http断点续传简单实现（java)

/* Nr0}*8#j  
**SiteFileFetch.java Q1u/QA:z7  
*/ m7.6;k.  
package NetFox; bjB4  
import java.io.*; >vc$3%L[$  
import java.net.*; 7G &I]>  
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public class SiteFileFetch extends Thread { Cc>+OUL  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Eh|v>Yew  
long[] nStartPos; //开始位置 qI5`:PH%n  
long[] nEndPos; //结束位置 ^U]B&+m  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 J(=io_\bO  
long nFileLength; //文件长度 <~-cp61z;  
boolean bFirst = true; //是否第一次取文件 rnS&^  
boolean bStop = false; //停止标志 "/
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File tmpFile; //文件下载的临时信息 ;n;bap  
DataOutputStream output; //输出到文件的输出流 -)$5[jM]  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） B0"55g*c  
public SiteFileFetch(SiteInfoBean bean) throws IOException 8;1,saA_9  
{ 5 p! rZ  
siteInfoBean = bean; 2mfKy9QxO  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;A;FR3=)  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); db5@+_  
if(tmpFile.exists ()) QK@[b3-h1  
{ 'MY0v_  
bFirst = false; Eao^/MKx-  
read_nPos(); .|z8WF*  
} )lDmYt7me  
else xty)*$C>  
{ (bo-JOOdY(  
nStartPos = new long[bean.getNSplitter()]; >Eqr/~Q  
nEndPos = new long[bean.getNSplitter()]; k;xIo(:  
} YK6zN>M}E  
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} |.Vs
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public void run() vG'I|OWg  
{ Z[?zaQ$  
//获得文件长度 rs+ ["h  
//分割文件 )H|cri~D  
//实例FileSplitterFetch O6Mxp-  
//启动FileSplitterFetch线程 gvu1  
//等待子线程返回 B`?}jJa9*  
try{ $, @,(M`i}  
if(bFirst) W~qVZ(G*U  
{ /+ Q3JS(  
nFileLength = getFileSize(); W2T6JFv  
if(nFileLength == -1) ((cRe6  
{ y`8bx94jB  
System.err.println("File Length is not known!"); > xie+ ^  
} ('&lAn  
else if(nFileLength == -2) Wdd}y`lS  
{ .<m]j;|6  
System.err.println("File is not access!"); k~[jk5te  
} $?GggP d  
else t&U9Z
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{ /zIG5RK>  
for(int i=0;i<nStartPos.length;i++) PD&e6;rj;  
{ YIe1AF}   
nStartPos = (long)(i*(nFileLength/nStartPos.length)); H!;N0",]N  
} 4%0s p  
for(int i=0;i<nEndPos.length-1;i++) k{vj,
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{ wQd8/&mmk  
nEndPos = nStartPos[i+1]; %0/qb0N&  
} !.t D.(XP  
nEndPos[nEndPos.length-1] = nFileLength; fc<y(uX  
} M<NY`7$^  
} _`^AgRE  
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//启动子线程 hAc|a9 o  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; OgC,oj,!/  
for(int i=0;i<nStartPos.length;i++) 5p:BHw;%;  
{ Xy!NBh7I  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K*b* ]hf{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Cc%{e9e*  
nStartPos,nEndPos,i); U$+,|\9  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8HJ,6Lr;  
fileSplitterFetch.start(); |W=-/~X  
} ">3t+A  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), G/(,,T}eG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); c(2?
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", /VufL+q1
 
nEndPos = " + nFileLength); WSxoGly  
// fileSplitterFetch[nPos.length-1].start(); p3mZw lO  
zx2`0%Q  
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//等待子线程结束 w6X:39d  
//int count = 0; -.MJ3  
//是否结束while循环 4[]*=  
boolean breakWhile = false; E#8|h(  
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while(!bStop) 
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{ Ij.mLO]  
write_nPos(); K39I j_3  
Utility.sleep(500); Te?PYV-  
breakWhile = true; %5KK#w "  
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for(int i=0;i<nStartPos.length;i++) CALD7qMK  
{ -p7 HQ/  
if(!fileSplitterFetch.bDownOver) 5i'?oXL  
{ KY%qzq,n  
breakWhile = false; *x p_#  
break; gPd,  
} 7!Im|7Ty  
} ,g"JgX  
if(breakWhile) OR+py.vK  
break; W[Z[o+7pK  
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//count++; }>621L3 -  
//if(count>4) RK$(  
// siteStop(); ph!h8@e  
} ta x:9j|~  
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System.err.println("文件下载结束！"); V588Leb?  
} K8Y/XE
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catch(Exception e){e.printStackTrace ();} cg.e(@(  
} Id*^H:]C#  
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//获得文件长度 c-T ^ aR  
public long getFileSize() [w/t  
{ 7`/qL "  
int nFileLength = -1; G"[pr%?  
try{ S=g-&lK  
URL url = new URL(siteInfoBean.getSSiteURL()); (0Qq rNs  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ak1)  
httpConnection.setRequestProperty("User-Agent","NetFox"); -IS9uaT5  
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int responseCode=httpConnection.getResponseCode(); #[W[|m  
if(responseCode>=400) iq:[+
  
