http断点续传简单实现（java)

/* ~C-,G"zw&G  
**SiteFileFetch.java  v,=v  
*/ `K*b?:0lp  
package NetFox; B z^|SkEit  
import java.io.*; q2hFOm  
import java.net.*; %SrM|&[  
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public class SiteFileFetch extends Thread { xl(@C*.sC1  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 7FLXx?nLY  
long[] nStartPos; //开始位置 )=J5\3O
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long[] nEndPos; //结束位置 ?+~cA^-3T  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 O}Hf62"  
long nFileLength; //文件长度 fH\X  
boolean bFirst = true; //是否第一次取文件 $=B8qZ+  
boolean bStop = false; //停止标志 |Os6V<u"  
File tmpFile; //文件下载的临时信息 !d,
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DataOutputStream output; //输出到文件的输出流 Qck|#tc  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） S${Zzt"  
public SiteFileFetch(SiteInfoBean bean) throws IOException 7Y
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{ oRM)%N#  
siteInfoBean = bean; Yw'NX5#)g  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); K
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }lP;
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if(tmpFile.exists ()) ljC(L/I  
{ eSEq{?>  
bFirst = false; FdzNE  
read_nPos(); n(1')?"mA  
} 08s_v=cF  
else lx |5?P  
{ ,E;;wdIt  
nStartPos = new long[bean.getNSplitter()]; 0p(L'  
nEndPos = new long[bean.getNSplitter()]; ,HB2hHD  
} |l0Ea  
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} \3Pv# )  
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public void run() P`$!@T0=
 
{ JhHWu<  
//获得文件长度 7 <9yH:1  
//分割文件 D}3T|N  
//实例FileSplitterFetch UlcH%pxTt1  
//启动FileSplitterFetch线程 GsQ*4=C  
//等待子线程返回 HOoPrB m  
try{ (#D*Pl  
if(bFirst) OFk8>"|  
{ WIr2{+#  
nFileLength = getFileSize(); 'G&{GVbXY  
if(nFileLength == -1) r%@Lej5+  
{ \f:z+F!6R  
System.err.println("File Length is not known!"); 7ZxaPkIu&%  
} urBc=3Rz  
else if(nFileLength == -2) rH8@69,B  
{ B9R(&<4  
System.err.println("File is not access!"); ^qG
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} kDvc" ,SD#  
else 0NDftcB]  
{ N8to
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for(int i=0;i<nStartPos.length;i++) T
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{ =(v^5
 
nStartPos = (long)(i*(nFileLength/nStartPos.length)); j;b42G~p  
} p;T{i._iL  
for(int i=0;i<nEndPos.length-1;i++) h!rM^  
{ +Y"r71|A6+  
nEndPos = nStartPos[i+1]; q h/F  
} }`(N:p  
nEndPos[nEndPos.length-1] = nFileLength; ;0rGiWC#  
} 'e)^m}:?D  
} ,`D~py,  
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//启动子线程 Y;4!i?el  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ldha|s.*  
for(int i=0;i<nStartPos.length;i++) Tm}rH]F&  
{ +mj*o(  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), te
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), d^03"t0O]  
nStartPos,nEndPos,i); N`@NiJ(O;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :W#rhuzC  
fileSplitterFetch.start(); +4;uF]T  
} 5|3e&  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M_v?9L  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); j9Ybx#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^G&3sF}  
nEndPos = " + nFileLength); @"
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// fileSplitterFetch[nPos.length-1].start(); aj8A8ma*}  
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//等待子线程结束 o[oM8o<  
//int count = 0; m!<i0thJ  
//是否结束while循环 m>USD?i  
boolean breakWhile = false; o#) {1<0vg  
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while(!bStop) T|J9cgtS  
{ L86n}+ P\  
write_nPos(); E)Gw0]G  
Utility.sleep(500); O[tvR:Nh  
breakWhile = true; Q!- 0xlx  
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W} WI; cI  
for(int i=0;i<nStartPos.length;i++) A.<H>=Z#O  
{ H]Hv;fcC  
if(!fileSplitterFetch.bDownOver) fjvN$NgVs  
{ \(226^|j  
breakWhile = false; 8fA_p}wp  
break; mxor1P#|  
} !It`+0S b  
} QaUm1i#
 
