http断点续传简单实现（java)

/* *d%U]Hby,  
**SiteFileFetch.java IJnh@?BC  
*/ 0/Q"~H?%  
package NetFox; X!'nfN  
import java.io.*; Adyv>T9  
import java.net.*; "~-Y'O  
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public class SiteFileFetch extends Thread { W{JNNf6G  
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SiteInfoBean siteInfoBean = null; //文件信息Bean OvFWX%uY  
long[] nStartPos; //开始位置 hp:8e@  
long[] nEndPos; //结束位置 h~F`[G/'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "@h 5 SF  
long nFileLength; //文件长度 |N^z=g P[  
boolean bFirst = true; //是否第一次取文件  ~wX4j  
boolean bStop = false; //停止标志 v<2B^(i}VB  
File tmpFile; //文件下载的临时信息 fBZ\,  
DataOutputStream output; //输出到文件的输出流 $hCPmiI  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） !uno!wUIYd  
public SiteFileFetch(SiteInfoBean bean) throws IOException `;'fCO!  
{ [
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siteInfoBean = bean; HJV8P2f8`  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); QqS?
-   
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); "-tTN  
if(tmpFile.exists ()) P@RUopu,i  
{ lMcSe8LBQa  
bFirst = false; vW\|% @hW,  
read_nPos(); [u=DAk?8  
} K9
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else TAXl73j_CY  
{ ~582'-=+  
nStartPos = new long[bean.getNSplitter()]; KP
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nEndPos = new long[bean.getNSplitter()]; p]7Gj&a  
} ;4g_~fB  
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} C}~/(;1V=  
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public void run() fK$N|r  
{ _:tclBc8R  
//获得文件长度 c=-2c&=&  
//分割文件 q|8p4X}/]  
//实例FileSplitterFetch "eH~/6A  
//启动FileSplitterFetch线程 c/c%-=  
//等待子线程返回 te+5@k#t  
try{ gUrb&#\X  
if(bFirst) TF@HwF"#  
{ wq( m%F  
nFileLength = getFileSize(); /@*J\0h(-  
if(nFileLength == -1) O>![IH(L  
{ 0M?nXHA[  
System.err.println("File Length is not known!"); vG
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} rLzYkZ  
else if(nFileLength == -2) >QusXD"L>  
{ x_&m$Fh  
System.err.println("File is not access!"); -}ebn*7i\  
} LqHeLN  
else <?TJ-  
{ cZ" Ut  
for(int i=0;i<nStartPos.length;i++) 's]+.3">L1  
{ B) 81mcy  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); I:~L!%  
} z"eh.&T  
for(int i=0;i<nEndPos.length-1;i++) ?gSk%]S/!  
{ ;,z^!bD  
nEndPos = nStartPos[i+1]; x+O}RD*G  
} @'EP$!c  
nEndPos[nEndPos.length-1] = nFileLength; UeRx ^  
} Xcq9*!%o  
} kUJ\AK  
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}G8RJxy  
//启动子线程 GXEOgf#i  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; /WDz;,X  
for(int i=0;i<nStartPos.length;i++) Lp \%-s#5s  
{ k?.HW?=zy  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), lA4Bq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), NLJD}{8Ot  
nStartPos,nEndPos,i); n7vLw7  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); l|-TGjsX  
fileSplitterFetch.start(); (u]ajT  
} zX
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), p6V`b'*>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); f77uqv(Y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Q#@gOn=W\  
nEndPos = " + nFileLength); O=1uF  
// fileSplitterFetch[nPos.length-1].start(); c;w~-7Q*|  
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//等待子线程结束 hfY Ieb#91  
//int count = 0; #lyvb.;  
//是否结束while循环 s0Ii;7fA{  
boolean breakWhile = false; %J`;  
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while(!bStop) KJa?TwnC  
{ ?ng?>!  