{ @qDrTH]5  
processErrorCode(responseCode); [J`G`s!  
return -2; //-2 represent access is error @V03a )6,h  
} cA%%IL$R  
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String sHeader; }Ho Qwy|&  
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for(int i=1;;i++) ,"B+r6}EF  
{ `Od5Gh  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Ei2'[PK  
//Utility.log(in.readLine()); :=J,z,H_U  
sHeader=httpConnection.getHeaderFieldKey(i); D1__n6g[  
if(sHeader!=null) ">#wOm+ +  
{ Z)jw|T'X
 
if(sHeader.equals("Content-Length")) 9W(dmde>  
{ } \ZaE~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *4V=z#  
break; 3YVi" k?2  
} g]*#%Xa  
} U"
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else [7[0^ad  
break;  EW3(cQbK  
} l5"OIq  
} #-bA[eQV  
catch(IOException e){e.printStackTrace ();} 7}X[ 4("bB  
catch(Exception e){e.printStackTrace ();} daYx76yP_?  
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Utility.log(nFileLength); Zl*X?5u  
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return nFileLength; }K&7%N4LZ  
} E2m8UBS  
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//保存下载信息（文件指针位置） cJrmm2.0kD  
private void write_nPos() -?0qf,W.  
{ /oriW;OF  
try{ t2lS ~l)  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0PWg;>^'  
output.writeInt(nStartPos.length); 2o'Wy  
for(int i=0;i<nStartPos.length;i++) UXh9:T'%  
{ !TUrQ  
// output.writeLong(nPos); {DR`;ea])1  
output.writeLong(fileSplitterFetch.nStartPos); +u3=dj"[  
output.writeLong(fileSplitterFetch.nEndPos); -:na:Vsi  
} v61[.oS  
output.close(); 6Aku1h  
} R;j!}D!4  
catch(IOException e){e.printStackTrace ();} #E&80#Z5  
catch(Exception e){e.printStackTrace ();} mVy|{O
h  
} 0:T|S>FsAm  
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//读取保存的下载信息（文件指针位置） 2* 2wY=  
private void read_nPos() 6*3.SGUY  
{ 2Tagr1L  
try{ hy`?E6=9+  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); fP. 6HF_p_  
int nCount = input.readInt(); wbst8*$  
nStartPos = new long[nCount]; lGOgN!?i  
nEndPos = new long[nCount]; 3h *!V6%q  
for(int i=0;i<nStartPos.length;i++) l
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{ fc |GArL#}  
nStartPos = input.readLong(); 
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nEndPos = input.readLong(); ;9c<K  
} lQe%Yh >rl  
input.close(); {62n7'U{  
}  {PVWD7  
catch(IOException e){e.printStackTrace ();} ?]}8o}G  
catch(Exception e){e.printStackTrace ();} iy%ZQ[Un  
} #N`~xZ|$  
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private void processErrorCode(int nErrorCode) j!_^5d#d  
{ :8|3V~%m  
System.err.println("Error Code : " + nErrorCode); [#rdfN'?U  
} u-M$45vct  
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//停止文件下载 *2C79hi1  
public void siteStop() ,,#rv-*  
{ YM.IRj2/1  
bStop = true; @P5@&G  
for(int i=0;i<nStartPos.length;i++) ecI 2]aKi  
fileSplitterFetch.splitterStop(); ~rJw$v  
}~~^ZtJ\  
:!YJ3:\  
} \C2P{q/m  
} v4a4*rBI"  
//负责部分文件的抓取 #`)-$vUv^f  
**FileSplitterFetch.java ne24QZ~}  
*/ _3G)S+7#  
package NetFox; M "P  
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import java.io.*; M9jo<+  
import java.net.*; YM*6W?  
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public class FileSplitterFetch extends Thread { a`X&;jH0ef  
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String sURL; //File URL k^\&.63(  
long nStartPos; //File Snippet Start Position 9Kx:^~}20o  
long nEndPos; //File Snippet End Position 4lf36K,  
int nThreadID; //Thread's ID Fj('l  
boolean bDownOver = false; //Downing is over SFgIY]  
boolean bStop = false; //Stop identical s@[t5R  
FileAccessI fileAccessI = null; //File Access interface p[cL#fBz  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException !;!~5"0~"  
{ /lQ0`^yB  
this.sURL = sURL; ko>O~@r  
this.nStartPos = nStart; VEKITBs  
this.nEndPos = nEnd; 4 Wd5Goe:  
nThreadID = id; LA%al @  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 sq|@9GS0T  
} b!~%a  
hg=G//
 
