http断点续传简单实现（java)

/* uN 62>  
**SiteFileFetch.java c5e\ckqm^  
*/ ]gksyxn3  
package NetFox; C4tl4df9  
import java.io.*; 2H[aY%1T  
import java.net.*; =bWq 3aP)P  
#\BI-zt  
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public class SiteFileFetch extends Thread { r5!M;hU1j  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ukf\*  
long[] nStartPos; //开始位置 tq[",&K  
long[] nEndPos; //结束位置 7 afA'.=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 gsWlTI  
long nFileLength; //文件长度 y%bqeo L~  
boolean bFirst = true; //是否第一次取文件 b^DV9mO4J  
boolean bStop = false; //停止标志 *.%)rm  
File tmpFile; //文件下载的临时信息 xKST-:c+  
DataOutputStream output; //输出到文件的输出流 {mnSTL`  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） L_ qv<iM$  
public SiteFileFetch(SiteInfoBean bean) throws IOException D.R|HqZ  
{ 2G5!u
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siteInfoBean = bean; '3UIri
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); GdeR#%z  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); zw0 r i6  
if(tmpFile.exists ()) 'Oy5G7^R  
{ GVc[p\h(  
bFirst = false; V'f5-E0  
read_nPos();
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} 7K]U|K#  
else b;`#Sea  
{ Xa%&.&V  
nStartPos = new long[bean.getNSplitter()]; bc=u1=~w  
nEndPos = new long[bean.getNSplitter()]; j X!ftm2  
} ?CW^*So  
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} ^@LhUs>3  
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public void run() ><  _Z  
{ 2:HP5  
//获得文件长度 y7IbE  
//分割文件 Y=Ar3O*F  
//实例FileSplitterFetch
n.Eoi4jV'  
//启动FileSplitterFetch线程 b}?@syy8  
//等待子线程返回 # pjyhH@  
try{ 'UXj\vJ3E  
if(bFirst) [cLU
*:  
{ >&Ui*  
nFileLength = getFileSize(); W "\tkh2  
if(nFileLength == -1) Zc\h15+P  
{ q~' K9  
System.err.println("File Length is not known!"); V.QzMF"o  
} K0DXOVT\  
else if(nFileLength == -2) z1SMQLk  
{ <j1d~XU}  
System.err.println("File is not access!"); WVT5VJ7*  
} xlPcg7  
else E_![`9i  
{ kG;eOp16R  
for(int i=0;i<nStartPos.length;i++) ?4,*RCaI  
{ :af;yu  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); qJFgbq4-  
} y%IG:kZ,  
for(int i=0;i<nEndPos.length-1;i++) ;/)Mcx]n  
{ ofPF}  
nEndPos = nStartPos[i+1]; T?]kF-   
} QC\g%MVG  
nEndPos[nEndPos.length-1] = nFileLength; TA@tRGP>  
} 9?l?G GmQ  
} v-7Rb)EP  
m
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//启动子线程 _sf#J|kQ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; JW%/^'  
for(int i=0;i<nStartPos.length;i++) -|k&L}\OB0  
{ =ve*g&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), g@k#J"Q'[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), vU8FHVytV  
nStartPos,nEndPos,i); "3Xv%U9@  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); rKy-u  
fileSplitterFetch.start(); G1?0Q_RN  
} J2oWssw"  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), lZS_n9Sc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); e0~sUVYf  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 22al  
nEndPos = " + nFileLength); Mg a@JA"  
// fileSplitterFetch[nPos.length-1].start(); Ha=_u+@  
=YXe1$ $  
4[LLnF--  
//等待子线程结束 {;Y 89&*R  
//int count = 0; x!"SD3r=4>  
//是否结束while循环 O:5Rp_?^  
boolean breakWhile = false; AK@`'$  
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while(!bStop) qLQ <1>u  
{ X6LhM
 
write_nPos(); 4GU/V\e|  
Utility.sleep(500); (xZr ]v ]U  
breakWhile = true; H[BD)  
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for(int i=0;i<nStartPos.length;i++) hzT{3YtY2  
{ V>b2b5QAH,  
if(!fileSplitterFetch.bDownOver) '%zN  
{ &v5G92  
breakWhile = false; 3I9T|wQ-]  
break; >63)z I  
} 7BL|x  
} /9x{
^  
if(breakWhile) _ztZ>'  
break; Vq3gceo'0A  
sU) TXL'_!  
;y>S7n>n:  
//count++; _GVE^yW~z  
//if(count>4) [[:UhrH-  
// siteStop(); J>rka]*  
} T>}0) s  
+hE',i.  
