http断点续传简单实现（java)

/* &/, BFx"  
**SiteFileFetch.java o#wF/ I  
*/ q#Qr@Jf  
package NetFox; _bks*.9}3b  
import java.io.*; Gf'V68,l$  
import java.net.*; TCF[i
E{  
uj/le0
 
ZcO!cR&*'J  
public class SiteFileFetch extends Thread { hoeTJ/;dm  
R/O_*XY  
1ck2Gxn  
SiteInfoBean siteInfoBean = null; //文件信息Bean T+4Musu{V  
long[] nStartPos; //开始位置 j`'=K_+nU  
long[] nEndPos; //结束位置 W3 8=fyD  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \aUbBa%!  
long nFileLength; //文件长度 %NS]z;G  
boolean bFirst = true; //是否第一次取文件 +TAm9eDNV  
boolean bStop = false; //停止标志 $9DZ5"  
File tmpFile; //文件下载的临时信息 c/2OR#$t  
DataOutputStream output; //输出到文件的输出流 =C\S6bF%  
ak;Z;  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ?\#4`9  
public SiteFileFetch(SiteInfoBean bean) throws IOException 4'rk3nT8  
{ Hab9~v ]  
siteInfoBean = bean; O.K8$  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [bT@Y:X@`  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); <qRw! 'S^  
if(tmpFile.exists ()) `g :<$3}  
{ u%[*;@;9+  
bFirst = false; .(1$Q6yG  
read_nPos(); !Xj m h$F  
} %r!#  
else H[Pb Wy:  
{ T8hQ< \g  
nStartPos = new long[bean.getNSplitter()]; BkqIfV%O  
nEndPos = new long[bean.getNSplitter()]; E>6zwp  
} nQ(#'9  
oG*lUh}  
$oua]8!  
mc$
c!Ax*  
} 63u'-Z"4  
)sS<%Xf  
s_*eX N  
public void run() &gEu%s^wR  
{ Vd1K{rH#  
//获得文件长度 .D>lv_kp  
//分割文件 'FUPv61()  
//实例FileSplitterFetch =k/n  
//启动FileSplitterFetch线程 tt[_+e\4  
//等待子线程返回 %mYIXsuH  
try{ 8m*\"_S{  
if(bFirst) W>Rv  
{ s{: Mu~v  
nFileLength = getFileSize(); g*tLqV  
if(nFileLength == -1) _fyw  
{ <?J7Z|  
System.err.println("File Length is not known!"); 9H)uTyuNi  
} b{dzbmak  
else if(nFileLength == -2) OVh/t#On  
{ Uq+ _#{2(  
System.err.println("File is not access!"); fVN}7PH7+  
} $cy:G  
else =4%C?(\  
{ yED^/=\)}  
for(int i=0;i<nStartPos.length;i++) AeJM[fCMa  
{ {oJa8~P  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 4 ?c1c  
} \S@A /t6pa  
for(int i=0;i<nEndPos.length-1;i++) k?8W2fC  
{ ) k2NF="o  
nEndPos = nStartPos[i+1]; JZnWzqFw  
} 0Its;|  
nEndPos[nEndPos.length-1] = nFileLength; mcXakWmi  
} 'OihA^e  
} 7S7!  
Y}#^n7*w~  
|zT0g]WH  
//启动子线程 i-=ff  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; y;>I'e  
for(int i=0;i<nStartPos.length;i++)  !fV6KkV  
{ ^/BE=$E\  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), k2WO*xa*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ~R8yj(  
nStartPos,nEndPos,i); @}Z/{Z[@  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %b&BLXW  
fileSplitterFetch.start(); @ixX?N)V  
} #<e7 Y0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), D
vKM>P%|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); bYgYP|@  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %N  
nEndPos = " + nFileLength); "PHv~_:^R  
// fileSplitterFetch[nPos.length-1].start(); g|HrhUT;  
,Ex\\p-  
2~U+PyeNz  
//等待子线程结束 e ^qnUjMy  
//int count = 0; %Uk/P  
//是否结束while循环 lG+ltCc$9  
boolean breakWhile = false; &sgwY  
*u>\&`h=  
iQIw]*h^  
while(!bStop) `;qZ$HH  
{ {.OoOqq9  
write_nPos(); (R}X(u  
Utility.sleep(500); Om"3Q/&  
breakWhile = true; Mfr#IzNHN  
Ny'v/+nQ  
UmE{>5Pt  
for(int i=0;i<nStartPos.length;i++) \|t0~sRwh  
{ _Xv/S_yW  
if(!fileSplitterFetch.bDownOver) >PVi 3S  
{ M(E_5@?3  
breakWhile = false; *Kkw,qp/  
break; t5APD?5 c  
} "3MUrIsB>  
} 4<K`yU]"  
if(breakWhile) 5gEfhZQ  
break; I}v#r8'!  
