http断点续传简单实现（java)

/* (q}LirR  
**SiteFileFetch.java wPcEv
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*/ 9GTp};Kg  
package NetFox; ,zK E$  
import java.io.*; ;3bUgI}.J  
import java.net.*; 3QdCu<eBZ  

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public class SiteFileFetch extends Thread { 2hryY  
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SiteInfoBean siteInfoBean = null; //文件信息Bean AKk&  
long[] nStartPos; //开始位置 HN5,MD[  
long[] nEndPos; //结束位置 qFq$a9w|@  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 WoNY8 8hT  
long nFileLength; //文件长度 2vsV:LS.  
boolean bFirst = true; //是否第一次取文件 /?z3*x  
boolean bStop = false; //停止标志 9v8^uPA  
File tmpFile; //文件下载的临时信息 ,LmP >Q.  
DataOutputStream output; //输出到文件的输出流 ~0?B  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） PqF&[M<)  
public SiteFileFetch(SiteInfoBean bean) throws IOException cJTwgm?  
{  tL<.B  
siteInfoBean = bean; w $`w
 
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^7=7V0>,:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); E2>+V{TF  
if(tmpFile.exists ()) \.Op6ECV9  
{ "{t]~urLd  
bFirst = false; asCcBp  
read_nPos(); /s=veiH  
} ~ ^   
else [/n@
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{ A%^7D.j  
nStartPos = new long[bean.getNSplitter()]; }owl7G3  
nEndPos = new long[bean.getNSplitter()]; *BF[thB:a  
} 'lu3BQvfh  
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} r=54@`O!  
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public void run() kBoQjOV`  
{ %*Uc,V  
//获得文件长度 @_#\qGY  
//分割文件 -R\dgS3  
//实例FileSplitterFetch )E^4U9v),  
//启动FileSplitterFetch线程 E\;%,19Ob  
//等待子线程返回 &%t&[Se_~  
try{ dB0 UZirb  
if(bFirst) 1v,R<1)&  
{ y%kZ##  
nFileLength = getFileSize(); u3pFH(
 
if(nFileLength == -1) %NC/zqPH~  
{ M:iH7K  
System.err.println("File Length is not known!"); e6jA4X+a  
} !H9^j6|  
else if(nFileLength == -2) WLfDXx2A  
{ ae]6F_Qtc*  
System.err.println("File is not access!"); UEfY'%x  
} X|ZAC!J5>  
else =_ b/g  
{ K,%CE ].  
for(int i=0;i<nStartPos.length;i++) d2-oy5cEB  
{ lmL$0{Yr  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); W}MN-0  
} ?A*!rW:l;  
for(int i=0;i<nEndPos.length-1;i++) G'(rjH>q  
{ ',LC!^:~Nw  
nEndPos = nStartPos[i+1]; ?#z<<FR  
} [+xsX
*+  
nEndPos[nEndPos.length-1] = nFileLength; HiH<'m"\.  
} PB8g4-?p6  
} U/|JAg#  
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//启动子线程 *)6\V}`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;^E_BJm  
for(int i=0;i<nStartPos.length;i++) pIYXYQ=Z  
{ s;* UP   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -V[x q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), VfP\)Rl
 
