http断点续传简单实现（java)

/* grzmW4Cw  
**SiteFileFetch.java 6qFzo1LO  
*/ rzIWQFv  
package NetFox; vJ}WNvncVF  
import java.io.*; qnboXGaFu  
import java.net.*; ; F'IS/ttX  
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public class SiteFileFetch extends Thread { F:T(-,  
} &+]UGv  
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SiteInfoBean siteInfoBean = null; //文件信息Bean G=|?aK{p  
long[] nStartPos; //开始位置 1F,U^O  
long[] nEndPos; //结束位置 Ig}hap]G  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 5=I({=/>  
long nFileLength; //文件长度 i/+^C($'f  
boolean bFirst = true; //是否第一次取文件 Os'E7;:1h  
boolean bStop = false; //停止标志 //BJaWq  
File tmpFile; //文件下载的临时信息 x-k-Pd  
DataOutputStream output; //输出到文件的输出流 h~\k;ca  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 9 da=q  
public SiteFileFetch(SiteInfoBean bean) throws IOException (WC =om  
{ m(U.BXo  
siteInfoBean = bean; tj~r>SRb+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); pNOE KiJ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 0*b8?e  
if(tmpFile.exists ()) :38h)9>RK  
{ kD)31P  
bFirst = false; b4cTn 6  
read_nPos(); pI-Qq%Nwt  
} U1y!R<qlp  
else v1~l=^4&  
{ J Fn
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{  
nStartPos = new long[bean.getNSplitter()]; ocWl]h].  
nEndPos = new long[bean.getNSplitter()]; a<q9~QS  
} ftTD-d  
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} `aAE4Ry?  
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public void run() Z,2?T
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{ @[9  
//获得文件长度 'RKpMdoz  
//分割文件 8(Te^] v#  
//实例FileSplitterFetch xaVX@ 3r.3  
//启动FileSplitterFetch线程 >8I~i:hn  
//等待子线程返回 3]?='Qq.(  
try{ Ebs]]a>PO  
if(bFirst) 01-rBto$  
{ h<3b+*wYJC  
nFileLength = getFileSize(); OP=brLGu0  
if(nFileLength == -1) x}K|\KXy  
{ HJN GO[*g  
System.err.println("File Length is not known!"); 1?H; c5?d&  
} gU+yqT7=  
else if(nFileLength == -2) "=s}xAM|A  
{ pP":,8Q{  
System.err.println("File is not access!"); ^g6v#]&WA  
} KJoa^e;~  
else hbJy<e1W  
{ =t-Ud^3  
for(int i=0;i<nStartPos.length;i++) yg'CL/P  
{ W`
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9`/e=RL  
} gPB=Z!  
for(int i=0;i<nEndPos.length-1;i++) ,= ApnNUgX  
{ *Ci&1Mu^Z  
nEndPos = nStartPos[i+1]; q;nAq%  
} j1g$LAe  
nEndPos[nEndPos.length-1] = nFileLength; 4bGvkxZo`$  
} plB8iN`x<  
} wsB-( 0-  
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//启动子线程 Sy <E@1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ty['yV-;a  
for(int i=0;i<nStartPos.length;i++) h SS9mQ  
{ dNf9,P_}  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +BtLd+)R  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <tbs,lcw;  
nStartPos,nEndPos,i); 6Zn[l,\  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :j3'+%'2  
fileSplitterFetch.start(); ;W5.g8  
} =@4,szLO  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), P?>:YY53  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); yOl
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]@z!r2[  
nEndPos = " + nFileLength); PU.j(0  
// fileSplitterFetch[nPos.length-1].start(); &2 Yo  
H4 O"^#5  
jbS@6 *_  
//等待子线程结束 [C4{C4TX  
//int count = 0; q[qX O5  
//是否结束while循环 nw/g[/<;  
boolean breakWhile = false; Zc_F"KJL  
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while(!bStop) <`SA>P  
{ 83V\O_7j  
write_nPos(); Vbp
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Utility.sleep(500); }|Q\@3&  
breakWhile = true; n%36a(] t  
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2 oL$I(83  
for(int i=0;i<nStartPos.length;i++) 5g-1pzP9  
{ ],!}&#|  
if(!fileSplitterFetch.bDownOver) h& 4#5{=  
{ ZKt{3P  
breakWhile = false; B]yO  
break; h#UPU7;  
} Z<d=v3q  
} ?H_@/?  
if(breakWhile) D]iyr>V6'  
break; V_$<^z|  
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//count++; ckFPx l.  
//if(count>4) x4kQGe(  
// siteStop(); ]lGkZyUhI  
} zwQ#Yvd  
<Af&Q0J  
] rqx><!  
System.err.println("文件下载结束！"); `dX0F=Ag?  
} 6rE8P#  
catch(Exception e){e.printStackTrace ();} TW1`{SM  
} Ew.6y=Ba  
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Es}`SIe/  
//获得文件长度 =[aiW|Y  
public long getFileSize() :##
$-K*W"  
{ y]R+/  
int nFileLength = -1; PyI"B96gz  
try{ voRb>xF  
URL url = new URL(siteInfoBean.getSSiteURL()); g51UIN]o-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); NoF|j57?u'  
httpConnection.setRequestProperty("User-Agent","NetFox"); B)DuikV.D  
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int responseCode=httpConnection.getResponseCode(); KIY`3Fl09  
if(responseCode>=400) u"7!EhX&  
{ L^CB#5uG  
processErrorCode(responseCode); Y<Ae_yLa  
return -2; //-2 represent access is error mmjWLrhlu  
} ?vWF[ DRd'  
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String sHeader; 2H8\P+  
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for(int i=1;;i++) Yevd h<  
{ 8.wtv5eZ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); "-:g.x*d  
//Utility.log(in.readLine()); j)ln"u0R^B  
sHeader=httpConnection.getHeaderFieldKey(i); "tJ[M  
if(sHeader!=null) vY4}vHH2  
{ WyB^b-QmDh  
if(sHeader.equals("Content-Length")) 73u97oe>1  
{ 3e-E/6zH6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); }3WP:E
t  
break; Ht}?=ZzW  
} v`Y{.>[H[  
} ql5&&e=-  
else W4P\HM>2  
break; <h+UC# .x  
} FD%OG6db];  
} (u@X5O(a  
catch(IOException e){e.printStackTrace ();} NyC&j`d  
catch(Exception e){e.printStackTrace ();} TntTR"6aD  
7;.Iat9gMf  
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Utility.log(nFileLength); fWIWRsy%  
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9  
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return nFileLength; 4%<wxrod  
} i&\ >/ 1  
inq {" 6  
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//保存下载信息（文件指针位置） q
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private void write_nPos() 'O2/
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{ f#I#24)RH  
try{ yZoJD{'?Sw  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ON>l%Ae4G  
output.writeInt(nStartPos.length); .n.N.e  
for(int i=0;i<nStartPos.length;i++) iM1E**WCtv  
{ g^po$%I '  
// output.writeLong(nPos); k MV1$  
output.writeLong(fileSplitterFetch.nStartPos); OM7AK B=S  
output.writeLong(fileSplitterFetch.nEndPos); fV6ddh  
} 7#
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output.close(); e=#D1
  
