http断点续传简单实现（java)

/* $BKGPGmh  
**SiteFileFetch.java ^vmT=f;TM  
*/ +U_> Bo  
package NetFox; [u\E*8  
import java.io.*; c+chwU0W  
import java.net.*; -jy-KC  
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public class SiteFileFetch extends Thread { ~H!s{$.5  
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SiteInfoBean siteInfoBean = null; //文件信息Bean MUsF/1  
long[] nStartPos; //开始位置 ka? |_(  
long[] nEndPos; //结束位置 vHSX3\(  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 p.^glz>B  
long nFileLength; //文件长度 ]7" W(  
boolean bFirst = true; //是否第一次取文件 5W_u|z+/g  
boolean bStop = false; //停止标志 S\=j; Uem  
File tmpFile; //文件下载的临时信息 jq#gFt*  
DataOutputStream output; //输出到文件的输出流 aHx(~&hRcL  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） tj/X7|  
public SiteFileFetch(SiteInfoBean bean) throws IOException rUvjc4O}  
{ _1jd{?kt  
siteInfoBean = bean; Z]f_?@0  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ))f%3_H  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 0Y[LzLn  
if(tmpFile.exists ()) WBT/;),}:  
{ R{Q*"sf  
bFirst = false; 1Q1NircJ  
read_nPos(); ,>%2`Z)  
} 1FCqkwq[
 
else mOji\qia  
{ Im7<\ b@  
nStartPos = new long[bean.getNSplitter()]; 'F>eieO
 
nEndPos = new long[bean.getNSplitter()]; h{xC0NC)  
} ParOWs~W/  
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} 6\>S%S2:  
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public void run() iq'hel  
{  pleLdGq  
//获得文件长度 xL8r'gV@  
//分割文件 6[fpe  
//实例FileSplitterFetch xG:eS:iT  
//启动FileSplitterFetch线程 l_bvwo  
//等待子线程返回 ~/Gx~P]  
try{ =kvfe" N0e  
if(bFirst) HE GMwRJG  
{ g-`HKoKe  
nFileLength = getFileSize(); C "XvspJ  
if(nFileLength == -1) bH4'j/3  
{ hu}`,2  
System.err.println("File Length is not known!"); 9qc<m'MZ  
} G"w ?{W@  
else if(nFileLength == -2) 0kxo  
{ I3 /^{-n  
System.err.println("File is not access!"); [>+R|;ln  
} JGQlx-qv  
else Yd]y`J?#  
{ NAd|n+[d  
for(int i=0;i<nStartPos.length;i++) PwP;+R};|  
{ :pj00  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); I&JVY8'  
} >iD&n4TK  
for(int i=0;i<nEndPos.length-1;i++) DM {r<?V  
{ sf{rs*bgp  
nEndPos = nStartPos[i+1]; NA%M)u{|  
} l&3f<e  
nEndPos[nEndPos.length-1] = nFileLength; NIZN}DnP  
} %Jy0?WN  
} h^_Sd"l3  
~2 L{m[s|  
`4^-@}  
//启动子线程 E"d\N-I  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _<tWy+.  
for(int i=0;i<nStartPos.length;i++) t^eWFX  
{ "|P8L| @*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), irj{Or^k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), g/Q"%GN,  
nStartPos,nEndPos,i); G.v zz-yG  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _,*ld#'s  
fileSplitterFetch.start(); W/03L, 1  
} o,o,(sII  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9G njJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); hP1}Do  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", _$s ;QI]x  
nEndPos = " + nFileLength); pxm{?eBz  
// fileSplitterFetch[nPos.length-1].start(); %`*`HU#X  
R^8L^8EL  
D7q%rO|F'  
//等待子线程结束 zTA+s 2  
//int count = 0; &'%b1CbE  
//是否结束while循环 ]2O52r  
boolean breakWhile = false; dkT
ewT
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M"cB6{st[  
#4hxbRN  
while(!bStop) tA#7Xr+  
{ :cDhqBMNr`  
write_nPos(); n~~0iU)  
Utility.sleep(500); fTQ_miAlP  
breakWhile = true; IQn|0$':Z  
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for(int i=0;i<nStartPos.length;i++) b4TZnO  
{ ODS8bD0!i  
if(!fileSplitterFetch.bDownOver) IE/F =Wr  
{ -+1_ 1!  
