http断点续传简单实现（java)

/* q2*1Gn9!j  
**SiteFileFetch.java #dQFs]:F  
*/ f9vitFkb+  
package NetFox; 5-UrHbpCZ#  
import java.io.*; ubMN  
import java.net.*; g1@rY0O  
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public class SiteFileFetch extends Thread { ?0+N  
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SiteInfoBean siteInfoBean = null; //文件信息Bean IUz`\B
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long[] nStartPos; //开始位置 <MoyL1=  
long[] nEndPos; //结束位置 /z:1n
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 f6 s .xQ  
long nFileLength; //文件长度 @TJ  
boolean bFirst = true; //是否第一次取文件 gyxC)br  
boolean bStop = false; //停止标志 K$O2 Fq@y  
File tmpFile; //文件下载的临时信息 "bz]5c~  
DataOutputStream output; //输出到文件的输出流 t+D= @"BZP  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） P_)=sj!>-  
public SiteFileFetch(SiteInfoBean bean) throws IOException l[C_vUg  
{ yQf(/Uxk*x  
siteInfoBean = bean; &joP-!"  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]~!CJ8d  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); O^@F?CG :1  
if(tmpFile.exists ()) U5p3b;  
{ Y(gai?  
bFirst = false; z<gII~%  
read_nPos(); stiYC#bI:  
} wj5,_d)  
else 1fC)&4W  
{ T8d=@8g,%  
nStartPos = new long[bean.getNSplitter()]; HVK0NI  
nEndPos = new long[bean.getNSplitter()]; a'r1or4  
} $-
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} 6C\WX(@4  
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public void run() Z[>fFg~N4  
{ HDaeJk  
//获得文件长度 Rtlc&Q.b  
//分割文件 mP's4  
//实例FileSplitterFetch (G(M"S SC  
//启动FileSplitterFetch线程 }pGjc_:']  
//等待子线程返回 ^# 4e_&4  
try{ )0g!lCfb  
if(bFirst) M^Tm{`O!  
{ \S&OAe/b  
nFileLength = getFileSize(); /U-+ClZi@  
if(nFileLength == -1) zKp R:F  
{ 7P]i|Q{  
System.err.println("File Length is not known!"); T(Bcp^N  
} a
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else if(nFileLength == -2) <":83RCS  
{ (:\L@j  
System.err.println("File is not access!"); q=-h#IF^  
} $4qM\3x0,  
else ]2YC7  
{ J:O&2g"g  
for(int i=0;i<nStartPos.length;i++) 1_l)$"  
{ kUfbB#.5L  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ei"c|/pO  
} ^bfU>02Q6p  
for(int i=0;i<nEndPos.length-1;i++) @(+\*]?^&  
{ Zj_2B_|WN#  
nEndPos = nStartPos[i+1]; _~*j=XRs  
} pred{HEye  
nEndPos[nEndPos.length-1] = nFileLength; Y88N*axDW.  
} '-Oh$hqCx|  
} VJl0UM3{J  
)1gT&sU0  
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//启动子线程 \RRSrPLd-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; hpYv*WH:  
for(int i=0;i<nStartPos.length;i++) teC/Uf5  
{ XBB>"  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q7{{r&|t&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), J<4_<.o(a  
nStartPos,nEndPos,i); E9Dy)f]#W  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); eu~ u-}.  
fileSplitterFetch.start();
[9j,5d&m  
} B9$pG  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), O*!f%}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %4t?X  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2J%L%6z8~  
nEndPos = " + nFileLength); \I^"^'CP  
// fileSplitterFetch[nPos.length-1].start(); 0c1=M|2  
!%DE(E*'(  
y?A*$6  
//等待子线程结束 EyA(W;r.  
//int count = 0; `T{CB) ?9  
//是否结束while循环 9_.pLLx  
boolean breakWhile = false; ,?IXfJ`c  
5|>ms)[RQ  
q/Ji}NGm  
while(!bStop) 0>D*d'xLd  
{ qn{4AWmJ  
write_nPos(); VUP. \Vry  
Utility.sleep(500); ,fN <I  
breakWhile = true; TU6YS<  
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<
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for(int i=0;i<nStartPos.length;i++) qs= i+  
{ y4aT-^C'  
if(!fileSplitterFetch.bDownOver) \2#K {  
{ 59v=\; UI  
breakWhile = false; +2}Ar<elP  
break; xj&~>&U){;  
} l-!"   
} Io>U-Zd\>  
if(breakWhile) Pth4_]US  
break; ygX!'evY  
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&  
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//count++; %[ *+  
//if(count>4) 4>H0a  
// siteStop(); .y_~mr&d  
} &gJ@"`r4  
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System.err.println("文件下载结束！"); <
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} H
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catch(Exception e){e.printStackTrace ();} gkq~0/  
} LWSy"Cs*  
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//获得文件长度 I")Ud?v0)  
public long getFileSize() NS+uiy  
{ D+
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int nFileLength = -1; M195[]  
try{ Qy=tkCN  
URL url = new URL(siteInfoBean.getSSiteURL()); ^h#A7 g  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Wf%)::G*uR  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^L Xr4  
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int responseCode=httpConnection.getResponseCode(); Z/v )^VR  
if(responseCode>=400) }g%&}`%'  
{ <S;YNHLC  
processErrorCode(responseCode); gu'+kw  
return -2; //-2 represent access is error ;i+(Q%LO  
} `ZP[-:`  
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String sHeader; L=s8em]7l  
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for(int i=1;;i++) I<xcVY9L  
{ /jq"r-S"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); !ueh%V Ky  
//Utility.log(in.readLine()); |L-- j  
sHeader=httpConnection.getHeaderFieldKey(i); C)9-{Yp  
if(sHeader!=null) r.:f.AY{  
{ mt e3k=17  
if(sHeader.equals("Content-Length")) G`;mSq6i  
{ Z vyF"4QN  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 5VfpeA`  
break; %V
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} [
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} SxC(:k2b;  
else : B1 "=ly  
break; +OB&PE  
} 8@T0]vH&  
} CyB1`&G>  
catch(IOException e){e.printStackTrace ();} A7|x|mW  
catch(Exception e){e.printStackTrace ();} K:pG<oV|}  
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Utility.log(nFileLength); U
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return nFileLength; =)]RD%Oq  
} A+3=OBpkW0  
!W=2ZlzS
 