} 2*gB~Jn4  
catch(IOException e){e.printStackTrace ();} p,(W?.ZDN?  
catch(Exception e){e.printStackTrace ();} ]i1OssV~>  
} S5H}   
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//读取保存的下载信息（文件指针位置） nHF~a?|FT  
private void read_nPos() `|92!Ej  
{ ;1_3E2E$  
try{ &Wdi 5T8  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !"E/6z2&(k  
int nCount = input.readInt(); i&)([C0z$  
nStartPos = new long[nCount]; qv:DpK  
nEndPos = new long[nCount]; o7PS1qcya<  
for(int i=0;i<nStartPos.length;i++) o1{3[=G  
{ Y>8JHoV  
nStartPos = input.readLong(); eqOT@~H  
nEndPos = input.readLong(); TB<$9FCHK  
} 9R-2\D]  
input.close(); d mTZEO  
} M,oZ_tY%  
catch(IOException e){e.printStackTrace ();} Ui1s
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catch(Exception e){e.printStackTrace ();} dxS5-aWy9w  
} f"AT@Ga]  
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private void processErrorCode(int nErrorCode) NCo!n$O1~  
{ 8B!QqLqK  
System.err.println("Error Code : " + nErrorCode); Bk5 ELf8pL  
} W|sU[dxZ  
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//停止文件下载 dd +lQJ c  
public void siteStop() a>d`g
 