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System.err.println("文件下载结束！"); ^4c,U9J=  
} di~]HUZh)  
catch(Exception e){e.printStackTrace ();} ,N53Iic  
} 8zhBA9Y#~  
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//获得文件长度 6iG(C.b  
public long getFileSize() 6cM<>&e  
{ ` ^DjEdUN  
int nFileLength = -1; JnfqXbE  
try{ sLb8*fak  
URL url = new URL(siteInfoBean.getSSiteURL()); 1N8;)HLIBJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'T\dkSJv;V  
httpConnection.setRequestProperty("User-Agent","NetFox"); vxZg &SRK  
kw*)/$5]  
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int responseCode=httpConnection.getResponseCode(); o]Gguw5W{  
if(responseCode>=400) |6aJwe+*  
{ j~bAbOX12  
processErrorCode(responseCode); [F+(^- (  
return -2; //-2 represent access is error e}c&LDgU  
} NmJ`?-Z  
1BJ<m5/1%  
t8QRi!\=  
String sHeader; (Yv{{mIy  
;B~P>n}}_]  
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for(int i=1;;i++) *m9{V8Yi2  
{ OsQkA2=  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); `H>b5  
//Utility.log(in.readLine()); >H>gH2qp  
sHeader=httpConnection.getHeaderFieldKey(i); j(iuz^I  
if(sHeader!=null) %Tv^GP{}  
{ fiVHRSX60  
if(sHeader.equals("Content-Length")) [:iv4>ZZ  
{ "xe=N  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (luKn&826  
break; S,''>`w  
} Tkw;pb  
} T dk ,&8  
else )0k']g5  
break; :P$#MC  
} %T!J$a)qf  
} (CJ.BHu]  
catch(IOException e){e.printStackTrace ();} N2ied^* 0  
catch(Exception e){e.printStackTrace ();} TJ(K3/)Z  
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/*$hx@ih  
Utility.log(nFileLength); fKHE;A*>%  
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return nFileLength; -oyO+1V  
} @?kM'*mrZM  
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"Pz}@=  
//保存下载信息（文件指针位置） +oc >S  
private void write_nPos() 2;$k(x]  
{ a.@qGsIH  
try{ QAPu<rdJP  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 80pid[F  
output.writeInt(nStartPos.length); C/=XuKE-
t  
for(int i=0;i<nStartPos.length;i++) 9Q;c,]  
{ 9H0Hu]zM  
// output.writeLong(nPos); ]y@F8$D!  
output.writeLong(fileSplitterFetch.nStartPos); 1LnyWZ  
output.writeLong(fileSplitterFetch.nEndPos); 0d^Z uTN  
} ObG|o1b  
output.close(); Q=uRKh  
} /9pM>Cd*Z  
catch(IOException e){e.printStackTrace ();} Wg`AZ=t  
catch(Exception e){e.printStackTrace ();} ^|!I+  
} N K]B?  
3+Qxg+<  
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//读取保存的下载信息（文件指针位置） %
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private void read_nPos() DZS]AC*  
{ a:,y Z  
try{ `d]IX^;  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); H*^
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int nCount = input.readInt(); =sJ _yq0#R  
nStartPos = new long[nCount]; Z?P~z07  
nEndPos = new long[nCount]; #H?t!DU  
for(int i=0;i<nStartPos.length;i++) @Ky> 9m{  
{ RyJ 1mAC  
nStartPos = input.readLong(); JA)?p{j  
nEndPos = input.readLong(); V r(J+1@  
} `:m!~  
input.close(); / $  :j  
} )4>2IQ  
catch(IOException e){e.printStackTrace ();} D4Al3fe  
catch(Exception e){e.printStackTrace ();} =L|tp%!  
} @`opDu!  
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private void processErrorCode(int nErrorCode) `1*nL,i  
{ W7"{r)7  
System.err.println("Error Code : " + nErrorCode); I:bD~Fb3  
} v
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99$ 5`R;  
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//停止文件下载 T9)nQ[  
public void siteStop() f4-a?bp  
{ 4(}J.-B  
bStop = true; ]5~s"fnG  
for(int i=0;i<nStartPos.length;i++) S##1GOO
 
fileSplitterFetch.splitterStop(); dkgSvi :!  
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} >Vy>O&r  
} j'[m:/  
//负责部分文件的抓取 iGB_{F~t4}  
**FileSplitterFetch.java du$|lxC  
*/ 0;S,tJg  
package NetFox; kGpa\c g1  
q~CA0AR  
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import java.io.*; f\'{3I29  
import java.net.*; (~zd6C1.  
