http断点续传简单实现（java)

/* qO`qJ/  
**SiteFileFetch.java jQj,q{eA  
*/ ;2giZ\  
package NetFox; f*xpE`&  
import java.io.*; <JI& {1  
import java.net.*; l+y-Fo@  
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public class SiteFileFetch extends Thread { 5 ZfP  
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SiteInfoBean siteInfoBean = null; //文件信息Bean v@EQ^C2.&  
long[] nStartPos; //开始位置 yy(A(}  
long[] nEndPos; //结束位置 bb=uF1  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 F#+.>!  
long nFileLength; //文件长度 Ey&aBYR  
boolean bFirst = true; //是否第一次取文件 HT`1E0G8)  
boolean bStop = false; //停止标志 ~y0R'oi  
File tmpFile; //文件下载的临时信息 uL?vG6% ^1  
DataOutputStream output; //输出到文件的输出流 7]22"mc  
d @rs3Q1z  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） t"s5\;IJ  
public SiteFileFetch(SiteInfoBean bean) throws IOException UU@fkk  
{ 8}BBOD  
siteInfoBean = bean; PoD^`()FR{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); '=cKU0 G#  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `EMi0hm&H  
if(tmpFile.exists ()) *i<\iMoW  
{ S-Ai3)t6  
bFirst = false; I+,
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read_nPos(); $EBb"+Y'T  
} rj
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else So4nJ><p  
{ s'_,:R\VM>  
nStartPos = new long[bean.getNSplitter()]; &:#m&,tQ  
nEndPos = new long[bean.getNSplitter()]; H}b\`N[nr  
} ]HvZ$  
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} %AR^+*Nu  
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public void run() 0rzVy/Z(  
{ _ 6:ww/  
//获得文件长度 %cW;}Y[?P  
//分割文件 J4yt N3  
//实例FileSplitterFetch QB1M3b  
//启动FileSplitterFetch线程 Q_}/ Pn$1  
//等待子线程返回 ; Zq/eiB  
try{ ?y-s20Kd  
if(bFirst) A0#Y, 1  
{ yr4ou  
nFileLength = getFileSize();
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if(nFileLength == -1) J_
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{ zLek&s&-  
System.err.println("File Length is not known!"); FDLd&4Ex  
} V-vlTgemwc  
else if(nFileLength == -2) <TjBd1  
{ zk>h u<_  
System.err.println("File is not access!"); |< N frz  
} NfF~dK|  
else koH4~m{  
{ %D^bahf  
for(int i=0;i<nStartPos.length;i++) &`@M8-m#F  
{ /4C`k=>  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); eF1.VLI  
} yDtOpM8<{  
for(int i=0;i<nEndPos.length-1;i++) $pFk"]=  
{ f9'] jJ+  
nEndPos = nStartPos[i+1]; 6q%ed UED  
} }aZrou3E  
nEndPos[nEndPos.length-1] = nFileLength; sb'p-Mj  
} _pSIJ3O  
} FDq{M?6i  
(2%>jg0M  
5\G)Q<A]*L  
//启动子线程 ]_2yiKv&  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; t:9 ZCu ay  
for(int i=0;i<nStartPos.length;i++) },6*Y*?{  
{ k!13=Gh  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fq Y1ggL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3'@&c?Fye  
nStartPos,nEndPos,i); $Q4=37H+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OROqT~6G  
fileSplitterFetch.start(); ylkqhs&  
} d;g-3Pf  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (9z|a,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);  ^Fp=y
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ,o)4p\nV  
nEndPos = " + nFileLength); VR v02m5  
// fileSplitterFetch[nPos.length-1].start(); AM?Ec1S #a  
lJj&kVHb  
MOLO3?H(  
//等待子线程结束 ji##$xC  
//int count = 0; A`C-sD>  
//是否结束while循环 r|bPR!0  
boolean breakWhile = false; )KE_t^$  
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)l{A{f6O  
while(!bStop) bs:QG1*.  
{ 2[BA(B  
write_nPos(); uRGB/ju^E  
Utility.sleep(500); ,TJ/3_lH  
breakWhile = true; =kO@Gk?  
