http断点续传简单实现（java)

/* O]m+u  
**SiteFileFetch.java ZIF49`Y4TF  
*/ FKmFo^^0  
package NetFox; JwXT%op9RP  
import java.io.*; z0do;_x]E  
import java.net.*; )K2HK&t:  
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ki)#d' }  
public class SiteFileFetch extends Thread { 1PatH[T[  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ZGd!IghL  
long[] nStartPos; //开始位置 9rA=pH%<>B  
long[] nEndPos; //结束位置 Ft!],n-n*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 NhYLtw^u  
long nFileLength; //文件长度 pf7it5  
boolean bFirst = true; //是否第一次取文件 J.|+ID+  
boolean bStop = false; //停止标志 T|TO}_x  
File tmpFile; //文件下载的临时信息 _hk.2FV:3m  
DataOutputStream output; //输出到文件的输出流 ?pzaG{  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） )<Hd T  
public SiteFileFetch(SiteInfoBean bean) throws IOException Alxx[l\<J  
{ &EnuE0BD  
siteInfoBean = bean; 9*(aUz9j  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); IOV(seEY  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @#-q^}3  
if(tmpFile.exists ()) qZA).12qS  
{ }_68j8`  
bFirst = false; _:"<[ >9  
read_nPos(); Kp,M"Y  
} TU 1I} ,  
else (/j); oSK  
{ Ck|8qUz-  
nStartPos = new long[bean.getNSplitter()]; ~7Tc$ "I  
nEndPos = new long[bean.getNSplitter()]; Mwr
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} >cCR2j,r  
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} #gcF"L||  
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{
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public void run() 8UVmv=T  
{ i|m3mcI%2  
//获得文件长度 <N9[?g)  
//分割文件 *^wm1|5  
//实例FileSplitterFetch Sh8"F@P8  
//启动FileSplitterFetch线程 Z7?~S
2{c  
//等待子线程返回  pn5Q5xc  
try{ jWE:ek*  
if(bFirst) 5qP:/*+  
{ [F6U+1n8e  
nFileLength = getFileSize(); /x1![$oC0  
if(nFileLength == -1) OUNd@o  
{ |]X  
System.err.println("File Length is not known!"); O|M{-)  
} ]&pds\  
else if(nFileLength == -2) y`XU~B)J1  
{ c>)Yt^q&K  
System.err.println("File is not access!"); 0PrLuej
z  
} Gnq?"</  
else p$3sME$L  
{ lH6OcD:kj  
for(int i=0;i<nStartPos.length;i++) pj?f?.^  
{ pxh"B\"4*  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); cj'}4(  
} 3skC$mpJHw  
for(int i=0;i<nEndPos.length-1;i++) &H`jL4S  
{ @-!}BUs?  
nEndPos = nStartPos[i+1]; K$E3QVa  
} j4R(B  
nEndPos[nEndPos.length-1] = nFileLength; 7M<'/s  
} /VN f{p  
} CyXRi}W.  
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//启动子线程 @8ppEFw  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; .w8J*JZ  
for(int i=0;i<nStartPos.length;i++) vbC\?\_  
{ ''\O
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Tw;3_Lj  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `u teg=  
nStartPos,nEndPos,i); \}"$ ?d'f  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f m)pulz  
fileSplitterFetch.start(); sWc*5Rt  
} )]H-BIuGm  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V#S9H!hm$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); e3nYbWBy]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", h1B16)  
nEndPos = " + nFileLength); uJC~LC N  
// fileSplitterFetch[nPos.length-1].start(); $4 S@  
|m^k_d!d  
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//等待子线程结束 Z:sg}  
//int count = 0; 6'!4jh  
//是否结束while循环 \b?" b  
boolean breakWhile = false; }:KEj_~.  