write_nPos(); 7"f$;CN?~  
Utility.sleep(500); `07u}]d8  
breakWhile = true; VI%879Z\e  
/Q"nQSG  
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for(int i=0;i<nStartPos.length;i++) o'Q)V  
{ ^zGgvFf>  
if(!fileSplitterFetch.bDownOver) "7!K'i  
{ |}*k|  
breakWhile = false; %E7+W{?*1  
break; :^SpKe(7  
} ->}K-n ),  
} qEE3x>&T]  
if(breakWhile) Z*kGWL  
break; v@k62@;
 
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//count++; qy@gW@IU  
//if(count>4) [E(DGt  
// siteStop(); -p>KFHj6  
} ewgcpV|spn  
)J_!ZpMC  
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System.err.println("文件下载结束！"); K0]'v>AWr  
} w\;=3C`  
catch(Exception e){e.printStackTrace ();} ?ZSG4La\  
} &a8#qv"l  
I TJ>[c]x  
`sN3iD!@R  
//获得文件长度 w2~(/RgO  
public long getFileSize() o lNL|WJ`w  
{ `hS<F" j  
int nFileLength = -1; 8N(bLGUG  
try{ bF'~&<c  
URL url = new URL(siteInfoBean.getSSiteURL()); 76)(G/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); j:|60hDz^  
httpConnection.setRequestProperty("User-Agent","NetFox"); mf@YmKbp  
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int responseCode=httpConnection.getResponseCode(); R*TCoEKO  
if(responseCode>=400) 8N6a=[fv<  
{ ^lu)'z%6  
processErrorCode(responseCode); AnPm5i.  
return -2; //-2 represent access is error Xr M[8a  
} KLqu[{y.'  
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String sHeader; D +)6#i Y  
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for(int i=1;;i++) *@G4i  
{ 5G){7]P+r"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); *^c4q|G.-  
//Utility.log(in.readLine()); v!@/  
sHeader=httpConnection.getHeaderFieldKey(i); /^uvY  
if(sHeader!=null) Njq#@*>[p  
{ 2O9dU 5b  
if(sHeader.equals("Content-Length")) ACl:~7;  
{ \\hZlCV,  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); M)EKS  
break; -5vc0"?E  
} z}C#+VhQ`  
} N,'JQch},8  
else (L|SE4  
break; 8+gx?pb  
} y%TR2CvT  
} 9qXHdpb#g"  
catch(IOException e){e.printStackTrace ();} M=o,Sav5*  
catch(Exception e){e.printStackTrace ();} I6y&6g  
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Utility.log(nFileLength); wc bs-arH  
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return nFileLength; r.i.w0B(  
} lu(G3T8  
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//保存下载信息（文件指针位置） //ZB B,[@  
private void write_nPos() f[.hN  
{ ?]9uHrdsN}  
try{ .
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output = new DataOutputStream(new FileOutputStream(tmpFile)); Q=PaTh   
output.writeInt(nStartPos.length); U"m!f*a  
for(int i=0;i<nStartPos.length;i++) N%r}0  
{ c_ygwO3.Q  
// output.writeLong(nPos); aGpRdF1;!  
output.writeLong(fileSplitterFetch.nStartPos); zo} SS[  
output.writeLong(fileSplitterFetch.nEndPos); Vg \-^$  
} a _  
output.close(); ~iwEhF  
} AF3t#)q  
catch(IOException e){e.printStackTrace ();} M8cLh!!  
catch(Exception e){e.printStackTrace ();} _"0n.JQg  
} 'hya#rC&(  
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//读取保存的下载信息（文件指针位置） lmmyDg1R  
private void read_nPos() [7I|8
  
{ )&dhE^ O  
try{ cWRB=`=qz  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !+hX$_RT  
int nCount = input.readInt(); )&R;!#;5  
nStartPos = new long[nCount]; ['R=@.  
nEndPos = new long[nCount]; hLm9"N'Pf  
for(int i=0;i<nStartPos.length;i++) M0]l!x#7  
{ 6J|f^W-fs  
nStartPos = input.readLong(); mu{%%b7|^  
nEndPos = input.readLong(); =JVRm 2#*  
} IB!Wrnj?  
input.close(); o~4n8  
} e#nTp b  
catch(IOException e){e.printStackTrace ();} p\-.DRwT`  
catch(Exception e){e.printStackTrace ();} iL,3g[g  
} :X4\4B*~  
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private void processErrorCode(int nErrorCode) $s]@%6f  
{ iMA)(ZS  
System.err.println("Error Code : " + nErrorCode); %BG5[XQ7  
} _-!
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//停止文件下载 w`7l;7[  
public void siteStop() ,o}[q92@w  
{ @
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bStop = true; zcZw}  
for(int i=0;i<nStartPos.length;i++) WX=+\`NyJ(  
fileSplitterFetch.splitterStop(); P)\f\yb  
3\WES!  