=phiD&=  
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for(int i=0;i<nStartPos.length;i++) %1Jd^[W  
{ "GLYyC  
if(!fileSplitterFetch.bDownOver) \^m.dIPdO  
{ LJ l1v  
breakWhile = false; =~$U^IsWA  
break; /h-6CR Ka  
} tGqQJT#mr7  
} (uT^Nn9L=  
if(breakWhile) 4ac1m,Jlt  
break; FpC~1Nau  
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//count++; [,nfAY  
//if(count>4) J=VyyUB  
// siteStop(); .h!9wGi`  
} X}?ESjZJ  
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<>&89E%j'  
System.err.println("文件下载结束！"); c&A]p
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} z0;9SZ9  
catch(Exception e){e.printStackTrace ();} 4)E|&)-fu8  
} dv[\.T`LY  
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3z$HKG  
//获得文件长度 /evaTQPz  
public long getFileSize() FSVS4mtiX\  
{ ^ `E@/<w8  
int nFileLength = -1; aulaX/'-_  
try{ [[&)cbv  
URL url = new URL(siteInfoBean.getSSiteURL()); WRY~fM  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F*X%N_n  
httpConnection.setRequestProperty("User-Agent","NetFox"); w. vY
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int responseCode=httpConnection.getResponseCode(); CHg]Ul  
if(responseCode>=400) Z3Gm  
{ ,NDxFy;d  
processErrorCode(responseCode); !rz)bd
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return -2; //-2 represent access is error *seu&  
} H}(=?
}+  
< )Alb\Z  
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String sHeader; at=D&oy4"+  
?U$}Rsk{#  
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for(int i=1;;i++) bt0djJRw  
{ Gk{W:866  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); V!H(;Tuuo  
//Utility.log(in.readLine()); ]}/mFY?7  
sHeader=httpConnection.getHeaderFieldKey(i); |o|gP8  
if(sHeader!=null) yIlV[_  
{
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if(sHeader.equals("Content-Length")) GPMrs)J*!  
{ 2h5tBEOX.s  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \!m!ibr  
break; ,v|CombIc.  
} v)%[  
} /5jKX 5r  
else exsQmbj* %  
break; vs+We*8H  
} 8~}s 3j4  
} dRHlx QUn  
catch(IOException e){e.printStackTrace ();} 'G52<sF  
catch(Exception e){e.printStackTrace ();} 2(hvv-  
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Utility.log(nFileLength); #`r(zI[  
+_P8'e%Iy  
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return nFileLength; <( c
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} 3.B4(9:>,  
]v<d0"2  
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//保存下载信息（文件指针位置） u0wn=Dg  
private void write_nPos() S3b|wUf  
{ umqLKf=x!  
try{ o; 6fvn  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ~v^%ze  
output.writeInt(nStartPos.length); Ri9Kr  
for(int i=0;i<nStartPos.length;i++) id3)6}  
{ ^}>zYt  
// output.writeLong(nPos); q^)=F_QvG  
output.writeLong(fileSplitterFetch.nStartPos); p1Y+
 
output.writeLong(fileSplitterFetch.nEndPos); &zO3
qt6  
} +SO2M|ru&  
output.close(); C{8i7D  
} kboizJp  
catch(IOException e){e.printStackTrace ();} 
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catch(Exception e){e.printStackTrace ();} Zlr{L]c  
} Sb'N];  
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//读取保存的下载信息（文件指针位置） Cc@=?  
private void read_nPos() ]d[Rf$>vu0  
{ ^).WW  
try{ (s5<  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >6*(}L9  
int nCount = input.readInt(); KuIBYaK, g  
nStartPos = new long[nCount]; <j{0!J@:  
nEndPos = new long[nCount]; XulaPq  
for(int i=0;i<nStartPos.length;i++) aytq4Ts  
{ X!HDj<  
nStartPos = input.readLong(); I/oIcQS!k  
nEndPos = input.readLong(); ~8XX3+]z:X  
} hN Z4v/  
input.close(); A
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} R.91v4J  
catch(IOException e){e.printStackTrace ();} cxAViWsf  
catch(Exception e){e.printStackTrace ();} TP{>O%b  
} S`ax*`  
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private void processErrorCode(int nErrorCode) pESB Il  
{ {E;2&d  
System.err.println("Error Code : " + nErrorCode); w> Tyk#7lw  
} IXbdS9,>F  
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//停止文件下载 M(_^'3u  
public void siteStop() BM|-GErE  
{ %'RI3gy  
bStop = true; 2N L:\%wz  
for(int i=0;i<nStartPos.length;i++) >{phyBy
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fileSplitterFetch.splitterStop(); 6T R8D\  
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} qf_hb  
} *37LN  
//负责部分文件的抓取 "bHtf_  
**FileSplitterFetch.java ~AEqfIx*^&  
*/ L4\SBO  
package NetFox; ipx@pNW;"  
} l:mN  
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import java.io.*; z*Myokhf  
import java.net.*; 9\AEyaJFZ  
 1m&!l6Jk  
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public class FileSplitterFetch extends Thread { C1ZFA![  
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String sURL; //File URL w/lXZg  
long nStartPos; //File Snippet Start Position p_rN1W Dd'  
long nEndPos; //File Snippet End Position 7yMieUF  
int nThreadID; //Thread's ID %Nwyx;>9^K  
boolean bDownOver = false; //Downing is over )![f\!'PI  
boolean bStop = false; //Stop identical o8~f  
FileAccessI fileAccessI = null; //File Access interface I ybl;u  
&*jxI[  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Q\&AlV  
{ ki[;ZmQqY  
this.sURL = sURL; r~S!<9f  
this.nStartPos = nStart; mp&Le YYn  
this.nEndPos = nEnd; K$Mx}m7l  
nThreadID = id; 3EbnZb  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [(D}%+2   
} ]7#^])>  
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5@w'_#!)  