{ +`$$^x  
bStop = true; X(#8EY}X  
for(int i=0;i<nStartPos.length;i++) HvZSkq^
  
fileSplitterFetch.splitterStop(); |-cXb.M[  
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} tt6GtYrC 1  
} G-:7,9  
//负责部分文件的抓取 7>0/$i#'Vl  
**FileSplitterFetch.java n`jG[{3t&  
*/ s bR*[2  
package NetFox; .SSyW
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import java.io.*; MpJ\4D5G  
import java.net.*; SL+n y(y  
p"H/N_b4  
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public class FileSplitterFetch extends Thread { O69TU[Vn  
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String sURL; //File URL !\Cu J5U  
long nStartPos; //File Snippet Start Position 0pH$MkQ  
long nEndPos; //File Snippet End Position utn,`v   
int nThreadID; //Thread's ID bcxR7<T,"9  
boolean bDownOver = false; //Downing is over t56PzT'M  
boolean bStop = false; //Stop identical {%&04yq+  
FileAccessI fileAccessI = null; //File Access interface \O,yWyU4  
q['3M<q  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException /L|x3RHs  
{ ~6QV?j  
this.sURL = sURL; OJM2t`}_t  
this.nStartPos = nStart; &5B/>ag1!  
this.nEndPos = nEnd; Are0Nj&?
 
nThreadID = id;  (wxi!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 B T {cTj0W  
} _~P&8  
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public void run() w`M`F<_\:  
{ *1:kIi7_  
while(nStartPos < nEndPos && !bStop) Q]RE,ZZ  
{ 8|L5nQ  
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try{ 0&\71txrzg  
URL url = new URL(sURL); DPmY_[OAE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C58B(Ndo  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9U )9u["DH  
String sProperty = "bytes="+nStartPos+"-"; T@zp'6\H  
httpConnection.setRequestProperty("RANGE",sProperty); g]BA/Dw  
Utility.log(sProperty); ~xws5n}F  
)U]q{0`  
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InputStream input = httpConnection.getInputStream(); ;/IXw>O(/  
//logResponseHead(httpConnection); VuK>lY&  
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byte[] b = new byte[1024]; LFYSur8  
int nRead; GyFA1%(o  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) \~U:k4  
{ YzEOfHL,  
nStartPos += fileAccessI.write(b,0,nRead); r5$!41   
//if(nThreadID == 1) VOg'_#I  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *7L1SjZw  
} G"Ey%Q2K  
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Utility.log("Thread " + nThreadID + " is over!"); sP=^5K`g  
bDownOver = true; l!\~T"-7;:  
//nPos = fileAccessI.write (b,0,nRead); H_1&>@ 3  
} h^14/L=|  
catch(Exception e){e.printStackTrace ();} W58%Zz4a  
} A4KkX  
} Uw3wR!:  
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oBo |eRIt|  
//打印回应的头信息 6 lEv<)cC  
public void logResponseHead(HttpURLConnection con) %ca`v;].  
{ 6J$I8b#/  
for(int i=1;;i++)
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{ 34_ V&8  
String header=con.getHeaderFieldKey(i); <R_)[{ 7  
if(header!=null) "%_T7A ![  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <w?k<%( 4  
Utility.log(header+" : "+con.getHeaderField(header)); 2l:cP2fa  
else 6UqDpL7^U  
break; 13Q87i5B  
} *Aug7 HlS  
} p^ OHLT  
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public void splitterStop() ]-;JHB5A_:  
{ zq3f@xOK  
bStop = true; pXA|'U5]  
} "Rtt~["%  
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} 3&+nV1  
#|=lU4Bf  
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/* hyhm{RC?[  
**FileAccess.java ~Ra8(KocD  
*//文件访问(定位，写) q{f (T\  
package NetFox; rD !GEU
 
import java.io.*; 2{oQ  
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public class FileAccessI implements Serializable{ 3Jj&wHp]  
-q?
,  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 H"?Ndl:  
RandomAccessFile oSavedFile; 1/?K/gL  
long nPos; %;aB#:p6  
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public FileAccessI() throws IOException G%K&f1q%  
{ KUHkjA_  
this("",0); .4<lw  
} "/3YV%to-#  
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public FileAccessI(String sName,long nPos) throws IOException 3l$D%y  
{ 4jjo%N  
oSavedFile = new RandomAccessFile(sName,"rw"); (iJ /  
this.nPos = nPos; 5%@~"YCo  
oSavedFile.seek(nPos); 15Jc PDV  
} 0E{DO<~  
*,=8x\Shp  
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public synchronized int write(byte[] b,int nStart,int nLen) O]61guxro  
{ ' hdLQ\J  
int n = -1; 'X?Iho  
try{
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oSavedFile.write(b,nStart,nLen); xokA_3,1F  
n = nLen; q &S@\b  
} OXB 5W#$  
catch(IOException e) h*3{IHAQ  
{ 5Y@Hb!5D  
e.printStackTrace (); Xxj<Ai2  
} 'Axe:8LA'  
dh%
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return n; ?>gr9w\  
} w U1[/  
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} i8%@4U/ J  
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/* _3#_6>=M  
**SiteInfoBean.java $)KNpdXh  
*/ SA%)xGRW  
package NetFox; 9 aKU}y  
QB;TQZ  
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public class SiteInfoBean { lAo4)  
Y3-f68*(  
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private String sSiteURL; //Site's URL ]Z52L`k  
private String sFilePath; //Saved File's Path }VHvC"  
private String sFileName; //Saved File's Name &MB1'~Q,hq  
private int nSplitter; //Count of Splited Downloading File 9Sl5jn  
xmfZ5nVL  
0;]VTz?P  
public SiteInfoBean() ZoCk]hk  
{//nSplitter的缺省值为5 +6^hp-G7  
//default value of nSplitter is 5 6 B7F  
this("","","",5); mXyg\5  
} Vo|[Z)MO`  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) C^:{y  
{ V6kDyl(  
sSiteURL= sURL; ID<[=es6  
sFilePath = sPath; KTeR;6oZn"  
sFileName = sName; k`s_31<  
this.nSplitter = nSpiltter; 0n={Mb  
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} bw!
*=<  
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public String getSSiteURL() 7|o}m}yVx
 
