http断点续传简单实现（java)

/* D6ck1pxkx  
**SiteFileFetch.java ^MddfBwk  
*/ =
} vG|  
package NetFox; 8L|C&Ymj  
import java.io.*; ,$}Q#q  
import java.net.*; G+%ZN  
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public class SiteFileFetch extends Thread { \DQ
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SiteInfoBean siteInfoBean = null; //文件信息Bean _X]?
 
long[] nStartPos; //开始位置 X`aED\#\h  
long[] nEndPos; //结束位置 .7kVC  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 #); 6+v  
long nFileLength; //文件长度 &pmJ:WO,h  
boolean bFirst = true; //是否第一次取文件 hqBwA1](a  
boolean bStop = false; //停止标志 yGD0}\!n  
File tmpFile; //文件下载的临时信息 \4vFEJSh  
DataOutputStream output; //输出到文件的输出流 /S;?M\  
}Ns_RS$  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） db4&?55Q  
public SiteFileFetch(SiteInfoBean bean) throws IOException 9Q.j <  
{ zc2,Mn2  
siteInfoBean = bean; yqBu7E$X  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Iy,)>V%iZV  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); D^TKv;%d  
if(tmpFile.exists ()) _n_i*p '2  
{ QWxQD'L'  
bFirst = false; N\Hd3Om  
read_nPos(); pD>3c9J'^F  
} J`x9XWYw  
else kh5V&%>?  
{ }BfwMq4E)n  
nStartPos = new long[bean.getNSplitter()]; aSK$#Xeu  
nEndPos = new long[bean.getNSplitter()]; ##n\9ipD  
} IcIMa  
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} 8ziYav  
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public void run() V2y[IeSQ  
{ _ Po9pZ  
//获得文件长度 Ec[:6}  
//分割文件 6@$[x* V  
//实例FileSplitterFetch 9rid98~d  
//启动FileSplitterFetch线程 pTN_6=Y"  
//等待子线程返回 w%ip"GT,  
try{ eU12*(  
if(bFirst) z^b\hR   
{ \UC4ai2MK  
nFileLength = getFileSize(); 6S&#8l  
if(nFileLength == -1) +amvQ];?Q8  
{ @%TQ/L^|  
System.err.println("File Length is not known!"); m&%N4Q~X>  
} _AO0:&  
else if(nFileLength == -2) AH} nTm  
{ rvG qUmSUs  
System.err.println("File is not access!"); [L\w]6  
} )N=wJN1  
else 4v!@9.!vQ  
{ 8t^"1ND  
for(int i=0;i<nStartPos.length;i++) ;'Y?wH[  
{ j[HKC0C6  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); L fi]s  
} X-duG*~  
for(int i=0;i<nEndPos.length-1;i++) d-*9tit  
{ oO|^ [b#  
nEndPos = nStartPos[i+1]; T-@pTJ !K9  
} {NFeX'5bP  
nEndPos[nEndPos.length-1] = nFileLength; 3}+/\:q*  
} 55I>v3 w  
} /}VQzF  
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//启动子线程 3xe8DD  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0g+@WK6y  
for(int i=0;i<nStartPos.length;i++) u7;A`  
{ i~.[iZf|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F>M$|Sc2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), zPmVECS  
nStartPos,nEndPos,i); GWW@8GNI  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4 hj2rK'y  
fileSplitterFetch.start(); VgdkCdWRm_  
} ]`NbNr]K  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *Z]| Z4Q/`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); GWhZ Mj  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", i-<=nD&?t  
nEndPos = " + nFileLength); A`r9"([-A  
// fileSplitterFetch[nPos.length-1].start(); Ao\Vh\rQkq  
lfA  BF  
^DH*@M  
//等待子线程结束 9,Mp/.T"\  
//int count = 0; ~;+vF
-]R  
//是否结束while循环 MJb = +L  
boolean breakWhile = false; wx!*fy4hL  
V;6M[ic}  
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while(!bStop) Z^|C~lp;n  
{ bXfOZFzq)  
write_nPos(); "VeUOdNA>  
Utility.sleep(500); 6?lg 6a/eO  
breakWhile = true; rNAu@B  
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for(int i=0;i<nStartPos.length;i++) EzyIsp> _  
{ $7r wara  
if(!fileSplitterFetch.bDownOver) P=@lkF!\#  
{ >R:+ml  
breakWhile = false; ,dp?'_q{  
break; ? 1{S_  
} cg.e(@(  
} [0LqZ<\5  
if(breakWhile) 10rGA=x'(  
break; 3azc`[hl  
{|gJC>f@  
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//count++; iK]g3ew|  
//if(count>4) ^zJ.W  
// siteStop(); OW}A48X[+  
} ##@#:B  
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System.err.println("文件下载结束！"); tb{{oxa,k  
} }ELCnN  
catch(Exception e){e.printStackTrace ();} nnNg^<[k3  
} Sg$\ab$  
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$te,\$&}  
//获得文件长度 l{U3;  
public long getFileSize() 6y_Z'@L  
{ [J`G`s!  
int nFileLength = -1; -],?kP  
try{ cQ41NX@I  
URL url = new URL(siteInfoBean.getSSiteURL()); Uq.~3V+u  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5r<(
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httpConnection.setRequestProperty("User-Agent","NetFox"); j*u9+.   
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h /QP=Zd  
int responseCode=httpConnection.getResponseCode(); :\JbWj_j  
if(responseCode>=400) N^]>R:Stu  
{ 4Jr[8P0/A9  
processErrorCode(responseCode); \#jDQ  
return -2; //-2 represent access is error /&d`c=nH  
} sri#L+I  
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String sHeader; _0["J:s9  
:"^< aLj  
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for(int i=1;;i++) UMwMXmZNJ  
{ ~ p.W*skD  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); P i!r}m  
//Utility.log(in.readLine()); )hW {>Y3x  
sHeader=httpConnection.getHeaderFieldKey(i); }.) 43(>]  
if(sHeader!=null) 4_I{Q^f  
{ 2P_^@g  
