http断点续传简单实现（java)

/* VLO!hA#  
**SiteFileFetch.java -^+!:0'
;  
*/ #Kd^t=k  
package NetFox; xU_Dg56z'&  
import java.io.*; KoL3CA"N  
import java.net.*; i`)h~V
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public class SiteFileFetch extends Thread { Rx>>0%e.  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Hp!c\z;  
long[] nStartPos; //开始位置 .*zWm  
long[] nEndPos; //结束位置 [TFd|ywn  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 cXY;Tw45  
long nFileLength; //文件长度 quEP"  
boolean bFirst = true; //是否第一次取文件 d5O_~xf&  
boolean bStop = false; //停止标志 X|iWnz+^  
File tmpFile; //文件下载的临时信息 eub2[,  
DataOutputStream output; //输出到文件的输出流 &>]c"?C*  
1>"[b8a/  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） /PuN+M  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,|r%tNh<8$  
{ vm y?8E6+  
siteInfoBean = bean; 9< $n'g  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Xi~%,~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Z+G.v=2q<  
if(tmpFile.exists ()) f,_EPh>  
{ ,fa'  
bFirst = false;
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read_nPos(); f1_b``M  
} V{y
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else !lk -MN.  
{ 1'G&PX  
nStartPos = new long[bean.getNSplitter()]; bI_T\Eft  
nEndPos = new long[bean.getNSplitter()]; +KzbaBK  
} 5UgxuuP4  
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} ;`f14Fb  
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public void run() Hido[  
{ G'M;]R9EP  
//获得文件长度 +6$|No  
//分割文件 ?b8 :  
//实例FileSplitterFetch 3m#/1=@o  
//启动FileSplitterFetch线程 \pVmSac,  
//等待子线程返回 dN%
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try{ Gz,?e]ZV  
if(bFirst) 'kC,pN{->  
{ 5S EyAhB  
nFileLength = getFileSize(); /YLHg5n8+  
if(nFileLength == -1) 1j!LK-  
{ pr) `7VuKp  
System.err.println("File Length is not known!"); NZTG)<  
} XDtMFig  
else if(nFileLength == -2) iaAj|:  
{ WE*L=_zDS  
System.err.println("File is not access!"); @5rl;C  
} 8?za&v  
else '<JNS8h  
{ =sYUzYm  
for(int i=0;i<nStartPos.length;i++) (T9Q6\sa  
{ Vx<`6uv
 
nStartPos = (long)(i*(nFileLength/nStartPos.length)); .yF@Ow  
} <Pm!#)-g9  
for(int i=0;i<nEndPos.length-1;i++) <?&Y_  
{ Y_gMoo  
nEndPos = nStartPos[i+1]; w1&\heSQ  
} I0qSx{K  
nEndPos[nEndPos.length-1] = nFileLength; (qbL=R"  
} n`Y"b&  
} 5Qh$>R4!"  
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XYh)59oM%  
//启动子线程 dKk#j@[n"  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; GGQ%/i]:  
for(int i=0;i<nStartPos.length;i++) X"k:+  
{ V`WSZ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z0'&@P$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2A95vC'u>|  
nStartPos,nEndPos,i); LJc"T)>$`  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fFNscY<4w  
fileSplitterFetch.start(); a$
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} CQANex4&\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), li37*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); j%`% DQ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", hE;|VSdo  
nEndPos = " + nFileLength); l"rX'g?  
// fileSplitterFetch[nPos.length-1].start(); TFAd  
JE*d-  
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//等待子线程结束 MtD0e@  
//int count = 0; PU2^4h/[`  
//是否结束while循环 _yRD*2 !;  
boolean breakWhile = false; ;Zy[2M  
c<a)Yqf"]  
}WV}in0
 
