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http断点续传简单实现(java)

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/* -u&6X,Oq\u  
**SiteFileFetch.java B.wYHNNV  
*/ *meZ8DV2DH  
package NetFox; c;%_EN%  
import java.io.*; wmk *h-  
import java.net.*; >NqYyW,%  
Ot:CPm@  
Vx(B{5>Vu  
public class SiteFileFetch extends Thread { kQ4dwF~  
+J_c'ChN  
8;z6=.4xtg  
SiteInfoBean siteInfoBean = null; //文件信息Bean 3,>0a  
long[] nStartPos; //开始位置 g3Ec"_>P  
long[] nEndPos; //结束位置 Mx6@$tQ%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 M^MdRu  
long nFileLength; //文件长度 l*ayd>`~x  
boolean bFirst = true; //是否第一次取文件 \qR7mI/*  
boolean bStop = false; //停止标志 `Y BC  
File tmpFile; //文件下载的临时信息 -#0qV:D  
DataOutputStream output; //输出到文件的输出流 tna .52*/  
@xQgY*f#  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) *n; !G8\  
public SiteFileFetch(SiteInfoBean bean) throws IOException AcS|c:3MUy  
{ p%iGc<vHX  
siteInfoBean = bean; 3Dg,GaRk  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); WzAb|&?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); JCz@s~f\y  
if(tmpFile.exists ()) F ;{n"3<  
{ .EpV;xq}  
bFirst = false; Cnnh7`  
read_nPos(); ^:6{22C{  
} WxW7qt  
else ~;Ov-^tp  
{  gG uZ8:f  
nStartPos = new long[bean.getNSplitter()]; <!L>Exh&r  
nEndPos = new long[bean.getNSplitter()]; bQE};wM,  
} k xP-,MD  
uJOJ-5}yt  
(H)2s Y  
0rh]]kj  
} (2$( ?-M  
EzDk}uKY0R  
)_1zRT|9  
public void run() =2Bg9!zW>  
{ JQ}$Aqk  
//获得文件长度 dODt(J}%  
//分割文件 #@^t;)|  
//实例FileSplitterFetch Z= jr-)kK  
//启动FileSplitterFetch线程 g$( V^  
//等待子线程返回 qi;f^9M%  
try{ OH;b"]  
if(bFirst) D0gZC  
{ ~ }F{vm  
nFileLength = getFileSize();  =Qh\D  
if(nFileLength == -1) RD\  
{ km)zMoE{c{  
System.err.println("File Length is not known!"); zfI>qJ+Nqt  
} 8'~[pMn`  
else if(nFileLength == -2) UjaK&K+M?  
{ Dpvk\t  
System.err.println("File is not access!"); #6ri-n  
} Uh7v@YMC  
else m6n?bEl6I  
{ wm]^3q I2  
for(int i=0;i<nStartPos.length;i++) MG[o%I96  
{ Ne#WI'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); +lJG(Qd  
} p+l!6  
for(int i=0;i<nEndPos.length-1;i++) cU0s p  
{ 9[1`jtm  
nEndPos = nStartPos[i+1]; 3mYiQ2  
} gfsI6/Y  
nEndPos[nEndPos.length-1] = nFileLength; EG0WoUX|  
} u1t% (_h  
} $SM# < @  
$tz;<M7B  
)_{dWf1  
//启动子线程 $}lbT15a  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; t>1Z\lE\"  
for(int i=0;i<nStartPos.length;i++) XD|E=s  
{ x;-. ZVF  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?g?L3vRK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), )\sc83L  
nStartPos,nEndPos,i); hy}8Aji&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kjEEuEv  
fileSplitterFetch.start(); 5nv<^>[J  
} |_o=^?z'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qP{/[uj[K  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7nHF@Y|*"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", .%.9n\b  
nEndPos = " + nFileLength); ,stN  
// fileSplitterFetch[nPos.length-1].start(); wSb 1"a  
3= xhoRX  
S>.SSXlM  
//等待子线程结束 Q@ 2i~Qo[  
//int count = 0; (Q%'N3gk  
//是否结束while循环 ~\=1'D^6CK  
boolean breakWhile = false; 7:9.&W/KE  
L!=4N!j  
,S'p %g  
while(!bStop) XEn*?.e  
{ _{R=B8Zz\  
write_nPos(); '&.#  
Utility.sleep(500); :> D[n1v  
breakWhile = true; #[zI5)Meh  
t'BLVCu  
(7XCA,KTGI  
for(int i=0;i<nStartPos.length;i++) W5?yy>S6N  
{ Vy*:ne  
if(!fileSplitterFetch.bDownOver) Xv< B1  
{ a["2VY6Eq@  
breakWhile = false; vJ\pR~?  