if(sHeader.equals("Content-Length")) $F7gH  
{ ~&lJT  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); "EYjY->  
break; >Ron+ oe  
} r)]CZ])  
} u2BW]T
]  
else ,M&0<k\  
break; Ti|++oC/&  
} >Mz|e(6  
} J<#`IaV  
catch(IOException e){e.printStackTrace ();} SzlfA%4+GR  
catch(Exception e){e.printStackTrace ();} 64']F1p0  
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Utility.log(nFileLength); 0,$-)Sk
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;T
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/)?P>!#;\  
return nFileLength; niEEm`"  
} fKz"z{\,0  
{kl{mJ*  
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//保存下载信息（文件指针位置） 6q[!X0u  
private void write_nPos() ,."(Gp  
{ nl9Cdi]o  
try{ E D^
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output = new DataOutputStream(new FileOutputStream(tmpFile)); -f2`qltjb  
output.writeInt(nStartPos.length); 0#fG4D_  
for(int i=0;i<nStartPos.length;i++) `6N-MsP  
{ Y+u-J4bj  
// output.writeLong(nPos); u%
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output.writeLong(fileSplitterFetch.nStartPos); 8C,utjy  
output.writeLong(fileSplitterFetch.nEndPos); Obyuh
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} ho]!G498  
output.close(); @Du}   
} Y`7#[g  
catch(IOException e){e.printStackTrace ();} #!Cter2  
catch(Exception e){e.printStackTrace ();} kad;Wa#h  
} V"by9p|V`  
sp Q4m  
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//读取保存的下载信息（文件指针位置） W+f&%En  
private void read_nPos() h@,e`Z  
{ IO!1|JMr6  
try{ )=E~CpKV  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); a5}44/%  
int nCount = input.readInt(); 9^QYuf3O  
nStartPos = new long[nCount]; wz*A<iU  
nEndPos = new long[nCount]; dXcPWbrU4  
for(int i=0;i<nStartPos.length;i++) u:u
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{ q= yZx)  
nStartPos = input.readLong(); n*m"L|:ff  
nEndPos = input.readLong(); }K/}(zuy1Y  
} TjUZv1(L  
input.close(); a][pTC\rb  
} W-!Bl&jF[  
catch(IOException e){e.printStackTrace ();} %-ZR~*  
catch(Exception e){e.printStackTrace ();} mbX)'. +L  
} E/7vIg F  
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private void processErrorCode(int nErrorCode) {Bq"$M!Y  
{ C9mzg  
System.err.println("Error Code : " + nErrorCode); ;o)=XEh8P  
} sUbz)BS#.  
:PD`PgQ  
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//停止文件下载 Z<N&UFw7QJ  
public void siteStop() P~\a)Szy  
{ ].-J.  
bStop = true; prlyaq;4  
for(int i=0;i<nStartPos.length;i++) G/fP(o-Wd  
fileSplitterFetch.splitterStop(); c+8>EU AW  
r
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} NF/Ti5y  
} rwL=R,   
//负责部分文件的抓取 %jZp9}h  
**FileSplitterFetch.java MvZ+n  
*/ <84C tv  
package NetFox; 5y%u
n  
{b|3]_-/  
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import java.io.*; ^Y{6;FJ  
import java.net.*; aYaG]&hb  
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public class FileSplitterFetch extends Thread { `J>E9p<  
'&-5CpDUs  
< QDr,Hj  
String sURL; //File URL \!UF|mD^tG  
long nStartPos; //File Snippet Start Position jr,&=C(  
long nEndPos; //File Snippet End Position ~U"by_  
int nThreadID; //Thread's ID %tzN@  
boolean bDownOver = false; //Downing is over vo(g0Au)  
boolean bStop = false; //Stop identical [y|^P\D  
FileAccessI fileAccessI = null; //File Access interface T_
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException !2zo]v4?  
{ Uz6{>OCvk|  
this.sURL = sURL; c~gNH%1XN  
this.nStartPos = nStart; xb =
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this.nEndPos = nEnd; 5JBB+g  
nThreadID = id; >JKnGeF  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ]aC':55(  
} %[]"QbF?  
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public void run() ?G$Om  
{ iK5]y+@8  
while(nStartPos < nEndPos && !bStop) +{,N X  
{ Vs_\ykO  
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try{ HGO#e  
URL url = new URL(sURL); !,cQ'*<W8-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z/2,al\  
httpConnection.setRequestProperty("User-Agent","NetFox"); f >mhFy  
String sProperty = "bytes="+nStartPos+"-"; ,f8}q]FTA  
httpConnection.setRequestProperty("RANGE",sProperty); /S:w
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Utility.log(sProperty); )XLj[6j0  
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)-bD2YA{  
InputStream input = httpConnection.getInputStream(); 1YOg1 n+k  
//logResponseHead(httpConnection); $}qDV> qo  
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byte[] b = new byte[1024]; 5f;n<EPy  
int nRead; FU_fCL8yA  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) L;/9L[s,  
{ LP.HS'M~u  
nStartPos += fileAccessI.write(b,0,nRead); Sm$p\ORa  
//if(nThreadID == 1) h5L=M^z!>  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); O&`U5w  
} UWQtvQ f  
;[(=kOI  
+7| [b  
Utility.log("Thread " + nThreadID + " is over!"); ]
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bDownOver = true; .)LZ`Ge3F  
//nPos = fileAccessI.write (b,0,nRead); 9{_8cpm4  
} b;S6'7Jf9  
catch(Exception e){e.printStackTrace ();} N]B)Fb  
} fNmE,~
 