public void run() <Z\MZ&{k{*  
{ C5
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while(nStartPos < nEndPos && !bStop) [JX}1%NA  
{ M9uH&CD6U  
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?=/}Ft  
try{ JL" 3#p}  
URL url = new URL(sURL); afxj[;p!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zxk??0]/  
httpConnection.setRequestProperty("User-Agent","NetFox"); %4|n-`:  
String sProperty = "bytes="+nStartPos+"-"; _'?8s6 H  
httpConnection.setRequestProperty("RANGE",sProperty); RT.wTJS;  
Utility.log(sProperty); WU+Jo@]y  
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InputStream input = httpConnection.getInputStream(); d&[M8(  
//logResponseHead(httpConnection); *pcbwd!/  
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byte[] b = new byte[1024]; b6LC$"t0  
int nRead; E]HND.`*>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) D+*uKldS;  
{ +WV_`Rx#  
nStartPos += fileAccessI.write(b,0,nRead); e5WdK  
//if(nThreadID == 1) >6.[i@RmWU  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Xa?6#
  
} )+jK0E1  
g9FVb7In_  
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Utility.log("Thread " + nThreadID + " is over!"); 5CH-:|(;=  
bDownOver = true; S`GXiwk  
//nPos = fileAccessI.write (b,0,nRead); C$AIP\j- )  
} 3]:p!Y`$  
catch(Exception e){e.printStackTrace ();} By51dk7  
} + e5  
} &9RW9u "  
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//打印回应的头信息 i-i}`oN  
public void logResponseHead(HttpURLConnection con)  MrKU,-  
{ |mQtjo  
for(int i=1;;i++) ^ RcIE (  
{ ReHd~G9  
String header=con.getHeaderFieldKey(i); \V"PmaP\  
if(header!=null) 07T;IV3#C5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); uDy>xJ|  
Utility.log(header+" : "+con.getHeaderField(header)); 9d,]_l.sB  
else m>Z\ rqOK  
break; % L %1g  
} iS:PRa1  
} rr07\;  
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!Z+*",]_  
public void splitterStop() 5ykk11!p$  
{
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bStop = true; JT.\f,z&  
} fo!Lp*'0  
7=QC+XSO  
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} bzj!d|T`  
+>i
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/* S}v{^vR  
**FileAccess.java l_YdIUl  
*//文件访问(定位，写) ?*
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package NetFox; 02J6Pn3  
import java.io.*; .J1Hg  
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public class FileAccessI implements Serializable{ sS1J.R  
o7@4=m}  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 SqA+u/"j2  
RandomAccessFile oSavedFile; ?ck^? p7  
long nPos; 1EAVMJ  
jy__Y=1}  
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public FileAccessI() throws IOException ;@7#w  
{ ax{-Qi7z-+  
this("",0); lU50.7<08  
} f@;>M9)<  
zZ+LisSs&  
}eDX8b8emA  
public FileAccessI(String sName,long nPos) throws IOException \HP,LH[P:  
{ xXY)KI N[  
oSavedFile = new RandomAccessFile(sName,"rw"); 8@LykJbP  
this.nPos = nPos; =:n[{/O=  
oSavedFile.seek(nPos); RESGI}
u  
} "13 :VTs[5  
s:jL/%+COZ  
;FgEE%  
public synchronized int write(byte[] b,int nStart,int nLen) [Tb3z:UUvf  
{ tEWj}rX   
int n = -1; N5w]2
xz!  
try{ )q]j?Z.  