break; N` aF{3[  
} a;QMA d!  
} rA2 g&  
if(breakWhile) 6b%WHLUeT  
break; ^xh}I5  
.mDM[e@'  
rF aF Bd  
//count++; 9so6WIWc  
//if(count>4) <Ard 7UT  
// siteStop(); `D`sr[3n  
} [[>wB[w  
I4i2+ *l}  
*g y{]  
System.err.println("文件下载结束!"); $ "E).j  
} 8wVY0oRnU  
catch(Exception e){e.printStackTrace ();} uHAT#\m:  
} xEf'Bmebk  
VYt!U  
)Psb>'X  
//获得文件长度 ]l'Y'z,}  
public long getFileSize() K$M^gh0  
{ qw@puw@D  
int nFileLength = -1; U+)xu>I  
try{ 3 dht!7/  
URL url = new URL(siteInfoBean.getSSiteURL()); w"OP8KA:^T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); L3 G \  
httpConnection.setRequestProperty("User-Agent","NetFox"); M9y <t'  
TUHi5K  
wD68tG$  
int responseCode=httpConnection.getResponseCode(); \[gReaI  
if(responseCode>=400) slg ]#Dy  
{ HPb]Zj  
processErrorCode(responseCode); ,$'])A?$  
return -2; //-2 represent access is error GP&vLt51  
} NZ/yBOD(  
J9\a{c;.  
9cEv&3  
String sHeader; $aN-Y?U%  
N@Y ljz|  
TF 'U  
for(int i=1;;i++) <$F\Nk|x  
{ yY[<0|o u  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); JJ{9U(`_y6  
//Utility.log(in.readLine()); (FJ9-K0b{n  
sHeader=httpConnection.getHeaderFieldKey(i); L=q+|j1>  
if(sHeader!=null) p98~&\QT  
{ 4hAl-8~Q6  
if(sHeader.equals("Content-Length")) O!Oumw,$  
{ :um|nRwy9  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); X{we/'>  
break; 6B@CurgB  
} YO}1(m  
} wjh=Q  
else _)]+hUw Y  
break; SB5&A_tr  
} td4[[ /  
} abJ" [  
catch(IOException e){e.printStackTrace ();} AJSx%?h:6  
catch(Exception e){e.printStackTrace ();} Qb)C[5a}  
HsnLm67'  
br0++}vwL  
Utility.log(nFileLength); 7\f\!e <  
?Y:8eD"*  
zN{K5<7o  
return nFileLength; \0mb 3Q'  
} ~(pmLZ<GW}  
lY{FSGp  
(tCUlX2  
//保存下载信息(文件指针位置) vfl5Mx4  
private void write_nPos() jCrpL~tWT  
{ H|ER  
try{ srYJp^sC  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^bc;[x&N  
output.writeInt(nStartPos.length); c%[#~;E  
for(int i=0;i<nStartPos.length;i++) KN?6;G{  
{  ;zYqsS  
// output.writeLong(nPos); a)S+8uU  
output.writeLong(fileSplitterFetch.nStartPos); )ZBY* lk9  
output.writeLong(fileSplitterFetch.nEndPos); YKE46q;J  
} nK$X[KrV'  
output.close(); B*~5)}1op  
} NvHJ3>"%  
catch(IOException e){e.printStackTrace ();} BWrv%7  
catch(Exception e){e.printStackTrace ();} !2z?YZhu  
} : C b&v07  
\mw(cM#:  
-0_d/'d  
//读取保存的下载信息(文件指针位置) IBQ@{QB  
private void read_nPos() +&Hr4@pgW  
{ jMbC Y07v  
try{ 6gT5O]]#o  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Pl<; [cB  