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public void run() @M?EgVmW  
{ (NN14  
while(nStartPos < nEndPos && !bStop) oYErG],  
{ h`rjDd  
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try{ #$C]0]|  
URL url = new URL(sURL); wSF#;lqd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
CyDf[C)=  
httpConnection.setRequestProperty("User-Agent","NetFox"); #R4KBXN  
String sProperty = "bytes="+nStartPos+"-"; L;7mt 4H  
httpConnection.setRequestProperty("RANGE",sProperty); [F{a-i-  
Utility.log(sProperty); P]{.e UB@c  
(w B[ ]O$@  
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InputStream input = httpConnection.getInputStream(); &'\+Z  
//logResponseHead(httpConnection); #e269FwN  
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byte[] b = new byte[1024]; |o) _=Fx  
int nRead; n(S-F g  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ,)G+h#Y[*  
{ t3JPxg]0k'  
nStartPos += fileAccessI.write(b,0,nRead); v("vUqhx2+  
//if(nThreadID == 1) NL})_.Og  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }*+?1kv  
} IvLo&6swW  
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Utility.log("Thread " + nThreadID + " is over!"); x"kc:F  
bDownOver = true; ]e0yC  
//nPos = fileAccessI.write (b,0,nRead); } $:uN  
} 11Kbj`sRZ  
catch(Exception e){e.printStackTrace ();} ZVo%ssVt  
} "*o54z5"  
} /rsr|`#  
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//打印回应的头信息 ?`+46U%  
public void logResponseHead(HttpURLConnection con) QN=a{  
{ r3a$n$Qw  
for(int i=1;;i++) )+]8T6~ N  
{ VV/6~jy0  
String header=con.getHeaderFieldKey(i); Y,O)"6ev  
if(header!=null) K/;FP'.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); t7|uZHKK  
Utility.log(header+" : "+con.getHeaderField(header)); (eS/Q%ZGK  
else (yk^%  
break; F,0@z/8a  
} HJl$v#]#+  
} J[9yQ  
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public void splitterStop() \Q.Qos  
{ sW)C6 #  
bStop = true; d4c-(ZRl  
} a\an  
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} %AbA(F  
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/* #W#GI"K  
**FileAccess.java Ui6f>0?  
*//文件访问(定位，写) d#:&Uw  
package NetFox; h4CDZ  
import java.io.*; srfFJX7*  
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public class FileAccessI implements Serializable{ UeB8|z  
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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 ;+]9KIa_Pq  
RandomAccessFile oSavedFile; '$u3i #.\  
long nPos; =ECw'  
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public FileAccessI() throws IOException QC.WR'.  
{ xq_%|p}y  
this("",0); Ws?BAfP  
} Gv[W)+3f  
)@.
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public FileAccessI(String sName,long nPos) throws IOException Ju$=Tn  
{ fq/F|c  
oSavedFile = new RandomAccessFile(sName,"rw"); 6GCwc
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this.nPos = nPos; xB{
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oSavedFile.seek(nPos); lTe}[@(  
} d;&'uiS  
U#G[#sd> K  
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public synchronized int write(byte[] b,int nStart,int nLen) \Ku=a{Ne  
{ +7?p&-r)x  
int n = -1; N#{d_v^H?d  
try{ 3#R~>c2  
oSavedFile.write(b,nStart,nLen); e#Jx|Ej=  
n = nLen; Tz.!  
} ey<u  
catch(IOException e) u`Djle  
{ R`ajll1  
e.printStackTrace (); NGB%fJ  
} r$=MBeT  
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return n; PETrMu<  
} M= !Fb  
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} +]
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/* x P{L%.  
**SiteInfoBean.java {'Nvs_{6  
*/ I=l() ET=  
package NetFox; rz+G]J  
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public class SiteInfoBean { b!SGQv(^M  
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private String sSiteURL; //Site's URL 6PT ,m  
private String sFilePath; //Saved File's Path +Y(cs&V*  
private String sFileName; //Saved File's Name }MY7<sMDOy  
private int nSplitter; //Count of Splited Downloading File eRIdN(pP  
aGmbB7[BZ  
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public SiteInfoBean() 9S)A6]  
{//nSplitter的缺省值为5 tOw[  
//default value of nSplitter is 5 Td![Id  
this("","","",5); r A9Rz^;xa  
} Ji:0J},m  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) IeJ@G)  
{ (OHd}YQ  
sSiteURL= sURL; m{0u+obi&w  
sFilePath = sPath; C,3yu,'  
sFileName = sName; D{s4Bo-  
this.nSplitter = nSpiltter; s
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+@K8:}lOW
 