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} "LxJPt\  
} @2$8o]et  
//负责部分文件的抓取 }`M6+.z3F  
**FileSplitterFetch.java @<6-uk3S  
*/ X_YD[  
package NetFox; V3+%KkN  
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import java.io.*; * ;M?R?+  
import java.net.*; )xK!i.  
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public class FileSplitterFetch extends Thread { mPD'"  
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String sURL; //File URL Ucy9fM  
long nStartPos; //File Snippet Start Position ;C{_T:LS  
long nEndPos; //File Snippet End Position }GC{~ SZ4  
int nThreadID; //Thread's ID aLq;a  
boolean bDownOver = false; //Downing is over 0=5i\*5 p  
boolean bStop = false; //Stop identical B~ez>/H^  
FileAccessI fileAccessI = null; //File Access interface gU%GM  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException v6n(<0:  
{ T*ic?!  
this.sURL = sURL; c"$_V[m  
this.nStartPos = nStart; A+l"  
this.nEndPos = nEnd; s-ou;S3s  
nThreadID = id; A^Zs?<C-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 POG5x  
} +OH."4Z  
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public void run() [5 V  
{ -s1VlS/  
while(nStartPos < nEndPos && !bStop) d{m
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{ Fi`:G}   
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try{ hf-S6PEsM  
URL url = new URL(sURL); 3OZ}&[3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2uHp%fv;  
httpConnection.setRequestProperty("User-Agent","NetFox"); fI|1@e1  
String sProperty = "bytes="+nStartPos+"-"; ?7+2i\L  
httpConnection.setRequestProperty("RANGE",sProperty); p[eRK .$!  
Utility.log(sProperty); "<(~  
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InputStream input = httpConnection.getInputStream(); Cnr48ukq  
//logResponseHead(httpConnection); TGLXvP& \  
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byte[] b = new byte[1024]; D5p22WY  
int nRead; FN R& :  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) gkdjH8
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{ 3YRzBf:h  
nStartPos += fileAccessI.write(b,0,nRead); r__M1 !3  
//if(nThreadID == 1) %Fv)$ :b  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); IW#(ICeb  
} #n"/9%35f`  
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Utility.log("Thread " + nThreadID + " is over!"); S!]}}fKEFm  
bDownOver = true; (`p(c;"*C!  
//nPos = fileAccessI.write (b,0,nRead); /$=^0v+  
} upr
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catch(Exception e){e.printStackTrace ();} Ame%:K!t  
} `jHGNi  
} fjFy$NX&>  
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//打印回应的头信息 ]*|K8&jxl  
public void logResponseHead(HttpURLConnection con) uz#9w\="  
{ cPbz7  
for(int i=1;;i++) ZS+2.)A  
{ q|l|gY1g)  
String header=con.getHeaderFieldKey(i); ^bG!k]U!2  
if(header!=null) 9PAp*`J@kr  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); UPYM~c+}  
Utility.log(header+" : "+con.getHeaderField(header)); bqO"k t  
else 1#(1Bs6X  
break; -ZB"Yg$l  
} -,dQ&Qf?  
} :9b RuUm  
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public void splitterStop() 7yp*I[1Qf>  
{ $#r(1 Ev  
bStop = true; )YFs  
} 1%,Z&@^j  
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} 5
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/* 8##jd[o&p~  
**FileAccess.java  Z-@}~#E  
*//文件访问(定位，写) !UTJ) &  
package NetFox; >$DqG$D  
import java.io.*; P `"7m-  
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public class FileAccessI implements Serializable{ 7,TWCVap  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 5WT\0]RUa  
RandomAccessFile oSavedFile; ' T]oV~H  
long nPos; `?x$J 6p  
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public FileAccessI() throws IOException s/M~RB!w  
{ J~q+G  
this("",0); dI-5%Um  
} ydQ
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public FileAccessI(String sName,long nPos) throws IOException .TC `\mV  
{ h86={@Le  
oSavedFile = new RandomAccessFile(sName,"rw"); w|C~{  
this.nPos = nPos;
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oSavedFile.seek(nPos); t5h_Q92N  
} Z<W6Avr  
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public synchronized int write(byte[] b,int nStart,int nLen) M;qL)vf  
{ 5H+k_U  
int n = -1; lIg2iun[n  
try{ fh#_Mj+y  
oSavedFile.write(b,nStart,nLen); sE6J:m(  
n = nLen; \aIy68rH,  
} %%6('wi  
catch(IOException e) c'";36y  
{ dH|^\IQ  
e.printStackTrace (); e-9unnk  
} C`wI6!  