breakWhile = false; 0 #*M'C#  
break; m417=wf  
} DH7B4P  
} Fh2$,$ 2  
if(breakWhile) xd[GJ;xvs  
break; fP|rD[  
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//count++; ly,3,ok  
//if(count>4) UO3Q
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// siteStop(); bbGSh|u+P  
} luA k$Es  
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System.err.println("文件下载结束！"); kjCXP  
} B 4s^X`?z  
catch(Exception e){e.printStackTrace ();} #jY\l&E  
} 9 Vn  
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//获得文件长度 syuW>Z8s
  
public long getFileSize() 2'R;z<_  
{ ?-'m#5i"  
int nFileLength = -1; /-Saz29f^Q  
try{ =+I~K'2  
URL url = new URL(siteInfoBean.getSSiteURL()); QU`M5{#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); NO(^P+s  
httpConnection.setRequestProperty("User-Agent","NetFox"); 93Z/|7  
f?KHp|  
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int responseCode=httpConnection.getResponseCode(); U`{'-L.  
if(responseCode>=400) *,C[yg1P  
{ r
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processErrorCode(responseCode); >Yr-aDV  
return -2; //-2 represent access is error @UbH;m  
} z ^e99dz  
+ZuT\P&kR5  
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String sHeader; :0G_n\  
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+C
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for(int i=1;;i++) M84{u!>[  
{ 1|]IWX|  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Vjv~RNGF  
//Utility.log(in.readLine()); Dt1v`T~=?  
sHeader=httpConnection.getHeaderFieldKey(i); nC-=CMWWr  
if(sHeader!=null) G~$.Af!9W  
{ ejr9e@D^  
if(sHeader.equals("Content-Length")) A`|Z2  
{ s& INcjC  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); X#625h  
break; " Bz\<e&u  
} u%TZ),ny-  
} U;o$=,_p  
else bn$('  
break; :v=^-&t  
} n*'i{P]  
} ,F&TSzH[@v  
catch(IOException e){e.printStackTrace ();} O)0}yF$0  
catch(Exception e){e.printStackTrace ();} %kS4v,
I  
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Utility.log(nFileLength); *=sMJY9#jE  
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return nFileLength; &U_YDUQ'L  
} ]lT8Z-h@  
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,  
$)HD`E  
//保存下载信息（文件指针位置） %l4;-x<e  
private void write_nPos() >GbCRN~  
{ \&{a/e2:S  
try{ xz$-_NWW  
output = new DataOutputStream(new FileOutputStream(tmpFile));  U(d K  
output.writeInt(nStartPos.length); 1Q5:Vo^B#  
for(int i=0;i<nStartPos.length;i++) TFfV?rBI  
{ >MTrq%.  
// output.writeLong(nPos); Ofx]  
output.writeLong(fileSplitterFetch.nStartPos); kp6{QKDj&  
output.writeLong(fileSplitterFetch.nEndPos); 3/aK#TjK  
} 1*x;jO>Hk  
output.close(); I]4L0r-  
} PRdyc+
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catch(IOException e){e.printStackTrace ();} Rm&^[mv  
catch(Exception e){e.printStackTrace ();} li @:  
} Qu x1N  
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//读取保存的下载信息（文件指针位置） +:IwP  
private void read_nPos() Mr0<b?I  
{ <W>T!;4!  
try{ 8vp*U  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));
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int nCount = input.readInt(); pmWt7 }  
nStartPos = new long[nCount]; y;\m1o2  
nEndPos = new long[nCount]; 1Bj
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for(int i=0;i<nStartPos.length;i++) tj'xjX  
{ Q!91uNL  
nStartPos = input.readLong(); v)f;dq^z-  
nEndPos = input.readLong(); Jbv[Ql#  
} ]+"25V'L  
input.close(); 3}7`?$5  
} !J6;F}Pd/  
catch(IOException e){e.printStackTrace ();} '%H\k5^  
catch(Exception e){e.printStackTrace ();} zu,F 0;De  
} ,+d\@:  
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private void processErrorCode(int nErrorCode) |]Eli%mNe  
{ F3?PlH:Y  
System.err.println("Error Code : " + nErrorCode); f-!P[6bY  
} '^{:HR#i  
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//停止文件下载 _.{I1*6Y2  
public void siteStop() qk{+Y  
{ @W1F4HYds  
bStop = true; 2
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for(int i=0;i<nStartPos.length;i++) n9%&HDl4  
fileSplitterFetch.splitterStop(); b2tUJ2p  
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} V JJ6q  
} {f(RYj  
//负责部分文件的抓取 m]?C @ina  
**FileSplitterFetch.java .eHOG]H  
*/ V0/PjD,jP  
package NetFox; T2dv!}7p  
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import java.io.*; {@&%Bq*&  
import java.net.*; ~Z>!SMXp<  
6Mj
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public class FileSplitterFetch extends Thread { Mb^E  
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String sURL; //File URL WAUgbImc{  
long nStartPos; //File Snippet Start Position Xl %ax!/  
long nEndPos; //File Snippet End Position ?'IY0^  
int nThreadID; //Thread's ID c-y`Hm2"  
boolean bDownOver = false; //Downing is over '@{Mq%`  
boolean bStop = false; //Stop identical k d9<&.y{  
FileAccessI fileAccessI = null; //File Access interface {8pN]=SaJ~  
#]kO/Mr  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException p.|M:C\xL  
{ ?/1Eu47  
this.sURL = sURL; T!%J x.^  
this.nStartPos = nStart; | zyO;  
this.nEndPos = nEnd; P#l"`C /  
nThreadID = id; MJM<  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 =#>F' A  
} _*.ImD  
)gHfbUYS  
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public void run() 0a}a  
{ (Zoopkxw  
while(nStartPos < nEndPos && !bStop) P;U(2;9 N  
{ )Y &RMYy  
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try{ 5Ly
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URL url = new URL(sURL); v+vM:At4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ku5vaP(  
httpConnection.setRequestProperty("User-Agent","NetFox"); sKwUY{u\M  
String sProperty = "bytes="+nStartPos+"-"; [:(hqi!  