int nCount = input.readInt(); u{FDdR9<  
nStartPos = new long[nCount]; E[O<S B I  
nEndPos = new long[nCount]; n @?4b8"  
for(int i=0;i<nStartPos.length;i++) _:X|.W  
{ p|Q*5TO  
nStartPos = input.readLong(); "Vr[4&`  
nEndPos = input.readLong(); o/C\d$i'  
} p_UlK8rb  
input.close(); V\})3i8  
} _[Vf547vS  
catch(IOException e){e.printStackTrace ();} H)aQ3T4N5  
catch(Exception e){e.printStackTrace ();} s TOa  
} i~3u>CT  
3d-%>?-ee  
E;d7ch  
private void processErrorCode(int nErrorCode) 2_ :n  
{ UjOB98Du  
System.err.println("Error Code : " + nErrorCode);  Y!WG)u5  
} +3a?` Z  
:>aQ~1f>]  
k{VE1@  
//停止文件下载 '{ [5M!B  
public void siteStop() Ja SI^go  
{ .`7cBsXH  
bStop = true; ,ZQZ}`x(  
for(int i=0;i<nStartPos.length;i++) *26334B.R  
fileSplitterFetch.splitterStop(); P_c,BlfGMH  
gtYAHi  
VR  
} 'kYwz;gp  
} V97,1`  
//负责部分文件的抓取 gr-fXZO  
**FileSplitterFetch.java /B5-Fx7j3  
*/ 6G}+gqbX  
package NetFox; JT9N!CGZ  
l c_E!"1  
hoT/KWD,  
import java.io.*; x+]!m/  
import java.net.*; y7S4d~&  
XyMG.r-,  
goJ|oi  
public class FileSplitterFetch extends Thread { j F-v% ?  
tTN?r 8  
+fx8muz:y  
String sURL; //File URL zZiJ 9 e  
long nStartPos; //File Snippet Start Position q~L^au8  
long nEndPos; //File Snippet End Position *cTO7$\[  
int nThreadID; //Thread's ID 2Bk$ lx7  
boolean bDownOver = false; //Downing is over ?0_7?yTR/  
boolean bStop = false; //Stop identical V:/7f*n7  
FileAccessI fileAccessI = null; //File Access interface /%A;mlf{  
tA$)cg+.  
cst}Ibf i  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException N$TL;T>  
{ =`Y.=RL+'n  
this.sURL = sURL; XhdSFxW}  
this.nStartPos = nStart; Xnuzr" 4u  
this.nEndPos = nEnd; tRw@U4=y  
nThreadID = id; 'cNKjL;  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9_fePS|Z4  
} okq[ o90  
O+=vEp(  
qn"D#K'&(  
public void run() {F N;'Uc  
{ }j1!j&&  
while(nStartPos < nEndPos && !bStop) k>E`s<3  
{ 5 cK@WE:  
l{ex?  
n:U>Fj>q  
try{ hNXBVIL<&  
URL url = new URL(sURL); qQxz(}REu9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); AGYm';z3  
httpConnection.setRequestProperty("User-Agent","NetFox"); i`)!X:j  
String sProperty = "bytes="+nStartPos+"-"; 2JmZ{  
httpConnection.setRequestProperty("RANGE",sProperty); U-0#0}_  
Utility.log(sProperty); yB LUNIr  
^*R(!P^  
Lt#'W  
InputStream input = httpConnection.getInputStream(); v&g0ta@  
//logResponseHead(httpConnection); 5)zn:$cz  
 .Qt4&B  
)[&_scSa  
byte[] b = new byte[1024]; ,J mbqOV?!  