(R<4"QbE  
Rx"Qwi,\U  
//count++; l1qwT0*6>  
//if(count>4) B3t>M) 9  
// siteStop(); M
\6`2q  
} gc~h!%'.I  
mlWIq]J  
=eoxT  
System.err.println("文件下载结束！"); N6[^62  
} .rm7S
d4K  
catch(Exception e){e.printStackTrace ();} Kx+Bc&X  
} LD~'^+W  
fEc_r:|\6  
cZzZNGY^ts  
//获得文件长度 /xbZC{R  
public long getFileSize() Z+W&C
@Uw  
{ ^ks^9*'|j  
int nFileLength = -1; CEq]B:[IC  
try{ e:D"_B  
URL url = new URL(siteInfoBean.getSSiteURL()); DOIWhd5:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3/=QZ8HA&-  
httpConnection.setRequestProperty("User-Agent","NetFox"); jFTV\|C  
26VdRy{[  
XL=R]IC<.  
int responseCode=httpConnection.getResponseCode(); gVJ#LJ  
if(responseCode>=400) `U
K+[`E  
{ BQ:Kx_   
processErrorCode(responseCode); L)'rM-nkFh  
return -2; //-2 represent access is error 15 11<,  
} "BfmX0&?  
73ljW  
==Mi1Q#5C  
String sHeader; &:#8ol(n5b  
Hk*cO;c  
}n%Rl\p  
for(int i=1;;i++) D>e\OfTR:  
{ l1Q+hz5"*U  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Pq>[q?>?  
//Utility.log(in.readLine()); I 47GQho  
sHeader=httpConnection.getHeaderFieldKey(i); HHTsHb{7  
if(sHeader!=null) hr6e1Er  
{ (zDk68=v  
if(sHeader.equals("Content-Length")) @h$0S+?:  
{
[(F<|f:n  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); dd7nO :]  
break; ]U1,Nh
Zu  
} 4`P2FnJ?  
} Sw@,<4S  
else &E riskI  
break; ,wi=!KzX  
} <?{}Bo0xG  
} .^IhH|U  
catch(IOException e){e.printStackTrace ();} ]</4#?_  
catch(Exception e){e.printStackTrace ();} +()t8,S,  
@H%=%ZwpO  
*Yu\YjLPG  
Utility.log(nFileLength); -yQ\3wli`  
^r_lj$:+$  
e=z_+gVm  
return nFileLength; x0h3jw+6  
} kok^4VV  
H"rzRd;S  
nWF4[<t  
//保存下载信息（文件指针位置） UZ\*]mxT  
private void write_nPos() '(X[ w=WXy  
{ b\;u9C2y'  
try{ `-EH0'w~"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); |ch^eb^7"  
output.writeInt(nStartPos.length); V<V\0n!0  
for(int i=0;i<nStartPos.length;i++) .!8X]trEg  
{ i;hc]fYb=K  
// output.writeLong(nPos); %SO%{.}Zf  
output.writeLong(fileSplitterFetch.nStartPos); <uKm%~xi<  
output.writeLong(fileSplitterFetch.nEndPos); T|s0qQi  
} Wejwj/EU%  
output.close(); ERRT_G?  
}
U%t/wq  
catch(IOException e){e.printStackTrace ();} 8{<[fZyC  
catch(Exception e){e.printStackTrace ();} [&qbc#L  
} {I-a;XBX  
k gu[!hD1  
7Jx-W|  
//读取保存的下载信息（文件指针位置） C{hcK 1-K  
private void read_nPos() <j 9Mt=8M  
{ "x|NG,<[9  
try{ %L13Jsw  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); XCIa2
Syo  
int nCount = input.readInt(); +Sd,l>8\  
nStartPos = new long[nCount]; R=?po=  
nEndPos = new long[nCount]; "c/s/$k//  
for(int i=0;i<nStartPos.length;i++) Ryq"\Q>+  
{ ZutB_uW  
nStartPos = input.readLong(); loUl$X.u  
nEndPos = input.readLong(); CSL{Q  
} y /:T(tk$  
input.close(); \;*}zX  
} d$_q=ywc  
catch(IOException e){e.printStackTrace ();} pP0Vg'V  
catch(Exception e){e.printStackTrace ();} uB<F.!3  
} {y:#
'n  
U7"BlT!V\  
H : T N  
private void processErrorCode(int nErrorCode) .K@x4 /1  
{ q#(/*AoU  
System.err.println("Error Code : " + nErrorCode); HD:%
Yv  
} |N$?_<H  
9S1Ti6A  
?YO=J  
//停止文件下载 t+ S
~u^  
public void siteStop() .i+* #djx  
{ (eRKR2% q  
bStop = true; WR a+zii,  
for(int i=0;i<nStartPos.length;i++) Itr7lv'5xx  
fileSplitterFetch.splitterStop(); {x|kg;  
E./__Mz@  
'>e79f-O)  
} P*SCHe'  
} zvGK6qCk  
//负责部分文件的抓取 TsX+. i'  
**FileSplitterFetch.java 9PKoNd^e  
*/ H9~%#&fF  
package NetFox; m(Y.X=E
Zr  
~n/Aq*  
TmYP_5g:  
import java.io.*; J`r,_)J"2  
import java.net.*; {,Bb"0 \  
_;e!ZZLG  
fQQsb 5=i  
public class FileSplitterFetch extends Thread { whY~=
lizn  
7V}]C>G  
8Z dUPW\e  
String sURL; //File URL NT@YLhs?  