@(P=Eh  
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public class FileSplitterFetch extends Thread { hcVJBK  
LjL[V'JL  
go+Q~NV  
String sURL; //File URL A:(*y 2  
long nStartPos; //File Snippet Start Position Dnc(l(  
long nEndPos; //File Snippet End Position  h:lt<y  
int nThreadID; //Thread's ID ;8!Z5H  
boolean bDownOver = false; //Downing is over G'YH6x,  
boolean bStop = false; //Stop identical 8|E'>+ D_-  
FileAccessI fileAccessI = null; //File Access interface BpX6aAx  
`eu9dLzH  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException nG_6oe*=I  
{ x0d~i!d  
this.sURL = sURL; r`c_e)STO  
this.nStartPos = nStart; kB5.(O  
this.nEndPos = nEnd; g$dsd^{O7  
nThreadID = id; 3\T2?w9u(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 099sN"kf  
} 8kP3+  
(C]o,7cYS  
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public void run() `9k0Gd  
{ s,a}?W  
while(nStartPos < nEndPos && !bStop) i-yy/y-N  
{ h*u`X>!!  
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try{ h*ZC*eV>  
URL url = new URL(sURL); 9n}p;3{f  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); QRLt9L  
httpConnection.setRequestProperty("User-Agent","NetFox"); RCRpzY+@  
String sProperty = "bytes="+nStartPos+"-"; dL|+d:v  
httpConnection.setRequestProperty("RANGE",sProperty); !n^OM?.
4  
Utility.log(sProperty); &~CY]PN.  
1>L(ul(qGF  
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InputStream input = httpConnection.getInputStream(); \c^45<G2qA  
//logResponseHead(httpConnection); %v2R.?F8  
+**!@uY  
1 hg}(Hix  
byte[] b = new byte[1024]; Y2'cs~~$Ce  
int nRead; Xy%p"b<  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) NY?;erX  
{ A=Ss6-Je  
nStartPos += fileAccessI.write(b,0,nRead); =_0UD{"_0  
//if(nThreadID == 1) aM4k *|H?  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); GKcv<G208  
} [V:\\$  
KF4PJi;*  
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Utility.log("Thread " + nThreadID + " is over!"); vB+ '  
bDownOver = true; jv&!Kw.Ug  
//nPos = fileAccessI.write (b,0,nRead); W0}B'VS.I  
} }- Wa`t7U  
catch(Exception e){e.printStackTrace ();}
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} \}]!)}G  
} YM DMH"3  
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//打印回应的头信息 VcoOeAKL  
public void logResponseHead(HttpURLConnection con) a5w:u5  
{ ~jsLqY*(+  
for(int i=1;;i++) i E CrI3s  
{ `UBYp p  
String header=con.getHeaderFieldKey(i); S%`0'lzzj  
if(header!=null) `:axzCrCfR  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 8.[SU  
Utility.log(header+" : "+con.getHeaderField(header)); %RDI!e<e}  
else x.q+uU$^  
break; 5ls6t{Ci  
} >KJ+-QuO&  
} $LU"?aAW  
%HJK;   
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public void splitterStop() {D=@n4JO  
{ `]W|8M  
bStop = true; nvPwngEQm  
} y99mC$"Ee`  
r-<F5<H+K@  
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} z[;z>8|c  
bcYF\@};  
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/*
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**FileAccess.java ->V<DZK  
*//文件访问(定位，写) ^(FdXGs[  
package NetFox; d m`E!R_  
import java.io.*; qo|WXwP2  
o !U 6?  
tdu$pC6  
public class FileAccessI implements Serializable{ .;N1N^  
g?ULWeZg5  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 >m$ 1+30X  
RandomAccessFile oSavedFile; FIsyiSY<j  
long nPos; pS7w' H  
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:n-]>Q>5=k  
public FileAccessI() throws IOException ~5oPpTAe  
{ PGoh1Uu  
this("",0); {.INnFGP@)  
} k-^mIJo}  
6g)GY"49  
H
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public FileAccessI(String sName,long nPos) throws IOException 1bn^.768l  
{ W*I(f]8:y`  
oSavedFile = new RandomAccessFile(sName,"rw"); 71t*%  
this.nPos = nPos; "9Q40w\  
oSavedFile.seek(nPos); ,]d/Q<  
} XcUwr  
AiO$<CS  
][p>Y>:b-  
public synchronized int write(byte[] b,int nStart,int nLen) 9eQxit7  
{ y#z  
int n = -1; t,+nQ9  
try{ HK0!P*  
oSavedFile.write(b,nStart,nLen); 7Bd-!$j+  
n = nLen; )x=1]T>v"'  
} vkEiOFU!u  
catch(IOException e) hFy;ffs.  