if(breakWhile) +uay(3m((  
break; bvfk  
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//count++;
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//if(count>4) zvABU+{jD  
// siteStop(); fYKOJ5f  
} C{TA.\   
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System.err.println("文件下载结束！"); "KcA  
} n>@oBG)!  
catch(Exception e){e.printStackTrace ();} >WY#4  
} DN4$Jva  
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//获得文件长度 [MuEoWrq(}  
public long getFileSize() t78k4?  
{ I*9e]m"  
int nFileLength = -1; 8XbA'% o  
try{ @lJzr3}WZ  
URL url = new URL(siteInfoBean.getSSiteURL()); <ZU=6Hq  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Gt9&)/#  
httpConnection.setRequestProperty("User-Agent","NetFox"); O=u1u}CP?  
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int responseCode=httpConnection.getResponseCode(); ]HpA5q1ck  
if(responseCode>=400) ~?B;!Csk  
{ 'SQG>F Uy  
processErrorCode(responseCode); (sVi\R  
return -2; //-2 represent access is error nUkaz*4qU  
} '_|h6<.k[  
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String sHeader; aF03a-qw<  
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for(int i=1;;i++) =8U&[F  
{ R<B7K?SxV~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 7G
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//Utility.log(in.readLine());
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sHeader=httpConnection.getHeaderFieldKey(i); ^eW}XRI  
if(sHeader!=null) J\e+}{  
{ JN7k2]{  
if(sHeader.equals("Content-Length")) N},n `Yl.  
{ 1q;#VS/D;H  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); iNMx"F0r  
break; 2NB L}x  
} qJ0fQI\  
} )BRKZQN  
else +F dB '  
break; lJ@][;  
} *)+ut(x|#  
} Z@hD(MS(C  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} LM2TZ  
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Utility.log(nFileLength); CbN!1E6).  
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return nFileLength; bXS:x  
} c6Y\n%d&  
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//保存下载信息（文件指针位置） \>Ef
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private void write_nPos() .7n\d55a  
{ *Vho?P6y\Y  
try{ y-CX}B#j  
output = new DataOutputStream(new FileOutputStream(tmpFile)); "
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output.writeInt(nStartPos.length); o/ui)U_  
for(int i=0;i<nStartPos.length;i++) Y#g4$"G9  
{ \W%UZs  
// output.writeLong(nPos); id$Ul?z8  
output.writeLong(fileSplitterFetch.nStartPos); 02Ia2e.f  
output.writeLong(fileSplitterFetch.nEndPos); L\;6y*K  
} &N3Y|2  
output.close(); VN%INUi@  
} j2 !3rI  
catch(IOException e){e.printStackTrace ();} g[w,!F  
catch(Exception e){e.printStackTrace ();} Z}-Vf$O~  
} JMTvSXr  
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//读取保存的下载信息（文件指针位置） KoS*0U<g6  
private void read_nPos() 5+fLeC;  
{ s`#(   
try{ v!%5&: c3  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 7w3CXY  
int nCount = input.readInt(); s@fTj$h  
nStartPos = new long[nCount]; Wa?; ^T  
nEndPos = new long[nCount]; Vx @|O%  
for(int i=0;i<nStartPos.length;i++)  YBnA+l*  
{ itzyCw2|#  
nStartPos = input.readLong(); <7Ae-!>x  
nEndPos = input.readLong(); IJ/sX_k  
} e${)w-R/e  
input.close(); }W ^: cp  
} (!:cen~|[  
catch(IOException e){e.printStackTrace ();} )Z %T27r,^  
catch(Exception e){e.printStackTrace ();} JAI)Eqqv]  
}  aH#l9kCb  
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private void processErrorCode(int nErrorCode) 3"{.37Q  
{ Zk[&IBE_  
System.err.println("Error Code : " + nErrorCode); JH8zF{?  
} q7&6r|w1I  
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#0Tq=:AE>  
//停止文件下载 Bphof0{<}  
public void siteStop() cm[c
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{ SRSvot};C  
bStop = true; 57 #6yXQ  
for(int i=0;i<nStartPos.length;i++) sCu+Lg~f  
fileSplitterFetch.splitterStop(); aj}(E+  
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}
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} l{D'uI[&  
//负责部分文件的抓取 D_8x6`z  
**FileSplitterFetch.java ;}'D16`j  
*/ *cO sv  
package NetFox; 5 QO34t2  
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import java.io.*; _@R0x#p5M  
import java.net.*; [{X^c.8G)  
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public class FileSplitterFetch extends Thread { *FJZiPy
 
