http断点续传简单实现（java)

/* dz+!yE\f$  
**SiteFileFetch.java g(i6Uj~)  
*/ g|uyQhsg  
package NetFox; !D['}%
 
import java.io.*; #%QHb,lhl  
import java.net.*; G?@W;o)  
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public class SiteFileFetch extends Thread { LQk^l`  
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SiteInfoBean siteInfoBean = null; //文件信息Bean &1<[@:;  
long[] nStartPos; //开始位置 >x*[izr/K  
long[] nEndPos; //结束位置 9soEHG=P  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *7H *ep
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long nFileLength; //文件长度 roc DO8f  
boolean bFirst = true; //是否第一次取文件 >m lQ@Z_O  
boolean bStop = false; //停止标志 'dBe,@  
File tmpFile; //文件下载的临时信息  ^cw9Yjh6  
DataOutputStream output; //输出到文件的输出流 v|~=rvXFC  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） (" :Dz_  
public SiteFileFetch(SiteInfoBean bean) throws IOException `Gv\"|Gn  
{ uz+WVmb  
siteInfoBean = bean; 2iM}YCV  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); v\dQjQu8m  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Tk[]l7R~  
if(tmpFile.exists ()) (bv{17K  
{ :@jctH~  
bFirst = false; %ZD]qaU0  
read_nPos(); P\K#q%8  
} Ox#vW6;)  
else G7CkP  
{ U&6A)SW,k  
nStartPos = new long[bean.getNSplitter()]; (${
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nEndPos = new long[bean.getNSplitter()]; ,Tar?&C:  
} \&+Y;:6  
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} >3D1:0Sg  
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public void run() oS$7k3s fj  
{ 40MKf/9  
//获得文件长度 \:Tq0|]Px  
//分割文件 9d|8c > I  
//实例FileSplitterFetch \5&Mg81  
//启动FileSplitterFetch线程 R98YGW_ dT  
//等待子线程返回 ^@8XJ[C,_  
try{ `},:dDHI  
if(bFirst) :k?`gm$  
{ ;/
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nFileLength = getFileSize(); B|a<=
~  
if(nFileLength == -1) Dksn  
{ Drtg7v{@\  
System.err.println("File Length is not known!"); M2ex 3
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} G{6@]72  
else if(nFileLength == -2) )jl@hnA  
{ : 8>zo  
System.err.println("File is not access!"); bC+ZR{M  
} :Ef!gpS}?R  
else zqt<[=O  
{ lHM} E$5  
for(int i=0;i<nStartPos.length;i++) 0~ nCT&V  
{ Z<>gx m<  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); \EU3i;BNT%  
} ][l5S*CC_  
for(int i=0;i<nEndPos.length-1;i++) GC# [&>L  
{ |sr\SCx  
nEndPos = nStartPos[i+1]; 9^g8VlQdT  
} wN'S+4  
nEndPos[nEndPos.length-1] = nFileLength; n:40T1:q  
} ,=CipL9]  
} pD[&,gV$  
~SBW`=aP}  
'fK=;mM  
//启动子线程 [sG`D-\P[  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *A!M0TK?i,  
for(int i=0;i<nStartPos.length;i++) A4(L47^  
{ XM!oN^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "Cxj_V@\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), i7T#WfF  
nStartPos,nEndPos,i); }2S!;swg+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6!0NFP~b  
fileSplitterFetch.start(); _YR#J%xa  
} cd,'37pZ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), cHr]{@7Cs  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); YIW9z{rrs  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", bE% Hm!  
nEndPos = " + nFileLength); 'X+aYF}Ye  
// fileSplitterFetch[nPos.length-1].start(); >CKa?N;  
5K9W5hA:D  
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//等待子线程结束 SE(<(w  
//int count = 0; *IbDA  
//是否结束while循环 i| cA)  
boolean breakWhile = false; |%8t.
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while(!bStop) wT+60X'  
{ YhglL!pC  
write_nPos(); l2W+VBn6  
Utility.sleep(500); *g}==o`  
breakWhile = true; OO/>}? ob  
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for(int i=0;i<nStartPos.length;i++) i: -IZL\  
{ 7ojh=imY  
if(!fileSplitterFetch.bDownOver) =3hJti9[  
{ !-qk1+<h  
breakWhile = false; o"RE4s\G~r  
break; YRZw|H{>t  
} Bz,D4E$  
} p=[dt  
if(breakWhile) O<!^^7/h0  
break; R-n%3oh  
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//count++; n}Thc6f3D  
//if(count>4) S|u5RU8*"|  
// siteStop(); mhIGunK;+  
} ;QuxTmWp^  
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System.err.println("文件下载结束！"); OdyL j  
} _`QMEr?  