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//保存下载信息（文件指针位置） I+Fr#1  
private void write_nPos() `]Vn[^?D  
{ a$6pA@7}  
try{ i\MW'b  
output = new DataOutputStream(new FileOutputStream(tmpFile)); !}xRwkN  
output.writeInt(nStartPos.length); [|HQfTp$  
for(int i=0;i<nStartPos.length;i++) +6Vu]96=KC  
{ "n<u(m8E  
// output.writeLong(nPos); A?c?(~9O  
output.writeLong(fileSplitterFetch.nStartPos); Zt4 r_7  
output.writeLong(fileSplitterFetch.nEndPos); a\I`:RO=<Z  
} @jD19=  
output.close(); lx~mn~;x  
} jH4Wu`r;m  
catch(IOException e){e.printStackTrace ();} I,lzyxRP  
catch(Exception e){e.printStackTrace ();} u #7AB>wi{  
} .GPuKP|  
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//读取保存的下载信息（文件指针位置） ]}AyDy6C  
private void read_nPos() c-
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{ 11yS2D   
try{ 
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *Kw/ilI  
int nCount = input.readInt(); ]^l-k@  
nStartPos = new long[nCount]; _Hq)mF  
nEndPos = new long[nCount]; *(<3 oIRS  
for(int i=0;i<nStartPos.length;i++) #.\X%!  
{ kc:2ID&
 
nStartPos = input.readLong(); ^KFwO=I@PV  
nEndPos = input.readLong(); O<w7PS  
} 885 ,3AdA  
input.close(); *|:]("i  
} G{oM2`c'#8  
catch(IOException e){e.printStackTrace ();} .w]S!=h  
catch(Exception e){e.printStackTrace ();} 8f|+045E@  
} [x|{VJ(h  
H=9\B}  
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private void processErrorCode(int nErrorCode) x68s$H  
{ }L*cP;m#  
System.err.println("Error Code : " + nErrorCode); Cqk6Igw  
} rW3fd.;kss  
M3 $MgsN:  
_qqJ>E<0  
//停止文件下载 _26F[R1><~  
public void siteStop() pF"IDC  
{ x;R9Gc[5  
bStop = true; b%,`;hy{  
for(int i=0;i<nStartPos.length;i++) \(bML#I  
fileSplitterFetch.splitterStop(); Zx]"2U#  
[HENk34  
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} e: :H1V  
} CR$5'#11)  
//负责部分文件的抓取 4%k_c79>  
**FileSplitterFetch.java ?wx|n_3<:  
*/ "GofQ5,|  
package NetFox;  `#lNur\x  
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u-. _;  
import java.io.*; 5q?ZuAAA  
import java.net.*; I(Yyg,1Z  
*^u5?{$l(  
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public class FileSplitterFetch extends Thread { R{hKl#j;>  
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.gWYKZM  
String sURL; //File URL U.G**v  
long nStartPos; //File Snippet Start Position K_B-KK(^  
long nEndPos; //File Snippet End Position u1&pJLK0[  
int nThreadID; //Thread's ID /wL}
+  
boolean bDownOver = false; //Downing is over 70:a2m  
boolean bStop = false; //Stop identical b#^UP  
FileAccessI fileAccessI = null; //File Access interface !285=cxz  
i4N'[ P}  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (;'?56  
{ ALiXT8q  
this.sURL = sURL; B@l/'$G  
this.nStartPos = nStart; }cG
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this.nEndPos = nEnd; /AP@Bhm  
nThreadID = id; M:qeqn+  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 969*mcq'  
} r"a0!]n  
`Q*L!/K+  
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public void run() <w.W[ak  
{ `bffw:;%  
while(nStartPos < nEndPos && !bStop)
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{ Qd 1Q~PBla  
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try{ %9xz[Ng  
URL url = new URL(sURL); jnX9] PkJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); QdL ;|3K9  
httpConnection.setRequestProperty("User-Agent","NetFox"); %J?;@ G)r  
String sProperty = "bytes="+nStartPos+"-"; 70l"[Y  
httpConnection.setRequestProperty("RANGE",sProperty); }r6SV%]:  
Utility.log(sProperty); #m6 eG&a  
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InputStream input = httpConnection.getInputStream(); b}p0&%I
 