while(!bStop) YZk.{#^c  
{ (UB?UJ
c  
write_nPos(); FX1H2N(  
Utility.sleep(500); S aH':UN  
breakWhile = true; FTQNS8  
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for(int i=0;i<nStartPos.length;i++) |kGQ~:k+P  
{ 5~[m]   
if(!fileSplitterFetch.bDownOver) nCS" l5  
{ 9Wv}g"KY0  
breakWhile = false; NXCvS0/h  
break; DS1{~_>nFu  
} !+u K@z&G  
} ;O
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if(breakWhile) Z0[d;m*  
break; ]5r@`%9  
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//count++; :>y;*x0w  
//if(count>4) ni85Ne$  
// siteStop(); t$e'[;w  
} GO)5R,  
!(HPx@_  
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System.err.println("文件下载结束！"); ek"Uq RY  
} 4a=QTq0p  
catch(Exception e){e.printStackTrace ();} mxE
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} Xp.$FJ1)  
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^ -4~pDv^  
//获得文件长度 TM5 Y(Q*  
public long getFileSize() '3b'moy  
{ 61w ({F  
int nFileLength = -1; .JOZ2QWm<  
try{ ?<` ;lu/eL  
URL url = new URL(siteInfoBean.getSSiteURL()); CTS1."kx1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); UqD ]@s`  
httpConnection.setRequestProperty("User-Agent","NetFox"); PthgxB^  
nV`U{}x  
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int responseCode=httpConnection.getResponseCode(); guG&3{&\s  
if(responseCode>=400) ?rjB9AC_;t  
{ s"XwO8yhM  
processErrorCode(responseCode); S1[, al  
return -2; //-2 represent access is error ^ L]e]<h(  
} d'"|Qg_'  
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String sHeader; Gr4v&Mz:  
>(-A"jf  
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for(int i=1;;i++) i),bAU!+m  
{ %E5b}E#  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); eyuyaSE  
//Utility.log(in.readLine()); q^:VF()d_z  
sHeader=httpConnection.getHeaderFieldKey(i); q|:wzdmNZ  
if(sHeader!=null) 3FtL<7B'.  
{ )3)7zulnXH  
if(sHeader.equals("Content-Length")) v2I? 5?j  
{ 4BSqL!i(  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 4i PVpro  
break; |;7mDhj=  
} r ^\(M {  
} L
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else S43J
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break; xr{Ym99E$  
} `KN>0R2k  
} x9AFN  
catch(IOException e){e.printStackTrace ();} lKB9n}P  
catch(Exception e){e.printStackTrace ();} zPxR=0|  
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Utility.log(nFileLength); )|vy}Jf7  
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return nFileLength; 2Kf/Id1  
} q" f65d4c  
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//保存下载信息（文件指针位置） i6KB\W2  
private void write_nPos() A[8m3L#k  
{ ol*,&C:{  
try{ 4qz+cB_  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Uns%6o  
output.writeInt(nStartPos.length); [8a(4]4  
for(int i=0;i<nStartPos.length;i++) yKoZj   
{ y]0O"X-G  
// output.writeLong(nPos); p<=Lh47 =  
output.writeLong(fileSplitterFetch.nStartPos); ~f(5l.  
output.writeLong(fileSplitterFetch.nEndPos); ;aV3j/  
}  =aZ d>{Y  
output.close(); (^35cj{s  
} "qNFDr(WM  
catch(IOException e){e.printStackTrace ();} 9zb1t1[W  
catch(Exception e){e.printStackTrace ();} gK QJ^a\!  
} 7;o:r$08&}  
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//读取保存的下载信息（文件指针位置） J?w_DQa
 
