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http断点续传简单实现(java)

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/* _1\poAy  
**SiteFileFetch.java \eT/%$  
*/ iAgOnk[  
package NetFox; ;xI0\a7  
import java.io.*; B/rzh? b  
import java.net.*; -zR.'x%  
CMFC"eS e  
IOS^|2:,  
public class SiteFileFetch extends Thread { K9^"NS3  
-FaaFw:Z;A  
r\B"?oqC  
SiteInfoBean siteInfoBean = null; //文件信息Bean +2El  
long[] nStartPos; //开始位置 lZBv\JE  
long[] nEndPos; //结束位置 C,(j$Id  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 m $)YYpX  
long nFileLength; //文件长度 ?o8a_9+  
boolean bFirst = true; //是否第一次取文件 X4Lsvvz%@  
boolean bStop = false; //停止标志 Agz=8=S%  
File tmpFile; //文件下载的临时信息 4':MI|/my_  
DataOutputStream output; //输出到文件的输出流 =8@RKG`>;  
^SgN(-QH  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Y1|^>C#a  
public SiteFileFetch(SiteInfoBean bean) throws IOException X&/(x  
{ r<v_CFJ  
siteInfoBean = bean; YN$`y1V  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); k~& o  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); eXc[3ceUr  
if(tmpFile.exists ()) J#+Op/mmo  
{ 3|jn,?K)N  
bFirst = false; @ }ZGY^  
read_nPos(); s* @QT8%  
} aE}=^%D  
else UC.8DaIPN  
{ tD865gi  
nStartPos = new long[bean.getNSplitter()]; xiEcEz'lk  
nEndPos = new long[bean.getNSplitter()]; 0,bt^a  
} &:-GI)[o  
4a#B!xW  
gNG.l  
\ =S3 L<  
} vs* >onCf  
C-_(13S  
W31LNysH!;  
public void run() t2~"B&7My  
{ !'+\]eA  
//获得文件长度 t$tsWAmiA[  
//分割文件 m9 ^m  
//实例FileSplitterFetch {`($Q$Q1  
//启动FileSplitterFetch线程 |C^ c0  
//等待子线程返回 3/SfUfWo  
try{ w{RNv%hJ$=  
if(bFirst) }klE0<W|5\  
{ )j]gm i"  
nFileLength = getFileSize(); 2*N&q|ED  
if(nFileLength == -1) <Sz>ZIISd  
{ -/@|2!d  
System.err.println("File Length is not known!"); zuK/(qZ  
} 9Ilfv  
else if(nFileLength == -2) 3csm`JVK  
{ 3| GNi~  
System.err.println("File is not access!"); Q@PJ)fwN  
} ' #;,oX~5  
else #FrwfJOV  
{ d4b 9rtM  
for(int i=0;i<nStartPos.length;i++) EI[e+@J  
{ MtMvpHk  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); SD)5?{6<  
} 7qCJ]%)b6  
for(int i=0;i<nEndPos.length-1;i++) 6 ,7/8  
{ aeN }hG  
nEndPos = nStartPos[i+1]; {JCSR2BB  
} #j(q/ T{x  
nEndPos[nEndPos.length-1] = nFileLength; W;xW: -  
} K0d-MC   
} RTdD]pE8Q  
Z!q2F%02FO  
.6lY*LI  
//启动子线程 ;t.SiA  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; s!8J.hD'I  
for(int i=0;i<nStartPos.length;i++) T4%i`<i  
{ M=" WUe_  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), D#vn {^c8O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), _ Yb Eo+  
nStartPos,nEndPos,i); sR7{i  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w>H%[\Qs  
fileSplitterFetch.start(); N7RG5?  
} 8GF[)z&|P:  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [[Jv)?jm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ZuF4N=;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", _qO;{%r  
nEndPos = " + nFileLength); wiK@o$S-  
// fileSplitterFetch[nPos.length-1].start(); |!jYv'%  
1 $KLMW  
Z9 ;nC zHm  
//等待子线程结束 e)ZyTuj  
//int count = 0; #T gz,e9  
//是否结束while循环 Egjk^:@  
boolean breakWhile = false; [9YlLL@  
{WM&  
e4>L@7  
while(!bStop) 4 _c:Vl  
{ = C$ @DNEc  
write_nPos(); qH {8n`  
Utility.sleep(500); ul z\x2[Pf  
breakWhile = true; E,ZB;  
R%]9y]HQ  
(> +k3  
for(int i=0;i<nStartPos.length;i++) N%n1>!X)!  
