http断点续传简单实现（java)

/* v6 U!(x  
**SiteFileFetch.java peVY2\1>R  
*/ \6wltTW]#  
package NetFox; @rYZ0`E9  
import java.io.*; 1Vy8eI`4  
import java.net.*; LO_Xrj  
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public class SiteFileFetch extends Thread { M7/5e3  
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SiteInfoBean siteInfoBean = null; //文件信息Bean p%$r\G-x  
long[] nStartPos; //开始位置 %@PcQJg U<  
long[] nEndPos; //结束位置 N/o?\q8  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 dHY@V>D'-  
long nFileLength; //文件长度 PA^*|^;Xh  
boolean bFirst = true; //是否第一次取文件 > SZ95@Oh  
boolean bStop = false; //停止标志 ;5/Se"Nd  
File tmpFile; //文件下载的临时信息 mfj{_fR3  
DataOutputStream output; //输出到文件的输出流 SD^::bH  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） z\|<h=EU  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]V/5<O1  
{ q]="ek&_  
siteInfoBean = bean; E:9RskI  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); &}u_e`A  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >&.N_,*  
if(tmpFile.exists ()) w~+*Vd~U  
{ D+!T5)>(  
bFirst = false; &MX&5@ Vu  
read_nPos(); l-XfUjJ  
} Qr R+3kxM  
else <sC(a7i1  
{ fQ9af)d  
nStartPos = new long[bean.getNSplitter()]; )zWu\JRp  
nEndPos = new long[bean.getNSplitter()]; (Mfqz
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} \Q#pu;Y*N]  
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} {Vu
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public void run() <2(X?,N5BD  
{ (hwzA *(c  
//获得文件长度 @>z.chM;  
//分割文件 <IZr..|O  
//实例FileSplitterFetch t 9(,JC0  
//启动FileSplitterFetch线程 q,sO<1wAT\  
//等待子线程返回 D!* SA  
try{ 3mo<O}}  
if(bFirst) gkK(7=r%  
{ EZWWvL  
nFileLength = getFileSize(); PlCw,=K8f  
if(nFileLength == -1) 2_Lu0Yrg  
{ Idu'+O4  
System.err.println("File Length is not known!"); eV_",W  
} MTwzL<@$  
else if(nFileLength == -2) b|87=1^m[  
{ 9+(b7L   
System.err.println("File is not access!"); HHx5VI  
} ]fY:+Ru  
else :LuA6  
{ "A[.7w  
for(int i=0;i<nStartPos.length;i++) {v!w2p@  
{ c:=HN-*vQ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); =?CIC%6m  
} .P8m%$'N  
for(int i=0;i<nEndPos.length-1;i++) Y3|_&\v6  
{ Oh}5
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nEndPos = nStartPos[i+1]; }G(#jOYk  
} 5#z7Hj&w  
nEndPos[nEndPos.length-1] = nFileLength; c CjN8<  
} =8vwaJ  
} #pW
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//启动子线程 :tENn r.9v  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ([m4dr  
for(int i=0;i<nStartPos.length;i++) <OiH%:G/1  
{ #+i5'p(4  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), MNh:NFCRA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {%2p(5FB  
nStartPos,nEndPos,i); 5bZ0}^FYF  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); JiqhCt\  
fileSplitterFetch.start(); D{7sfkcJ  
} N/C$8D34  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #x;d+Q@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &gh>'z;`r  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ht\_YiDg3  
nEndPos = " + nFileLength); =m|<~t  
// fileSplitterFetch[nPos.length-1].start(); 7LaRFL.,kO  
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//等待子线程结束 Y;\@ 5TgQ,  
//int count = 0; a{e1g93}  
//是否结束while循环 {
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boolean breakWhile = false; p>U= Jg  
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while(!bStop) Us[F@  
{ _or_Vw!  