} @SU8\:(U  
X AQGG>  
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//打印回应的头信息 =WIE>*3[  
public void logResponseHead(HttpURLConnection con) WMW1B}Z3  
{ (C,e6r Y  
for(int i=1;;i++) iaY5JEV:CA  
{ T"n{WmVQ  
String header=con.getHeaderFieldKey(i); -glugVq  
if(header!=null) Rw{$
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); IikG/8lP  
Utility.log(header+" : "+con.getHeaderField(header)); V?OuIg%=:  
else {DU"]c/S  
break; q_cC7p6t  
} ~mtTsZc  
} ~j=xiP  
0CT}DQ._^N  
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public void splitterStop() Vwjk[ DOL  
{ \I?w)CE@R  
bStop = true; {}V$`L8  
} 7; p4Wg7k}  
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} 9/#0
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/* 2;8Xz6T  
**FileAccess.java $30oc Tt{  
*//文件访问(定位，写) W7t >&3l  
package NetFox; |~z3U>  
import java.io.*; Odm#wL~E  
IE2CRBfs  
<3b'm*  
public class FileAccessI implements Serializable{ ^V[/(Lq  
)CJES!! W  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 M&r2:Whk  
RandomAccessFile oSavedFile; 1Q]Rd  
long nPos; |+98h&U~  
Z
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public FileAccessI() throws IOException 5UE409Gn'  
{ g+/0DO_F3  
this("",0); j.DHqHx  
} T.kyV|  
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-LTKpN`[@  
public FileAccessI(String sName,long nPos) throws IOException +=7:4LFOL  
{ _g[-=y{Bb  
oSavedFile = new RandomAccessFile(sName,"rw"); /#f^n]v  
this.nPos = nPos; 6Opa{]  
oSavedFile.seek(nPos); WSRy%#  
} (?vK_{  
-ey)J +?t  
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public synchronized int write(byte[] b,int nStart,int nLen) r$ =qQ7^#  
{ P^pFqUL7#  
int n = -1; 1]T|6N?  
try{ {6h|6.S2  
oSavedFile.write(b,nStart,nLen); %]!adro~  
n = nLen; obO}NF*g^  
} yYY Nu`  
catch(IOException e) L;S}s, 2x  
{ qy ,"X)^#  
e.printStackTrace (); ?n.)&ZIx0  
} ?R|th Z  
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return n; -p`L%xj\  
} 4J5pXlzV  
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} v`x|]-/M&  
:'}@Al9=>  
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/* }$&xTW_  
**SiteInfoBean.java D<bI2  
*/ G(/DtY]  
package NetFox; %?9Ok  
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public class SiteInfoBean { +6l]]*H  
H=p`T+  
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private String sSiteURL; //Site's URL zT[6eZ8m  
private String sFilePath; //Saved File's Path w^HjZV  
private String sFileName; //Saved File's Name Qqc]aVRF  
private int nSplitter; //Count of Splited Downloading File . o7m!  
4;n6I)&.(  
&qpr*17T  
public SiteInfoBean()
{;toI  
{//nSplitter的缺省值为5 4#x5MM  
//default value of nSplitter is 5 MFTkqbc  
this("","","",5); J;_}lF9d@  
} 'o|30LzYgQ  
k.("3R6v:  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) `>0MNmu  
{ B`*ZsS=R-  
sSiteURL= sURL; 5;0g!&-t#  
sFilePath = sPath; @KX \Er  
sFileName = sName; (" LQll9  
this.nSplitter = nSpiltter; +a-6Q ~  
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5` Te\H  
} J)P$2#  
O+g3X5f+  
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public String getSSiteURL() 5N%93{L  
{ IDnC<MO>  
return sSiteURL; /}Jj
 