{ 7(+OsE  
if(!fileSplitterFetch.bDownOver) M'>D[5;N~  
{ lD;,I^Lt6  
breakWhile = false; Up!ZCZ$RC  
break; :#Ex3H7  
} dEAAm=K,<  
} u75)>^:I   
if(breakWhile) %1 VNP(E  
break; ZB_16&2Ow  
]`/R("l[  
^ T:qT*v  
//count++; 2=!3[> B  
//if(count>4) c=jI.=mi3  
// siteStop(); YjIED,eRv  
} _/z)&0DO  
?V\9,BTb)  
xP5mL3j  
System.err.println("文件下载结束!"); xj00eL  
} \{+nXn  
catch(Exception e){e.printStackTrace ();} B;D:9K  
} .olP m3MC  
#1qVFU  
~D`oP/6  
//获得文件长度 MRVz:g\mi  
public long getFileSize() u{{xnyl?  
{ HA3SQ  
int nFileLength = -1; x4HMT/@AG2  
try{ Edn$0D68u_  
URL url = new URL(siteInfoBean.getSSiteURL()); GHgEbiY:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !ovZ>,1  
httpConnection.setRequestProperty("User-Agent","NetFox"); Cf1wM:K|8  
sKB-7  
s>M~g,xTU  
int responseCode=httpConnection.getResponseCode(); 7L~ zI>2  
if(responseCode>=400) jO3u]5}.6  
{ `6S=KRv  
processErrorCode(responseCode); A*26'  
return -2; //-2 represent access is error j2{,1hj  
} UN .[,%<s  
V jB`~  
^* /v,+01f  
String sHeader; LN3dp?;_{  
7^t(RNq  
'*LN)E> d  
for(int i=1;;i++) :Z]+Z_9p  
{ Hb AMoow!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); %_@5_S  
//Utility.log(in.readLine()); HfeflGme*  
sHeader=httpConnection.getHeaderFieldKey(i); 6`5 @E\"E  
if(sHeader!=null) KutgW#+40  
{ Q"K>ML>0  
if(sHeader.equals("Content-Length")) Xx<&6 4W  
{ =*>4Gh i  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Nec(^|[   
break; ~ GT\RAj[  
} % x*Ec[l  
} d @kLLDP  
else qL;T&h  
break; (7jB_ p%  
} ,ZP3F+XKb  
} U#]eN[  
catch(IOException e){e.printStackTrace ();} )!*M 71  
catch(Exception e){e.printStackTrace ();} zf;[nz  
dV=5_wXZ$  
z9kX`M+  
Utility.log(nFileLength); UV8r&O  
c+i`Zd.m<  
yjFQk,A  
return nFileLength; >=W#z  
} ,JBw$ C  
A%w]~ chC9  
'%RK KA  
//保存下载信息(文件指针位置) ;@Hi*d[  
private void write_nPos() <C96]}/ ?  
{ '>mb@m  
try{ -r'seb5  
output = new DataOutputStream(new FileOutputStream(tmpFile)); |{LaZXU&  
output.writeInt(nStartPos.length); WAmoKZw2  
for(int i=0;i<nStartPos.length;i++) -hR\Y 2?  
