http断点续传简单实现（java)

/* q.Z0Q  
**SiteFileFetch.java +/x|P-  
*/ t MA
  
package NetFox; >6jyd{  
import java.io.*; r)U9u 0  
import java.net.*; -bo0!@MK  
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public class SiteFileFetch extends Thread { A4(^I u  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Ij#%Qu  
long[] nStartPos; //开始位置 F!zZIaB]  
long[] nEndPos; //结束位置 `DWzp5Ax  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]S;e#u{QE  
long nFileLength; //文件长度 jUBlIVl]  
boolean bFirst = true; //是否第一次取文件 I&1Mh4yu  
boolean bStop = false; //停止标志 M{O2O(  
File tmpFile; //文件下载的临时信息 Eq'{uV:  
DataOutputStream output; //输出到文件的输出流 zg8m(=k'  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ^0X86  
public SiteFileFetch(SiteInfoBean bean) throws IOException n-H0cm  
{ &w/aQs~  
siteInfoBean = bean; Yng9_w9Y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); cC4*4bMm  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); D}b+#G(m[  
if(tmpFile.exists ()) 9J2%9,^  
{ {wA@5+[  
bFirst = false; wond>m 3  
read_nPos(); /V&$SRdL*  
} WGp81DNS|  
else xwK<f6H!y  
{ o^DiIoor  
nStartPos = new long[bean.getNSplitter()]; tw*qlbFHv  
nEndPos = new long[bean.getNSplitter()]; QM;L>e-ZY  
} 173/A=]  
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} M%9PVePOe  
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public void run() Fnll&TF  
{ )5yZSdA  
//获得文件长度 7NJ1cQ-}t  
//分割文件
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//实例FileSplitterFetch #( X4M{I  
//启动FileSplitterFetch线程 o{zo-:>Jp  
//等待子线程返回 M-|4cd]6  
try{ 9LCV"xgX  
if(bFirst)
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{ %&z9^}Vd[  
nFileLength = getFileSize(); &x;v&  
if(nFileLength == -1) hnG'L*HooE  
{ $!KV]]  
System.err.println("File Length is not known!"); m_(+-G
  