int nRead; ?p[O%_Xf  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) R*1kR|*_)  
{ 1u]P4Gf=  
nStartPos += fileAccessI.write(b,0,nRead); vMSW$Bx ;  
//if(nThreadID == 1) Oajv^H,Em  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L6 6-LMkH  
} ^T4Ay=~{  
b'x$2K;E  
H L<s@kEZ  
Utility.log("Thread " + nThreadID + " is over!"); S"snB/  
bDownOver = true; iO!6}yJ*V  
//nPos = fileAccessI.write (b,0,nRead); P\~{3U  
} )_jSG5k  
catch(Exception e){e.printStackTrace ();} t~K%.|'0  
} IGj`_a  
} PfW|77  
"oc$  
}4%/pOi:f  
//打印回应的头信息 FQeYx-7  
public void logResponseHead(HttpURLConnection con) O>DNC-m)i{  
{ fW0$s`  
for(int i=1;;i++) Lx|',6S  
{ #j@OLvXh  
String header=con.getHeaderFieldKey(i); !ZtSbOC'  
if(header!=null) ?~ULIO'  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Q]JX`HgPaU  
Utility.log(header+" : "+con.getHeaderField(header)); e`U Qz$4!  
else <"&'>?8j  
break; 3" Vd==oK~  
} aSaAC7sFk  
} rjojG59U>  
: iY$82wQ  
(wt+`_6  
public void splitterStop() XYbyOM VI  
{  7 Yv!N  
bStop = true; wODvc9p}]  
} ahIE;Y\j'  
E)YVfM  
H/cTJ9zz  
} Q .RO  
"G?9b  
CJ w$j`k  
/* L`K;IV%;  
**FileAccess.java VQ |^   
*//文件访问(定位,写) p!"(s/=  
package NetFox; 9R]](g#  
import java.io.*; G!-J$@P  
m/${8  
3o8\/-*<  
public class FileAccessI implements Serializable{ Y)p4]>lT+8  
!*a[jhx  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 hLuJWjCV  
RandomAccessFile oSavedFile; F1u)i  
long nPos; #\FT EY!  
q.oLmX  
M9"Sgb`g  
public FileAccessI() throws IOException RV!<?[  
{ k ojG- M  
this("",0); r,'O ).7  
} /7p>7q 9g  
*TnzkNN_,  
nxRwWj57  
public FileAccessI(String sName,long nPos) throws IOException G=$}5; t  
{ 3V-6)V{KaE  
oSavedFile = new RandomAccessFile(sName,"rw"); cf*zejbw  
this.nPos = nPos; 9)ea.Gu  
oSavedFile.seek(nPos); zl)&U=4l  
} YN#XmX%  
:WX0,-Gn  
!C`20,U  
public synchronized int write(byte[] b,int nStart,int nLen) jH0Bo;  
{ /yK"t< p  
int n = -1; ?`. XK}  
try{ f)Y  
oSavedFile.write(b,nStart,nLen); A'g,:8Ou  
n = nLen; C_-E4I Z)  
} ?aJ6ug  
catch(IOException e) xwLy|&  
{ IK?]PmN4}  
e.printStackTrace (); plku-O;]  
} dQ6GhS ~  
lPS*-p#IZ  
&7][@v  
return n; /co%:}ln  
} j`9Nwa  
BTs0o&}e  
"_)|8|gN  
} #JS`e_3Rr  
SsRVd^=;x  
JN^bo(kb  
/* k/^g*  
**SiteInfoBean.java _80ns&q  
*/ vf_OQ4'G,  
package NetFox; t?.\|2  
u\5g3BH  
d$Em\*C  
public class SiteInfoBean { {G.jB/  
Z:^3Fm->+  
^srs$ w]  
private String sSiteURL; //Site's URL Mdm0g  
private String sFilePath; //Saved File's Path '>]&rb09|  
private String sFileName; //Saved File's Name `]&*`9IK{  
private int nSplitter; //Count of Splited Downloading File uQ1jwYK`7  
-$L(y@%X^  
%yhI;M^  
public SiteInfoBean() >;}]pI0T  
{//nSplitter的缺省值为5 K P6PQgc  
//default value of nSplitter is 5 LaT8l?q q  
this("","","",5); v>:=w|.HC  
} tQf!|]#J  
j@SYXKL~  
4tnjXP8  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;_p fwa4  
{ \CwtX(6.  
sSiteURL= sURL; j`Nh7+qs  
sFilePath = sPath; ITQ9(W Un  
sFileName = sName; kYtHX~@  
this.nSplitter = nSpiltter; ,4yG(O$)  
w>vmF cp  
fO+U HSC  
} N1s.3`  
u#!GMZJN  
DUo0w f#D^  
public String getSSiteURL() bN!u}DnN  
{ p_gA/. v=  
return sSiteURL; PS/W h  
} -;<>tq'3`  
d}VALjXHX!  
