http断点续传简单实现（java)

/* oFjIA!  
**SiteFileFetch.java W3`>8v1?o  
*/ zJe#m|Z  
package NetFox; f{SB1M   
import java.io.*; @`\VBW  
import java.net.*; (&/2\0QV  
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public class SiteFileFetch extends Thread { *s@Qtgu  
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SiteInfoBean siteInfoBean = null; //文件信息Bean V_plq6z  
long[] nStartPos; //开始位置 P[s8JDqu  
long[] nEndPos; //结束位置 +P.+_7+:  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ^C2\`jLMY  
long nFileLength; //文件长度 gV&z2S~"  
boolean bFirst = true; //是否第一次取文件 +`?Y?L^ J  
boolean bStop = false; //停止标志 WJI[9@^I~  
File tmpFile; //文件下载的临时信息 pr%nbl  
DataOutputStream output; //输出到文件的输出流 \u6^Varw  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 7 |DHplI  
public SiteFileFetch(SiteInfoBean bean) throws IOException L^Jk=8  
{ =zwOq(Bh W  
siteInfoBean = bean; ~-wPP
{!  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); jxYc2  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); (O0Urm  
if(tmpFile.exists ()) oK 6(HF'&  
{ f/CuE%7BR  
bFirst = false; 4CGPOc  
read_nPos(); ^eW}XRI  
} J\e+}{  
else JN7k2]{  
{ N},n `Yl.  
nStartPos = new long[bean.getNSplitter()]; 1q;#VS/D;H  
nEndPos = new long[bean.getNSplitter()]; @A)R_p  
} +V&{*f)  
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} j0@[Br%7  
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public void run() $s<N
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{ 7FRmx4(!  
//获得文件长度 y8fsveX  
//分割文件 ;5@ t[r  
//实例FileSplitterFetch &+G"k~%  
//启动FileSplitterFetch线程 qKJSj   
//等待子线程返回 Y!;|ld  
try{ |!y A@y?  
if(bFirst) #r3l[bKK  
{ |HZTN"  
nFileLength = getFileSize(); pmX#E  
if(nFileLength == -1) 9cJH"  
{ ? w^-  
System.err.println("File Length is not known!"); .7n\d55a  
} O]qU[y+  
else if(nFileLength == -2) t(="h6i  
{ aF7nvu*N  
System.err.println("File is not access!"); *5xJv  
} 7'OtruJ  
else TRsE %  
{ q4V7  
for(int i=0;i<nStartPos.length;i++) vf8\i-U=  
{  6m6zA/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); <8,cuX\  
} ne^imht  
for(int i=0;i<nEndPos.length-1;i++) a')|1DnR  
{ ^B+!N;  
nEndPos = nStartPos[i+1]; !+:ov'F  
} - M,7N}z@;  
nEndPos[nEndPos.length-1] = nFileLength; }x&N^Ky3c  
} SXt{k<|  
} Bn!$UUC  
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//启动子线程 v!%5&: c3  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %TsPyiYl  
for(int i=0;i<nStartPos.length;i++) s@fTj$h  
{ Wa?; ^T  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Vx @|O%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <x!GE>sf+  
nStartPos,nEndPos,i); UUMtyf  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [V}S<Xp  
fileSplitterFetch.start(); IJ/sX_k  
} e${)w-R/e  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), A19;1#$=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); A4ISNM7R[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", k^OV56  
nEndPos = " + nFileLength); >"Q@bQ:e  
// fileSplitterFetch[nPos.length-1].start(); t+Op@*#%  
}6 K^`!  
~@kU3ZGJZ  
//等待子线程结束 oHs2L-G  
//int count = 0; D\e8,,H  
//是否结束while循环 x|{IwA9  
boolean breakWhile = false; 8|$3OVS  
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while(!bStop) z,|{fKtY}  
{ qgDRu]ba  
write_nPos(); [b$4Shx  
Utility.sleep(500); LzCw+@-umw  
breakWhile = true; is/scv<  
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for(int i=0;i<nStartPos.length;i++) n6k9~"?  