nStartPos,nEndPos,i); &/"a E  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >TBXT+  
fileSplitterFetch.start(); FOMJRq  
} vZ.<OD4  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), < *;GJ{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); jvL!pEC!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 9n;6zVV%`  
nEndPos = " + nFileLength); 5$cjCjY  
// fileSplitterFetch[nPos.length-1].start(); (K84J*;  
X?n=UebO^  
: T7(sf*!*  
//等待子线程结束 \x]\W#C  
//int count = 0; PJe_qP  
//是否结束while循环 L G5_\sY!  
boolean breakWhile = false; 8UqH"^9.Q7  
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while(!bStop) ,-8-Y>[  
{ 5I^;v;F  
write_nPos(); `M 'tuQ M  
Utility.sleep(500); ~ A
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breakWhile = true; @7C.0>W_A  
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for(int i=0;i<nStartPos.length;i++) 1;V_E2?V  
{ @DY"~ccH  
if(!fileSplitterFetch.bDownOver) QKlsBq  
{ f
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breakWhile = false; >][D"  
break; 0< vJ*z|_  
} !Hl]&  
} l!&ik9m  
if(breakWhile) 9!W$S[ABRB  
break; xy"'8uRi  
$/;K<*O$  
Yv@n$W`:  
//count++; WulyMcJ  
//if(count>4) bE'{zU}o  
// siteStop(); 0gaHYqkA>}  
} OWT%XUW=  
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System.err.println("文件下载结束！"); Sp:w _;{#  
} Rb&9!z  
catch(Exception e){e.printStackTrace ();} g
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} +qC[X~\  
]S[?tn  
 -D'XxOI  
//获得文件长度 Bdb}4X rL  
public long getFileSize() iRlZWgj4^  
{ ~"SQwE|  
int nFileLength = -1; Y7r;}^+WY  
try{ }l[e@6r F  
URL url = new URL(siteInfoBean.getSSiteURL()); U$& '>%#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >Bf3X&uS  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2%`= LGQC  
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int responseCode=httpConnection.getResponseCode(); dgoAaS2M  
if(responseCode>=400) OoH-E.lp  
{ sVw:d_ E  
processErrorCode(responseCode); !
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return -2; //-2 represent access is error m:[I$b6AY  
} p^<(.+P4  
H)7v$A,5%  
 ID,_0b  
String sHeader; 9,`i[Dzp  
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for(int i=1;;i++) L-D4>+  
{ 
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); z06,$OYz  
//Utility.log(in.readLine()); vB_3lAJt@  
sHeader=httpConnection.getHeaderFieldKey(i); ~nfOV*  
if(sHeader!=null) x"NQatdq  
{ 86Q3d%;-yo  
if(sHeader.equals("Content-Length")) 2J&~b8:  
{ "IT7.!=@9  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); %gAT\R_f  
break; (b<0=U  
} $KGMAg/H  
} dVEs^ZtI  
else |yeQz  
break; pQ:^ ziwa3  
} 6` TwP\!$/  
} Z}uY%]  
catch(IOException e){e.printStackTrace ();} )-Hs]D:  
catch(Exception e){e.printStackTrace ();} "}*D,[C5e  
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Utility.log(nFileLength); `7:uc@  
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return nFileLength; {Fw"y %a^  
} Si?s69  
/#M1J:SV  
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//保存下载信息（文件指针位置） U\?D;ABQ%  
private void write_nPos() ~. vridH  
{ S1U0sP@o  
try{ (!5Ta7X  
output = new DataOutputStream(new FileOutputStream(tmpFile)); o
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output.writeInt(nStartPos.length); eb\SpdM6  
for(int i=0;i<nStartPos.length;i++) S7f.^8  
{ Y_:jc{?  
// output.writeLong(nPos); b3E1S+\=~  
output.writeLong(fileSplitterFetch.nStartPos); S=!WFKcJR  
output.writeLong(fileSplitterFetch.nEndPos); <7\j\`  
} i3N{Dt  
output.close(); (is',4^b  
} $ItmYj.m  
catch(IOException e){e.printStackTrace ();} s"`~Xnf  
catch(Exception e){e.printStackTrace ();} m.m6.  
} :&vX0 Ce:  
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//读取保存的下载信息（文件指针位置） FDLo|aP/v  
private void read_nPos() [8sYEh  
{ KQNQ<OE4  
try{ [q2:d^_F
A  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); OlRXgJ  
int nCount = input.readInt(); 4@{cK
|  
nStartPos = new long[nCount]; d/Q#Z  
nEndPos = new long[nCount]; t2(X  
for(int i=0;i<nStartPos.length;i++) .))jR:{3  
{ =eU=\td^  
nStartPos = input.readLong(); vYm:V:7Y2  
nEndPos = input.readLong();
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} /f1]U LmC:  
input.close(); Q
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} t[`LG)  
catch(IOException e){e.printStackTrace ();} Gg'!(]v  
catch(Exception e){e.printStackTrace ();} .T9$O]:o  
} < bC'.m  
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private void processErrorCode(int nErrorCode) ,XEIg  
{ *gwlW/%Fz  
System.err.println("Error Code : " + nErrorCode); ]{6/6jl  
} u>fMO9X}2  
?;CIS$$r  
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//停止文件下载 D#&9zR86F  
public void siteStop() &>Ve4!i q  
{ Hh^ "c}  
bStop = true; =\%
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for(int i=0;i<nStartPos.length;i++) K`Kv.4  
fileSplitterFetch.splitterStop(); .8|wc  
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} j J{F0o  
} LRu,_2"  
//负责部分文件的抓取 rH`\UZ{cc  
**FileSplitterFetch.java prj(  
*/ 940:NOgm  
package NetFox; DH?n~qKpC  
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import java.io.*; nKm# kb  
import java.net.*; p [C 9g  
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public class FileSplitterFetch extends Thread { ~6t!)QATnp  
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%jjPs.  
String sURL; //File URL e&z@yy$  
long nStartPos; //File Snippet Start Position 0!3. .5==  
long nEndPos; //File Snippet End Position 2X\Pw  
int nThreadID; //Thread's ID -H6[{WVW!  
boolean bDownOver = false; //Downing is over m~ ah!QM  
boolean bStop = false; //Stop identical 6AJk6W^Z  
FileAccessI fileAccessI = null; //File Access interface jlj ge=#c2  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException "KP]3EyPc  
{ [y9a.*]u/@  
this.sURL = sURL; .gg0rTf=-  
this.nStartPos = nStart; 6U !P8q  
this.nEndPos = nEnd; vd ls
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nThreadID = id; DSwb8q  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 X=whZ\EZ  
} J]TqH`MA  
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public void run() X+]>pA  
{ lZ-U/$od  
while(nStartPos < nEndPos && !bStop) S3Y.+. 0U  
{ GmR3 a  
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try{ jvB[bS`<H  
URL url = new URL(sURL); U)8yd,qG[%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $$m0mK
  