{ &b6@_C9  
// output.writeLong(nPos); -GWzMBS S  
output.writeLong(fileSplitterFetch.nStartPos); :E&T}RN  
output.writeLong(fileSplitterFetch.nEndPos); Nu2]~W&  
} tP(bRQ>  
output.close(); v*fc5"3eO  
} SF7b1jr  
catch(IOException e){e.printStackTrace ();} 4kF .  
catch(Exception e){e.printStackTrace ();} t\bxd`,  
} @>nk^ l  
z==}~|5  
8lGgp&ey  
//读取保存的下载信息(文件指针位置) &trh\\I"  
private void read_nPos() :h^UC~[h 3  
{ O8N0]Mz  
try{ &r5%WRzpYT  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); YJvT p~  
int nCount = input.readInt(); ` "":   
nStartPos = new long[nCount]; <\>ak7m  
nEndPos = new long[nCount]; B:#0B[  
for(int i=0;i<nStartPos.length;i++) wvaIgy%z  
{ {#M{~  
nStartPos = input.readLong(); uWtS83i  
nEndPos = input.readLong(); 2LH;d`H[0  
} |=}~>!!  
input.close(); IeI% X\G  
} U105u.#7  
catch(IOException e){e.printStackTrace ();} $hp?5K M  
catch(Exception e){e.printStackTrace ();} ;~$ $WU  
} RW[<e   
$<e .]`R  
;p!hd }C  
private void processErrorCode(int nErrorCode) )mVYqlU"  
{ (wF$"c3'{  
System.err.println("Error Code : " + nErrorCode); `3P62M<  
} sZBO_](S  
_H<OfAO  
6Q.whV%y  
//停止文件下载 Ki;5 =)  
public void siteStop() QO1Gq9  
{ /M `y LI  
bStop = true; ~0GX~{;r  
for(int i=0;i<nStartPos.length;i++) VZbIU[5  
fileSplitterFetch.splitterStop(); ;OqLNfU3y  
#f;1f8yrN  
zn$ Ld,  
} <%uZwk>#  
} TiEJyd`P  
//负责部分文件的抓取 '6J$X-  
**FileSplitterFetch.java u`,R0=<4  
*/ bO3KaOC8N  
package NetFox; 48rYs}  
>8t[EsW/  
Yx c >+mx  
import java.io.*; @|A&\a-"J  
import java.net.*; sswAI|6ou  
4tNgK[6M  
&Sp:?I-  
public class FileSplitterFetch extends Thread { 7B"aFnK;[J  
I3b-uEHev  
o;C)!  
String sURL; //File URL d0E5;3tQ  
long nStartPos; //File Snippet Start Position :u93yH6~8  
long nEndPos; //File Snippet End Position q`zR6  
int nThreadID; //Thread's ID [c )\?MWW  
boolean bDownOver = false; //Downing is over -ouL4  
boolean bStop = false; //Stop identical sJ()ItU5i  
FileAccessI fileAccessI = null; //File Access interface scwlW b<N  
?KW?] o  
I65GUX#DV  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException :\We =oX  
{ kIo?<=F8T  
this.sURL = sURL; $R36`wk  
this.nStartPos = nStart; KO$8lMm$  
this.nEndPos = nEnd; 5|z[%x~f  
nThreadID = id; f 2f $aZ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位  ]^%3Y  
} K 2v)"|T)  
Yb/^Qk59  
=5F49  
public void run() CcE TS}Q0C  
{ +O6@)?pI  
while(nStartPos < nEndPos && !bStop) y+h=x4t  
{ Gl9a5b  
B`Pi\1H6%  
{+}Lc$O#C  
try{ $% t  
URL url = new URL(sURL); qILr+zH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); mAKi%)  
httpConnection.setRequestProperty("User-Agent","NetFox"); EB,>k1IJ  
String sProperty = "bytes="+nStartPos+"-"; rR;Om1 -,  
httpConnection.setRequestProperty("RANGE",sProperty); Gu=bPQOj  
Utility.log(sProperty); vS<e/e+  
#k, kpL<a  
><^@1z.J  
InputStream input = httpConnection.getInputStream(); ~.tu#Y?  
//logResponseHead(httpConnection); Sj+#yct-  
PX'%)5:q;i  
:#;?dMkTY  
byte[] b = new byte[1024]; `dhK$jYD  
int nRead; fRmc_tx  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .=S{  
{  _>l,%n  
nStartPos += fileAccessI.write(b,0,nRead); I&0yUhn  
//if(nThreadID == 1) z /=v@@tj  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); NeP1 #  
} ( d.i np(  
hJ :+*46  
f5v|}gMAX  
Utility.log("Thread " + nThreadID + " is over!"); %iNDRLR%I  
bDownOver = true; IA'AA|v  
//nPos = fileAccessI.write (b,0,nRead); To+{9"$,  
} Ws(>} qjy  
catch(Exception e){e.printStackTrace ();} ?a}~yz#B(  
} ]]4E)j8  
}  + h&V;  
f#jAjzmYL  
=O<BMq{d  
//打印回应的头信息 rO~D{)Nu  
public void logResponseHead(HttpURLConnection con) VTdZ&%@  
{ mB\|<2  
for(int i=1;;i++) 0=iJT4IEJ  
{ o2L/8q.  
