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http断点续传简单实现(java)

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/* A6]X aF  
**SiteFileFetch.java M%`CzCL u  
*/ gAWi&  
package NetFox; 3?a`@C&x  
import java.io.*; HTT&T9]  
import java.net.*; 3\@2!:>  
IZj`*M%3  
olv?$]  
public class SiteFileFetch extends Thread { iW(LD1~7  
`!Z?F]):G  
<`uu e  
SiteInfoBean siteInfoBean = null; //文件信息Bean |Q 3d7y  
long[] nStartPos; //开始位置 &L$9Ii  
long[] nEndPos; //结束位置 ZI!:  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 }6%XiP|  
long nFileLength; //文件长度 r[i^tIv6As  
boolean bFirst = true; //是否第一次取文件 ]|tg`*l!>  
boolean bStop = false; //停止标志 Cjr]l!  
File tmpFile; //文件下载的临时信息  RbTGAA  
DataOutputStream output; //输出到文件的输出流 KhfADqji|  
JE-*o"&  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Bk~C$'x4  
public SiteFileFetch(SiteInfoBean bean) throws IOException bh1$ A  
{ W+#Q>^Q>  
siteInfoBean = bean; cb /Q<i  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); +Pb:<WT}%  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 'JMW.;Lh?X  
if(tmpFile.exists ()) *^|\#UIk  
{ ?d-w#<AiV  
bFirst = false; BA: x*(%~  
read_nPos(); ESRj<p%W  
} &~P4yI;,  
else 1OM Xg=Y  
{ Gy/w #4xj  
nStartPos = new long[bean.getNSplitter()]; uKP4ur@1  
nEndPos = new long[bean.getNSplitter()]; FSA%,b; U  
} \uOM,98xS  
'_G\_h}5  
q k^FyZ<  
I;t@wbY,  
} tJ6@Ot  
'-%1ILK$3r  
.@,t}:lD  
public void run() d#0:U Y%~  
{ z9ADF(J?0'  
//获得文件长度 ]@Zv94Z(  
//分割文件 6i[Ts0H%<!  
//实例FileSplitterFetch >NBc-DX^  
//启动FileSplitterFetch线程 'Nl hLu  
//等待子线程返回 />S^`KSTM  
try{ pNb2t/8%%  
if(bFirst) Sk|e#{  
{ HJAiQ[m5s  
nFileLength = getFileSize(); 0qJ (RB  
if(nFileLength == -1) :>fT=$i@  
{ OKMdyyO<l  
System.err.println("File Length is not known!"); sr6 BC.  
} ;n Bf  
else if(nFileLength == -2) Wn=sF,c  
{ c9-$^yno  
System.err.println("File is not access!"); <l5i%?  
} =tP9n;D  
else nv:Qd\UM  
{ T%eBgseS  
for(int i=0;i<nStartPos.length;i++) JI-i7P  
{ cpjwc@UMe  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); H:c5 q0O^x  
} 9i5?J]o^  
for(int i=0;i<nEndPos.length-1;i++) (lM,'  
{ F<I*?${[  
nEndPos = nStartPos[i+1]; ;98&5X\u<  
} [nO3%7t@  
nEndPos[nEndPos.length-1] = nFileLength; $K^l=X  
} #h[>RtP:  
} (I}owr5:  
w[-)c6JyE  
wN!\$i@E:  
//启动子线程 P?h1nxm`'  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; T/'z,,Y  
for(int i=0;i<nStartPos.length;i++) $IE}fgA@5  
{ QXZXj#`  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jU&m*0nL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), f#!+l1GV  
nStartPos,nEndPos,i); z^QrIl/<c2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); n?@zp<  
fileSplitterFetch.start(); TRm#H $  
} ZG^<<V$h  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ] ]U)wg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %b^4XTz  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", wSjDa.?'  
nEndPos = " + nFileLength); 44ty,M3  
// fileSplitterFetch[nPos.length-1].start(); _X4Y1zh  
Z`tmuu  
1jg* DQ7L  
//等待子线程结束 4,sE{%vb  
//int count = 0; cz9J&Le>  
//是否结束while循环 0~ho/_  
boolean breakWhile = false; ST?{H SCz  
|!PL"]?  
