http断点续传简单实现（java)

/* Eu.qA9,@U  
**SiteFileFetch.java U^BXCu1km  
*/ MmH_gR  
package NetFox; KxmPL  
import java.io.*; fMPq  
import java.net.*; Q0Qm0B5eY  
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public class SiteFileFetch extends Thread { %C0O?q  
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SiteInfoBean siteInfoBean = null; //文件信息Bean e uHu}  
long[] nStartPos; //开始位置 O>M*mTM  
long[] nEndPos; //结束位置 #UCQiQfP  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 yVQz<tX|  
long nFileLength; //文件长度 KGmc*Jwy  
boolean bFirst = true; //是否第一次取文件 wn|@D<  
boolean bStop = false; //停止标志 ^
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File tmpFile; //文件下载的临时信息 I7z/GA\x  
DataOutputStream output; //输出到文件的输出流 J?quYlS  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） jI`To%^Y  
public SiteFileFetch(SiteInfoBean bean) throws IOException Kx185Q'W  
{ np\2sa`  
siteInfoBean = bean; *M<BPxh0w]  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Dh(T)yc  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !riMIl1  
if(tmpFile.exists ()) f\_!N "HW  
{ [j]J_S9jJ  
bFirst = false; ec4%Wk2  
read_nPos(); ]!G>8Rc  
} <`j[;>O  
else 2vdQ&H4  
{ *a,.E6C*  
nStartPos = new long[bean.getNSplitter()]; |4> r"  
nEndPos = new long[bean.getNSplitter()]; =#2qX>?  
} ^}/ E~Sg7\  
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} eOPCYyN  
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public void run() Q=L$7   
{ maUHjI 5A-  
//获得文件长度 }42qMOi#w1  
//分割文件 vs])%l%t  
//实例FileSplitterFetch <Z:8~:@  
//启动FileSplitterFetch线程 pebx#}]p-  
//等待子线程返回 -C-OG}XjI  
try{ @W\4UX3dK  
if(bFirst) ddq 1NW  
{ pY!dG-;  
nFileLength = getFileSize(); +>:_kE]?nX  
if(nFileLength == -1) /z)3gsF  
{ @S"pJeP/f  
System.err.println("File Length is not known!"); a3dzok  
} Hl2f`GZ   
else if(nFileLength == -2) U]!.~ji3  
{ +.(}u ,:8  
System.err.println("File is not access!"); YUVc9PV)Ws  
} 7hF,gl5  
else OT}Yr9h4  
{ O`[iz/7m  
for(int i=0;i<nStartPos.length;i++) yEpN,A  
{ $mI:Im`s  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ZA_zKJ[[7  
} nze1]3
`  
for(int i=0;i<nEndPos.length-1;i++) Ih-3t*L  
{ =SK+\j$  
nEndPos = nStartPos[i+1]; w{e3U7;  
} jQxPOl$-  
nEndPos[nEndPos.length-1] = nFileLength; ,hTwNVWI9  
} '6.>Wdd  
} 0qL V(L  
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/,Dwu?Lcqp  
//启动子线程 ]o[X+;Tj|  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; b1+hr(kMRM  
for(int i=0;i<nStartPos.length;i++) 9oje`Ay  
{ #7~tL23}]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), uH ny ]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !M]%8NTt2  
nStartPos,nEndPos,i); :,%J6Zh?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?zhI=1ED%  
fileSplitterFetch.start(); 3Zaq#uA  
} *qO]v9 j  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9QOr,~~s  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); dE5 5  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", lRv#1'Y  
nEndPos = " + nFileLength); u 5Eo  
// fileSplitterFetch[nPos.length-1].start(); k_K,J6_)  
$#G6m`V  
/zl3&~4  
//等待子线程结束 4/HY[FT  
//int count = 0; |.Nr.4Yp  
//是否结束while循环 sP6 ):h  
boolean breakWhile = false; 6^]`-4*W  
;# R3k  
?#BZ `H  
while(!bStop) JNxW6 cK  
{ #aitESbT  
write_nPos(); q,;".3VQ  
Utility.sleep(500); BcZEa^^~os  
breakWhile = true; ERfd7V<c>  
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for(int i=0;i<nStartPos.length;i++) ;OQ'B=uK  
{ 670J{b  
if(!fileSplitterFetch.bDownOver) #$rf-E5g-K  
{ 7y>Tn`V8G  
breakWhile = false; I%;Rn:zl  
break; < -Hs<T|tW  
} !y>lOw})Q  
} DC
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if(breakWhile) %PQldPL8  
break;  &7L~PZ  
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84[|qB,ML  
//count++; d3EjI6R*z  
//if(count>4) Wk/fB0  
// siteStop(); 4r_!>['`"  
} W:VW_3  
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System.err.println("文件下载结束！"); ?gd'M_-J,  
}
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catch(Exception e){e.printStackTrace ();} `xISkW4%  
} "NxOOLL  
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//获得文件长度 Xy[}Gp  
public long getFileSize() nHI(V-E2:H  
{ gb]hOB7g  
int nFileLength = -1; D",A$(lG  
try{ :0nK`$'  
URL url = new URL(siteInfoBean.getSSiteURL()); Ezi' 2S
c  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); VKT@2HjNT`  
httpConnection.setRequestProperty("User-Agent","NetFox"); |2qR^Hd&5  
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int responseCode=httpConnection.getResponseCode(); h^['rmd  
if(responseCode>=400) $TR=3[j  
{ n)tU9@4Np  
processErrorCode(responseCode);