oSavedFile.write(b,nStart,nLen); jKCqH$  
n = nLen; C!/8e (!N  
} `i>B|g-  
catch(IOException e) Z_OqXo=  
{ 9h,yb4jPP  
e.printStackTrace (); 1z};"A  
} WJFTy+bD  
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return n; t1RwB23  
} 8#Z\}gGz  
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} k0e|8g X  
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/* s<r.+zqW  
**SiteInfoBean.java _KkVI7a  
*/ x4m_(CtK  
package NetFox; :J4C'N  
)r|zi Z{F  
#:\+7mCF  
public class SiteInfoBean { J*lYH]s  
MTITIecw=  
VGDEP!)-8  
private String sSiteURL; //Site's URL z5*O@_r+.b  
private String sFilePath; //Saved File's Path D16;6K'{  
private String sFileName; //Saved File's Name e~ 78'UH  
private int nSplitter; //Count of Splited Downloading File n%ArA])_&  
P2:Q+j:PX  
;'
18  
public SiteInfoBean() Y)j,(9  
{//nSplitter的缺省值为5 5$"[gdt)T  
//default value of nSplitter is 5 {8bY7NH|  
this("","","",5); l-h7ksRs  
} "RJk7]p`*  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 2,e|,N"zN  
{ |xgCV@  
sSiteURL= sURL; e/% ;  
sFilePath = sPath; 1yRd10  
sFileName = sName; XOU-8;d  
this.nSplitter = nSpiltter; Boj{+rE0  
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\7tvNa,C  
} k&"qdB(I  
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public String getSSiteURL() +U/"F|M  
{ Lp]C![\>U  
return sSiteURL; (uK), *6B  
} BiLreZ~"  
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public void setSSiteURL(String value) [MXXY  
{ ?
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sSiteURL = value; <sFf'W_3{  
} yExyx?j.  
m}'@S+k^  
Rw=E_q{  
public String getSFilePath() ,G/X"t ~  
{ jeBj   
return sFilePath; @k #y-/~?  
} oJu4vGy0  
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public void setSFilePath(String value) Y(yJ|y&  
{ i\z0{;f|GX  
sFilePath = value; U)%u`C
0  
} Jsnmn$C  
[[DFEvOEh  
3@ukkO)   
public String getSFileName() zr9Pm6Rl  
{ &E'
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return sFileName; RkV3_c  
} Sm_:SF!<D6  
^
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h=y(2xA  
public void setSFileName(String value) :Du{8rV  
{ u]-El}*[  
sFileName = value; K~%5iVO~\  
} U"kK]Stk<  
1'pQ,  
Cv7RCjMw  
public int getNSplitter() 44{:UhJkx  
{ 3K:Xxkk  
return nSplitter; XBt0Ez  
} knZd}?I*  
`/Jr8J_  
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public void setNSplitter(int nCount) 5e8-?w%e  
{ g\nL n#  
nSplitter = nCount; A"ph!* i{  
} kRa$jD^?  
} jtpNo~O  
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/* Z:gsguX  
**Utility.java AG%es0D[H  
*/ {cHTg04  
package NetFox; K{h]./%  
Cu<ojN- $  
.z7f_KX^  
public class Utility { pnb
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public Utility() Ec/+9H6g  
{ BU\NBvX$  
 cJ{P,K  
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} 9.}3RAB(cv  
<sG>[\i  
//线程睡眠 =n?@My?;  
public static void sleep(int nSecond) H t$%)j9  
{ o|.me G  
try{ b|'LtL$Y  
Thread.sleep(nSecond); *hgsS~  
} cwU6}*_zn  
catch(Exception e) \aRB   
{ ;G&O"S><]c  
e.printStackTrace (); ~i {)J  
} t~#+--(  
} `b$I)UUm  
-0){C|,6  
//日志 n9yv.p]  
public static void log(String sMsg) Ase1R=0  
{ ECfY~qK  
System.err.println(sMsg); wC@U/?  
} aa3YtNpP  
F&Z>B};  
N.J:Qn`(  
public static void log(int sMsg) TJa%zi  
{ 49>yIuG
 
System.err.println(sMsg); +eat,3Ji  
}  %tjEVQa  
} Q'LU?>N)/  
, >6X_XJQ  
}trMQ  
/* ld0WZj  
**TestMethod.java A#\X-8/  
*/ xk<0QYv   
package NetFox; Jx,s.Z0@7,  
S
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public class TestMethod { s@9#hjv2  
SxyFFt  
%|||M=akk  
public TestMethod() 7] H4E.(l  
{ ///xx/weblogic60b2_win.exe C_;6-Q%V  
try{ w%"q=V  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Cq'r 'cBZ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); g M.(BN  
SiteFileFetch fileFetch = new SiteFileFetch(bean); iE{SqX  
fileFetch.start(); eLWzd_ln  
} ![Y$[l  
catch(Exception e){e.printStackTrace ();} ijT^gsLL  
?/g(Y  
q9Wtu7/  
} tp0*W _<4  
=
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public static void main(String[] args) S|i //I%_  
{ JD.z}2+  
new TestMethod(); kSrzIq<xre  
} @:8|tJu8b  
} ^B>6!  
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