write_nPos(); asW W@E  
Utility.sleep(500); {#t7lV'4  
breakWhile = true; t.!?"kP"c  
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for(int i=0;i<nStartPos.length;i++) s_Z5M2o  
{ 1q ZnyJ  
if(!fileSplitterFetch.bDownOver) 6d5q<C_3t  
{ $5#DU__F/  
breakWhile = false; OZKZv,  
break; 4Qi-zNNB  
} ,\T`gh  
} >of9m  
if(breakWhile) CTqhXk[  
break; &i805,lx  
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//count++; D=f$-rn  
//if(count>4) B<|Vm.D  
// siteStop(); 5IgO4<B  
} 6!6R3Za$  
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System.err.println("文件下载结束！"); HKC&grp  
} Wa!C2n
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catch(Exception e){e.printStackTrace ();} juWbd|ad"  
} ?>R(;B|ER  
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}_}LaEYAo  
//获得文件长度 c?Zi/7  
public long getFileSize() >2'A~?%  
{ A/Sj>Y1j  
int nFileLength = -1; N7q6pBA"E  
try{ B90fUK2g  
URL url = new URL(siteInfoBean.getSSiteURL()); {\h:k\k  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ubKp P%Z  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'v(b^x<ZS  
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int responseCode=httpConnection.getResponseCode(); =FAIbM>u  
if(responseCode>=400) +wEsfYW  
{ Tj2
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processErrorCode(responseCode); ^%1u3  
return -2; //-2 represent access is error ]P_yN:~  
} zq$0 ?vGd  
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String sHeader; I,/E.cRV<  
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for(int i=1;;i++) uesIkJ^Q[  
{ j3R}]F'C*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +}g6X6m  
//Utility.log(in.readLine()); z wn#
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sHeader=httpConnection.getHeaderFieldKey(i); Lu71Qdu09  
if(sHeader!=null) *y~~~ 'J/  
{ e\ZV^h}TQ  
if(sHeader.equals("Content-Length")) gP!k[E,Q8  
{ Gfepm$*%  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); "`KT7  
break; VTO92Eo  
} nwi8>MG  
} \h}sA  
else ?%T]V+40  
break; E]pDp /D  
} j^/^PUR  
} z>*\nomOn=  
catch(IOException e){e.printStackTrace ();} TQpR'  
catch(Exception e){e.printStackTrace ();} EQy~ ^7V B  
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Utility.log(nFileLength); E,/nK  
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return nFileLength; #Fh:
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} =s:Z-*vy!  
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//保存下载信息（文件指针位置） d263#R  
private void write_nPos() )SaMfP1=v  
{ =|V#~p*  
try{ Om8Sgy?  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 3[R[`l]v?  
output.writeInt(nStartPos.length); \mFgjPz  
for(int i=0;i<nStartPos.length;i++) H96|{q=  
{ Jb|dpu/e  
// output.writeLong(nPos); k7nke^,|  
output.writeLong(fileSplitterFetch.nStartPos); dFk$rr>q  
output.writeLong(fileSplitterFetch.nEndPos); $L72%T  
} h\|T(597.  
output.close(); |4Os_*tRKU  
} d-I&--"ju  
catch(IOException e){e.printStackTrace ();} lgefTT GX)  
catch(Exception e){e.printStackTrace ();} <,t6A?YoMP  
} Go7 oj'"  
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//读取保存的下载信息（文件指针位置） As|e=ut(  
private void read_nPos() i@ehD@.dH  
{ ^5R2~  
try{ Y";KWA}b  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !!)NER-dv  
int nCount = input.readInt(); r:t3Kf`+E-  
nStartPos = new long[nCount]; > q8)~  
nEndPos = new long[nCount]; riSgb=7q9  
for(int i=0;i<nStartPos.length;i++) M ~6$kT  
{ lG`%4}1  
nStartPos = input.readLong(); .6pVt_f0/  
nEndPos = input.readLong(); V+$fh2t  
} ._6Q "JAB  
input.close(); nCLEAe$W\=  
} =AX"'q  
catch(IOException e){e.printStackTrace ();} 2zkOs:  
catch(Exception e){e.printStackTrace ();} \| 'Yuh  
} D0X!j,Kc  
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private void processErrorCode(int nErrorCode) ($,qxPOn  
{ N@I=X-7nh|  
System.err.println("Error Code : " + nErrorCode); TV?MB(mN  
} ey`E E/WV  
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//停止文件下载 +-Z `v  
public void siteStop() p<\7" SB=  
{ ,HK-mAH   
bStop = true; ]}
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for(int i=0;i<nStartPos.length;i++) ^K:-r !v^  
fileSplitterFetch.splitterStop(); ,-SWrp
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} 6P02=  
} PeJIa %iE  
//负责部分文件的抓取 !WTL:dk  
**FileSplitterFetch.java && b;Wr  
*/ xks Me  
package NetFox; 2k^'}7G%  
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import java.io.*; 5I/lFoy7  
import java.net.*; fN6n2*wr(  
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public class FileSplitterFetch extends Thread { 1/J6<FVq  
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String sURL; //File URL "-Wb[*U;  
long nStartPos; //File Snippet Start Position f7&9IW`7F^  
long nEndPos; //File Snippet End Position =OFx4#6a  
int nThreadID; //Thread's ID <sls1,  
boolean bDownOver = false; //Downing is over 0CK3jdZ+X  
boolean bStop = false; //Stop identical k\-h-0[|  
FileAccessI fileAccessI = null; //File Access interface Hm
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException plM:7#eA  
{ ,OFNV|S$  
this.sURL = sURL; yV*4|EkvW  
this.nStartPos = nStart; m"wP]OQH*+  
this.nEndPos = nEnd; ^p3W}D  
nThreadID = id; ]#vi/6\J  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 sEi9<$~R@0  
} ZKai*q4?  