} {f3T !e{  
else if(nFileLength == -2) ^5"s3Qn  
{ >cSc   
System.err.println("File is not access!"); VCvuZU{<  
} {\lu; b!  
else *,pG4kh!  
{ pD`7N<F 3  
for(int i=0;i<nStartPos.length;i++) =b !f  
{ CQ3;NY=o  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); P9Rq'u  
} H#wn3O  
for(int i=0;i<nEndPos.length-1;i++) 9\Yj`,i
5  
{ BnAia3z  
nEndPos = nStartPos[i+1]; Pi)`[\{  
} \JN<"/  
nEndPos[nEndPos.length-1] = nFileLength; +2C:]  
} p,ZubRJ"  
} 2eb :(D7Cq  
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^qV*W1|0  
//启动子线程 b6);bX>e  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; eFZ`0
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for(int i=0;i<nStartPos.length;i++) `db++Z'C  
{ @c7 On)sy  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fN
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), A
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nStartPos,nEndPos,i); i,* DWD+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V^?
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fileSplitterFetch.start(); G7zfyw}W  
} p3sz32RX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )`;?%
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3tOnALv  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5l{_E:.1  
nEndPos = " + nFileLength); 0]i#1Si~@  
// fileSplitterFetch[nPos.length-1].start(); L`];i8=I  
CIYD'zR[2  
M|Z]B<_x  
//等待子线程结束 d{9jd{ _#G  
//int count = 0; k]I<%  
//是否结束while循环 kiqq_`66  
boolean breakWhile = false; QN*'MA"M  
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while(!bStop) ){8^l0b  
{ ~EX/IIa{  
write_nPos(); ~-'nEATE  
Utility.sleep(500); #?8'Z/1)  
breakWhile = true; Av+
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for(int i=0;i<nStartPos.length;i++) FDpNM\SR1l  
{ &({X9  
if(!fileSplitterFetch.bDownOver) lD 9'^J  
{ syBYH5  
breakWhile = false; MPNBA1s  
break; !k%Vw18  
} U
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} cl14FrpYu  
if(breakWhile) ><^A4s  
break; u9k##a4.E  
=}_c=z?UY  
7F.>M  
//count++; 5E}0
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//if(count>4) T>W(Caelq  
// siteStop(); 8fZ\})t  
} (3=.3[  
wk)gxn1A,  
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System.err.println("文件下载结束！"); ^c.b@BE  
} 85Ms*[g  
catch(Exception e){e.printStackTrace ();} 31J7# S2  
}  3nR|*t;  
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@(Q4  
//获得文件长度 4}#*M2wb  
public long getFileSize() M!mTNIj8~  
{
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int nFileLength = -1; uK): d&]Ux  
try{ e#&[4tQF  
URL url = new URL(siteInfoBean.getSSiteURL()); <6-(a;T!7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *1%=?:$(r6  
httpConnection.setRequestProperty("User-Agent","NetFox"); d|DIqT~{W  
[y>Q3UqN  
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int responseCode=httpConnection.getResponseCode(); /sJk[5!z  
if(responseCode>=400)  Zp]Bs  
{ 7Zr jU{  
processErrorCode(responseCode); {TUCa  
return -2; //-2 represent access is error
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} Re,0RM
\  
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String sHeader; v-OGY[|97  
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for(int i=1;;i++) GpxGDN3?  
{ XwlUkw"q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); cDE?Xo'!  
//Utility.log(in.readLine()); MS,H12h  
sHeader=httpConnection.getHeaderFieldKey(i); "fz-h  
if(sHeader!=null) ?;uzx7@F  
{ /?2yo{Fg  
if(sHeader.equals("Content-Length")) t"RgEH@  
{ ilFM+x@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); a ,W5T8  
break; etGquW.  
} unjo&  
} [-Q"A 6!Zd  
else <&W3\/xx  
break; /Tv< l  
} z[OW%(vrm  
} |a^ydwb  
catch(IOException e){e.printStackTrace ();} \k;raQR4t*  
catch(Exception e){e.printStackTrace ();} !?Ow"i-lp  
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Utility.log(nFileLength); t}*teo[  
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return nFileLength; >@]E1Qfe  
} t7)Y@gRy  
7d'@Z2%J0  
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//保存下载信息（文件指针位置） .fQDj{  
private void write_nPos() :q6hT<f;  
{ #9 }Oqm  
try{ Y]P $|JW):  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )%#hpP M^  
output.writeInt(nStartPos.length); O
7
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for(int i=0;i<nStartPos.length;i++) i<%(Z[9Lk  
{ GI6 EZ}.MZ  
// output.writeLong(nPos);  hA/FK  
output.writeLong(fileSplitterFetch.nStartPos); ZO0_:T
#Z  
output.writeLong(fileSplitterFetch.nEndPos); a&Z|3+ZA  
} bS0^AVA  
output.close(); /B}]{bcp$  
} QW~o+N~~  
catch(IOException e){e.printStackTrace ();} ]YOQIzkL4}  
catch(Exception e){e.printStackTrace ();} RsrZ1dhPvV  
} "gK2!N|#  
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C,fIwqOr3  
//读取保存的下载信息（文件指针位置） 6EPC$*Xp!  
private void read_nPos() nz>A\H  
{ ,ew<T{PL  
try{ h]MSjC.X  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); aIqNNR  
int nCount = input.readInt(); -B`;Sx  
nStartPos = new long[nCount]; #*Mk@XrV  
nEndPos = new long[nCount];
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for(int i=0;i<nStartPos.length;i++) T,H]svN
5p  
{ av`b8cGg  
nStartPos = input.readLong(); ;7 IVg[f  
nEndPos = input.readLong(); ]FFU,me2  
} I s8|  
input.close(); <GoE2a4Va  
} poXkH@[O  
catch(IOException e){e.printStackTrace ();} B]]M?pS  
catch(Exception e){e.printStackTrace ();} d(]LRIn~1  
} K-vso4@BJ  
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private void processErrorCode(int nErrorCode) RNi&OG(  
{ "KFCA9u-  
System.err.println("Error Code : " + nErrorCode); oh:t ex<  
} zGz5|u  
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o+aB[+  
//停止文件下载 A:p0p^*  
public void siteStop() +;*])N%q  
{ ZS}2(t   
bStop = true; e?f[t*td  
for(int i=0;i<nStartPos.length;i++) @j^qT-0M  
fileSplitterFetch.splitterStop(); TmQ2;3%  
-iJ[9O  
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} { !FrI@  
} ^ro?.,c T  
//负责部分文件的抓取 tcRK\  
**FileSplitterFetch.java Gt 2rJ<>  
*/ wS:323 !l$  
package NetFox;  c<4pu  
F*]AjD-  
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import java.io.*; gzC\6ca
 