private void read_nPos() ?UAuUFueA  
{ Ba@~:  
try{ \^*:1=|7u]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); xy7A^7Li  
int nCount = input.readInt(); A{ ~D_q  
nStartPos = new long[nCount]; a8JAJkFB  
nEndPos = new long[nCount]; ?E"192,z@  
for(int i=0;i<nStartPos.length;i++) /iFn=pk1?  
{
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nStartPos = input.readLong(); S>0%jCjW  
nEndPos = input.readLong(); h(HpeN%`#  
} ywA
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input.close(); oI{.{]  
} l.o/H|  
catch(IOException e){e.printStackTrace ();} B18BwY  
catch(Exception e){e.printStackTrace ();} |${4sUR  
} ~j'D%:[+VH  
; R}>SS'  
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private void processErrorCode(int nErrorCode) =G:Krc8w@  
{ pPBXUu'  
System.err.println("Error Code : " + nErrorCode); miaH,hm  
} j~k,d.17M  
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f?UI+TU  
//停止文件下载 +d6onO{8  
public void siteStop() R%WY!I8C  
{ ?>h ~"D#  
bStop = true; wuH*a3(  
for(int i=0;i<nStartPos.length;i++) Iw`tbN L[  
fileSplitterFetch.splitterStop(); * @4@eQF  
; BN81;  
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} T/3LJGnY  
} e"t0 rScA  
//负责部分文件的抓取 >[;W~*  
**FileSplitterFetch.java -i`jS_-Cv-  
*/ {$z54nvw$  
package NetFox; 5G`HJ6  
:hZM$4  
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import java.io.*; XPX?+W=mv  
import java.net.*; TmG)
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public class FileSplitterFetch extends Thread { e_=K0fFz  
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String sURL; //File URL SY+0~5E  
long nStartPos; //File Snippet Start Position efXnF*Z  
long nEndPos; //File Snippet End Position /TpTR-\I0  
int nThreadID; //Thread's ID _eKO:Y[e  
boolean bDownOver = false; //Downing is over l r&7 qu  
boolean bStop = false; //Stop identical xsH1)  
FileAccessI fileAccessI = null; //File Access interface /}m)FaAi  
mXRkR.zu+  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException s* (a  
{ ai_ve[A  
this.sURL = sURL; <,M"kF:  
this.nStartPos = nStart; Y:!L  
this.nEndPos = nEnd; 3+
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nThreadID = id; {XOl &  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 '0HOL)cIz  
} = QBvU)Ki  
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public void run() KnG7w^  
{ ).71gp@&  
while(nStartPos < nEndPos && !bStop) LCB-ewy#E  
{ Ixa0;nxj  
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try{ oai=1vt@  
URL url = new URL(sURL); MKBDWLCB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w)EYj+L  
httpConnection.setRequestProperty("User-Agent","NetFox"); f!'i5I]  
String sProperty = "bytes="+nStartPos+"-"; ok\-IU?  
httpConnection.setRequestProperty("RANGE",sProperty); bT,_=7F  
Utility.log(sProperty); m Q9
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InputStream input = httpConnection.getInputStream(); Af _4Z]F  
//logResponseHead(httpConnection); QL7b<xDQC*  
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byte[] b = new byte[1024]; *z~,|DQ(A  
int nRead; Ev7.!  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) P{o)Ir8Tt  
{ 3]*Kz*i  
nStartPos += fileAccessI.write(b,0,nRead); '9}&@;-_  
//if(nThreadID == 1) hE&6;3">  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); B\Nbt!Ps  
} UA$IVK&{  
:r*hY$v  
~Gfytn9x.;  
Utility.log("Thread " + nThreadID + " is over!"); KsKE#])&l  
bDownOver = true; ?EFRf~7JP  
//nPos = fileAccessI.write (b,0,nRead); wK(]E%\  
} ,6>3aD1w~q  
catch(Exception e){e.printStackTrace ();} ^-"I
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} mh3S?Uc  
} ~Zr}QO}G  
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//打印回应的头信息 "6jt$-?  
public void logResponseHead(HttpURLConnection con) NH/A`Wm  
{ gv`_+E{P  
for(int i=1;;i++) u$d[&|`>_  
{ -.h)CM@L  
String header=con.getHeaderFieldKey(i); 5
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if(header!=null) {[!<yUJ`S#  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ozRO:*51  
Utility.log(header+" : "+con.getHeaderField(header)); ce;7  
else =ANr|d  
break; _KM? ?&  
} =dAAb\:  
} !8G)`'  
aGbG@c8PRi  
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public void splitterStop() M_E,pg=rWI  
{ kPX+n+$  
bStop = true; Ph=NH8  
} $)#orZtzr  
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} 9Vt ^q%DC  
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/* E*YmHJ:k  
**FileAccess.java (7g"ppf  
*//文件访问(定位，写) /GgID!8  
package NetFox; Cu+p!hV  
import java.io.*; <MS>7Fd2  
p:xyy*I  
`Q*`\-8J  
public class FileAccessI implements Serializable{ -YQh F;/  
4V:W 8k 9D  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 6y^ zC?  
RandomAccessFile oSavedFile; Y~}MfRE3z  
long nPos; ~<_#%R!  
6,=Z4>  
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public FileAccessI() throws IOException *O$
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{ &| (K#|^@  
this("",0); .eN
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} =aVvv+T
 
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I">">  
public FileAccessI(String sName,long nPos) throws IOException X`g<"Ka  
{ +t,b/K(?]  
oSavedFile = new RandomAccessFile(sName,"rw"); fn<dr(Dx  
this.nPos = nPos; zLl-{Kk  
oSavedFile.seek(nPos); HAH\#WE  
} 3Ws(],Q  
r%;|gIky  
G `|7NL   
public synchronized int write(byte[] b,int nStart,int nLen) x_7$g<n  
{ {gzQ/|}#z-  
int n = -1; h!wq&Vi4  
try{ GSRf/::I}4  
oSavedFile.write(b,nStart,nLen);  GAfc9  
n = nLen; p.:|Z-W$  
} - egTZW-  
catch(IOException e) eztK`_n  
{ S
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e.printStackTrace (); {e&fBX6;  
} |r+ x/,2-  
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~;oXLCL0})  
return n; #btz94/~O  
} ILCh1=?{9r  
{U-
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} F(1E@xs  
5"h4XINZ  
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/* -Jd