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return -2; //-2 represent access is error dj3|f{kg{  
} UV?[d:\>'  
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String sHeader; ~af8p {  
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for(int i=1;;i++) (2: N;  
{ +:}kZDl@ X  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());  NI^{$QMj  
//Utility.log(in.readLine()); b([:,T7  
sHeader=httpConnection.getHeaderFieldKey(i); y^9bfMA  
if(sHeader!=null) I9;xzES  
{ S<V-ZV&_:U  
if(sHeader.equals("Content-Length")) TKK,Y{{  
{ 1d`cTaQ-  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); K-Re"zsz  
break; 8098y,mQe  
} bi+9R-=&  
} KCE=|*6::|  
else 5n:nZ_D  
break; g&Z"_7L~  
} N
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} _jW>dU^B  
catch(IOException e){e.printStackTrace ();} 9p5= _  
catch(Exception e){e.printStackTrace ();} %z30=?VL  
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:*=Ns[Y  
Utility.log(nFileLength); iM8sX B  
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return nFileLength; kl=xu3j  
} D2{L=  
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//保存下载信息（文件指针位置） ?fB5t;~E  
private void write_nPos() K6-6
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{ FzVZs#O  
try{ lBS"3s384  
output = new DataOutputStream(new FileOutputStream(tmpFile)); \]t]#D>0  
output.writeInt(nStartPos.length); 5~QhX22  
for(int i=0;i<nStartPos.length;i++) tbg*_ZQO u  
{ 3eWJt\}?B  
// output.writeLong(nPos); 2H6:np|O  
output.writeLong(fileSplitterFetch.nStartPos); ?gU}[]  
output.writeLong(fileSplitterFetch.nEndPos); ka/nQ~_#<  
} b(/j\NWC  
output.close(); XJc ,uj7  
} -ovoRI^6`}  
catch(IOException e){e.printStackTrace ();} l(#1mY5!q8  
catch(Exception e){e.printStackTrace ();} [O(m/  
} 0',[J  
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//读取保存的下载信息（文件指针位置） _p0)vT  
private void read_nPos() @$oZ|ZkZ  
{ 0iF-}o  
try{ @' d6iYk_  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); "sD1T3!\)Q  
int nCount = input.readInt(); w=|py>%  
nStartPos = new long[nCount]; wE?CvL  
nEndPos = new long[nCount]; JwB"\&'1ZS  
for(int i=0;i<nStartPos.length;i++) cu)U7  
{ @cPflb  
nStartPos = input.readLong(); Vu%n&uF  
nEndPos = input.readLong(); YKY2Cw  
} yWNOG 2qAP  
input.close(); &f"T,4Oh  
} 7|Xe&o<n  
catch(IOException e){e.printStackTrace ();} g>_OuQ|c  
catch(Exception e){e.printStackTrace ();} b;*c:{W)  
} _H8*ReFG  
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private void processErrorCode(int nErrorCode) a_MFQf&KV  
{ Ia#"/`||  
System.err.println("Error Code : " + nErrorCode); <*_o0;h|  
} d+0^u(gc!8  
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//停止文件下载 Dm
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public void siteStop()
#~S>K3(  
{ Q,~x#  
bStop = true; >nK%^T  
for(int i=0;i<nStartPos.length;i++) F_v-}bbcFQ  
fileSplitterFetch.splitterStop(); |kseKZ3  
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} 57<Di!rt  
} x}|+sS,g  
//负责部分文件的抓取 \s
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**FileSplitterFetch.java dZD
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*/ 85D? dgV  
package NetFox; ^&MK42,\  
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import java.io.*; t!:)L+$3  
import java.net.*; o0l7
4  
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public class FileSplitterFetch extends Thread { 5B?i
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String sURL; //File URL WL1\y|  
long nStartPos; //File Snippet Start Position $ser+Jt=  
long nEndPos; //File Snippet End Position ceG&,a$\  
int nThreadID; //Thread's ID A?r^V2+j  
boolean bDownOver = false; //Downing is over 'g hys1H  
boolean bStop = false; //Stop identical VX!hv`E  
FileAccessI fileAccessI = null; //File Access interface SO_>c+Dw  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ]Jn2Ra"j  
{ JD
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this.sURL = sURL; 03_pwB)^  
this.nStartPos = nStart; mf9hFy*<4  
this.nEndPos = nEnd; Mg\TH./Y:  
nThreadID = id; *VDVC0R  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 iZ "y7s  
} lE'wfUb  
)~dOmfw%|  
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public void run() M)O[j}N  
{ 6.19g'{sB  
while(nStartPos < nEndPos && !bStop) 1qZG`Vz  
{ ^1 ;BiQ  
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try{ h/?6=D{  
URL url = new URL(sURL); SY T$3|a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;MPKJS68@  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9go))&`PJL  
String sProperty = "bytes="+nStartPos+"-"; T?rH ,$:  
httpConnection.setRequestProperty("RANGE",sProperty); > c:Zx!  