//logResponseHead(httpConnection); }\B`tAN  
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jAmAT/1  
byte[] b = new byte[1024]; VC\43A,9  
int nRead; O/>$kG%ge  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) AS[
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{ 1y l2i|m+  
nStartPos += fileAccessI.write(b,0,nRead);
52BlFBNV  
//if(nThreadID == 1) 2Tt@2h_L  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Bhl
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} Ft>Abj,6  
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0}k[s+^  
Utility.log("Thread " + nThreadID + " is over!"); ig]*Z  
bDownOver = true; iK1<4
)  
//nPos = fileAccessI.write (b,0,nRead); #vYdP#nWb  
} Nrva?W_i  
catch(Exception e){e.printStackTrace ();} Iw8;",e2  
} tB4- of3+  
} v&%GK5j7O  
]FvN*@lG  
l~wx8 ,?G  
//打印回应的头信息 W\o(f W  
public void logResponseHead(HttpURLConnection con) eP$0TDZ  
{ xXM`f0s@+]  
for(int i=1;;i++) ]QM6d(zDA  
{ )Fk%,H-1  
String header=con.getHeaderFieldKey(i); `9Zoq=/  
if(header!=null) 0Np}O=>  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9`+c<j4/B  
Utility.log(header+" : "+con.getHeaderField(header)); 5@bLDP  
else KD*,u{v;  
break; !9DqW&8  
} MOY.$M,1  
} .HF+JHIUu  
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public void splitterStop() `UL#g![J  
{ "?hEGJ;m"  
bStop = true; &F*s.gL  
} B@` 87  
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.  
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} J5}-5sV^  
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8E"Ik~  
/* UMuqdLaT9  
**FileAccess.java 8P0XY S@  
*//文件访问(定位，写) 7OYNH0EH  
package NetFox; :O)\v!Z  
import java.io.*; *<#jr  
4:=']C  
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public class FileAccessI implements Serializable{ L"A,7@:Vd  
\@vR*E  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ")"VQ|$y  
RandomAccessFile oSavedFile; 2@@OjeANsX  
long nPos; LX'.up11X5  
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public FileAccessI() throws IOException KlDW'R$  
{ T>e!DOW;  
this("",0); =0TnH<`  
} mS5'q q;t  
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1w/1k6`0  
public FileAccessI(String sName,long nPos) throws IOException ifl`QZp_  
{ t6BggO"_u  
oSavedFile = new RandomAccessFile(sName,"rw"); @*e|{;X]hy  
this.nPos = nPos; S)of.Nq.;  
oSavedFile.seek(nPos); *P_(hG&c  
} s3kHNDdC  
b2
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fi^I1*S  
public synchronized int write(byte[] b,int nStart,int nLen) $As;Tvw.  
{ @|v4B[/  
int n = -1; I3]-$  
try{ ?*|AcMw5
 
oSavedFile.write(b,nStart,nLen); trcG^uV  
n = nLen; Q{T6t;eH  
} 7T9m@  
catch(IOException e) MWl?pG!Y  
{ [X]yj  
e.printStackTrace (); IL`X}=L_  
} G?CaCleG  
:0x,%V74_!  
A94ZG:  
return n; '=K [3%U  
} bhDV U(%I6  
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S7]\tw_L)  
} EITA[Ba B`  
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/* ]Ir{9EE v  
**SiteInfoBean.java ZDuP|" ^  
*/ (T:OZmEO.  
package NetFox; jA_wOR7$  
!D6  
<"
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public class SiteInfoBean { @zo}#.g  
\JmfQrBQ  
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private String sSiteURL; //Site's URL j06?Mm_c2  
private String sFilePath; //Saved File's Path e59P6/z  
private String sFileName; //Saved File's Name "zFv?ay  
private int nSplitter; //Count of Splited Downloading File qNb|6/DG  
fd~a\5%e  
+@*}_%^l"  
public SiteInfoBean() P7ktr?V0a  
{//nSplitter的缺省值为5 9D@ $Y54  
//default value of nSplitter is 5 \1|]?ZQ\K  
this("","","",5); aK>5r^7S  
} !kCMw%[  
b-4gHW
 