catch(Exception e){e.printStackTrace ();} jyg>'"W  
} s
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HWoMzp5="3  
//获得文件长度 &flcJ`  
public long getFileSize() < :eKXH2  
{ PTpCi
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int nFileLength = -1; ZPM7R3%V)z  
try{ T5pc%%q  
URL url = new URL(siteInfoBean.getSSiteURL()); 2mj>,kS?c  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4mBM5Tv  
httpConnection.setRequestProperty("User-Agent","NetFox"); UlN}SddI9  
/Y\q&}  
#9"lL1  
int responseCode=httpConnection.getResponseCode(); b N>Ar  
if(responseCode>=400) rf$[8d  
{ \2@9k`  
processErrorCode(responseCode); J=^5GfM)J  
return -2; //-2 represent access is error $a\X(okx  
} tvzO)&)$  
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String sHeader; IP !zg|c,  
<9=RLENmY"  
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for(int i=1;;i++) mMhe,8E&  
{ _;(QMeR  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); AsZyPybq  
//Utility.log(in.readLine()); a3Z()|t>  
sHeader=httpConnection.getHeaderFieldKey(i); QBoX3w=  
if(sHeader!=null) @J@bD+Q+0  
{ #lVSQZO~a  
if(sHeader.equals("Content-Length")) N/^[c+J  
{ l%2B4d9"v  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 1d.>?^uE  
break; |@-y+vbA*  
} Dh
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} ; zy;M5l5.  
else _x#r,1V+D  
break; i3Nt?FSN  
} +xmZK<{<  
} Git2Cet  
catch(IOException e){e.printStackTrace ();} gA
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catch(Exception e){e.printStackTrace ();} r:^`005  
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Utility.log(nFileLength); A@k=Mk  
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return nFileLength; ER$~kFE2yP  
} kS7T'[d  
}>j1j^c1='  
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//保存下载信息（文件指针位置） T5U(B3j_  
private void write_nPos() H @E-=Ly  
{ 8J9o$Se  
try{ {24Pv#ZG#^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); .Qj`_q6=  
output.writeInt(nStartPos.length); 0Zl1(;hx@  
for(int i=0;i<nStartPos.length;i++) VHws9)  
{ ]Otl(\v(h  
// output.writeLong(nPos); LyXABQ]  
output.writeLong(fileSplitterFetch.nStartPos); 1hp@.Fv  
output.writeLong(fileSplitterFetch.nEndPos); GHWpL\A{8`  
} M9S[{Jj*  
output.close(); }fxH>79g  
} -3b0;L&4>x  
catch(IOException e){e.printStackTrace ();} [ 06B)|s  
catch(Exception e){e.printStackTrace ();} r?2C%GI`  
} X4*/h$48 w  
:Ws3+OI'm3  
*KV]MdS  
//读取保存的下载信息（文件指针位置） qdu:kA:]  
private void read_nPos() d{GXFT;0  
{ WI'csM;M#  
try{ 4]8PF  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); z#*GPA8Em:  
int nCount = input.readInt(); CUw 9aH  
nStartPos = new long[nCount]; 1r w>gR  
nEndPos = new long[nCount]; %s)E}cGH  
for(int i=0;i<nStartPos.length;i++) 
~GY;{  
{ @49^WY  
nStartPos = input.readLong(); ^jhHaN]G^  
nEndPos = input.readLong(); #wm)e)2@  
} bmddh2  
input.close(); CblL1q8  
} f%auz4CZz  
catch(IOException e){e.printStackTrace ();} /3Gv51'  
catch(Exception e){e.printStackTrace ();} Ox43(S0~  
} )5V1HWjU  
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private void processErrorCode(int nErrorCode) KoXXNJax  
{ 1X9sx&5H  
System.err.println("Error Code : " + nErrorCode); n2O7n@8  
} C,z]q$4  
1Q;`<=  
>zhbipA  
//停止文件下载  3i$AR  
public void siteStop() rC*nZ*  
{ (c*Dvpo1  
bStop = true; YvHn~gNPhs  
for(int i=0;i<nStartPos.length;i++) +yea}uUE  
fileSplitterFetch.splitterStop(); Rx<pV_|H,  
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<(t<gS#  
} JT-Zo OZ  
} E|Lh$9XONA  
//负责部分文件的抓取 n*xNMw1x"T  
**FileSplitterFetch.java aY+>85?g  
*/ LtvyWc`  
package NetFox; ) D`_V.,W  
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import java.io.*; / q!&I  
import java.net.*; @<sP1`1  
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public class FileSplitterFetch extends Thread { ]-`{kX  
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String sURL; //File URL MdfkC6P  