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while(!bStop) rMLp-aR'  
{ pxCK;]  
write_nPos(); '+?"iVVo  
Utility.sleep(500); NnDxq%l%  
breakWhile = true; 8TLgNQP
 
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for(int i=0;i<nStartPos.length;i++) 34%RZG_o'  
{ odjT:Vr  
if(!fileSplitterFetch.bDownOver) ;7E7!t^  
{ CsoiyY -2  
breakWhile = false; i*Sqda $  
break; 7 /VK##z  
} b`~p.c%(  
} P(,p'I;j  
if(breakWhile) -ZRO@&tMD  
break; +'I+o5*  
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//count++; VcSVu  
//if(count>4) \KQ71yqY  
// siteStop(); g1W.mAA3B  
} =/y]d<g  
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&U5{Hm9Ynr  
System.err.println("文件下载结束！"); _m gHJ0v'  
} {B?Wu3-  
catch(Exception e){e.printStackTrace ();} !'&n-Q  
} r^3acXl  
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//获得文件长度 S+atn]eU@  
public long getFileSize() VC\S'z  
{ \n8]M\<  
int nFileLength = -1; T|7}EAR=b  
try{ .<x&IJ 
/  
URL url = new URL(siteInfoBean.getSSiteURL()); gv)P]{%^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lOuHVa*}  
httpConnection.setRequestProperty("User-Agent","NetFox"); \{Z;:,S  
pb ~uE  
]* F\"C@  
int responseCode=httpConnection.getResponseCode(); j.w@
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if(responseCode>=400) aI6$?wus  
{ h]5C|M|  
processErrorCode(responseCode); JORGj0v  
return -2; //-2 represent access is error 7=TF.TW)  
} v/68*,z[  
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String sHeader; vq^f}id  
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s:/8[(A  
for(int i=1;;i++) 4'`{H@]tb  
{
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); U(Nu%  
//Utility.log(in.readLine()); K9$>Yxe|  
sHeader=httpConnection.getHeaderFieldKey(i); \?0&0;5  
if(sHeader!=null) Tx|Ir+f6L  
{ E.7  
if(sHeader.equals("Content-Length")) e;Ti&o}  
{ !`g~F\l  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); hyCh9YOu)  
break; ]h* c,.  
} ]>LhkA@V  
} Z&1T  
else )Dw,q~xgg0  
break; 8\^}~s$$A
 
} V5sg#|
&  
} =j5
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catch(IOException e){e.printStackTrace ();} -Zf@VW,NI  
catch(Exception e){e.printStackTrace ();} ;aI[=?<x  
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 [F0s!,P  
Utility.log(nFileLength); ~$:|VHl  
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return nFileLength; KIui(n#/  
} q|o}+Vr  
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//保存下载信息（文件指针位置） y#Fv+`YDl  
private void write_nPos() Ir`eL  
{ kbTm^y"  
try{ f,V<;s  
output = new DataOutputStream(new FileOutputStream(tmpFile)); \ e\?I9  
output.writeInt(nStartPos.length); \m7-rV6r  
for(int i=0;i<nStartPos.length;i++) Qy^1*j<@&  
{ 4L ;% h  
// output.writeLong(nPos); WHsgjvh"  
output.writeLong(fileSplitterFetch.nStartPos);  tBq nfv  
output.writeLong(fileSplitterFetch.nEndPos); pm*xb
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} #MX'^RZ>2  
output.close(); =|M>
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} o<<xY<  
catch(IOException e){e.printStackTrace ();} ohFJZ'  
catch(Exception e){e.printStackTrace ();} F~%]6^$w  
} //T>G_1  
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//读取保存的下载信息（文件指针位置） A )^`?m3  
private void read_nPos() %\D)u8}  
{ A?CcHw rT  
try{ y4t7`-,~  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Y ;u<GOe  
int nCount = input.readInt(); l>Z5 uSG  
nStartPos = new long[nCount]; T*#/^%HSG  
nEndPos = new long[nCount]; vy0X_DPCr  
for(int i=0;i<nStartPos.length;i++) 1Ty<\bZ=  
{ jNLw=  
nStartPos = input.readLong(); oFy=-p+C  
nEndPos = input.readLong(); jGXO\:sO  
} v1BDP<qU2  
input.close(); g .onTFwN  
} #JgH}|&a$  
catch(IOException e){e.printStackTrace ();} N}pw74=1  
catch(Exception e){e.printStackTrace ();} /4a._@1h[y  
} *+j*{>E  
$^OvhnL/  
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private void processErrorCode(int nErrorCode) ue4Vcf  
{ 0J?~N`#O|  
System.err.println("Error Code : " + nErrorCode); Y' %^NP}o  
} G?EoPh^m  
(yF:6$:#  
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//停止文件下载 N['qgO/  
public void siteStop() &>%T^Y|J4  
{ Sz^ veh?  