I8gNg Z  
while(!bStop) '. "_TEIF  
{ nEsD+ }E?  
write_nPos(); >.Gmu  
Utility.sleep(500); uBRlvNJ  
breakWhile = true; _c>ww<*3  
B r#{  
k77IXT_7u  
for(int i=0;i<nStartPos.length;i++) OvX&5Q5  
{ {nKw<F2  
if(!fileSplitterFetch.bDownOver) :|W=2( >  
{ `}?;Ow&2CY  
breakWhile = false; QOXo(S  
break; 3lp'U&3`5  
} Lm4`O %  
} J>A9]%M  
if(breakWhile) 01?+j%k=m/  
break; 5C!zEI)  
}%u #TwZ  
D -tRy~}  
//count++; K+}0:W=P  
//if(count>4) V~dhTdQ5}  
// siteStop(); [q?RJmB]  
} c*ueI5i  
* 1;4&/93o  
^`kwSC  
System.err.println("文件下载结束!"); b-<0\@`Z#  
} v?VDASR2`  
catch(Exception e){e.printStackTrace ();} >Q/;0>V  
} 1#=9DD$4  
h <4`|Bg+  
/i,n75/y?  
//获得文件长度 Lu}jk W*  
public long getFileSize() %nZ:)J>kz  
{ 9`*ST(0/  
int nFileLength = -1; `D77CC]vU  
try{ 5pJe`}O4  
URL url = new URL(siteInfoBean.getSSiteURL()); "TA0--6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); LaQ7A,]  
httpConnection.setRequestProperty("User-Agent","NetFox"); h+W$\T)  
'f6H#V*C  
@[g7\d  
int responseCode=httpConnection.getResponseCode(); 3jAr"xc  
if(responseCode>=400) O t)}:oG  
{ &4:R(]|  
processErrorCode(responseCode); M(a%Qk?]/  
return -2; //-2 represent access is error Vc9rc}  
} lOt7 ij(,L  
e-rlk5k%f  
MZV$YD^S  
String sHeader; x4* bhiu  
+.!D>U$)}  
a$=~1@  
for(int i=1;;i++) @s1T|}AJ  
{ 6M >@DRZ'|  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); =^KgNQ   
//Utility.log(in.readLine()); |6 Q5bV  
sHeader=httpConnection.getHeaderFieldKey(i); 8* A%k1+  
if(sHeader!=null) v@=qVwX  
{ @-sWXz*W  
if(sHeader.equals("Content-Length")) ,>-jZtm  
{ P P J^;s  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); p^8a<e?f~f  
break; xxur4@p!  
}  8oJl ]  
} [#Qf#T%5h  
else ;U=b 6xE  
break; G[>NP#P  
} bG]0|  
} 1d< b\P0  
catch(IOException e){e.printStackTrace ();} % 6 *c40  
catch(Exception e){e.printStackTrace ();} Z<;W*6J  
N (4H}2  
~2Wus8X-  
Utility.log(nFileLength); #Nh'1@@  
EnWv9I<  
)95k3xo  
return nFileLength; /wLBmh1"  
} qSNCBn '  
rQ.zqr  
o-=|}u]mz  
//保存下载信息(文件指针位置) f8;?WSGyD2  
private void write_nPos() }<^mUG  
{ OInl?_,,T#  
try{ N-K/jY  
output = new DataOutputStream(new FileOutputStream(tmpFile)); !'N@ZZ  
output.writeInt(nStartPos.length); m54>}  
for(int i=0;i<nStartPos.length;i++) #4Z e2T|  
{ 1b~21n  
// output.writeLong(nPos); #+ch  
output.writeLong(fileSplitterFetch.nStartPos); #NFB=o JI  
output.writeLong(fileSplitterFetch.nEndPos); 94w)Yln  
} Q$U5[ TZm  
output.close(); (X "J)x aQ  
} \ivxi<SR  
catch(IOException e){e.printStackTrace ();} 'V?FeWp  
catch(Exception e){e.printStackTrace ();} 0OM^,5%8  
} i M !`4  
#uU(G\^T  
1b3 a(^^E  
//读取保存的下载信息(文件指针位置) DKj iooD  
private void read_nPos() .Exvuo`F  
{ f]i"tqoI  
try{ =6~  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ?"Ez  
int nCount = input.readInt(); ;<M}ZL@m  
nStartPos = new long[nCount]; Ikdj?"+O  
nEndPos = new long[nCount]; Z+v,o1  
for(int i=0;i<nStartPos.length;i++) `^[k8Z(  
{ A;L ]=J  
nStartPos = input.readLong(); N~,Ipf  
nEndPos = input.readLong(); O]tR~a  
} %j\&}>P4$  
input.close(); ui>jJ(  
} Kzrd<h]`)  
catch(IOException e){e.printStackTrace ();} uP* kvi:e  