long nStartPos; //File Snippet Start Position 6a!X`%N=  
long nEndPos; //File Snippet End Position VEZ/-s/  
int nThreadID; //Thread's ID 0\o'd\  
boolean bDownOver = false; //Downing is over ?k?Hp:8?=  
boolean bStop = false; //Stop identical yI;Qb7|^  
FileAccessI fileAccessI = null; //File Access interface Zn!SHj  
#WG(V%f]  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException t
8[:}[Jx  
{ [6tQv<}^
 
this.sURL = sURL; @'
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this.nStartPos = nStart; $7*Ml)H!9  
this.nEndPos = nEnd; vtT:c.~d  
nThreadID = id; &Gt9a-ne  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +Snjb0  
} :4Vt  
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}A;Xd/,'r  
public void run() (TQXG^n$gY  
{ 'mM5l*{  
while(nStartPos < nEndPos && !bStop) !1_:nD  
{ G7
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try{ %"6IAt  
URL url = new URL(sURL); NlMx!f>b%/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o_5@R
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httpConnection.setRequestProperty("User-Agent","NetFox"); s'^#[%EgB  
String sProperty = "bytes="+nStartPos+"-"; s5dh]vNN  
httpConnection.setRequestProperty("RANGE",sProperty); Lsz`nD5  
Utility.log(sProperty); a`uT'g[*  
1,J.  
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InputStream input = httpConnection.getInputStream(); wtKh8^:YD  
//logResponseHead(httpConnection); (qrT0D6  
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byte[] b = new byte[1024]; fYi!Z/Ck2  
int nRead; 6M9rC[h\  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) H6eGLg={  
{ #Grm-W9E  
nStartPos += fileAccessI.write(b,0,nRead); L5W>in5(  
//if(nThreadID == 1) $9~1s/('  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @:@rks&  
} vX\e* v  
GSH{1VS_b  
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Utility.log("Thread " + nThreadID + " is over!"); @!da1jN  
bDownOver = true; +9J>'oe'D  
//nPos = fileAccessI.write (b,0,nRead); /~[R u  
} >>r:L3<!  
catch(Exception e){e.printStackTrace ();} *Y ZLQT  
} -G 'lyH  
} e{,/  
mI%/k7:sf  
NsHveOK1.  
//打印回应的头信息 pS\>X_G3  
public void logResponseHead(HttpURLConnection con) AngwBZ@  
{ ._Xtb,p{  
for(int i=1;;i++) lUEyo.xVt  
{ 7w*&Yg]  
String header=con.getHeaderFieldKey(i); d8#j@='a*  
if(header!=null) ?+\,a+46P_  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 7fqYSMHR  
Utility.log(header+" : "+con.getHeaderField(header)); Dhoj|lc  
else I1~g?jpH  
break; |9I;`{@  
} O)R0,OPb
  
} B .mV\W  
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*@nUas2"  
public void splitterStop() ?s]`G'=>V`  
{ JPG!c
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bStop = true; 4/?Zp4g  
} )QD}R36Ic  
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} ise}> A!t  
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/* }nl)*l  
**FileAccess.java rYQ@"o0/Y  
*//文件访问(定位，写) v_0!uT5~NE  
package NetFox; #8jd,I%L  
import java.io.*; MavO`m&Cg  
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public class FileAccessI implements Serializable{ df& |Lc1J  
W)cLMGet  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 }HorR2(`N  
RandomAccessFile oSavedFile; #+0R!Y  
long nPos; >ULp!  
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public FileAccessI() throws IOException GcW}<g}  
{ bf/loMtD  
this("",0); ?y)X$D^  
} 9K<a}QJP  
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~*[4DQ[\  
public FileAccessI(String sName,long nPos) throws IOException 5FI>T=QF  
{ iGLYM-  
oSavedFile = new RandomAccessFile(sName,"rw");
-d'|X`^nE  
this.nPos = nPos; {2r7:nvR  
oSavedFile.seek(nPos); |81N/]EER  
} 6~WE#z_  
'Y\"^'OU\  
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public synchronized int write(byte[] b,int nStart,int nLen) wlg#c6#q  
{ 22~X~=  
int n = -1; )fc"])&8  
try{ :w%bw\}  
oSavedFile.write(b,nStart,nLen); q)+n2FM  
n = nLen; :OaQq@V  
} n9!3h?,g  
catch(IOException e) [)>8z8'f  
{ mp3_n:R?  
