http断点续传简单实现（java)

/* rQTG-& ,  
**SiteFileFetch.java Ms+SJ5Lg  
*/ 6G_{N.{(  
package NetFox; )M7~RN  
import java.io.*; W(.svJUgb.  
import java.net.*; z38Pi  
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public class SiteFileFetch extends Thread { Z 2$S'}F  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 8CvNcO;H0  
long[] nStartPos; //开始位置 m/,8\+  
long[] nEndPos; //结束位置
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 q)YHhH\  
long nFileLength; //文件长度 1gLET.I:  
boolean bFirst = true; //是否第一次取文件 p DU+(A4>  
boolean bStop = false; //停止标志 VArMFP)cz  
File tmpFile; //文件下载的临时信息 )"E1/$*k  
DataOutputStream output; //输出到文件的输出流 %GMCyT  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ;H?tcb*  
public SiteFileFetch(SiteInfoBean bean) throws IOException :8?l=B9("g  
{ /6y;fx  
siteInfoBean = bean; V[7D4r.j  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); A\.{(,;kp  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); x Y}.mP  
if(tmpFile.exists ()) gN<J0c)  
{ Scmew  
bFirst = false; /-=h|A#Kh  
read_nPos(); V.ae 5
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} HisH\z/i5)  
else Enp;-wG:-  
{ 7--E$!9O,  
nStartPos = new long[bean.getNSplitter()]; +.*=Fn22  
nEndPos = new long[bean.getNSplitter()]; "!D,9AkZS  
} =:H EF;!  
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} #aKUD  
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public void run() &uf|Le4  
{ 4-C'2?  
//获得文件长度 T?7++mcA  
//分割文件 |HwEwL+  
//实例FileSplitterFetch ]tmMk7  
//启动FileSplitterFetch线程 +zl[C  
//等待子线程返回 acj-*I  
try{ nM99AW  
if(bFirst) iD>H{1 h  
{ IPt !gSp  
nFileLength = getFileSize(); =RofC9,  
if(nFileLength == -1) Lo=n)cV1,  
{ cSmy M~[  
System.err.println("File Length is not known!"); <s'0<e!./t  
} TW1#'G_#  
else if(nFileLength == -2) _93:_L  
{ -Q%Pg<Q-#  
System.err.println("File is not access!"); +Y>oNX1KN  
} H,LJ$ py  
else #+|0
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{ fC$@m_-KD  
for(int i=0;i<nStartPos.length;i++) #jPn7  
{ A5sz[k  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9A9T'g)Du  
} Iq 0ew  
for(int i=0;i<nEndPos.length-1;i++) n`T4P$pt  
{ U+!&~C^y  
nEndPos = nStartPos[i+1]; {~XnmBs  
} SUjo%3R  
nEndPos[nEndPos.length-1] = nFileLength; v'r)d-T   
} J_9[xmM  
}
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//启动子线程 wGxH  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; gq="&  
for(int i=0;i<nStartPos.length;i++) al7D3J  
{ (D{J|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {P)O#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), SnM^T(gtS3  
nStartPos,nEndPos,i); ^@Z8_PZo  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f85~[3 J  
fileSplitterFetch.start(); )g KC}_h=  
} ?F*I2rt#  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (/X]9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @3bVjQ`4f  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", l\|sHn/  
nEndPos = " + nFileLength); nwIj?(8x  
// fileSplitterFetch[nPos.length-1].start(); {.J<^V  
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//等待子线程结束 6E.[F\u  
//int count = 0; s-~`Ao' <  
//是否结束while循环 DgB;6Wl  
boolean breakWhile = false; _CBMU'V  
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while(!bStop) Z$zX%w  
{ d]N_<@tx9  
write_nPos(); }
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Utility.sleep(500); >P//]nn  
breakWhile = true; jBl$r{L  
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for(int i=0;i<nStartPos.length;i++) 8~&=vc  
{ [8%q@6[  
if(!fileSplitterFetch.bDownOver) 7nP{a"4_  
{ eBY/Y6R  
breakWhile = false; y9
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break; }w8y
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} zL'S5'<F|  
} N>1d]DrQR  
if(breakWhile) ef/43+F^x  
break; >Psq" Xj  
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//count++; Z'Pe%}3  
//if(count>4) #rNc+  
// siteStop(); UT[{NltH  
} $xcZ{C  
{L [   
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System.err.println("文件下载结束！"); 'yV*eG?^&  
} 34nfL: y  
catch(Exception e){e.printStackTrace ();} 5fYWuc9}z  
} }w-M.  