} ono4U.C9  
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5>BK%`  
public void setSSiteURL(String value) >2bK
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{ PV|uPuz  
sSiteURL = value; ^Ge+~o?x  
} j'9"cE5_  
i4^o59}8  
#fT*]NN  
public String getSFilePath() XsnF~)YW  
{ LPMU8Er  
return sFilePath; J[f;Xlh  
} (`y*V;o4  
626Z5Afg  
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public void setSFilePath(String value) A.hd Kl  
{ 1
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sFilePath = value; {?'fyEeg  
} R|wGU)KEc'  
_.L4e^N&UO  
<n]x#0p  
public String getSFileName() +$oF]OO  
{ PRz/inru-  
return sFileName; 31/Edd"]  
} MEwo}=B  
v
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5 ~TdD6}  
public void setSFileName(String value) 3B1cb[2y  
{ ^^5&QSB:'  
sFileName = value; N^3N[l
D{  
} \Gc+WpS(  
Z)jw|T'X
 
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public int getNSplitter() qK)73eNSR  
{ DZi!aJ  
return nSplitter; o865(<p  
} 5}`_x+$%(`  
M)U{7c$c7  
H,b5C_D29  
public void setNSplitter(int nCount) @|\}.M<e*)  
{ =jN*P?  
nSplitter = nCount; }Hn/I,/  
} k{'0[,mx#  
} fMOU
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9(@\&>)  
/* XGl+S  
**Utility.java qHxqQ'ks;  
*/ y\a1iy  
package NetFox; '0FhL)x?"T  
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*hw\35%P`?  
public class Utility { b[`Yi1^]%g  
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public Utility() ';<
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{ xXM{pd  
utIX  %0  
%"P,1&\^  
} Dc_yM  
@;'o2   
//线程睡眠 C+T
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public static void sleep(int nSecond) P'`r  
{ \_lod kf  
try{ Rj4|Q:XG  
Thread.sleep(nSecond); 0zi~p>*nJC  
} $C `;fA
 
catch(Exception e) Z4lO?S5%J  
{ YGrg  
e.printStackTrace (); zRyuq1Zyc,  
} vMS |$L  
} YxP&7oq  
7(5 4/  
//日志 q}]XYys  
public static void log(String sMsg) UXh9:T'%  
{ `DC2gJKk%  
System.err.println(sMsg); l g-X:Z.  
} )'~6HO8Z  
={z*akn,  
RRI"d~~F6  
public static void log(int sMsg) -:na:Vsi  
{ PbmDNKEh{  
System.err.println(sMsg); S;)w.  
} 6Aku1h  
} tQjLOv+?=  
:$n=$C-wp  
#E&80#Z5  
/* {j7uv"|X7  
**TestMethod.java ]bK=FIK2  
*/ ']>Mp#j  
package NetFox; C%U`"-%n@7  
un=2}@
'  
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public class TestMethod { Uv?|G%cD-  
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public TestMethod() x#Q>J"g  
{ ///xx/weblogic60b2_win.exe {fEwA8Ir  
try{ lr{?"tl_  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); u_'!_T L  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 4lM8\Lr  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 2OwV^-OG  
fileFetch.start(); N @#c,,  
} #fL8
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catch(Exception e){e.printStackTrace ();} \igmv]G%  
rS?pWTg"8  
E-{^E.w1  
} ;?6No(/  
r} P<iX
 
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public static void main(String[] args) 9&2Vm;F_  
{ V~hlq$jn<Y  
new TestMethod(); PZm:T+5H  
} PmR~c,  
} ~j#]tElb  
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