{ h;jIYxj  
if(!fileSplitterFetch.bDownOver) (#;`"Yu  
{ "kc/J*u-3  
breakWhile = false; M|] "W  
break; HE
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} P bQk<"J1  
} WAn'kA  
if(breakWhile) 9+keX{/c  
break; >,DbNmi  
(L`j0kPN  
WMj}kq)SY)  
//count++; =V^.}WtO  
//if(count>4) B7"PIkk;  
// siteStop(); n!qV>k9Y  
}  H}:LQ~_2  
)>c>oMgl  
[=|jZVhT  
System.err.println("文件下载结束！"); IVW1]y  
} i.:. Y  
catch(Exception e){e.printStackTrace ();} ~i.k$XGA  
} TFcT3]R[rL  
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//获得文件长度
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public long getFileSize() U#1bp}y  
{ _wdG|{p
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int nFileLength = -1; 3su78et}  
try{ "gD-8C3  
URL url = new URL(siteInfoBean.getSSiteURL()); F9*g=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); p7H3J?`w1+  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5cWw7V<m  
=v*.p=
r  
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int responseCode=httpConnection.getResponseCode(); rL5z]RY  
if(responseCode>=400) t5lO'Ll*Q]  
{ b9XW9O`B  
processErrorCode(responseCode); !|<=ZF2  
return -2; //-2 represent access is error Ks\ NE=;5  
} d9n?v)<v  
b<]n%Q'n  
*~/OOH$"  
String sHeader; 8KH\`
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for(int i=1;;i++) WF\)fc#;_o  
{ ZR\VCVH\^  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 21(p|`X  
//Utility.log(in.readLine()); #);[mW{F  
sHeader=httpConnection.getHeaderFieldKey(i); &[hLzlrg  
if(sHeader!=null) vp(;W,ba:|  
{ #b7$TV  
if(sHeader.equals("Content-Length")) wR{'y)$  
{ =
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); V _c@b%  
break; +<prgP`v  
} ;us%/kOR  
} ",)Qc!^P$  
else jV8q)=}*)  
break; hkOsm6  
} "l >Igm  
} 4Bl{WyMJ|  
catch(IOException e){e.printStackTrace ();} ` }3qhar  
catch(Exception e){e.printStackTrace ();} yAN=2fZm  
?3O9eZY@  
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Utility.log(nFileLength); YSaJeU>@  
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return nFileLength; +x1eJug4  
} Tz9`uW~Mf  
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//保存下载信息（文件指针位置） apk4j\i?5  
private void write_nPos() H}LS??P  
{ \a+(=s(;  
try{ +D1d=4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); wKH ::!  
output.writeInt(nStartPos.length); M3~K,$@  
for(int i=0;i<nStartPos.length;i++) /cZ-tSC)o  
{ cT\I[9!)  
// output.writeLong(nPos); _GKB6e%  
output.writeLong(fileSplitterFetch.nStartPos); iKas/8  
output.writeLong(fileSplitterFetch.nEndPos); phE &7*!Q  
} (Y^X0yA/  
output.close(); O+RP3ox"  
} RaTH\>n  
catch(IOException e){e.printStackTrace ();} <9sO  
catch(Exception e){e.printStackTrace ();} F,5r9^,_  
} }$\M{#C~  
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//读取保存的下载信息（文件指针位置） u`(- -  
private void read_nPos() =YG _z^'  
{ ` gW<M  
try{ 45&8weXO:'  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); bZx!0>h  
int nCount = input.readInt(); M_LXg%  
nStartPos = new long[nCount]; CU7F5@+  
nEndPos = new long[nCount]; ^2wLxXO6  
for(int i=0;i<nStartPos.length;i++) %Qmk2  
{ YJ:3!B>Zo  
nStartPos = input.readLong(); IHp_A  
nEndPos = input.readLong(); I!wX[4p eg  
} G Xt4j  
input.close(); uGs;}<<8  
} LB/C-n.`  
catch(IOException e){e.printStackTrace ();} K 0hu:1l)  
catch(Exception e){e.printStackTrace ();} >E,U>@+  
} m4:^}O-#  
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private void processErrorCode(int nErrorCode) I-ag
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{ OTZ_c1
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System.err.println("Error Code : " + nErrorCode); rfw-^`&{  
} wC-Rr^q  
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G4 G5PXi  
//停止文件下载 U=8@@yE  
public void siteStop() U}$DhA"r"  
{ 4'p=p#o  
bStop = true; >]=j'+]  
for(int i=0;i<nStartPos.length;i++) na^sBq?\  
fileSplitterFetch.splitterStop(); MuBx#M/  
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} t\v+ogbk)  
} 1
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//负责部分文件的抓取 +u'I0>)S  
**FileSplitterFetch.java {RB-lfrWs  
*/ 7FO'{Qq  
package NetFox; xmGk*W)P  
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import java.io.*; joul<t-  
import java.net.*; gh6d&ucQ^  
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public class FileSplitterFetch extends Thread { $mGvJ*9  
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String sURL; //File URL O--7<Q\  
long nStartPos; //File Snippet Start Position IaFr&  
long nEndPos; //File Snippet End Position &L^CCi  
int nThreadID; //Thread's ID h8jD}9^  
boolean bDownOver = false; //Downing is over [@fz1{*  
boolean bStop = false; //Stop identical wNE$6  
FileAccessI fileAccessI = null; //File Access interface Y\2|x*KwvF  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException OlD`uA  
{ s=Q(C[%I  
this.sURL = sURL; U/;]zdP.K  
this.nStartPos = nStart; m=qOg>k  
this.nEndPos = nEnd; A"Q@W<.  