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//获得文件长度 q03+FLEfC  
public long getFileSize() # s7e/GdKb  
{ xvomn`X1  
int nFileLength = -1; p1("  
try{ {-f%g-@L6|  
URL url = new URL(siteInfoBean.getSSiteURL()); eKZS_Qd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C[d1n#@r  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]>%2,+5  
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int responseCode=httpConnection.getResponseCode(); :{B']~Xf  
if(responseCode>=400) w0vsdM;G  
{ }X/YMgJ  
processErrorCode(responseCode); {FS)f  
return -2; //-2 represent access is error #;?/fZjY  
} [x]~G  
Ih4$MG6QC  
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String sHeader; gGx(mX._L?  
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for(int i=1;;i++) l-S0Gn/'X  
{ ~*<`PDO?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); e4tC[6;  
//Utility.log(in.readLine()); GlRjbNW?Q  
sHeader=httpConnection.getHeaderFieldKey(i); 'c
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if(sHeader!=null) +{C)^!zBK  
{ d2^/  
if(sHeader.equals("Content-Length")) K_-m:P  
{ hZ!kh3@:`  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); "?lz[K>  
break; GIn%yB'  
} {2q0Ko<  
} 8eYEi  
else =tP^vgfQ  
break;  + #E?)  
} 7J ?s&x  
} B([-GpZt[  
catch(IOException e){e.printStackTrace ();} 'J5F+,\Ka  
catch(Exception e){e.printStackTrace ();} K2e*AE*  
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Utility.log(nFileLength); c~;VvYu  
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return nFileLength; "Z;({a$v  
} @!
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//保存下载信息（文件指针位置） AXSip  
private void write_nPos() v?}
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{ f?ibyoXL  
try{ MX7Ix{  
output = new DataOutputStream(new FileOutputStream(tmpFile)); yWE\)]9  
output.writeInt(nStartPos.length); '}B"071)<  
for(int i=0;i<nStartPos.length;i++) MI
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{ kv,!"<  
// output.writeLong(nPos); %*wEzvt*  
output.writeLong(fileSplitterFetch.nStartPos); CR%h$+dzy  
output.writeLong(fileSplitterFetch.nEndPos); l^B4.1rT  
} O>a1S*mxP  
output.close(); @TX@78fWz=  
} aR('u:@jHi  
catch(IOException e){e.printStackTrace ();} U1pE2o-  
catch(Exception e){e.printStackTrace ();} 5>daWmD  
} MSeg7/MF  
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//读取保存的下载信息（文件指针位置） kR^h@@'F"  
private void read_nPos() Dm8fcD  
{ ^blw\;LB  
try{ js"5{w&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !Ko>   
int nCount = input.readInt(); F kf4R5Y?  
nStartPos = new long[nCount]; 6sQ;Z|!Pz  
nEndPos = new long[nCount]; ID!S}D  
for(int i=0;i<nStartPos.length;i++) G/~gF7  
{ b7I0R;Zj  
nStartPos = input.readLong(); %6 GM[1__  
nEndPos = input.readLong(); 3&AJN#c  
} yt="kZ  
input.close(); LP|YW*i=IQ  
} SJMbYjn0J  
catch(IOException e){e.printStackTrace ();} w5~j|c=_W  
catch(Exception e){e.printStackTrace ();} nXoDI1<[  
} q>>1?hzA  
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private void processErrorCode(int nErrorCode) eI2HTFyT  
{
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System.err.println("Error Code : " + nErrorCode); aGi`(|shW  
} {"{]S12N  
\R]2YY`EP  
L3xN#W;m7  
//停止文件下载 *.k*JsU~B  
public void siteStop() 2y;vX|lX]  
{ ~&qvS  
bStop = true; su1fsoL0  
for(int i=0;i<nStartPos.length;i++) Dv/7w[F  
fileSplitterFetch.splitterStop(); h4|}BGO  
<,n:w[+!`P  
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} nQ+5jGP1  
} FjtS  
//负责部分文件的抓取 k_wcol,W  
**FileSplitterFetch.java x< 2]UB`  
*/ R<6y7?]bZ  
package NetFox; Qg(;>ops  
}8aqSD<:  
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import java.io.*; :?g+\:`/0j  
import java.net.*; ,@?9H ~\  
rXD:^wUSc  
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public class FileSplitterFetch extends Thread { 9wldd*r  
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String sURL; //File URL 8zj&e8&v  
long nStartPos; //File Snippet Start Position 5 D^#6h 4  
long nEndPos; //File Snippet End Position l/zv >  
int nThreadID; //Thread's ID MkJBKS  