catch(Exception e){e.printStackTrace ();} RxqNgun@  
} )c4tGT<  
YD[HBF)~j  
5[4wN( )  
private void processErrorCode(int nErrorCode) qHub+"2  
{ _|u}^MLO  
System.err.println("Error Code : " + nErrorCode); AJ}FHym_ZQ  
} v/ N[)<  
Ro]Z9C>1o  
`-{l$Hn9|~  
//停止文件下载 *,z/q6  
public void siteStop() s>/Xb2\  
{ {g.YGO  
bStop = true; YIRe__7-NU  
for(int i=0;i<nStartPos.length;i++) (c[u_~ ;  
fileSplitterFetch.splitterStop(); TX=894{nGh  
_p6 r5Y  
5.\p]>|G1  
} mS'Ad<  
} ;d}>8w&tfy  
//负责部分文件的抓取 Z4i))%or  
**FileSplitterFetch.java x:Q\pZ  
*/ !\7 M7  
package NetFox; ~6;I"0b5  
3`&FXgo  
*>a=ku:?  
import java.io.*; WOn<;'}M&  
import java.net.*; bN/8 ~!  
R>0[w$  
SEM?vQ 0"}  
public class FileSplitterFetch extends Thread { HTYyX(ya  
X|a{Z*y;r*  
%e]G]B%  
String sURL; //File URL 7dY_b  
long nStartPos; //File Snippet Start Position 6B8!}6Ojc  
long nEndPos; //File Snippet End Position .T3N"}7[  
int nThreadID; //Thread's ID )vO"S  
boolean bDownOver = false; //Downing is over 5@xR`g-  
boolean bStop = false; //Stop identical F\r"Y)|b=  
FileAccessI fileAccessI = null; //File Access interface "d)Yq Q  
#ELe W3 S}  
b\0>uU  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException B2kZ_4rB  
{ fx|d"VF[  
this.sURL = sURL; t}k:wzZ@  
this.nStartPos = nStart; b@CjnAZ  
this.nEndPos = nEnd; 6]iU-k0b  
nThreadID = id; W+a/>U  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #HgN wM  
} "Vq= Ph  
J>v[5FX+  
 skl3/!  
public void run() vSHPN|*  
{ d3q%[[@  
while(nStartPos < nEndPos && !bStop) xmnBG4,f  
{ <<01@Q <  
znE1t%V  
dXxf{|gk>  
try{ 5@5 *}[M  
URL url = new URL(sURL); >h8m)Q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c~tl0XU1  
httpConnection.setRequestProperty("User-Agent","NetFox"); ZRf9'UwS  
String sProperty = "bytes="+nStartPos+"-"; |Lg2;P7\  
httpConnection.setRequestProperty("RANGE",sProperty); &lLk[/b  
Utility.log(sProperty); ,;t:x|{%  
_]*YSeh=  
JxinfWk  
InputStream input = httpConnection.getInputStream(); {?:]'c  
//logResponseHead(httpConnection); ;\w3IAa|V  
~qqxHymc  
<<LLEdB  
byte[] b = new byte[1024]; bRu 9*4t  
int nRead; kqKT>xo4EZ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5)< Y3nU~  
{ 48 wt  
nStartPos += fileAccessI.write(b,0,nRead); %JBLp xnq  
//if(nThreadID == 1) ta{24{?M\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); eOb--@~8  
} rY(7IX  
~T;:Tg*  
KD A8x W  
Utility.log("Thread " + nThreadID + " is over!"); M ]047W  
bDownOver = true; `F/R:!v  
//nPos = fileAccessI.write (b,0,nRead); E "=4(   
}  +#,J`fV%  
catch(Exception e){e.printStackTrace ();} Z5TA4Q+Q  
} Rf0so   
} we _CF*zj  
eHvUgDt  
l8?C[, K%  
//打印回应的头信息 :jv(-RTI  
public void logResponseHead(HttpURLConnection con) L'Cd` .yVO  
{ A4,%l\di<  
for(int i=1;;i++) BlpyE[h T  
{ JE}VRMNr  
String header=con.getHeaderFieldKey(i); 5, ,'hAq_  
if(header!=null) !@lx|= #  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); a!bW^?PcK  
Utility.log(header+" : "+con.getHeaderField(header)); U Y*`R  
else bXJ(QXHd%  
break; d_we?DZ|  
} a_!H_J  
} N & b3cV  
iT&4;W=72~  
rSv,;v  
public void splitterStop() *DIY;)K  
{ *=oO3c0|b,  
bStop = true; +- qk\sQ  
} ez32k[eV!  