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public void run() U+&Eps&NI  
{ "NTiQ}i  
while(nStartPos < nEndPos && !bStop) XJ7pX1nf  
{ "6Z(0 iu:{  
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try{ M[(
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URL url = new URL(sURL); S1U[{R?,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w[AL'1s]  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]88qjKL  
String sProperty = "bytes="+nStartPos+"-"; $dG:29w  
httpConnection.setRequestProperty("RANGE",sProperty); U_WO<uhC  
Utility.log(sProperty); IRTD(7"oyp  
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InputStream input = httpConnection.getInputStream(); DKF '*  
//logResponseHead(httpConnection); Rx?ze(  
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byte[] b = new byte[1024]; R[@}Lg7+v  
int nRead; X!m lC51  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ],Yy)<e.  
{ /@I`V?Q!a  
nStartPos += fileAccessI.write(b,0,nRead); 6"R'z#{OF  
//if(nThreadID == 1) >T-4!ZvS\j  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =nqHVRA  
} dg_w$#  
'c# }^@G  
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Utility.log("Thread " + nThreadID + " is over!"); uF<?y0t  
bDownOver = true; ~0@fK<C)O  
//nPos = fileAccessI.write (b,0,nRead); AWJA?  
} QQv%>=_`  
catch(Exception e){e.printStackTrace ();} <T&v\DN  
} '.&Y)A6!  
} D}Sww5ZmP  
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//打印回应的头信息 l>KkAA
 
public void logResponseHead(HttpURLConnection con) '.k'*=cq0  
{ ^b.#4i(v  
for(int i=1;;i++) 6[SIDOp*^  
{ <>728;/C  
String header=con.getHeaderFieldKey(i); 6&il>  
if(header!=null) @_1cY#!  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); c94=>p6  
Utility.log(header+" : "+con.getHeaderField(header)); p}<60O"r$  
else ?'_6M4UKa  
break; gtePo[ZH.P  
} B9Hib1<8  
} X0REC%  
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{`,)<R>}  
public void splitterStop() dqs~K7O^E  
{ V:vqt@  
bStop = true; !F.h+&^D
;  
} PcqS#!t  
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} p4 =/rkq  
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/* ,~DV0#"  
**FileAccess.java e[s}tjx  
*//文件访问(定位，写) P-3f51Q  
package NetFox; =1@LMIi5x  
import java.io.*; EC 1|$Co  
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public class FileAccessI implements Serializable{ =4l @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 v?Utz~lQ  
RandomAccessFile oSavedFile; gu+zfvkcY  
long nPos;
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public FileAccessI() throws IOException kwL|gO1L  
{ -%@ah:iJ  
this("",0); 5doi4b>]!  