{ %zhSSB=BJ  
return sSiteURL; ih|&q  
} ,vBB". LY'  
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z(#dL>d$'  
public void setSSiteURL(String value) :8N{;aui  
{ Qo*OC 9E`  
sSiteURL = value; s{42_O?,c  
} nB/`~_9  
?u0qYep:  
i@ 86Ez  
public String getSFilePath() iP1yy5T  
{ H29vuGQjq  
return sFilePath; k7(lwEgNG  
} k,ezB+  
iRM ?_
|  
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public void setSFilePath(String value) ?=HoU3  
{ J0o,ZH9  
sFilePath = value; p4$4;)  
} `7.$ A U  
ij.NSyk9  
Z2-"NB  
public String getSFileName() aY DM)b}  
{ #eF k  
return sFileName; #T8PgmR  
} `3z6y&dmx  
]?NiY:v  
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public void setSFileName(String value) G'wyH[ d/  
{ $J0o%9K   
sFileName = value; eQMa9_  
} nB}eJD|  
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ke)<E98DC  
public int getNSplitter() ,pUB[w\  
{ N{6-a  
return nSplitter; Q<yvpT(  
}
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public void setNSplitter(int nCount) 
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{ ]H<}6}
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nSplitter = nCount; jY ;Hdb''  
} mILCC}Kt  
} f?(g5o*2  
is^5TL%@  
8:Dkf
v  
/* J?1Eh14KZ  
**Utility.java *|gl1S  
*/ P~PM$e  
package NetFox; lXD=uRCI  
u]]mbER*t#  
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public class Utility { JZE<oQ_Jm  
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public Utility() %H3iX^}*  
{ UgOhx-8  
[]?*}o5&>T  
/74)c~.W  
} Gsz$H_  
]}.|b6\  
//线程睡眠 V|<'o<h8  
public static void sleep(int nSecond) lQ4$d{m`  
{ Q,};O$h  
try{ 4Vd[cRh2  
Thread.sleep(nSecond); gyU=v{].  
} +KOhDtLMG  
catch(Exception e) X9rao n  
{ '"h}l`  
e.printStackTrace (); _<?z-K_;I  
} T^ #1T$  
} L:.Rv0XT  
{yMkd4v  
//日志 V8Z@y&ny  
public static void log(String sMsg) ZbH_h]1$D  
{ j_b/66JyN  
System.err.println(sMsg); Zj0h0Vt  
} 7>EMr}f C  
PH?<)Wj9i  
('.I)n  
public static void log(int sMsg) 8[a N5M]  
{ Ft_g~]kZo  
System.err.println(sMsg); FR\r/+n:t0  
} _j~y;R)  
} !|cM<}TF,  
:\%hv>}|  
B|=S-5pv*  
/*
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**TestMethod.java V2g"5nYT  
*/ \\Z?v,XsS  
package NetFox; }$* z:E  
Q
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public class TestMethod { AR g]GV/L  
|Vp ?  
`*]r+J2  
public TestMethod() V-"#Kf9  
{ ///xx/weblogic60b2_win.exe !.O;S
G  
try{ %PPkT]~\  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 2Ic)]6z R  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 'yh)6mid  
SiteFileFetch fileFetch = new SiteFileFetch(bean); e'fo^XQn[  
fileFetch.start(); 6 I43a1[s  
} cq/@ng*o  
catch(Exception e){e.printStackTrace ();} R0F&!y!B  
*~.'lE%[U  
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} Xod/GYG  
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public static void main(String[] args) s1X?]A  
{
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new TestMethod(); X& XD2o"rt  
} B~ j3!?  
} !VHw*fL|r  
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