httpConnection.setRequestProperty("User-Agent","NetFox"); P5?VrZy  
String sProperty = "bytes="+nStartPos+"-"; _ARG "  
httpConnection.setRequestProperty("RANGE",sProperty); BFW b0;+  
Utility.log(sProperty); Qa_V
 
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InputStream input = httpConnection.getInputStream(); -NJpql{Cb  
//logResponseHead(httpConnection); t/;0/ql\  
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byte[] b = new byte[1024]; y-3'qq'E  
int nRead; ^ 4<D%\  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) B$2b=\  
{ g{DehBM  
nStartPos += fileAccessI.write(b,0,nRead); LXo$\~M8G8  
//if(nThreadID == 1) s0' haU  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3
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} 7{}E{/  

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Utility.log("Thread " + nThreadID + " is over!"); =T9h7c R  
bDownOver = true; vIJ5iLF  
//nPos = fileAccessI.write (b,0,nRead); JhFn"(O  
} -Rw3[4>@O"  
catch(Exception e){e.printStackTrace ();} '*y(F*7+  
} OCrTzz8  
} V
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_+By=B.'  
P#hRqETw  
//打印回应的头信息 h]s6)tII  
public void logResponseHead(HttpURLConnection con) XA!a^@<H  
{ 3l?|+sU>O  
for(int i=1;;i++) AT1cN1:4?  
{ R/v|ZvI  
String header=con.getHeaderFieldKey(i); u&Ic  
if(header!=null) p*c(dkOe8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); N] sbI)Z@  
Utility.log(header+" : "+con.getHeaderField(header)); &AJ bx  
else Y|LL]@Lv  
break; k";dK*hD,  
} C!^A\T7p  
} MOQ6&C`7q  
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public void splitterStop() M^'1Q.K  
{ .9vS4C  
bStop = true; F&6#j  
} bBs{PI2(p1  
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} |V\{U j  
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/* s8,YQ5-  
**FileAccess.java o)5zvnu7  
*//文件访问(定位，写) twr{jdY9  
package NetFox; /^xv1F{  
import java.io.*; ZFtR#r(~41  
4N,[Gs<7  
x >ah,  
public class FileAccessI implements Serializable{ *}89.kCBF  
)(G<(eiD  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 tlQ6>v'  
RandomAccessFile oSavedFile; W]eILCo
 
long nPos; R7Qj<,  
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public FileAccessI() throws IOException E9\"@wu[d  
{ }SWfP5D@  
this("",0); T@ESMPeU:X  
} k4$zM/ob  
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public FileAccessI(String sName,long nPos) throws IOException (m2%7f.I  
{ y<6Sl6l*  
oSavedFile = new RandomAccessFile(sName,"rw"); *N$XQ{o  
this.nPos = nPos; u;9iuc`*  
oSavedFile.seek(nPos); 75;RAKGi  
} Xd:{.AXW  
}T.>p#z  
$Zyuhji^  
public synchronized int write(byte[] b,int nStart,int nLen) }'Ap@4  
{ B`QF;,3S  
int n = -1; U=JK  
try{ d"n>Q Tn\  
oSavedFile.write(b,nStart,nLen); PV,Z@qm@^  
n = nLen; PFpFqJ)Cs"  
} sBZn0h@  
catch(IOException e) ?M'CTz}<\  
{ |[n\'Xy;{
 
e.printStackTrace (); eWqS]cM#  
} \{<ml n  
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#tZ!D^GQHq  
return n; 6%p6BK6  
} CL2zZk{u_  
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} G h+;Vrx  
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/* e/Z{{FP%6  
**SiteInfoBean.java iyCH)
MA  
*/ mIf)=RW  
package NetFox; MX~h>v3_R4  
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2n>mISy+  
public class SiteInfoBean { !jl^__ .DR  
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private String sSiteURL; //Site's URL l1zPL3"u_^  
private String sFilePath; //Saved File's Path *H/)S5
 