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String sURL; //File URL R-P-i0~  
long nStartPos; //File Snippet Start Position K+6e?5t  
long nEndPos; //File Snippet End Position y7
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int nThreadID; //Thread's ID  kQ  
boolean bDownOver = false; //Downing is over `ImE% r!  
boolean bStop = false; //Stop identical 'fL"txW  
FileAccessI fileAccessI = null; //File Access interface uWrQ&}@  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException {f{ZHi|  
{ x=#VX\5k:  
this.sURL = sURL; r `eU~7  
this.nStartPos = nStart; l (3bW1{n  
this.nEndPos = nEnd; Xj*vh m%i  
nThreadID = id; #
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 P/`I.p;  
} ^#0U ?9  
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public void run() sp*Vqd  
{ z;u  
while(nStartPos < nEndPos && !bStop) C^)
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{ !|<=ZF2  
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try{ i>_u_)-  
URL url = new URL(sURL); Vn~UB#]'3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  RDtU43  
httpConnection.setRequestProperty("User-Agent","NetFox"); Q#IG;  
String sProperty = "bytes="+nStartPos+"-"; nQGQWg`  
httpConnection.setRequestProperty("RANGE",sProperty); FV,4pi  
Utility.log(sProperty); ,y%3mR_~  
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InputStream input = httpConnection.getInputStream(); @2*]"/)*0  
//logResponseHead(httpConnection); iH.$f /)N  
0 &GRPu27  
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byte[] b = new byte[1024]; t&9A ]<n%,  
int nRead; BW,mwq  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) iS
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{ wd/< 8>2X  
nStartPos += fileAccessI.write(b,0,nRead); MfmACd^3$  
//if(nThreadID == 1) &x >B  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); q%5eVG  
} q:<{% U$  
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Utility.log("Thread " + nThreadID + " is over!"); ]
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bDownOver = true; }(<%`G6N  
//nPos = fileAccessI.write (b,0,nRead); hb{u'=  
} G7=pBf  
catch(Exception e){e.printStackTrace ();} W0=O+0$^  
} 9!><<7TS  
} MaD3[4@#  
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sN("+ sZ.n  
//打印回应的头信息 iZZ (4  
public void logResponseHead(HttpURLConnection con) -WQ^gcO=7  
{ LOTP*Syjf  
for(int i=1;;i++) <40rYr$/J  
{ +D1d=4  
String header=con.getHeaderFieldKey(i); 7n90f2"m  
if(header!=null) fo4.JyBk  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4 QZ?}iz  
Utility.log(header+" : "+con.getHeaderField(header)); /\)a  
else ^V|Oxp'7_  
break; ;=? ~ -_  
} oBUxKisW  
} )a3IQrf=  
IL_d:HF|1  
;sch>2&ZWU  
public void splitterStop() ejA%%5q  
{ Erk?}E  
bStop = true; Ys!>+nL|  
} vS;1/->WD  
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} r_YIpnJ  
7#<c>~   
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/* |7KeR-  
**FileAccess.java x3rlJs`$;  
*//文件访问(定位，写) )NR Q2  
package NetFox; BA=,7y&;j  
import java.io.*; ]m#5`zGK1|  
4:9KR[y/  
KQ[!o!%  
public class FileAccessI implements Serializable{ r 6eb}z!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  8L*GE  
RandomAccessFile oSavedFile; 8J)xzp`*)  
long nPos; VxFOYC>p  
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public FileAccessI() throws IOException L^^4=ao0  
{ Kq.:G%  
this("",0); -VZRujl  
} .q][? mW3  
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public FileAccessI(String sName,long nPos) throws IOException 3DaQo0N  
{ =_]2&(?  
oSavedFile = new RandomAccessFile(sName,"rw"); "S&%w8V  
this.nPos = nPos; >]=j'+]  
oSavedFile.seek(nPos); na^sBq?\  
} MuBx#M/  
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_7
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public synchronized int write(byte[] b,int nStart,int nLen) >5G>D~b  
{ iBudmT8  
int n = -1; .qob_dRA  
try{ xmGk*W)P  
oSavedFile.write(b,nStart,nLen); bw&myzs  
n = nLen;
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} YwcPX`eg  
catch(IOException e) A$.fv5${  
{ //Ai.Q.J[  
e.printStackTrace (); 0Aa`p3.)  
} YK{a
 