} R)qK{wq(1E  
x8*@<]!  
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public String getSSiteURL() 69/qH_Y  
{ hdee]qLS  
return sSiteURL; MYeGr3V3  
} -X#qW"92q  
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public void setSSiteURL(String value) >eaK@
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{ =;HmU.Uek%  
sSiteURL = value; ~b{j`T  
} 9TW  
.[#bOp*  
We*c_;@<  
public String getSFilePath() jRIm_)  
{ ecy41y'~:  
return sFilePath; $Uxg$pqO  
} JSm3ZP|GqJ  
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public void setSFilePath(String value) T?E[LzZg  
{ - dt<w;>W  
sFilePath = value; S~DY1e54GF  
} b`sph%&  
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public String getSFileName() xF3H\`{4x  
{ ;F<)BEXC<  
return sFileName; E={W^k!Vz:  
} i<Be)Y-'  
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public void setSFileName(String value) o<-+y\J8K  
{ (&u)FB*  
sFileName = value; oWUDTio#[  
} dO[w3\~  
wfrWpz=FO  
d.&~n`Rv!p  
public int getNSplitter() C&'Y@GE5  
{ (8(z42  
return nSplitter; v+*l|!v  
} ico(4KSk  
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public void setNSplitter(int nCount) AcF;5h  
{ ^MWfFpJV!]  
nSplitter = nCount; ?%HtPm2< %  
} YtrMJ"  
} rLcQG  
|7I.DBjR;  
m H'jr$ ?  
/* !2N#H~{  
**Utility.java 6X:-Z3  
*/ O!uB|*  
package NetFox; 4>^ %_Xj[  
<u"#Jw/VP  
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public class Utility { V@K}'f~  
;
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public Utility() ? F fw'O  
{ 'F
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} ki^[~JS>'  
bah5 f  
//线程睡眠 W.n@  
public static void sleep(int nSecond) W^&t8
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{ s:cS 9A8  
try{ ~%Yh`c EP  
Thread.sleep(nSecond); xMhR;lKY  
} $YaL3n  
catch(Exception e) p9_45u`u2  
{ '7'cKp  
e.printStackTrace (); Z/uRz]Hi  
} :ykZ7X&  
} %_SE$>v^  
HA"dw2|  
//日志 [dU/;Sk5  
public static void log(String sMsg) "Jnq~7]  
{ S_2I8G^A  
System.err.println(sMsg); dGh<R|U3  
} ieS
5*@^k  
PD/JXExK  
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public static void log(int sMsg) Qn%*kU0X  
{ web&M!-  
System.err.println(sMsg); !b _<_Y{l  
} ~?b(2gn  
} a/)TJv  

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{/0,lic  
/* A7b7IM
[  
**TestMethod.java [V jd)%  
*/ l]v *h0!  
package NetFox; }.b[az\T  
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public class TestMethod { 053W2Si   
6/#= dv  
dqKTF_+VhA  
public TestMethod() Y?%6af+  
{ ///xx/weblogic60b2_win.exe v@t*iDa?7  
try{ @Qc['V)  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); wH${q@z_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); H8-,gV  
SiteFileFetch fileFetch = new SiteFileFetch(bean); B-&J]H  
fileFetch.start(); am"/Anml|  
} p6HZ2Q:a  
catch(Exception e){e.printStackTrace ();} 10}Zoq|)n  
)
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o$-8V:)6d  
} @$nI\n?*  
T:!sfhrZ~<  
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public static void main(String[] args) 40c#zCE  
{ 5W{>5.Arx)  
new TestMethod(); Y\%}VD2k  
} q90S>c,  
} ToMX7xz6  
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