private String sFileName; //Saved File's Name sB:
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private int nSplitter; //Count of Splited Downloading File XC6|<pru  
ww %c+O/  
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public SiteInfoBean() H$?MPA-c  
{//nSplitter的缺省值为5 W:<2" &7  
//default value of nSplitter is 5 ,+BFpN'  
this("","","",5); "n3n-Y#'  
} #vK99S2  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) x!I@cP#O  
{ ){/n7*#Th%  
sSiteURL= sURL; t_I-6`8o]  
sFilePath = sPath; nZj&Ma7R  
sFileName = sName; pDP* 3  
this.nSplitter = nSpiltter; "=]'"'B:  
G:+D1J]  
%
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} vB7]L9=@"  
}c8et'HYf  
S~ckIN]
 
public String getSSiteURL() N*m;A6?  
{ Jyd[Sc)  
return sSiteURL; {>9<H]cSP  
} w,6gnO  
i|H^&$|  
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public void setSSiteURL(String value) 'O~_g5kC  
{ De$Ic"Z9L  
sSiteURL = value; MIr[_  
} tWZ8(E$  
{nZP4jze  
8}oe))b  
public String getSFilePath() f~?5;f:E  
{ Yc[vH=gV}  
return sFilePath; A5fzyG
 
} C.=%8|Zy  
}rVLWt
 
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public void setSFilePath(String value) qzY:>>d'  
{ 3 P\4K  
sFilePath = value; J'#o6Ud  
} SPTx-b[  
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public String getSFileName() !=vsY]  
{ F+zHgE  
return sFileName; IL&R&8'  
} =AK6^v&on  
}e"2Nc_UG  
>0N$R|B&  
public void setSFileName(String value) L!5="s[}  
{ F ww S[3  
sFileName = value; J=t}N+:F`b  
} o9D#d\G  
nm|"9|/  
IQ#Kod;)  
public int getNSplitter() SX?hu|g_r  
{ `sdbo](76  
return nSplitter; U z)G Y  
} 0rDQJCm  
<aMihT)dd  
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public void setNSplitter(int nCount) d8jP@
>  
{ j}%C;;MPH  
nSplitter = nCount; $xcU*?=K  
} O[
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} >\Iy <M  
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5n2}|V$VqP  
/* a,t]>z95  
**Utility.java _A$V~Hp9q  
*/ {y!77>Q/  
package NetFox; rj eKG-Z@  
:n}t7+(>U  

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public class Utility { }WNgK
w  
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public Utility() :;3y^!  
{ FbPoyh  
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s\ ]Rgi>w  
} _l]rt  
W<H^V"^  
//线程睡眠 ra\2BS)X  
public static void sleep(int nSecond) &2Cu"O'.i  
{ JR/^Go$^  
try{
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Thread.sleep(nSecond); _@]@&^K$E  
} :e4[isI  
catch(Exception e) g5~1uU$O  
{ ")qO#b4  
e.printStackTrace (); 75H5{#)  
} 03y
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} %lK]m`(  
 7w|4BRL
 
//日志 FU(s jB  
public static void log(String sMsg) #w]:<R^  
{ ZsDn
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System.err.println(sMsg); wW;!L=j  
} )Chx,pcx<  
/a
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8!dA1]2;  
public static void log(int sMsg) !P* z=  
{ "(y|iS$^T  
System.err.println(sMsg); A!5)$>!o  
} Z}6H529[  
} }"9jCxXL  
[hXU$Y>"0  
 W-U[7n  
/* H!{Cr#=  
**TestMethod.java L sMS`o6  
*/ \5^GUT  
package NetFox; iu.+bX|b  
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public class TestMethod { R*psL&N  
?IV3"\5  
,`< [ej   
public TestMethod() M&O .7B1}  
{ ///xx/weblogic60b2_win.exe 1QH5<)Oa  
try{ {wp"zaa  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); owc#RW9 7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); > jvi7  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3YPoObY  
fileFetch.start(); CVBy&o"6A  
} +-OqO3R  
catch(Exception e){e.printStackTrace ();} hGvuA9d~  
8MPXrc,9-  
as6YjE.Yy  
} fg1["{\  
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_[.3I1kG  
public static void main(String[] args) [Y]\sF;J  
{ y"SVZ} ;|  
new TestMethod(); h"G#} C]  
} u($y<Q)=  
} K%A:W  
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