Utility.log(sProperty); #c:kCZt#  
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InputStream input = httpConnection.getInputStream(); )4m_A
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//logResponseHead(httpConnection); d.AC%&W  
 :,~K]G  
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byte[] b = new byte[1024]; 9!#EwPD$#  
int nRead; n[Co
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) M*`hDdS  
{ y/tSGkMv  
nStartPos += fileAccessI.write(b,0,nRead); $r15gfne>  
//if(nThreadID == 1) F0.zi>5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &d,Wy"WPi  
} ]0-<>  
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Utility.log("Thread " + nThreadID + " is over!"); ^Xs]C|=W  
bDownOver = true; q.T:0|  
//nPos = fileAccessI.write (b,0,nRead); H,K`6HH  
} ?1w"IjUS  
catch(Exception e){e.printStackTrace ();} ag;dc  
} FN\GE\H  
} kOI !~Qk  
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//打印回应的头信息 6tm\L  
public void logResponseHead(HttpURLConnection con) O{q&]~,  
{ vRr9%zx  
for(int i=1;;i++) V
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{ &<0ZUI |S3  
String header=con.getHeaderFieldKey(i); Z@M6!;y#  
if(header!=null) \fi}Q\|C  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Nfb`YU=  
Utility.log(header+" : "+con.getHeaderField(header)); X-/Ban  
else bVK$.*,  
break;  }_%P6  
} {y-`QS  
} "DpKrVuG  
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public void splitterStop()  zy>}L #  
{ .8H}Lf\  
bStop = true; (0C&z/  
} AC4 l<:Yh  
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}  S^j,f'2  
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/* PGX+p+wB  
**FileAccess.java CDCC1BG"  
*//文件访问(定位，写) ti9}*8  
package NetFox; W[|[;{  
import java.io.*; c;!9\1sr  
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public class FileAccessI implements Serializable{ OKPJuV`y6  
_tWE8r,
 
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 }N,>A-P  
RandomAccessFile oSavedFile; ],&\%jd<  
long nPos; ])N%^Qe$U  
%wL,v.}  
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public FileAccessI() throws IOException KyLp?!|>  
{ MZ~.(&  
this("",0); M[s\E4l:t  
} d+5:Qrr  
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public FileAccessI(String sName,long nPos) throws IOException #ZTLrq5b  
{ _]o5R7[MQ  
oSavedFile = new RandomAccessFile(sName,"rw"); t.U{Bu P  
this.nPos = nPos; Pz`hX$  
oSavedFile.seek(nPos); \
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} hk;bk?:m  
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public synchronized int write(byte[] b,int nStart,int nLen) D9o*8h2$  
{ qjLo&2)  
int n = -1; aQ|hi F}  
try{ 8*Zvr&B,G  
oSavedFile.write(b,nStart,nLen); 4bI*jEc\[  
n = nLen; ~6d5zI4\  
} 3cThu43c  
catch(IOException e) [Vp\$;\nT  
{ Le&;g4%  
e.printStackTrace (); :e2X/tl#  
} v}P!HczmMP  
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return n; =]b9X7}  
} gZ`DT  
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} wd+O5Lr.R  
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/* b:Dg}  
**SiteInfoBean.java / O)6iJ  
*/ >{XScxaB`  
package NetFox; $1e pf  
uV77E*+7\  
yjpz_<7a=  
public class SiteInfoBean { f_'"KF[%  
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} 07r  
private String sSiteURL; //Site's URL ? s4oDi|:  
private String sFilePath; //Saved File's Path 1b[NgOXY=  
private String sFileName; //Saved File's Name c F=P!2@  
private int nSplitter; //Count of Splited Downloading File SQ<f  
KN, 4@4  
3EOyq^I%  
public SiteInfoBean() }]GbUC!Zb  
{//nSplitter的缺省值为5 J6auUm` `  
//default value of nSplitter is 5 4J}3,+  
this("","","",5); !.eAOuq  
} "TFwHe3C4  
26PD[af64O  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) `]{Psc6_=  
{ ,`)OEI|1d  
sSiteURL= sURL; ccMd/  
sFilePath = sPath; :rmauKR  
sFileName = sName; AT ymKJ
 
this.nSplitter = nSpiltter; iNLDl~uU  
pVz*ZQ[]  
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} {(0I
d!  