import java.net.*; @V<tg"(c  
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public class FileSplitterFetch extends Thread { C6/,-?%)  
]jy6C'Mp  
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String sURL; //File URL KIuYWr7&  
long nStartPos; //File Snippet Start Position 52:oe1-8  
long nEndPos; //File Snippet End Position TuX#;!p6  
int nThreadID; //Thread's ID =Qz8"rt#  
boolean bDownOver = false; //Downing is over ;vd%=vR  
boolean bStop = false; //Stop identical Bp4QHv9xqL  
FileAccessI fileAccessI = null; //File Access interface y`\/eX  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException `;i| %$TU  
{ j)J4[j  
this.sURL = sURL; (s"_NUj6  
this.nStartPos = nStart; N5~g:([k  
this.nEndPos = nEnd; 5V%K'a(  
nThreadID = id; 43 |zjE  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 i{%~&!  
} KsHovv-A  
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public void run() 46$u}"E  
{ *h]qh20t  
while(nStartPos < nEndPos && !bStop) (*hA0&n  
{ tuUk48!2I  
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try{ )B8[w  
URL url = new URL(sURL); {;z3$/JB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $`]<4I9d  
httpConnection.setRequestProperty("User-Agent","NetFox"); [q_Yf!(m-  
String sProperty = "bytes="+nStartPos+"-"; Z1q'4h=F.  
httpConnection.setRequestProperty("RANGE",sProperty); 5"@<7/2qI  
Utility.log(sProperty); Te5_T&1Z  
#%+IU  
&_!BMzp4  
InputStream input = httpConnection.getInputStream(); OP
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//logResponseHead(httpConnection); dJCu`34Y'|  
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byte[] b = new byte[1024]; "I_3!Yu  
int nRead; ] niWRl
 
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "7gS*v,r  
{ GK\'m@k  
nStartPos += fileAccessI.write(b,0,nRead); `[Lap=.'.  
//if(nThreadID == 1) Sgr<z d'b  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~r|.GY  
} YM#XV*P0 q  
BPi>SI0  
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Utility.log("Thread " + nThreadID + " is over!"); )\^%w9h  
bDownOver = true; H&%=>hyX  
//nPos = fileAccessI.write (b,0,nRead); 0&EX-DbV  
} 6x -PGq  
catch(Exception e){e.printStackTrace ();} 3ON]c13  
} 6bqJM#y@  
} uomFE(  
+ES.O]?>  
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//打印回应的头信息 2%WZ-l!i  
public void logResponseHead(HttpURLConnection con) 9:BGA/?  
{ MT
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for(int i=1;;i++) ifBJ$x(B.  
{ GWP"i77y0s  
String header=con.getHeaderFieldKey(i); TF3Tha]  
if(header!=null) t`DUY3>36  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0<>iMrD  
Utility.log(header+" : "+con.getHeaderField(header)); e HOm^.gd  
else E}a3.6)p  
break; KY_qK)H  
} %%-kUe  
} XK&#K? M  
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public void splitterStop() uCUBs(iD  
{ T!;<Fy"p  
bStop = true; @MN>ye'T  
} jCa{WV:K}  
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} (@&|  
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/* OB"QWdh  
**FileAccess.java =jG3wf*  
*//文件访问(定位，写) bFflA  
package NetFox; m7!l3W2  
import java.io.*; i!Ne<Q  
^Jkj/n'  
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public class FileAccessI implements Serializable{ 1hMk\ -3S  
Fx.uPY.a  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 HX <;=m  
RandomAccessFile oSavedFile; -><_J4  
long nPos; QeQbO  
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w
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public FileAccessI() throws IOException &V2G<gm0  
{ [jLx}\]  
this("",0); &GbCJ  
} ( Ni
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public FileAccessI(String sName,long nPos) throws IOException m1`ln5(R  
{ YE-kdzff
 
oSavedFile = new RandomAccessFile(sName,"rw"); "n05y}  
this.nPos = nPos; )lW<:?k  
oSavedFile.seek(nPos); CiMN J  
} W>,b1_k c  
3g6R<Ez  
.}0Cg2W  
public synchronized int write(byte[] b,int nStart,int nLen) ^7_<rs  
{ 0\i&v  
int n = -1; &MKv_  
try{ 6: M  
oSavedFile.write(b,nStart,nLen); %Ajf|Go0/G  
n = nLen; J}.p6E~j  
} _R8-Hj E  
catch(IOException e) "%Rx;xw|  
{ 4b<:67 %  
e.printStackTrace (); &2Y>yFB ,  
} :`uo]B"  
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return n; hxtu^E/  
} ~o8$/%Oeb/  
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} ZBnf?fU  
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/* %iX+"  
**SiteInfoBean.java D)mqe-%1  
*/ \"uR&D  
package NetFox; $QY(7Z"  
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public class SiteInfoBean { gfp#G,/B  
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private String sSiteURL; //Site's URL &yP9vp="  
private String sFilePath; //Saved File's Path ho0T$hB  
private String sFileName; //Saved File's Name @F=4B0=  
private int nSplitter; //Count of Splited Downloading File 4sG^bZ,  
 9((v.  
2.CI^.5&  
public SiteInfoBean() ;BpuNB  
{//nSplitter的缺省值为5 7gvkd+-*  
//default value of nSplitter is 5 7Xw#  
this("","","",5); 2N>:GwN  
}
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sl`\g1<{`  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) gx#TRp}-
 