e.printStackTrace (); x)ZH;)  
} RLNuH2y
;  
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return n; G| oG:  
} )%w8>1}c  
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} q.Z#7~6`3  
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/* h\\2r>  
**SiteInfoBean.java Q$/FgS  
*/ "0zXpQi,B  
package NetFox; 6D"`FPC  
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public class SiteInfoBean { luk2fi<$  
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s FYJQ90it  
private String sSiteURL; //Site's URL 14!a)Ijl  
private String sFilePath; //Saved File's Path 9k[},MM  
private String sFileName; //Saved File's Name @i-@mxk6<  
private int nSplitter; //Count of Splited Downloading File DeQ'U!?+N  
b:cK>fh0_  
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public SiteInfoBean() KVpAV$|e  
{//nSplitter的缺省值为5 SLOYlRGCi  
//default value of nSplitter is 5 9~%]|_(  
this("","","",5); PFgjW
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} l'".}6S  
QYw4kD}  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) edk9Qd9  
{ _XNR um4  
sSiteURL= sURL; <sYw%9V  
sFilePath = sPath; {)9HS~e T  
sFileName = sName;
@<TZH  
this.nSplitter = nSpiltter; {&u7kWD|  
T^
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ss@}Dt^  
} He-Ja  
lWw!+[<:q1  
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public String getSSiteURL() C"Q=(3  
{ AnE_<sPA  
return sSiteURL; =)1YYJTe9  
} `m;"I  
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public void setSSiteURL(String value) G[<[#$(  
{  [Ro0eH  
sSiteURL = value; /Q>{YsRRB  
} 3/IWO4?_  
dzE Q$u/I  
?$@KwA  
public String getSFilePath() m-S33PG{  
{ ;E? hz  
return sFilePath; m#'rI=}!  
} b|8>eY  
*5_8\7d  
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public void setSFilePath(String value) #JR,C -w  
{ &c?hJ8"  
sFilePath = value; Ed0>
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} Z0 IxYEp  
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public String getSFileName() $aPHl  
{ VfA5r`^  
return sFileName; Xt,,AGm}  
} KkL:p?@n  
]1|Ql*6y,  
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public void setSFileName(String value) A;WwS?fyQ  
{ s3_e7D ^H  
sFileName = value; b~Pxgfu"  
} Y^ZBA\D2,k  
['4\O43yv  
*v nxP9<  
public int getNSplitter() Rp`_Grcd  
{ +`s&i%{1>  
return nSplitter; h6T/0YhWLP  
} ['OCw {<  
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public void setNSplitter(int nCount) e=n{f*KG`  
{ F`BgKH!  
nSplitter = nCount; HLoQ}oK|K  
}
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} |CZnq-,C  
Oz#EGjz  
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/* VmOFX:
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**Utility.java +/!=Ub[:U  
*/ A{8K#@!  
package NetFox; 0nD=|W\@{  
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public class Utility { o,Tr^e$  
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public Utility() dp[w?AMhM9  
{ B/sBYVU  
[*
?_  
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} |:e|~sism  
H?`)[#  
//线程睡眠 ^L8Wn6s'  
public static void sleep(int nSecond) <h@z=ijN  
{ l\=-+'Y  
try{ NHFEr
 
Thread.sleep(nSecond); Bd[L6J)  
} CmJ?_>  
catch(Exception e) pg?i
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{ 7Js>!KR  
e.printStackTrace (); e\A(#l@g  
} 2%{YYT   
} hM36QOdm  
`z?KL(rI  
//日志 =,AC%S_D~  
public static void log(String sMsg) gaw4NZd)0  
{ hLyTUt~\L  
System.err.println(sMsg); WBw M;S#%  
} I| W'n-4Y  
:zj9%4A  
2-$bh  
public static void log(int sMsg) W<rTq0~$?  
{ $@_<$t  
System.err.println(sMsg); G+hF [b44'  
} Q_QKm0!  
} iBKb/Oi6  
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/* {HIR>])o  
**TestMethod.java EREolCASb  
*/ p- "Z'$A`  
package NetFox; l- 1]w$ y  
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public class TestMethod { e' U"`)S  
"xDx/d8B  
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public TestMethod() 2<[eD`u  
{ ///xx/weblogic60b2_win.exe SLJ&{`"7
 
try{ '9*5-iO  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Q5p+W  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); /lS+J(I  
SiteFileFetch fileFetch = new SiteFileFetch(bean); kfqpI  
fileFetch.start(); VDByj "%  
} atLV`U&t  
catch(Exception e){e.printStackTrace ();} m/YH^N0  
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} @cuD8<\i  
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public static void main(String[] args) $=P
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{ Qy=
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new TestMethod(); \Y!T>nWn)I  
} lX98"}  
} Y{k>*: Ax_  
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