nThreadID = id; *^ \FIUd  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 UK*qKj.)  
} 2q}..  
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public void run() 7+w'Y<mJ  
{ ) uP\>vRy  
while(nStartPos < nEndPos && !bStop) A>.2OC+  
{ ji
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try{ ,)~E
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URL url = new URL(sURL); [&Hkn5yq  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %~*jae!f  
httpConnection.setRequestProperty("User-Agent","NetFox"); g<\z=H  
String sProperty = "bytes="+nStartPos+"-"; em2_pq9q  
httpConnection.setRequestProperty("RANGE",sProperty); 6@4n'w{"  
Utility.log(sProperty); `#IcxweA  
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InputStream input = httpConnection.getInputStream(); |Y_ -  
//logResponseHead(httpConnection); `0#H]=$2h  
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byte[] b = new byte[1024]; !F!3Q4  
int nRead; &S74mV  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ZI ?W5ISdg  
{ 6ew "fCrH!  
nStartPos += fileAccessI.write(b,0,nRead); 2H?d+6Pt3  
//if(nThreadID == 1) %c^ m\E  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yZ}d+7T}  
} +~2rW8  
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Utility.log("Thread " + nThreadID + " is over!"); L*?!Z^k  
bDownOver = true; e&X>F"z2  
//nPos = fileAccessI.write (b,0,nRead); lj&>cScC  
} Zzd/K^gg  
catch(Exception e){e.printStackTrace ();} 8V4V3^_xs  
} /c+)C"  
} nbdGt  
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//打印回应的头信息 Gg0#H^s( (  
public void logResponseHead(HttpURLConnection con) 7el<5chZ  
{ X`20f1c6q>  
for(int i=1;;i++) |k-
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{ YT2'!R 1  
String header=con.getHeaderFieldKey(i); sM\&.<B  
if(header!=null) lUh*?
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); ]T{E (9  
Utility.log(header+" : "+con.getHeaderField(header)); ]"x\=A  
else 9]_GNk-D  
break; !}&"W,,0  
} r!/0 j)  
} DOL%'k?B  
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public void splitterStop() $T dC/#7  
{ -a) T6:e  
bStop = true; hH+bt!aH  
} _GbE^  
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} fCEz-TMW  
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/* RLKj u;u  
**FileAccess.java ~oi_r8K  
*//文件访问(定位，写) C*wdtEGq  
package NetFox; kN'Thq/ZE  
import java.io.*; Mz|L-62  
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y' tRANxQ  
public class FileAccessI implements Serializable{ LC
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 q6[}ydV  
RandomAccessFile oSavedFile; P79R~m`  
long nPos; V;[p438o  
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public FileAccessI() throws IOException mCb 9*|  
{ 0o68rF5^s  
this("",0); { R*Y=Ie  
} ~ v1W  
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public FileAccessI(String sName,long nPos) throws IOException 29O]S8  
{ FP;":iRL  
oSavedFile = new RandomAccessFile(sName,"rw"); Yk>8g;<  
this.nPos = nPos; {,V$*  
oSavedFile.seek(nPos); @P70W<<  
} OJ[rj`wrW^  
A +!sD5d  
w#{l4{X|  
public synchronized int write(byte[] b,int nStart,int nLen) 0(TvQ{  
{ 7s]Wq6  
int n = -1; ]%XK)[:5_=  
try{ <$C<Ba?;?  
oSavedFile.write(b,nStart,nLen); (n=Aa;  
n = nLen; ?Y!^I2Y6  
} @W [{2d  
catch(IOException e) i_YW;x  
{ 97x%2.\:  
e.printStackTrace (); >x?2Fz.  