{ b}axw+  
sSiteURL= sURL; "tm2YUG},s  
sFilePath = sPath; )=2iGEVW  
sFileName = sName; tEZ@v(D  
this.nSplitter = nSpiltter; F2lTDuk>C  
8/]5h%  
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} iN=-N=  
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public String getSSiteURL() qm8[ ^jO&  
{ t13wQ
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return sSiteURL; LzP+l>m  
} 0oc5ahp  
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public void setSSiteURL(String value) _6xC4@~h*  
{ 1iig0l6\m  
sSiteURL = value; l3rr2t  
} {rf.sN~M  
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):kDWc  
public String getSFilePath() %h(J+_"L6  
{ auK*\Wjm
?  
return sFilePath; bw&8"k>D?  
} aF]4%E  
*FmY4w  
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public void setSFilePath(String value) s<h]2W  
{ ]>B>.s  
sFilePath = value; MV'q_{J  
} V*Ta[)E  
ER;?[!  
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public String getSFileName() 7A<X!
a  
{ Pp#  
return sFileName; : M=0o<  
} 4,4S5u[|  
8Qd*OO  
=ss(~[  
public void setSFileName(String value) .!/w[Z]  
{ 1wAD_PI|BH  
sFileName = value; td@I ;d2  
} bys5IOP{]o  
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@
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public int getNSplitter() EX@wenR  
{ 76epkiz;=  
return nSplitter; C&wp*  
} v,, .2UR4  
x *:v]6y  
V7DMn@Ckw  
public void setNSplitter(int nCount) lrQNl^K}=  
{ 'vCl@x$  
nSplitter = nCount; BRSIg]  
} DL<b)# h#  
} %'o'Kh''=  
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/* D`hl}  
**Utility.java  KEPNe(H  
*/ aoqG*qh}b  
package NetFox; T"IDCT'z  
<DR$WsDG  
-8zdkm8k  
public class Utility { yjE$o?A  
H^ds<I<)  
@V}!elV  
public Utility() \RT3#X+  
{ K&4FFZ  
h~`^H9?M  
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}  MFyi#nq  
'ws@I?!r  
//线程睡眠 s|vx2-Cu]  
public static void sleep(int nSecond) +[Izz~_p  
{ X=@bzL;eq  
try{ 3~%M4(  
Thread.sleep(nSecond); gq~K(Q<O<  
} NT=)</v  
catch(Exception e) >H5_,A}f  
{ /$d#9Uv  
e.printStackTrace (); GYrUB59  
} /H*[~b  
} *X!+wK-+  
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//日志 FwV5{-(  
public static void log(String sMsg) 8iPA^b|sz{  
{ \0;EHB  
System.err.println(sMsg); io
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} s(:N>K5*  
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"td ,YVK  
public static void log(int sMsg) je74As[  
{ To;r#h  
System.err.println(sMsg); [33=+Ca  
} O{Z bpa^  
} #iT3aou  
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^3C%&  
/* gMPvzBpP  
**TestMethod.java =&mdxKoT0  
*/ n],"!>=+  
package NetFox; ?:7.3{|Aq  
d z\yP v~  
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public class TestMethod { ={I(i6  
8Ib5  
rs@qC>_C0  
public TestMethod() 
s-S|#5  
{ ///xx/weblogic60b2_win.exe 2SYV2  
try{ uXdR-@80*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); "9,+m$nj  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }^PdW3O*m,  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 6~Y`<#X5J  
fileFetch.start(); rk `]]  
} $kh6-y@  
catch(Exception e){e.printStackTrace ();} b@[\+P] "  
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} ~ym-Szo  
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public static void main(String[] args) L)_L#]Yy  
{ Q".
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new TestMethod(); X-5&c$hv  
} nNcmL/
(  
} !,N),xG}~  
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