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return n; K/`RZ!  
} )1Nnn  
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} sG2 3[t8  
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/* KVxb"|[  
**SiteInfoBean.java :-La $I>  
*/ fhKiG%i'l  
package NetFox; .To:tN#  
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public class SiteInfoBean { e oSM@Isu  
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private String sSiteURL; //Site's URL J"/z?!)IB  
private String sFilePath; //Saved File's Path t<F]%8S  
private String sFileName; //Saved File's Name j#t8Krd] "  
private int nSplitter; //Count of Splited Downloading File ^G
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public SiteInfoBean()  ii  y3  
{//nSplitter的缺省值为5 B
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//default value of nSplitter is 5 GA.bRN2CI2  
this("","","",5); AUsQj\Nm%  
} Fx5d@WNa>  
6L9[U^`@  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) v9m;vWp  
{ Tw;qY  
sSiteURL= sURL; WwtE=od  
sFilePath = sPath; yr2L  
sFileName = sName; \&&(ytL  
this.nSplitter = nSpiltter; ~49N  
/I'u/{KB  
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} e>9Z:vY
 
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public String getSSiteURL() o Xi}@  
{ Du:p!nO  
return sSiteURL; YQV?S  
} An #Hb=  
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public void setSSiteURL(String value) Wk#h,p3  
{ E8_Le  
sSiteURL = value; R{uJczu  
} s^YTI\L \  
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public String getSFilePath() RE $3| z  
{ |
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return sFilePath; %=9yzIjbAt  
} 5%?b5(mnD  
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public void setSFilePath(String value) 1D
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{ o.3YM.B#  
sFilePath = value; ]]=fA 4(  
} XL PpxG  
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public String getSFileName() }"?nU4q;S  
{ Zxc7nLKF~  
return sFileName; (s$u_aq77  
} ? x"HX|n  
!@<@QG
-  
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public void setSFileName(String value) -9>LvLU  
{ zf3:<CRX5  
sFileName = value; G/z\^Q  
} a=*ALd_&0  
%7v@n+Q  
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public int getNSplitter() 9Ue7 ~"=  
{ uR:=V9O  
return nSplitter; Yi&-m}  
} m io1kDq<  
=^Sw*[eiy  
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public void setNSplitter(int nCount) u-QO>3oY6  
{ 2zKo  
nSplitter = nCount; z_Wm HB  
} Yn4)Zhkk  
} ,<$YVXe/  
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/* xY2}Wr j,  
**Utility.java XpgV09.EE  
*/ | 7 m5P
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package NetFox; _}zo /kDA  
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public class Utility { p,w|=@=  
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public Utility() 6Q2orn[
 
{ ,2,SG/BB  
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}
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*H5PT  
//线程睡眠 CZJHE>  
public static void sleep(int nSecond) BbrT f"`  
{ Y9i9Uc.]  
try{ Nmp>UE,7[  
Thread.sleep(nSecond); -@ZzG uS(  
} \5'O.*pr  
catch(Exception e) %j*k  
{ 4ZI!,lv*  
e.printStackTrace (); 3}B5hht"D  
} Km)X_}|  
} x
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//日志 .Vo"AuC}  
public static void log(String sMsg) vuR5}/Ev  
{ ImWXzg3@{  
System.err.println(sMsg); 3(!/["@7  
} IXZ(]&we
 
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public static void log(int sMsg) 2{t)DUs  
{ {)B9Z I{+A  
System.err.println(sMsg); CKv&Re  
} ^\M dl  
} ,`<^F:xl  
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/* S3uyn78hI  
**TestMethod.java >|a\>UgC  
*/ 3ppuQQ  
package NetFox; Fweh =v  
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public class TestMethod { w]};0v&\~s  
)A="eW_>  
9&jQ 35  
public TestMethod() f}[H `OF  
{ ///xx/weblogic60b2_win.exe #
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try{ ~J0,)_b%*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >P<z |8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [ULwzjss#L  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Zc-#;/b3T  
fileFetch.start(); )xB$LJM8  
} dh&W;zs  
catch(Exception e){e.printStackTrace ();} 2m_'z  
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} p?Ed- S  
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public static void main(String[] args) k}D[Hp:m  
{ _yj1:TtCNT  
new TestMethod(); 4,2(nYF  
} BwC<rOU  
} |*:tyP%m^  
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