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}4KW@L[g  
public String getSSiteURL() '!@A}&]  
{ 8Fx]koP.  
return sSiteURL; mu>] 9ZW  
} /.@x 4cdS  
. s-5N\  
xB,/dMdTj  
public void setSSiteURL(String value) +7Rt{C,  
{ iAHZ0Du  
sSiteURL = value; 2@*<9-9  
} 5Pqt_ZWy  
O! (85rp/  
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public String getSFilePath() nl9kYE [  
{ [yF^IlSs  
return sFilePath; :`5;nl63  
} |0]YA  
)f[C[Rd  
%mL5+d-oP  
public void setSFilePath(String value) ;-Ado8  
{ `
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sFilePath = value; 5"uNj<.V  
} y($EK(cb  
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f}blB?e  
public String getSFileName() wt\m+!u`  
{ y9ip[Xn-$:  
return sFileName; =h7[E./U1  
} |?yE^$a  
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public void setSFileName(String value) Rdj8*f  
{ ?sE@]]z  
sFileName = value; {83C,C-  
} J@gm@ jLc  
"u5KbJW  
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public int getNSplitter() jJ<;2e~OW  
{ (gDQ\t@3-  
return nSplitter; ;t~*F#p(!  
} lJlhl7  
$':
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public void setNSplitter(int nCount) G ~A$jStm
 
{ }pKv.  
nSplitter = nCount; Q!`)e@r  
} XJ O[[G`  
} zF?31\GOX  
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 d~sJ=)  
/* M6&~LI.We=  
**Utility.java #)FDl70S8  
*/ 73VQ@Jn  
package NetFox; #1B}-PGCm  
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F
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public class Utility { m|lM.]2_  
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public Utility() brj[c>
ID  
{ aj?2jU~Pq  
*|^,DGfQ6  
;}UzJe ,S  
} L,WkJe3  
'V1!&Q6  
//线程睡眠 %pH)paRAP  
public static void sleep(int nSecond) lS#7xh  
{ X:U=MWc>  
try{ tg3zXJ4k_  
Thread.sleep(nSecond); H<$pHyxU  
} x\6];SXX  
catch(Exception e) o>.AdZby  
{ 2G ZF/9}  
e.printStackTrace (); p%tE v  
} Jb7iBQ2%  
} `t%|.=R  
D/e&7^iK  
//日志 iQu^|,tHEM  
public static void log(String sMsg) |^?`Q.|c$  
{ <>VIDE  
System.err.println(sMsg); Qg[heND  
} b$dBV}0 L  
8>ESD}(  
>B`Cch/'U  
public static void log(int sMsg) t?KUK>>w  
{ ::v;)VdX+*  
System.err.println(sMsg); -Sx0qi'%  
} aXX,Zu^  
} 4{Q$!O>  
1k$2LQ  
eU`
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/* ]F !'M  
**TestMethod.java 3xP~~j;7  
*/ JR])xPI`  
package NetFox; Kq$:\B)<c  
@51z-T  
l+|1G  
public class TestMethod { cW=Qh-`jU;  
U[IQ1AEr  
0,:iE\
 
public TestMethod() $|rCrak;  
{ ///xx/weblogic60b2_win.exe +I*k0"gj6  
try{ h]<GTWj  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _cR6ik zW(  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); NS h%t+XU]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3T"2S[gT  
fileFetch.start(); VIb;96$Or  
} I+*osk  
catch(Exception e){e.printStackTrace ();} B^H4Q 4-  
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!&qx7eOSpP  
} &Q2NU$  
yVT&rQ"{  
pi|\0lH6W  
public static void main(String[] args) ]gb _Nv  
{ +8]W\<Kp  
new TestMethod(); }*0,>w>  
} f+{c1fb>s  
} ur?d6a  
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