR  
} *5.wwV  
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public void setNSplitter(int nCount) zjh:jrv~  
{ `a83bF35  
nSplitter = nCount; [NAfy~X*  
} /Ry%K4$  
} )z\#  
c BZ,"kp-  
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/* Ar[|M2|  
**Utility.java : NA(nA 3  
*/ DxwR&S{  
package NetFox; YoW)]n  
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public class Utility { }Nd1'BVf  
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public Utility() ;N?(R\*8  
{ (WJ)!  
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} 3]GMQA{L)  
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//线程睡眠 VnVBA-#r|  
public static void sleep(int nSecond) ^3BPOK[*gB  
{ i%[gNh  
try{ 4
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Thread.sleep(nSecond); =\|,hg)c  
} %~x?C4L8  
catch(Exception e) ah hl  
{ a#"orc j  
e.printStackTrace (); '~Cn+xf4]  
} )v_v 7 ~H&  
} ,}&TZkN{-  
v@tEHRadz  
//日志 gT0yI;g]  
public static void log(String sMsg) "3\y~<8%'  
{ ||>4XDV#  
System.err.println(sMsg); hNsi 8/  
} NLY=o@<  
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public static void log(int sMsg) ,|s*g'u  
{ A5J41yH  
System.err.println(sMsg); v}N\z2A  
} ~HhB@G!3  
} #Zw:&' QB  
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@,GL&$Y:W  
/* \Q(a`6U  
**TestMethod.java Fz';H  
*/ aqN{@|  
package NetFox; \OtreYi  
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public class TestMethod { 't}\U&L.{  
.FHk1~\%z^  
G@#lf@M
]  
public TestMethod() y;Cs#eo  
{ ///xx/weblogic60b2_win.exe F`m}RL]g  
try{ babL.Ua8o  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #WSqh +  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); W/bW=.d Jd  
SiteFileFetch fileFetch = new SiteFileFetch(bean); I2WP/  
fileFetch.start(); 'z5jnI  
} pT->qQ3;  
catch(Exception e){e.printStackTrace ();} =~hb&  
A~PR  
TT/H"Ri}Jp  
} tngB;9c+w  
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public static void main(String[] args) Z8ea)_{#  
{ e' o2PW  
new TestMethod(); =yZq]g6Q  
} Zh;wQCDj  
} wDh]vH[  
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