boolean bDownOver = false; //Downing is over qAH^BrJ  
boolean bStop = false; //Stop identical $6wSqH?q  
FileAccessI fileAccessI = null; //File Access interface ,pGA|ob  
4}/gV)  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException EwFq1~  
{ `P !idg*  
this.sURL = sURL; pInEB6L.P  
this.nStartPos = nStart; Q. O4R
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this.nEndPos = nEnd; (Q% @]  
nThreadID = id; *P`wuXn}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :"!Z9l\@  
} *#Ia8^z=p  
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1@t.J>  
public void run() ki@C}T5  
{ H8? Y{H  
while(nStartPos < nEndPos && !bStop) xp95KxHHo  
{ S!=R\_{u$  
5= &2=
 
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try{ _!DH/?aU  
URL url = new URL(sURL); r/ g{j  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jF}kV%E  
httpConnection.setRequestProperty("User-Agent","NetFox"); g%S/)R,,ct  
String sProperty = "bytes="+nStartPos+"-"; 7:uz{xPK6  
httpConnection.setRequestProperty("RANGE",sProperty); a4~B  
Utility.log(sProperty); 1Xm>nF~  
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InputStream input = httpConnection.getInputStream(); DAWF =p]  
//logResponseHead(httpConnection); q 9xA.*  
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byte[] b = new byte[1024]; "ckK{kS4~  
int nRead; wW\@^5  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) P* 0kz@  
{ L f"!:]  
nStartPos += fileAccessI.write(b,0,nRead); [y'blCb  
//if(nThreadID == 1) N'EZJoH  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U-1UWq  
} !fn%Q'S  
H<i!C|AF  
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Utility.log("Thread " + nThreadID + " is over!"); 8o%Vn'^t  
bDownOver = true; {X(nn.GpC  
//nPos = fileAccessI.write (b,0,nRead); Z@Q*An  
} :g63*d+/G  
catch(Exception e){e.printStackTrace ();} oydP}X  
} *aCVkFp  
} IP#vfM  
~210O5^  
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//打印回应的头信息 ,(x`zpp _  
public void logResponseHead(HttpURLConnection con) )Wq1af   
{ d>)=|  
for(int i=1;;i++) HLPRTta.  
{ U3:|!CC)T  
String header=con.getHeaderFieldKey(i); i:jXh9+  
if(header!=null) B;=Z^$%T  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0$Rn|yqf%  
Utility.log(header+" : "+con.getHeaderField(header)); >KrI}>!9r  
else 7MrHu2rZ=  
break; LZ_VLW9wE  
} Qv~@  
} 4lX_2QT]E  
%4!^AA%  
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public void splitterStop() >@ 8'C"F  
{ X+A@//,7  
bStop = true; (jU_lsG  
} 8/)\nV$0
Y  
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} tP! %(+V  
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/* !zOj`lx  
**FileAccess.java nrev!h  
*//文件访问(定位，写) #b428-  
package NetFox; y$-@|M$GG  
import java.io.*; Psx"[2iZm  
(,o@/ -o  
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public class FileAccessI implements Serializable{ &)Qq%\EP4  
r?[[.zm"7  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节
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RandomAccessFile oSavedFile; =6ru%.8U,  
long nPos; 'q:7PkN!p  
n!Y_SPg   
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public FileAccessI() throws IOException /Lr`Aka5  
{ &D{!zF  
this("",0); e6_8f*o|s  
} w`8H=Hf  
B`R@%US  
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public FileAccessI(String sName,long nPos) throws IOException (OES~G  
{ Ot47.z  
oSavedFile = new RandomAccessFile(sName,"rw"); 7P(o!%H  
this.nPos = nPos; b1#C,UWK  
oSavedFile.seek(nPos); oZ/"^5  
} V]J"v#!{  
j$_?g!I=gK  
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public synchronized int write(byte[] b,int nStart,int nLen) bs\kb-\R  
{ $#n9C79Z@  
int n = -1; iP9]b&  
try{ tik*[1it  
oSavedFile.write(b,nStart,nLen);  N{g7  
n = nLen; &uE )Vr4R  
} FEu}zt@  
catch(IOException e) ,_(=w.F   
{ ;0kAm Vy  
e.printStackTrace (); U1/I(w  
} wxK71OH  
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return n; ] +%`WCr9  
} ,2Ed^!`  
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v `/nX->  
} :kI[Pf!z  
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/* GjW(&p$&  