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return n; }`yiT<z  
} f f7(  
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} ^Y{D^\},  
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/* ):EBgg4-N  
**SiteInfoBean.java /HZumV?  
*/ yg]2erR  
package NetFox; zdSh:  
F~U!1)  
]TstSF=  
public class SiteInfoBean { irTv4ZE'+l  
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private String sSiteURL; //Site's URL _~aG|mAj
 
private String sFilePath; //Saved File's Path S'B6jJK2x  
private String sFileName; //Saved File's Name x
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private int nSplitter; //Count of Splited Downloading File ;3C:%!CdA]  
BpLEPuu30  
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public SiteInfoBean() Kt#,]]  
{//nSplitter的缺省值为5 DG;y6#|p  
//default value of nSplitter is 5 VhEMk\  
this("","","",5); ,)~E
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} >NV=LOO  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _x1EZ&dh  
{ q6`GI6  
sSiteURL= sURL; 8O1K[sEjui  
sFilePath = sPath; HI&kP+,y  
sFileName = sName; R|!B,b(  
this.nSplitter = nSpiltter; xn}BB}s{t  

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} w?csV8ot  
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public String getSSiteURL() 5,b]V)4  
{ #G3N(wV3  
return sSiteURL; 6Gn4aso
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} > 7`&0?  
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public void setSSiteURL(String value) }fhHXGK.  
{ 0'$p$K  
sSiteURL = value; 3}&ZOO 
 
} UEzi*"-v2  
!d9AG|  
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public String getSFilePath() >{Rb 3Z]  
{ !D.0 (J  
return sFilePath; j nwQV  
} E@ h y7X  
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public void setSFilePath(String value) Tvf~P w  
{ L*?!Z^k  
sFilePath = value; e&X>F"z2  
} lj&>cScC  
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public String getSFileName() /c+)C"  
{ nbdGt  
return sFileName; EH`0  
} UCqs}U8  
aW5~Be$ _  
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public void setSFileName(String value) L~FTr  
{ sM\&.<B  
sFileName = value; K}I0o!(#  
} ipKG!  
\k&1*b?h  
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public int getNSplitter() |#5 e|z5(  
{ T<jfAE  
return nSplitter; Ae|P"^kZ  
} DOL%'k?B  
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& QZVq"  
public void setNSplitter(int nCount) m=&j@  
{ (N U0Tw  
nSplitter = nCount; M$CVQ>op:  
} `"y{;PCt_  
} >BqCkyM9Kf  
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ged,>  
/* gAE!aKy  
**Utility.java kC^.4n om  
*/ 
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package NetFox; QdDtvJLf  
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public class Utility { IbdM9qo7  
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6 nGY^  
public Utility() -gKpL\  
{ h-'wV${b  
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} dm^H5D/A  
U'3Fou}  
//线程睡眠 Xm[Czd]%  
public static void sleep(int nSecond) $U'3ME
Ew  
{ R+. Nn  
try{ }V^e7d  
Thread.sleep(nSecond); WV_`1hZX  
} |>sv8/!  
catch(Exception e) 44C+h    
{ )W9_qmYd"  
e.printStackTrace (); /| GH0L  
} H%.zXQ4}n  
} |[w^eg  
^HFo3V }h  
//日志 q,,j',8kq/  
public static void log(String sMsg) (UW6F4:$  
{ ( Yi=v'd  
System.err.println(sMsg); ^]rxhpS  
} T7GQ^WnA  
;nf&c;D  
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public static void log(int sMsg) R@ QQNYU.D  
{ rdI]\UH  
System.err.println(sMsg); )<LI%dQ:'l  
} +2O=s<fp  
} MuSaK %  

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u`p_.n:5)  
/* 1jOKcm'#  
**TestMethod.java Qk7J[4  
*/ v!!;js^  
package NetFox; {"4<To]z  
J8h7e}n?  
B "n`|;r5  
public class TestMethod { rU*q@y Px  
9UmBm#"  
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public TestMethod() \L#QR  
{ ///xx/weblogic60b2_win.exe }*-u$=2  
try{ 5vGioO  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Riq|w+Q  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 4Bo<44-,  
SiteFileFetch fileFetch = new SiteFileFetch(bean); A5+
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fileFetch.start(); <rMv0y+r  
} FAd``9kRT  
catch(Exception e){e.printStackTrace ();} x)\V lR  
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} >e_%M50  
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)[ w&C_>]  
public static void main(String[] args) \Jf9npz3  
{ x,-S1[#X;  
new TestMethod(); ??+:vai2  
} X4 Y
 
} $/.<z(F  
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