String header=con.getHeaderFieldKey(i); \l~h#1|%;s  
if(header!=null) lbY>R@5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); n3w2&  
Utility.log(header+" : "+con.getHeaderField(header)); i F Ab"VA  
else T+fU +GLD  
break; E^!%m8--  
} `i-&Z`  
} i || /=ai  
K67x.PZ  
-3Ffk:  
public void splitterStop() = ~yh[@R)  
{  2r[,w]  
bStop = true; V2*b f`/V  
} r |(Lb'k  
Jad'8}0J  
+W}f0@#)<  
} 8PQ& 7o  
1/z1~:Il  
$]9d((u4  
/* 0y(d|;':  
**FileAccess.java C1_NGOvT  
*//文件访问(定位,写) CA3.fu3(p  
package NetFox; c{[d@jt O  
import java.io.*; 6Z3v]X  
p|Ln;aYc  
X'5te0v`3  
public class FileAccessI implements Serializable{ e2;"> tp6?  
7YsFe6D"  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 c;Li~FLR  
RandomAccessFile oSavedFile; I|:*Dy,~  
long nPos; OIN]u{S  
4CDmq[AVS[  
k;%}%"EVZ  
public FileAccessI() throws IOException 2$jY_{B+x  
{ nX   
this("",0); P~~RK& +i  
} Axr 'zc  
JO _a+Yl  
bBZvL  
public FileAccessI(String sName,long nPos) throws IOException @sVBG']p  
{ XOxm<3gXn  
oSavedFile = new RandomAccessFile(sName,"rw"); 3M^ /   
this.nPos = nPos; C?z C|0  
oSavedFile.seek(nPos); @x)z" )>  
} Q (`IiV   
'0[l'Dt'  
__zsrIUJ  
public synchronized int write(byte[] b,int nStart,int nLen) >~6 ;9{@  
{ L,R9jMx?_  
int n = -1; \PL92HV  
try{ %bddR;c  
oSavedFile.write(b,nStart,nLen); rt"\\sOlMB  
n = nLen; Y#uf 2>J  
} hj-M #a  
catch(IOException e) Z";o{@p  
{  ;v.l<AOE  
e.printStackTrace (); }UX>O  
} Xc'yz 2B  
<n0-zCf  
nPKf~|\1{  
return n; R_/T bz  
} HgbJsv$  
eE1w<] Eg  
$+$+;1[  
} $.v5G>- )3  
GAQVeL1  
ZQ@^(64  
/* ([s2F%S`@  
**SiteInfoBean.java HAP9XC(F]  
*/ ,~c:P>v=  
package NetFox; KWM.b"WnXr  
F7a\Luae  
QRx'BY$5  
public class SiteInfoBean { KrG$W/<tg  
$YFn$.70\  
%$S.4#G2  
private String sSiteURL; //Site's URL Zb3E-'G+  
private String sFilePath; //Saved File's Path Ktg6*L/  
private String sFileName; //Saved File's Name 3xbA]u;gp  
private int nSplitter; //Count of Splited Downloading File u6|P)8?`  
"c=\?   