,oH\rrglf  
$B?8\>_?  
} <eEIR  
B](R(x>L  
33<{1Y[Q6E  
/* 3!F^ vZ.  
**FileAccess.java G~y:ZEnN[  
*//文件访问(定位,写) OB9E30  
package NetFox; &S xF"pYV  
import java.io.*; 8SRUqe[H]  
q`mxN!1[  
sDBSc:5+e  
public class FileAccessI implements Serializable{ ~8&->?{  
! 7V>gWhR  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 H_@6!R2  
RandomAccessFile oSavedFile; DNZ,rL:h  
long nPos; b4wT3  
445JOP  
M-].l3  
public FileAccessI() throws IOException :q3w;B~  
{ 3:Nc`tM_  
this("",0); 3PvxU|*F  
} U;iCH  
Gjeb)Y6N  
g"" 1\rc=  
public FileAccessI(String sName,long nPos) throws IOException MJX4;nbl  
{ ??aO3Vm{  
oSavedFile = new RandomAccessFile(sName,"rw"); QlvP[Jtr  
this.nPos = nPos; I(7 GVYM  
oSavedFile.seek(nPos); Pqx?0 f)  
} mf g>69,w  
fsPsP`|  
6p }a!  
public synchronized int write(byte[] b,int nStart,int nLen) ShL!7y*rT{  
{ F(.`@OO  
int n = -1; oUsfO-dET^  
try{ hN K wQ  
oSavedFile.write(b,nStart,nLen); 43h06X`  
n = nLen; HqsqUS3[  
} [2xu`HT02  
catch(IOException e) Y[)mHs2  
{ nHeJ20  
e.printStackTrace (); xO:h[  
} u(3 uZ:  
XK\nOHLS  
!pU^?Hy=  
return n; l[_antokn  
} >Z*b0j  
ZDaHR-%Y  
d)U(XiK'  
} | eCVq(R  
s%y<FXUj  
j~Fd8]@  
/* [Y!HQ9^LEp  
**SiteInfoBean.java XM5)|D  
*/ ':}9>B3 S  
package NetFox; h/A\QW8Sd  
;]xc}4@=mg  
_)<5c!  
public class SiteInfoBean { uQbag]&j  
;;i419  
SVwxK/Fci  
private String sSiteURL; //Site's URL DM v;\E~D  
private String sFilePath; //Saved File's Path zmZU"eWp)  
private String sFileName; //Saved File's Name p:b{>lM  
private int nSplitter; //Count of Splited Downloading File qF^P\cD  
HOu$14g  
k@%5P-e}  
public SiteInfoBean() $-]G6r  
{//nSplitter的缺省值为5 .9Oj+:n  
//default value of nSplitter is 5 !21G $ [H  
this("","","",5); UVLS?1ra  
} CLZ j=J2  
>0:3CpO*  
O[$X36z  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?glx8@  
{ N:Q.6_%^  
sSiteURL= sURL; 2{WZ?H93a  
sFilePath = sPath; vv)w@A:Vn)  
sFileName = sName; y|B HSc3  
this.nSplitter = nSpiltter; uPcx6X3]  
q]f7D\ M  
i@6g9\x+  
} |FT.x9e-  
m;"[b (u  
~t2" L|i  
public String getSSiteURL() U) xeta+  
{ %!-t7K^mFq  
return sSiteURL;  *`qI<]!  