7OuzQzhcK  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) -7jP'l=h  
{ J|4q9$  
sSiteURL= sURL; xS.Rpx/8  
sFilePath = sPath; '](4g/%  
sFileName = sName; T,N"8N{K"  
this.nSplitter = nSpiltter; rHe*/nN%*  
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I#lvaoeN  
} b^
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public String getSSiteURL() O`Ht|@[6  
{ YdsY2  
return sSiteURL; ]j.=zQP?'  
} j{}-zQ]n  
S}fU2Wi  
V.<$c1#=$  
public void setSSiteURL(String value) P(iZGOKUs=  
{ CbPCj.MH  
sSiteURL = value; hv" 'DP  
} [f`^+,U  
@ qFE6!  
K&1o!<|  
public String getSFilePath() u=j|']hp#&  
{ 
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return sFilePath; QG{).|pm  
} yWS#{|o(  
p1}Y|m!  
'p0|wM_  
public void setSFilePath(String value) Y)D~@|D,  
{ `v2]Jk<  
sFilePath = value; DGfhS`
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} *qx<bY@F  
9{OH%bF  
Eu%19s;u  
public String getSFileName() oL?[9aww  
{ t:A,p
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return sFileName; 00DWXGt20o  
} -Vj'QqZ  
xL.T}f~y2>  
NpmPm1Ix .  
public void setSFileName(String value) Znl&.,c)  
{ X`,4pSQ;  
sFileName = value; 1\v$8pP+  
} Y>OL2g  
k:?+75?$  
eFO+@  
public int getNSplitter() n])-+[F  
{ M~&|-Hm  
return nSplitter; #3uBq(-Z  
} {HgW9N(  
re.%$D@  
s3G\L<~mB  
public void setNSplitter(int nCount) Effp^7 3  
{ Salu[)+?  
nSplitter = nCount; Sr7+DCr  
} !*46@sb:  
} >.R6\>N%  
A<6V$e$:2  
H>AzxhX[n  
/* kvU0$1  
**Utility.java ?$O5w*  
*/ ":,HY)z  
package NetFox; ++KY+j.^  
vS~y~uU%6  
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public class Utility { 5io7!%  
q.(p.uD  
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public Utility() Q:LyD!at  
{ ~"l a2  
vPG!S{4  
b0a'Y"oef4  
} `1%SXP1  
#vO3*-hs  
//线程睡眠 o3H+.u
$  
public static void sleep(int nSecond) Xco$ yF%  
{ _/[n/"gn  
try{ l<<G".?  
Thread.sleep(nSecond); 1B3,lYBM  
} mB(*)PwZ  
catch(Exception e) .js4
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{ -;$+`<%  
e.printStackTrace (); UQ|zSalv,  
} F"a^`E&  
} PVO9KWv**  
*$(=I6b  
//日志 p71%-nV  
public static void log(String sMsg) QN(f8t(  
{ &%pB; dk  
System.err.println(sMsg); #( nheL  
} X$JO<@x  
{nQ}t }B  
1A23G$D  
public static void log(int sMsg)  =erA.u  
{ Vvx(7p-GQ  
System.err.println(sMsg); $"{V],:T |  
} ADX}  
} XA])<dZ  
+DKrX  

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/* 
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**TestMethod.java F~d !Ub$>  
*/ Zn3iLAPBX  
package NetFox; QnxkD)f*0  
gb:Cc,F,%  
K/[v>(<  
public class TestMethod { | -Di/.  
k;3P;@3,W  
~QdwoeaD  
public TestMethod() hE:P'O1  
{ ///xx/weblogic60b2_win.exe ;hs:wLVa"  
try{ =nnS X-x  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); )EO/P+&  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 7>{edNy!,  
SiteFileFetch fileFetch = new SiteFileFetch(bean); #},]`"n\  
fileFetch.start(); wrG*1+r
 
} #)R;6"  
catch(Exception e){e.printStackTrace ();} s)=L6t^a6  
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c7\bA7.  
} !U`T;\,v5  
p)ZlQ.d#Y  
?l,i(I  
public static void main(String[] args) *Oz
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{ 17D167\X  
new TestMethod(); }sy3M
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} LWbWj ^  
} K=sQ_j.&Z  
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