httpConnection.setRequestProperty("RANGE",sProperty); T&nIH[}v  
Utility.log(sProperty); ".7\>8A#a  
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InputStream input = httpConnection.getInputStream(); `LOW)|6r`  
//logResponseHead(httpConnection); sXwa`_{  
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byte[] b = new byte[1024]; fZavZ\qU  
int nRead; Q;?rqi ,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Ih<.2  
{ _$P1N^}Zs  
nStartPos += fileAccessI.write(b,0,nRead); 0^83:C ^{  
//if(nThreadID == 1) \h@3dJ4  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); awl3|k/  
} }0}=-g&  
LaX<2]Tx:  
'Bwv-J  
Utility.log("Thread " + nThreadID + " is over!"); x K ;#C  
bDownOver = true; mu{\_JX.A  
//nPos = fileAccessI.write (b,0,nRead); /li
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} ugzrG0=lx  
catch(Exception e){e.printStackTrace ();} uqvS  
} ctMH5"F&1  
} -BC`p 8  
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Th!;zu^t  
//打印回应的头信息 PJL [En*  
public void logResponseHead(HttpURLConnection con) D@)L?AB1f  
{ 57Bxx__S4`  
for(int i=1;;i++) JqV}>"WMV  
{ lx<!*2 -^  
String header=con.getHeaderFieldKey(i); Om(Ir&0  
if(header!=null) 7hhv/9L1  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 8?LHYdJ  
Utility.log(header+" : "+con.getHeaderField(header)); @xeJ$ rlu  
else tz9"#=}0  
break; tu's]3RE  
} 4hx4/5[^  
} 6w4HJZF~  
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public void splitterStop() 30W.ks5(  
{ WO
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bStop = true; E?FUr?-[  
} TPn#cIPG  
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} Z~]G+(  
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/* _%u t#  
**FileAccess.java ~?:>=x  
*//文件访问(定位，写) V8rS~'{\  
package NetFox; W[:CCCDL  
import java.io.*; s6k(K>Pl  
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public class FileAccessI implements Serializable{ _p'u!.a?!  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 *i {e$Zv'  
RandomAccessFile oSavedFile; e>x+Xj1  
long nPos; J7HY(7Nx  
3+&k{UZjt  
t +|t/1s2  
public FileAccessI() throws IOException &F8*>F^7  
{ v]#[bqB.b  
this("",0); i>KgkRZL#  
} n~ZZX={a  
<}G/x*N  
rv c%[HfW;  
public FileAccessI(String sName,long nPos) throws IOException 1DlXsup&?#  
{ vX_;Y#uD  
oSavedFile = new RandomAccessFile(sName,"rw"); ?R_fg  
this.nPos = nPos; A b+qLh&?  
oSavedFile.seek(nPos); ^VEaOKMr  
} NA$%Up  
ipE|)Ns  
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public synchronized int write(byte[] b,int nStart,int nLen) U6.hH%\}@  
{ p6&<eMwFA  
int n = -1; @1D3E=  
try{ @Z5,j)  
oSavedFile.write(b,nStart,nLen); {Wndp%  
n = nLen; j`#H%2W\;  
} %Fx^"  
catch(IOException e) #pyFIUr=w  
{ 0\Tp/Ph  
e.printStackTrace (); bB)$=7\  
} >7r%k,`  
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return n; cl`7|;v|?  