Z?C4a }  
public void setSSiteURL(String value) w Oj88J)  
{ >\&= [C  
sSiteURL = value; NkoofhZ  
} W/a,.M  
7 y>(H<^>  
pMDH  
public String getSFilePath() {70 Ou}*  
{  )Oo2<:"  
return sFilePath; D2V v\f  
} pd7O`.3  
t#{x?cF  
*{Yi}d@h(  
public void setSFilePath(String value) R @OSqEnr  
{ PJ0Jjoh"Y  
sFilePath = value; 6."PS4}:  
} EqoASu  
g@}6N.]#  
S_j1=6 #^  
public String getSFileName() IY0 3"  
{ 9D%qXU  
return sFileName; q$|0)}  
} L1rA T  
Pwg/Vhfh  
:+<t2^)rD  
public void setSFileName(String value) PRZ8X{h  
{ B3eNFS  
sFileName = value; m}rh|x/?  
} X;(oz]tr$  
3]!h{_:u  
YK7\D:  
public int getNSplitter() @OY1`Eu O  
{ V*>73I  
return nSplitter; {dZ!I  
} t(wZiK}  
7 T mK  
VZt;P%1;h  
public void setNSplitter(int nCount) |$Qp0vOA}  
{ uvR0TIF4  
nSplitter = nCount; i]LU4y %'  
} :&qC<UD  
} h)7v1,;w'  
>eEnQ}Y  
)CFk`57U  
/* LgO i3  
**Utility.java `S5>0r5[  
*/ ?rAi=w&c  
package NetFox; a^%8QJW  
]"C| qR*  
cO8`J&EK  
public class Utility { 3L?WTS6(u  
V[4(~,9  
BN_!Y)F l  
public Utility() IES41y<  
{ 1d=0q?nH  
{bW"~_6}  
Q -M rH   
} "9)1K!tH  
37J\i ]  
//线程睡眠 H<v c\r  
public static void sleep(int nSecond) @QvfN>T  
{ (qNco8QKu3  
try{ zNNzsT8na  
Thread.sleep(nSecond); &*X3c h  
} RmcYa j^=  
catch(Exception e) m]bL)]Z  
{ l :f9Ih  
e.printStackTrace (); ztRWIkI q  
} e@='Q H  
} QBg}2.  
NvXj6U*%  
//日志 U;x99Go:  
public static void log(String sMsg) !O 0ZD4/{4  
{ `=_7I?  
System.err.println(sMsg); NTXws4'D  
} ^hQ:A4@q  
FCsyKdM  
DR.3 J`?K  
public static void log(int sMsg) [V!^\g\6  
{ TKj/6Jz|  
System.err.println(sMsg); u!=]zW%  
} -~QlHp&SY  
} P^'>dOI0w  
O+CF/ipX/  
v*vub#wP  
/* YHwVj?6W  
**TestMethod.java 5Ws:Ei{R  
*/ F9>(W#aC  
package NetFox; $i1>?pb3  
RW|UQY#  
<MI$N l  
public class TestMethod { @LwVmR |{  
OF<[Nh\.  
mvW^P`nB  
public TestMethod() Mt7X<?GZm  
{ ///xx/weblogic60b2_win.exe 'ugR!o1  
try{ B=o#LL  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); !VJT"Ds_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); QrrZF.  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ;&7qw69k  
fileFetch.start(); jS5t?0  
}  JsAb q  
catch(Exception e){e.printStackTrace ();} @n ~ND).  
bOnukbJ  
YV2pERl  
} qB` 0^V  
\k$]GK-  
v]d?6g  
public static void main(String[] args) $AL|d[[T[  
{ A-@-?AR  
new TestMethod(); ;1(qGy4  
} 0X}w[^f  
} DI"dY ug#  
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