**SiteInfoBean.java g&p(XuN  
*/ x1wD`r  
package NetFox; 8d'/w}GV  
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public class SiteInfoBean { sV5k@1Y  
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private String sSiteURL; //Site's URL q'H6oD`  
private String sFilePath; //Saved File's Path l<=k#d  
private String sFileName; //Saved File's Name I&15[:b=-  
private int nSplitter; //Count of Splited Downloading File wsrdBxd5  
GBg  
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public SiteInfoBean()  7Tr '<(A  
{//nSplitter的缺省值为5 t4;gY298  
//default value of nSplitter is 5 P;y!Y/$C  
this("","","",5); o\W>$$EXD  
} 7?k3jDK  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ~IO'"h'w  
{ dQH8s  
sSiteURL= sURL; M^l%*QF[,q  
sFilePath = sPath; b?Q$UMAbH  
sFileName = sName; ?en-_'}~a  
this.nSplitter = nSpiltter; L28wT)D-  
{Gfsiz6  
K-*ZS8  
} z/5TYv
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kW
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public String getSSiteURL() It3@ Cd>  
{ HWou&<EK  
return sSiteURL; uW}M1kq?+l  
} }|=Fnyj  
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public void setSSiteURL(String value) [UdJ(cGf  
{ o4rf[.z  
sSiteURL = value; YyYp-0#  
} 4yMi9Ri4H  
Mp5Z=2l5  
ZZxt90YR'5  
public String getSFilePath() ,HE{&p2y  
{
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return sFilePath; Y.52`s6F  
} M>BVnB_,-  
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public void setSFilePath(String value) 2B6y1"B  
{ 0'5N[Bvp  
sFilePath = value; vvG*DGL)qL  
} [W'2z,S`WD  
'vZWkeo  
Zwtz )ZII  
public String getSFileName() ZS&+<kGD  
{ ^|h.B$_F,  
return sFileName; &xC5Mecb*  
} +9;6]4  
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public void setSFileName(String value) 8js1m55KT  
{ H7{kl  
sFileName = value; _4lKd`  
} cGg~+R2P  
gHH[QLD=I  

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public int getNSplitter() Wjd_|Kui  
{ N
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return nSplitter;
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} B1U7z1<  
8(:O5#  
|)ALJJ=+  
public void setNSplitter(int nCount) )*BG-nM u  
{ T' )l  
nSplitter = nCount; YipL_&-  
} Q"GZh.m  
} FCt %of#  
V9D>Xh!0H  
 
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/* o7fJ@3B/  
**Utility.java (;nh?"5  
*/ 0{47TX*YX  
package NetFox; _GL:4  
E^Z?X2Z  
#<R6!"TNoz  
public class Utility { ]RI+:f  
E*UE?4FSw|  
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public Utility() IKeO&]k  
{ CjUYwAy$k  
7Nlk:f)*-  
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} e3]v *<bj  
4~z-&>%  
//线程睡眠 LHd9q^D  
public static void sleep(int nSecond) z--Y  
{ I@:"Qee  
try{ :r}C&3  
Thread.sleep(nSecond); ..UA*#%1  
} Z90]I<a~  
catch(Exception e) ?
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{ o8u;2gZx  
e.printStackTrace (); A/88WC$v  
} 7,5Bur  
} my%MXTm2  
nG0R1<  
//日志 1EA#c>I$  
public static void log(String sMsg) 
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{ {_~vf  
System.err.println(sMsg); cr~.],$Om  
} nfksi``Vq  
$) m$c5!  
1x^Vv;K  
public static void log(int sMsg) h}4yz96WD  
{ B0D  
System.err.println(sMsg); kbZp
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} hRZYvZ3  
} moL3GV%]Gq  
;2[),k  
>35W{d  
/* UHR%0ae  
**TestMethod.java @W-0ybv  
*/ {%c&T S@s  
package NetFox; O~mQ\GlW  
*auT_*  
\&[(PNl  
public class TestMethod { C=qL0  
gF
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ojc.ykP$  
public TestMethod() 6B+?X5-6DH  
{ ///xx/weblogic60b2_win.exe R]3j6
\  
try{ J vq)%t8q>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 2"_5Yyb  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); v[V7$.%5Q  
SiteFileFetch fileFetch = new SiteFileFetch(bean); pfHfw,[  
fileFetch.start(); vIf-TQw  
} l+j !CvtI  
catch(Exception e){e.printStackTrace ();} nDyA][  
3^5h:OaT  
u~PZK.Uf0  
} oU se~  
kPoz&e_@  
|AS~sjWSJ  
public static void main(String[] args) dh9@3. t  
{ -fp/3-  
new TestMethod(); -ijzo%&qA  
} d"L(eI}G  
} m_.9PZ  
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