} y t7>,  
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} $y{.fjy3  
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/* -hq^';,  
**SiteInfoBean.java 7yjun|Lt}X  
*/ .[+}nA,g%~  
package NetFox; jz
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tN.$4+  
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public class SiteInfoBean { _2{2Xb  
OO</d:  
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private String sSiteURL; //Site's URL ]$#9B-uB  
private String sFilePath; //Saved File's Path SAdo9m'  
private String sFileName; //Saved File's Name -q8l"i>h=  
private int nSplitter; //Count of Splited Downloading File ^j2ve's:  
L c )i  
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public SiteInfoBean() j3H_g
^  
{//nSplitter的缺省值为5 z]KJ4  
//default value of nSplitter is 5 X"9N<)C  
this("","","",5); ~dzD7lG6  
} ]~~G<Yh:=  
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t/_\w"  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 5$Kd<ky  
{ OT(0~,.GJ  
sSiteURL= sURL; y}is=h3  
sFilePath = sPath; u8t|!pMF8  
sFileName = sName; Mp=T;Nz  
this.nSplitter = nSpiltter; |!/+T^u  
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} yo(MJ^=d  
X|&H2y|*7  
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public String getSSiteURL() q<Qjc  
{ irvd>^&jDC  
return sSiteURL; \ueCbfV!Z4  
} Jd?qvE>Pp  
59p'U/|  
IG7,-3  
public void setSSiteURL(String value) 6QJ.=.>b  
{ C]fX=~?bGQ  
sSiteURL = value; _q}Cnp5  
} 5;G0$M0  
}/#*opcv  
n).*=YLN  
public String getSFilePath() KUq7Oa!  
{ )wXE\$  
return sFilePath; ti$60Up  
} ;nJ2i?"  
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public void setSFilePath(String value) 'Z:wEt!  
{ KFRf5^%  
sFilePath = value; `(gQw~|z  
} cK2;)
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public String getSFileName() =CD.pw)B1
 
{ rqnxR
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return sFileName; +v'2s@e` #  
} =v'Aub  
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public void setSFileName(String value) "5z@A/Z/  
{ )v*k\:
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sFileName = value; K
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} /9,'.  
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'9
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public int getNSplitter() dG8mE&$g  
{ c5uC?b].  
return nSplitter; 6k![v@
2R  
} xB[W8gQ6fa  
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public void setNSplitter(int nCount) PIXqd,  
{ ZHUW1:qs  
nSplitter = nCount; /R?[/`)f&  
} `rK@> -  
} BTYYp1  
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/* ^
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**Utility.java i(.V`G=  
*/ A.@wGy4  
package NetFox; _cC1u7U9  
10.ZBfn  
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public class Utility { 7[uN;B#V  
'r ^.Ao5  
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public Utility() :-lq Yd5^  
{ DU)q]'[u  
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} "KS"[i!3j  
7'65+c[&  
//线程睡眠 LFqY2,#i  
public static void sleep(int nSecond) K"|~D0Qgo  
{ #_`p 0wY  
try{ 
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Thread.sleep(nSecond); :VWN/m  
} |(TEG.<g  
catch(Exception e) Y2'HP)tfIw  
{ WNb2"W  
e.printStackTrace (); \x:U`T  
} \IYv9ScAx  
} Vgkj4EE  
N6p
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//日志 )V+/@4  
public static void log(String sMsg) I<,~>'cq.  
{ {T,}]oX  
System.err.println(sMsg); US^%pd  
} $T:;KcW)  
<P ?gP1_zi  
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public static void log(int sMsg) _(~LXk
^C  
{ Y2tBFeWY  
System.err.println(sMsg); !4gHv4v;  
} n[r1h=?j3  
} ujN~l_4  
{dP6fr1z  
$)c[FR~a  
/* MxI*ml8z?  
**TestMethod.java 5Ma."?rW   
*/ o0F,!}  
package NetFox; KHx;r@{<  
O"kb*//  
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public class TestMethod { 'vu]b#l3  
ZZwIB3sNhf  
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public TestMethod() u|.|dv'mbp  
{ ///xx/weblogic60b2_win.exe :xq{\"r  
try{ "VHT5k  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .iP>?9$f"  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ^c9_F9N  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 6[RTL2&W  
fileFetch.start(); 1JdMw$H  
} ~Ym*QSD  
catch(Exception e){e.printStackTrace ();} ]bmf}&  
f%1\1_^g  
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} !FyO5`v  
K
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public static void main(String[] args) B0p;Zh  
{ _3N,oCRm  
new TestMethod(); T][c^K*  
} l+@k:IK  
} +t1+1Zv  
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