lZ'NL bK  
public SiteInfoBean() izOtt^#DZt  
{//nSplitter的缺省值为5 J/WPffqD  
//default value of nSplitter is 5 yG{'hx6H  
this("","","",5); SkVW8n*s  
} -&%#R_RV  
XP~4jOL]  
{-tCLkE 3  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) =[3I#s?V  
{ rC$ckug  
sSiteURL= sURL; ps^Z)x`GV  
sFilePath = sPath; n*hHqZl  
sFileName = sName; (hs[B4nV  
this.nSplitter = nSpiltter; cC b'z1  
u0Irf"Ab  
nu|;(ly  
} mQ:lj$Gf  
?kISAA4x  
Sycs u_je  
public String getSSiteURL() 9!}&&]Q`  
{ `gSqwN<x%  
return sSiteURL; ;WWUxrWif  
} +)dQd T0Fq  
+'x|VPY.PG  
5W(G~m?jC6  
public void setSSiteURL(String value) mtvfG  
{ t,)` Zu$  
sSiteURL = value; now\-XrS  
} uwU;glT  
+Gg6h=u  
S{XV{o  
public String getSFilePath() ~L<q9B( @  
{ [f!sBJ!  
return sFilePath; Mnn\y Tblp  
} 6p=AzojoB  
_ )b:F=4j  
@rB!47!  
public void setSFilePath(String value) :} i #ODJ  
{ 0hp*(, L  
sFilePath = value; `%SFu  
} j,?>Q4G  
}`FC'!(   
FZ)_WaqGf  
public String getSFileName() ""|vhgP  
{ _l<e>zj  
return sFileName; HTA@en[5  
} p(g0+.?`~  
S:"R/EE(  
Lnc _)RF  
public void setSFileName(String value) :OT~xU==H  
{ 5xtIez]x?  
sFileName = value; 2K0HN  
} aY&He~  
A%qlB[!:  
y9kydu#q  
public int getNSplitter() $k5mI1~  
{ V<A_c^unO  
return nSplitter; J$JXY@mBSC  
} f?}~$agc  
B! $a Y  
+n_`*@SE  
public void setNSplitter(int nCount) U{6i5;F#H  
{ w7GF,a  
nSplitter = nCount; %%5K%z,R#  
} @62QDlt;  
} x=7hOI5u  
p^S]O\;M7  
Z\Qa6f!  
/* ZU\TA|  
**Utility.java "N\>v#>C  
*/ t 1gH9  
package NetFox; CvDy;'{y1  
vl+vzAd  
C QO gR GW  
public class Utility { T"ors]eI  
I`"B<=zi  
94Wf ]  
public Utility() 1xAZ0X#  
{ CDOqdBQ  
5[NF  
u xif-5  
} LU "e9  
a:nMW'!  
//线程睡眠 MHZ!noAr  
public static void sleep(int nSecond) ~&)  
{ Id-?her>B  
try{ R?bF b|5t  
Thread.sleep(nSecond); m<]b]FQ  
} _c| aRRW  
catch(Exception e) eTi r-7  
{ +o&&5&HR  
e.printStackTrace (); Z[+H$=$%  
} ;533;(d* o  
} TK"!z(p  
NY]`1yy  
//日志 O}VI8OB(&  
public static void log(String sMsg) E*rnk4Y  
{ X2ShxD|  
System.err.println(sMsg); 9AJMm1 _  
} hN% h.;s  
"n'LF?/H'  
z>_jC+  
public static void log(int sMsg) -.#He  
{ M+Rxt.~6  
System.err.println(sMsg); \gd.Bl  
} {UX[SAQ  
} X8U._/'N  
G4Y]fzC  
Q{9#Am^6w  
/* e [D'0L  
**TestMethod.java Yjo$^q  
*/ +bnz%/v  
package NetFox; v&CKtk!3{  
!Pmv  
Rb_HD  
public class TestMethod { /mST<{(_G\  
v&:R{  
T""y)%  
public TestMethod() GdN'G  
{ ///xx/weblogic60b2_win.exe y@!kp*0  
try{ n1Ag o3NM  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); r{m"E^K,  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); *.ffyBI*~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 1zE_ SNx  
fileFetch.start(); , O=@I  
} 'WH@Zk/l  
catch(Exception e){e.printStackTrace ();} E|2klA^+*  
G $u:1&   
'ad|@Bh  
} wzAp`Zs2Dm  
ldJ eja~Xl  
IQK__)  
public static void main(String[] args) 6"Tr$E  
{ %v++AcE  
new TestMethod(); |L{<=NNs:D  
} dy u brIG  
} ZgO7W]Z4  
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