} w(_:+-rqQ<  
L-U4 8 i  
p`&{NR3+  
public void setSSiteURL(String value) s \3]0n9  
{ c8]%,26.  
sSiteURL = value; h*KDZ+{)  
} A #SO}c  
c)Ef]E\  
9wc\~5{li  
public String getSFilePath() =>>Dnp  
{ K)l*$h&-  
return sFilePath; D`Vb3aNB=L  
} #p;<X|Hc}8  
2=fLb7  
LjGLi>kI~  
public void setSFilePath(String value) GCQOjqiR  
{ cEp/qzAiD%  
sFilePath = value; w=-{njMz6&  
} OAo03KW  
 n}b/9  
\Qv:7;?  
public String getSFileName() Vm@VhCsp  
{ X`v6gv5qj  
return sFileName; (/&ht-~EL  
} Q ijO%)  
Qu<HeSA_  
8Rw:SU9H?T  
public void setSFileName(String value) #,lbM%a  
{ \QSD*  
sFileName = value; ~ cu+QR)  
} c uAp,!  
/^{Q(R(X<  
GRL42xp'*D  
public int getNSplitter() /;Cx|\  
{ xPT$d,~"  
return nSplitter; cbou1Ei   
} uVZm9Sp  
"/^kFsvp  
s#0m  
public void setNSplitter(int nCount) j;Lp@~M  
{ biV|W@JM  
nSplitter = nCount; 26zif  
} uGlz|C  
} M>RLS/r>d  
NJ}x qg  
uY3$nlhP6  
/* 1Ogtzf  
**Utility.java ByWad@-6i  
*/ tx3p, X  
package NetFox; ;F,6]LH!  
-jTK3&5  
_mQ~[}y+?  
public class Utility { k ;vOPcw  
[daR)C  
LWM& k#i  
public Utility() :SF8t`4`  
{ R*dXbI&,e  
Ax!@vL&@  
TxkvHiq2  
} Bt\V1)  
I.6#>=  
//线程睡眠 =`(\]t"I  
public static void sleep(int nSecond) aQ 6T2bQ  
{ hA~5,K0b  
try{ h*[sV  
Thread.sleep(nSecond); W89J]#v)k  
} .d)H2X  
catch(Exception e) wE <PXBl\b  
{ M@.?l=1X  
e.printStackTrace (); qP%[ nY  
} T5-'|+  
} |>I4(''}  
%s%e5hU  
//日志 QmPHf*w[  
public static void log(String sMsg) TlQ5'0&I  
{ Tkf4`Gxd  
System.err.println(sMsg); %%O_:@9x,  
} c$hoqi |tD  
7,9zj1<  
c%n%,R>  
public static void log(int sMsg) #0qMYe>Y  
{ exm*p/  
System.err.println(sMsg); C\[g>_J  
} Q},uM_" +  
} fV/  
LTD;  
<8Q?kj  
/* !%C&hH\  
**TestMethod.java *UG=dl#F#  
*/ P}p6{  
package NetFox; oP<E)  
eY$Q}BcW  
+7)/SQM5  
public class TestMethod { ^yF2xJ)9-  
f=MR.\  
/0F <GBQ"v  
public TestMethod() vi.q]$ohbV  
{ ///xx/weblogic60b2_win.exe b(g?X ( &  
try{ OEN'c0;5  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Zf`dd T  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); (e{pAm  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0 .t1p(x;  
fileFetch.start(); W&k2z,|  
} TH}+'m  
catch(Exception e){e.printStackTrace ();} O~g0R6M6e  
&_c5C  
{7q +3f <  
} myY@Wp  
{5:V hW}  
cm7>%g(oQo  
public static void main(String[] args) B7qiCX}pD  
{ lT]dj9l  
new TestMethod(); Ed~2Qr\65  
} D8_-Dvp7H  
} EabZ7zFoN  
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