bStop = true; @\|_  
for(int i=0;i<nStartPos.length;i++) R_sr?V|"  
fileSplitterFetch.splitterStop(); `8^TTQ  
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} cWi}V  
} T(f/ ?_%  
//负责部分文件的抓取 Min ^>  
**FileSplitterFetch.java ebT:/wu,2  
*/ =x<ge_Y  
package NetFox; {DU`[:SQZg  
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import java.io.*; 2$?C7(kW  
import java.net.*; -i)ZQCE  
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public class FileSplitterFetch extends Thread { t.laO. 3  
/9HVY %n  
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String sURL; //File URL *^f<W6xc  
long nStartPos; //File Snippet Start Position lTd #bN  
long nEndPos; //File Snippet End Position p1&b!*o-&  
int nThreadID; //Thread's ID H-~6Z",1  
boolean bDownOver = false; //Downing is over QA<Jr5Ys  
boolean bStop = false; //Stop identical XmEq2v  
FileAccessI fileAccessI = null; //File Access interface i%/Jp[e\W>  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException xYmxc9)2  
{ ,=Mt`aN  
this.sURL = sURL; |QU <e  
this.nStartPos = nStart; } \XfH  
this.nEndPos = nEnd; `}mcEl  
nThreadID = id; K Pt5=a  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 byTh/H  
} Olh<,p+x  
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public void run() o| #Qu8Lk  
{ c )G3k/T5  
while(nStartPos < nEndPos && !bStop) 4WJ.^(  
{ cFeXpj?GV  
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try{ 7T1=q{#M  
URL url = new URL(sURL); z"0I>gl  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8Le||)y,\  
httpConnection.setRequestProperty("User-Agent","NetFox"); (>r[-Bft  
String sProperty = "bytes="+nStartPos+"-"; Cq%IE^g<  
httpConnection.setRequestProperty("RANGE",sProperty);
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Utility.log(sProperty); D|Q#gcWpo  
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InputStream input = httpConnection.getInputStream(); @}@Z8$G^  
//logResponseHead(httpConnection); O*0l+mop  
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byte[] b = new byte[1024]; M+w=O!dq  
int nRead; ptU\[Tq  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *T5!{  
{ w]]8dz  
nStartPos += fileAccessI.write(b,0,nRead); ]=>F.GE  
//if(nThreadID == 1) . koYHq  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \'|>p/5I  
} mG
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Utility.log("Thread " + nThreadID + " is over!"); y#q?A,C@n
 
bDownOver = true; b)=[
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//nPos = fileAccessI.write (b,0,nRead); Kjs.L!W
 
} MM(xk  
catch(Exception e){e.printStackTrace ();} ;xzUE`uUfJ  
} hRK/T7v  
} 1+}{8D_F  
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><gG8MH0'  
//打印回应的头信息 QNpqdwu%h  
public void logResponseHead(HttpURLConnection con) S/4^ d &Gr  
{ g7OqX \  
for(int i=1;;i++) gK[YQXfTy  
{ @te
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String header=con.getHeaderFieldKey(i); .=X}cJ]`[  
if(header!=null)
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); [%77bv85.G  
Utility.log(header+" : "+con.getHeaderField(header)); A'jP7P  
else joiL{  
break; 2oNk93D  
} wid;8%m  
} %F-ZN^R  
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public void splitterStop()
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{ |MFF7z{%  
bStop = true; a
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} YKO){f5  
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} 6WU(%  
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/* "a8j"lPJ  
**FileAccess.java r=X}%~_8X  
*//文件访问(定位，写) )6|yb65ZUX  
package NetFox; rL+!tH  
import java.io.*; ]3KhgK%c8  
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public class FileAccessI implements Serializable{ w8Sp<6*  
gG-BVl"59  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 iVy7elT;R  
RandomAccessFile oSavedFile; $!8-? ?ML  
long nPos; PDrZY.-
 
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public FileAccessI() throws IOException rzh#CnL3  
{ pO ml8SQf  
this("",0); %2XHNW  
} z#]Jv!~EPE  
;S57w1PbVA  
&:
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public FileAccessI(String sName,long nPos) throws IOException jF=gr$  
{ 1DvR[Lx%  
oSavedFile = new RandomAccessFile(sName,"rw"); {`K m_<Te!  
this.nPos = nPos; ds?v'|  
oSavedFile.seek(nPos); lJE93rXU  
} 59O?_F9  
WIv?}gi: X  
}RwSp!}C  
public synchronized int write(byte[] b,int nStart,int nLen) S%yd5<%_  
{ a^=-Mp  
int n = -1; 3WUTI(  
try{ ($}`R xj1@  
oSavedFile.write(b,nStart,nLen);
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n = nLen; L7VG`h;  
} \>7^f 3m  
catch(IOException e) O }(
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{ ^V#@QPK9  
e.printStackTrace (); lsy?Ac  
} GQ9\'z#+  
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`  
return n; op6CA"w  
} 1. rj'  
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l PK +$f$  
} ,=|ZB4HA  
+ j
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,B0_MDA +  
/* ^Nmg07_R  
**SiteInfoBean.java A` AaTP  
*/ Dg} Ka7H  
package NetFox; 69J4=5lX  
j& <i&  
6Qx#%,U^ J  
public class SiteInfoBean { 8'f4 Od ?  