} \L#QR  
}*-u$=2  
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return n; Riq|w+Q  
} xK!DtR
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} : ~'Z(-a  
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/* 4@~a<P#  
**SiteInfoBean.java afy
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*/ SEU\}Ni{  
package NetFox; K!7q!%Ju  
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public class SiteInfoBean { *zSxG[s  
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private String sSiteURL; //Site's URL W2n*bNI  
private String sFilePath; //Saved File's Path ioWJj.%  
private String sFileName; //Saved File's Name NE[y|/  
private int nSplitter; //Count of Splited Downloading File 0&B:\  
;&7,73!  
y*(_\\
 
public SiteInfoBean()
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{//nSplitter的缺省值为5 -=>U =|  
//default value of nSplitter is 5 () <`t}FQ  
this("","","",5); @4@PuWI0-  
} <hMtE
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) .o"<N  
{ @4&, #xo  
sSiteURL= sURL; p~FQcW'a~  
sFilePath = sPath; ~ ;XYwQ"  
sFileName = sName; W{\EE[XhCf  
this.nSplitter = nSpiltter; D8EeZUqU  
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} SLg+H  
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hLSTSD}  
public String getSSiteURL() G#'Q~N  
{ drs-mt8  
return sSiteURL; Vl4Z_viNH  
} ?^Pq/V
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$(XgKq&xWZ  
public void setSSiteURL(String value) db^a
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{ {GK(fBE  
sSiteURL = value; PM8Ks?P#u  
} }D Z)W0RDe  
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public String getSFilePath() FQ0KUb}0  
{ ~JAjr(G#o  
return sFilePath; /=q.tDH=I  
} F G3Sk!O6  
P6:;Y5e0  
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public void setSFilePath(String value) %mJ~F*Dy  
{ -E}>h[;qZ  
sFilePath = value; au,jAk  
} 8H7O/n  
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public String getSFileName() |G)Y8 #D  
{ Q g$($   
return sFileName; {v,{x1  
} })KJ60B  
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5Yn{?r\#F  
public void setSFileName(String value) W _J&M4  
{ ) b
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sFileName = value; ENO? ;  
} b~jIv:9T  
wKGogf[(%  
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public int getNSplitter() n}0za#G  
{ is9}ePC7Xu  
return nSplitter; 5GaoJ v  
} oPCrD.s  
[gpOuTW  
AfUZO^<  
public void setNSplitter(int nCount) |xp$OL"a  
{ Hw
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nSplitter = nCount; *}>Bkq9h  
} *X~B-a|nJ  
} PEfE'lGj  
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sfyBw  
/* Mm "Wk  
**Utility.java |3 ;u"&(P  
*/ ]/LWrQD
  
package NetFox; \{[D|_   
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{,i=>%X*  
public class Utility { G4O,^ v;Q  
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public Utility() qx Wgt(Os  
{ IY V-*/ |  
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} /X@7ju
;  
:-w@^mli  
//线程睡眠 #m[vn^8B]y  
public static void sleep(int nSecond) @55bE\E?@  
{ XIqv{w  
try{ MJ1W*'9</W  
Thread.sleep(nSecond); ==nYe{2  
} w
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catch(Exception e) +d@v AxP  
{ giaD9$C  
e.printStackTrace (); T}V7SD.  
} = vY]G5y  
} &1*4%N@'  
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//日志 h0T< :X  
public static void log(String sMsg) c=jcvDQ6W  
{ F#jCEq  
System.err.println(sMsg); y=-{Q  
} A(q~{  
|VTWw<{LX  
V/`#B$6  
public static void log(int sMsg) 4Sg<r,G  
{ \H,V 9!B  
System.err.println(sMsg); +]A+!8%Z  
} iPA@<D%  
} -zPm{a  
Dm>T"4B`/  
Z"l`e0{  
/* 6].yRNy"  
**TestMethod.java <+<)xwOQ ]  
*/ (hpTJsZ  
package NetFox; :[A?A4l  
|}M~kJ)  
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public class TestMethod { R"m.&%n  
'wCS6_K  
R'vdk<  
public TestMethod() 3js)niT9u  
{ ///xx/weblogic60b2_win.exe E^oEG4X@  
try{ 3Qqnw{*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); "g x5XW&  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); @:S$|D~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); :X3
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fileFetch.start(); \%w7D6dEZ  
} \B*k_W/r@  
catch(Exception e){e.printStackTrace ();} #rh0r`  
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} )fxo)GS  
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D /,|pC  
public static void main(String[] args) 5Z^$`$/.v#  
{ zi?qK?m  
new TestMethod(); /IGrp
.}  
} A>qd2  
} 1gF*Mf_7  
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