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**SiteInfoBean.java GpPM?  
*/ ^X_ ;ZLg.  
package NetFox; 0-PT%R  
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\X %#-y  
public class SiteInfoBean { GQg 2!s(  
kt Z~r. +  
&DGqY5=  
private String sSiteURL; //Site's URL "`K_5"F  
private String sFilePath; //Saved File's Path \@PMj"p|:  
private String sFileName; //Saved File's Name =9,mt K~  
private int nSplitter; //Count of Splited Downloading File Y
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dZ"}wKbO  
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public SiteInfoBean() e3n^$'/\r  
{//nSplitter的缺省值为5 [e,xC!2  
//default value of nSplitter is 5 53/$8=  
this("","","",5); ;PVE= z+y  
} {31X  
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2G|}ENC  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) lYe2;bu  
{ /E/6(c  
sSiteURL= sURL; (M;d*gNr  
sFilePath = sPath; @<P;F  
sFileName = sName; MuO(%.H  
this.nSplitter = nSpiltter; :hOB  
,PpVZq~  
%dw0\:P?Q  
} ?/}IDwuh  
/slCK4vFc  
?`vGpi~  
public String getSSiteURL() ,P`:`XQ>_B  
{ \B 8j9  
return sSiteURL;  Dt5AG  
} kK/>,Eg  
hRKJKQ@7
 
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public void setSSiteURL(String value) cl23y}J_?  
{ Hv"qRuQ?[  
sSiteURL = value; PtPx(R3  
} 4EeVO5  
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public String getSFilePath() r 'ioH"=  
{ rf/]VAK  
return sFilePath; 1.2qh"#  
} ty;a!yjC  
&6GW9pl[  
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public void setSFilePath(String value) abVEi[nP  
{ 0kp{`3ce  
sFilePath = value; Ayw {I#"  
} 4d`f?8vS  
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4\U"e*  
public String getSFileName() YqKQm+G  
{ x;JC{d#  
return sFileName; W'zI~'K  
} FLumI-se!  
 ^AwDZX  
^6UE/4x!y  
public void setSFileName(String value) wVv@   
{ ,=u!hg  
sFileName = value; 2j^8{Agz  
} O8*yho  
q\s>Oe6$  
/GP:W6:6z6  
public int getNSplitter() FYa
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{ #FGj)pu  
return nSplitter; of_Om$  
} > W^"*B  
s|Vbc@t  
{bNKyT  
public void setNSplitter(int nCount) )"bP]t^_  
{ Nk\/lK\  
nSplitter = nCount; f2P2wt.$  
} X5)].[d  
} TwZmZE ?!  
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as  
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/* M;X}v#l|XI  
**Utility.java Qv;^nj{\qV  
*/ %vWh1-  
package NetFox; om0g'Qa  
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public class Utility { /pgn?e'lk  
 4V 5  
y=e|W=<D&  
public Utility() RZ9chTX/  
{ D0p>Q^w  
-H](2}  
'CjcFP  
} {dNWQE*\c  
sTzt  
//线程睡眠 c ^+{YH;k  
public static void sleep(int nSecond) X_J(P?  
{ Xa=oEG  
try{ D]5cijO6  
Thread.sleep(nSecond); idP2G|Z  
} ujoJ6UOG  
catch(Exception e) g5hMZPOmP  
{ I(
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e.printStackTrace (); 05[k@f$n  
} l%xjCuuhU  
} V%'+ ob6  
j |:{ B  
//日志 J*r%b+  
public static void log(String sMsg) \9jvQV/y  
{ .hytn`+9  
System.err.println(sMsg); (Q][d+} /  
} &6#Ft]6~  

fpPHw)dTd  
]=T-Cv=t  
public static void log(int sMsg) {);<2]o| 6  
{ lX|d:HFtP  
System.err.println(sMsg); 0%GQXiy  
} i.6+CA  
} 4
^AdSuV  
vvcA-k?  
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/* Pa\"l'!>^  
**TestMethod.java KMogwulG  
*/ Ga#5xAI{a  
package NetFox; 4ROuy+Ms'  
gKWsmx!["  
EnnE@BJ"  
public class TestMethod { -k"5GUc|  
t7qY!S (  
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public TestMethod() DE_<LN  
{ ///xx/weblogic60b2_win.exe A

vn)%9  
try{ w{5v*SHl}`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); tw%z!u[a  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Dt\rMSjZ9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); kB $?A8Olu  
fileFetch.start(); b1ma(8{{{  
} cfA)Ui  
catch(Exception e){e.printStackTrace ();} }D\i1/Y  
k86j& .m
_  
l#k&&rI5x.  
} &d/x1=  
;<)<4N"  
:B"Y3
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public static void main(String[] args) m6^n8%  
{ b?{\
t;  
new TestMethod(); urA kV#d#  
} R8![ $mkU  
} *wD| eK7  
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