} {ywwJ  
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public FileAccessI(String sName,long nPos) throws IOException 
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{ X-(4/T+v  
oSavedFile = new RandomAccessFile(sName,"rw"); JO+tY[q  
this.nPos = nPos; &T~X`{V]`  
oSavedFile.seek(nPos); -Ep#q&\  
} %,~?;JAj  
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public synchronized int write(byte[] b,int nStart,int nLen)  ]%FAJ\  
{ a4*976~![  
int n = -1; p6
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try{ zX4RqI  
oSavedFile.write(b,nStart,nLen); N+@ Ff3M  
n = nLen; 6-fv<Pn  
} R$8{f:Pj  
catch(IOException e) (+[%^96 
 
{ xcU!bDV  
e.printStackTrace (); 7J!s"|VS  
} W(R~K -  
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| @$I<  
return n; q]I aRho  
} Dzf\m>H[  
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} e-`.Ht  
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/* o3/o2[s  
**SiteInfoBean.java #-<Go
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*/ BEvY&3%l  
package NetFox; bo/9k 4N3  
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@,TIw[p  
public class SiteInfoBean { [Hx(a.,d  
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private String sSiteURL; //Site's URL VMRfDaO9  
private String sFilePath; //Saved File's Path !>n!Q*\(Ov  
private String sFileName; //Saved File's Name T+ZA"i+   
private int nSplitter; //Count of Splited Downloading File $3G^}A"  
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public SiteInfoBean() ld@+p  
{//nSplitter的缺省值为5 e
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//default value of nSplitter is 5 |HD>m'e  
this("","","",5); 8O9^g4?  
} +w^,!gA&  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) in<.0v9w  
{ 
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sSiteURL= sURL; t{jY@JT|  
sFilePath = sPath; b>OB}Is  
sFileName = sName; w\o6G7  
this.nSplitter = nSpiltter; W~;Jsd=f  
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} V;xPZ2C;  
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public String getSSiteURL() 6r<a
  
{ Lz.khE<  
return sSiteURL; R+Hu?Dv&F  
} |p&EP2?T  
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public void setSSiteURL(String value) &/]en|f"  
{ :^3)[.m  
sSiteURL = value; {x_.QWe5  
} 0N$7(.  
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public String getSFilePath() _w4G|j$C  
{ @/.# /  
return sFilePath; ["EXSptB  
} 7sxX?u  
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public void setSFilePath(String value) n9+33^ PT  
{ s Z[[ymu8  
sFilePath = value; 0vm>*M*p
 
} W/!P1M n  
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public String getSFileName() d^aVP  
{ P[ :_"4U  
return sFileName; OB(oOPH  
} x950,`zy  
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public void setSFileName(String value) VO|ECB2e  
{ w+R/>a(]  
sFileName = value; 2F:qaz  
} u;_h%z5K  
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public int getNSplitter() e Wux  
{ ^~YT<cJ1h  
return nSplitter; wsWFD xR  
} {=ox1+d  
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public void setNSplitter(int nCount) ;t{q]"? W  
{ o6[.$C  
nSplitter = nCount; )@N d3Z  
} '[{<aEo  
} UucI>E3?P{  
X/~uF9a'<  
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/* Jbu2y'zE  
**Utility.java }mj9$=B4  
*/ '>"{yi-  
package NetFox; /sA&}kX}E  
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public class Utility { 2FIL@f|\7z  
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public Utility() Q1,sjLO-a  
{ 7Z< ~{eD,  
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}  ? }M81  
j]BRfA  
//线程睡眠 8>v_th  
public static void sleep(int nSecond) @sXv5kZ
:  
{ Al-`}g+^  
try{ :>1nkm&Eg  
Thread.sleep(nSecond); ==dKC;  
} vgwpuRL5b  
catch(Exception e) n3a.)tcC  
{ _%nz-I  
e.printStackTrace (); ^e.-Ji  
} pE5v~~9Ikv  
} UT<e/  
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//日志 [8iY0m_Qe  
public static void log(String sMsg) #CC5+  
{ jc5[r;#  
System.err.println(sMsg); "?8)}
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} |?!i},Ki;  
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public static void log(int sMsg) ue_wuZi  
{ I^
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System.err.println(sMsg); UY',n,  
} Hb)FeGsd).  
} w' 7sh5  
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/* /WuYg OI  
**TestMethod.java C~ 1]  
*/ 1R2IlUlzFr  
package NetFox; EgjJywNhd2  
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public class TestMethod { n>Ff tVZNJ  
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public TestMethod() jeC=s~  
{ ///xx/weblogic60b2_win.exe c[h~=0UtJ  
try{ 6mM9p)"$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); * ,hhX psa  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); NAR6q{c  
SiteFileFetch fileFetch = new SiteFileFetch(bean); :viW  
fileFetch.start(); (>al-vZ6A  
} lzEynMO+  
catch(Exception e){e.printStackTrace ();} qe0D[L  
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} u^Q`xd1  
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public static void main(String[] args) 51|ky-
  
{ ~>u.d  
new TestMethod(); cQU/z"?+  
} EeuYRyK  
} EQ1**[$  
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