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-mRA#  
private String sSiteURL; //Site's URL ,;(PwJe  
private String sFilePath; //Saved File's Path SL;9Q[  
private String sFileName; //Saved File's Name ~d6DD;`K  
private int nSplitter; //Count of Splited Downloading File "Q?k'^@  
l"2OP6d  
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6  
public SiteInfoBean() uvV;Mlo]  
{//nSplitter的缺省值为5 Qbyv{/  
//default value of nSplitter is 5 qfK`MhA}  
this("","","",5); &d5ia+#  
} <~n$1aA  
j'BMAn ?  
##EYH1P]  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) hYM@?/(q  
{ Xa[?^P  
sSiteURL= sURL; ;\\@q"n%<  
sFilePath = sPath; Vgyew9>E  
sFileName = sName; ltD37QZQ  
this.nSplitter = nSpiltter; 3l3'bw2  
YJl("MZ  
61jI  
} [fKUyIY_  
!V,{_(LT  
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public String getSSiteURL() 8G5m{XTS(  
{ hDp6YV,q  
return sSiteURL; N~NQ6:R[  
} cPU/tkc  
IrWD%/$H  
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public void setSSiteURL(String value) 3Bx:Ntx<  
{ <1.A=_ M  
sSiteURL = value; ulER1\W  
} "eWYv3z~-  
/M*a,o  
zdEPDdB  
public String getSFilePath() }LijnHH.  
{ Eyh51IB.  
return sFilePath; Q]w&N30  
} ?w+Ix~k  
Zt&6Ua[Y}  
@bnG:np  
public void setSFilePath(String value) K&U7H:  
{ `/MvQ/  
sFilePath = value; =l0Jb#d  
} 3,Q^& 1  
#zRbx  
?
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public String getSFileName() q=DN {a:  
{ h'$9C  
return sFileName; &09U@uc$  
} \#>T~.Y7K  
/g$G_}  
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public void setSFileName(String value) V86Xg:?7  
{ W5'3$,X9  
sFileName = value; vUnRi=:|  
} b77>$[xB  
( &frUQm  
]Bm>-*@0N  
public int getNSplitter() l?q%?v8  
{ ]l(wg]  
return nSplitter; s#S%#LM  
} iK IOh('G  
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{" 4e+y  
public void setNSplitter(int nCount) nxJee=qH  
{ N*@aDM07  
nSplitter = nCount; 3w!c`;c%  
} &BvZF  
} XZ/[v8  
\G2B?>E;  
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/* i"j(b|?
e  
**Utility.java +~ #U7xgq/  
*/ :~ A%#  
package NetFox; 5c;h&  
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i#%a-I:
M  
public class Utility { 1H,g=Y4f%  
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public Utility() 1[*{(e  
{ 1,V`8 [  
e62Dx#IY  
 6st^4S5  
} sIl33kmv  
|Cdvfk  
//线程睡眠 lZQ/W:OE  
public static void sleep(int nSecond) Sc]P<F7N]  
{ 9%IlW  
try{ 1KYN>s:  
Thread.sleep(nSecond); a?
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} Q8MS,7y/  
catch(Exception e) XTDE53Js&  
{ w&BGJYI  
e.printStackTrace (); cW``M.d'F  
} F.)!3YE  
} 7rHS^8'H&  
ofW+_DKB?l  
//日志 $A}QY5`+~S  
public static void log(String sMsg) M3z
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{ lr2rQo>  
System.err.println(sMsg); :h:@o h_=  
} E:nt)Ef,  
2>\\@1  
/dDzZ%/@  
public static void log(int sMsg) eu'1H@vX(  
{ }xlKonk  
System.err.println(sMsg); @rb l^  
} :o"8MZp  
} dZGbC9  
CDp8)=WJFF  
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/* 5% nt0dc  
**TestMethod.java 50a
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*/ s T3p
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package NetFox; #3kXmeyrD  
8G ]w,eF  
[$ :  
public class TestMethod { 4(vyp.f  
0p fnV%  
cbKL$|  
public TestMethod() !ax;5@J  
{ ///xx/weblogic60b2_win.exe ^t'3rft  
try{ &k T"oK  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); w5]l1}rl  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); :k46S<RE  
SiteFileFetch fileFetch = new SiteFileFetch(bean); )'q%2%Ak  
fileFetch.start(); KIL18$3J  
} )qPSD2h  
catch(Exception e){e.printStackTrace ();} GL
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} |t\|:E>" }  
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.9LL+d  
public static void main(String[] args) ke/_k/  
{ >Csbjf6  
new TestMethod(); fo\\o4Qyh  
} r3I,11B  
} \Kd7dK9&]  
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