{ LQRQA[^  
e.printStackTrace (); HOJs[m
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} (Hb:?(  
[QoK5Yw{  
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return n; 9CWezI+  
} &&8IU;J  
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} B][U4WJ)  
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/* fY51:0{  
**SiteInfoBean.java qh|_W(`y  
*/ c]n1':FT"  
package NetFox; y[)>yq y  
26I_YL,S  
d\|?-hY`[  
public class SiteInfoBean { :*Z4yx  
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v4`"1Ss,K  
private String sSiteURL; //Site's URL t!W(_8j  
private String sFilePath; //Saved File's Path
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private String sFileName; //Saved File's Name yW1)vD7  
private int nSplitter; //Count of Splited Downloading File pz\ +U7  
* KDI}B>  
(a.z9nqGA  
public SiteInfoBean() ' V^6XI  
{//nSplitter的缺省值为5 4ew" %Cs*  
//default value of nSplitter is 5 P2BWuhF  
this("","","",5); }@'$b<!B  
} M"p  
:8=ikwQ  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) QwJVS(Gs4  
{ [!HEQ8 2g  
sSiteURL= sURL; Y)0*b5?1r  
sFilePath = sPath; 5cL83FQh  
sFileName = sName; LrM=*Rh,O  
this.nSplitter = nSpiltter; 9kN}c
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} "}u.v?HYz  
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public String getSSiteURL() fHE<(  
{ :|V$\!o'U  
return sSiteURL; jSh5!6O
  
} $2oTkOA   
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public void setSSiteURL(String value) BgurzS4-  
{ b
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sSiteURL = value; c]x1HvPE  
} #|Y5,a,{  
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public String getSFilePath() |{BIHgMh  
{ {C 6=[  
return sFilePath; *W4m3Lq  
} RkH W  
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public void setSFilePath(String value) wxR,OR  
{ j`JMeCG=Ee  
sFilePath = value; Pu7_ v  
} Ed0QQyC@9  
oI0M%/aM  
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public String getSFileName() !*s?B L  
{ H
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return sFileName; <6EeD5{*  
} ~+Rc}K  
}\
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public void setSFileName(String value) Fu SL}P  
{ <Y*+|T+&d  
sFileName = value; `_BNy=`s*  
} > A Khf  
^`*9QjY  
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public int getNSplitter() -MW_|MG  
{ 3*]eigi)  
return nSplitter; RTvqCp  
} 00G%gQXk,  
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public void setNSplitter(int nCount) YNLV9.P6  
{ Of-Rx/
 
nSplitter = nCount; DNOueU  
} &Lt}=3G  
} '{a/2
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/* '[U8}z3  
**Utility.java W0y '5`  
*/ ~o82uw?  
package NetFox; )`SES."  
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~"!]
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public class Utility { ZW-yP2  
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c]$i\i#  
public Utility() AjmVc])  
{ Ao&\EcIOT  
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} +!k&Yje  
>NqYyW,%  
//线程睡眠 #hW;Ju73  
public static void sleep(int nSecond) iDN;m`a  
{ 3t`P@n
L0;  
try{ 9iXeBC  
Thread.sleep(nSecond); ,/YF-L$(t  
} j;%
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catch(Exception e) 4FEk5D  
{ ]p*l%(dhY  
e.printStackTrace (); T#M,~lD  
} l=]cy-H  
} FjK3 .>'  
y]2qd35u_A  
//日志 flk=>
h|  
public static void log(String sMsg) ~oI1zNz/  
{  gG uZ8:f  
System.err.println(sMsg); d1T,eJ}  
} l-K9LTd  
7]^M>#  
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public static void log(int sMsg) EzDk}uKY0R  
{ HKF H/eV  
System.err.println(sMsg); 9w"h  
} E8>Rui@9  
} HuB<k3#sPy  
z)'Mk[  
#rxVd 7f  
/* RD\  
**TestMethod.java NxjB/N  
*/ 8*8Zc/{  
package NetFox; %TX@I$Ba  
=.
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}xBc0gr  
public class TestMethod { tYZ[68  
r~N"ere26  
i%ZW3MrY~  
public TestMethod() iOwx0GD.n  
{ ///xx/weblogic60b2_win.exe HU
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try{ bS
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?dD&p8{  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); M(jgd  
SiteFileFetch fileFetch = new SiteFileFetch(bean); )\sc83L  
fileFetch.start(); 9UKp?SIF  
} uIcn{RZ_z  
catch(Exception e){e.printStackTrace ();} .{
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cs T2B[f9D  
} s_x:T<]  
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public static void main(String[] args) A/s>PhxV  
{ '&.#  
new TestMethod(); !,[C]Q1  
} p[<Dk$7K  
}
<,3^|$c%  
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