long nStartPos; //File Snippet Start Position mLg{6qm(q  
long nEndPos; //File Snippet End Position 2gwZb/'i  
int nThreadID; //Thread's ID B`*f(  
boolean bDownOver = false; //Downing is over ,!I?)hwOC  
boolean bStop = false; //Stop identical p?V?nCv1O  
FileAccessI fileAccessI = null; //File Access interface /^'Bgnez  
MyH[vE^b  
G'O/JM  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 5 o#<`_=J  
{ {Z#e{~m#  
this.sURL = sURL; >I4p9y(u  
this.nStartPos = nStart; |.(CIu~b   
this.nEndPos = nEnd; 4bi NGl~  
nThreadID = id; i,#k}CNu  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 q]eFd6  
} 3
82*  
F!gNt<fZ  
jC%35bi  
public void run() ym|NT0_0  
{ zJ;>.0  
while(nStartPos < nEndPos && !bStop) 6 u-$  
{ X>Al:?`}N  
SOp=~

z  
yuHZ&e  
try{ 2mqK3-c  
URL url = new URL(sURL); KdT[*-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); DH:GI1Yu>I  
httpConnection.setRequestProperty("User-Agent","NetFox"); iuC7Y|  
String sProperty = "bytes="+nStartPos+"-"; 1~2R^#rm  
httpConnection.setRequestProperty("RANGE",sProperty); q^a|
wTC  
Utility.log(sProperty); D<U 9m3  
bmOqeUgB  
OXHvT/L`  
InputStream input = httpConnection.getInputStream(); r{\BbUnf)  
//logResponseHead(httpConnection); TN35CaSmq  
b!0DH[XKV  
9u,8q:I.?  
byte[] b = new byte[1024]; G'f9N^w  
int nRead; <4bz
/^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) u8YB)kG  
{ <S1??  
nStartPos += fileAccessI.write(b,0,nRead); -<qxO  
//if(nThreadID == 1) )Hbb&F  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {O^TurbTFA  
} mn]-rTr  
t;8\fIW5  
Al7<s  
Utility.log("Thread " + nThreadID + " is over!"); B.$PhmCG  
bDownOver = true; 5@P%iBA4(3  
//nPos = fileAccessI.write (b,0,nRead); "h=6Q+Ze  
} d^F|lc ]8  
catch(Exception e){e.printStackTrace ();} &<,SV^wag  
} l~bKBz  
} qib7Z]j  
6HoqEku/Q  
[X,A'Q  
//打印回应的头信息 ugYw<  
public void logResponseHead(HttpURLConnection con) /+VIw`E  
{ C
jZZm^O  
for(int i=1;;i++) R?cUy8?'S  
{ _!n}P5  
String header=con.getHeaderFieldKey(i); QR<`pmB~y  
if(header!=null) 43zUN  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +TC1nkX  
Utility.log(header+" : "+con.getHeaderField(header)); *>jjMyn  
else LA-_3UJx  
break; B?LXI3sQZ  
} }N3V
5cab  
} 3bC+Mco  
><;Q@u5~  
kt^yj"C>  
public void splitterStop() D+Cm<ZT~  
{ 5h0>!0  
bStop = true; R A:jzht  
} ![ZmV  
57~Uqt  
nV}8M  
} _%Bz,C8  
No) m/17y  
Sp:l;SGd  
/* WsR+Np@c  
**FileAccess.java 4qhWm"&CM  
*//文件访问(定位，写) 5[C~wvO  
package NetFox; $>*Yhz `  
import java.io.*; rH&G<o&,  
#~^btL'dHF  
$;2)s}ci  
public class FileAccessI implements Serializable{ o(*F])d
;  
"O*x' XhN  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |; $Bb866/  
RandomAccessFile oSavedFile; J$Fnm\  
long nPos; c<wavvfUo  
P;vxT}1  
e+'%!w"B  
public FileAccessI() throws IOException Z%}4bJ  
{ B0d%c&N${  
this("",0); G@gh#[b  
} jd 1jG2=f  
%j7:tf=  
O:Va&Cyj*  
public FileAccessI(String sName,long nPos) throws IOException I"@p aLZ  
{ q"akrI38  
oSavedFile = new RandomAccessFile(sName,"rw"); ['cz;2{:W  
this.nPos = nPos; 4KXc~eF[M"  
oSavedFile.seek(nPos); XphE loL  
} !:WW  
IG< H"tQ  
J8?2R^;{  
public synchronized int write(byte[] b,int nStart,int nLen) n9%]-s\Hn  
{ 5t\HJ`C1Z  
int n = -1; u%u&F^y  
try{ 1<.5ub*i4  
oSavedFile.write(b,nStart,nLen); RRADg^}l|"  
n = nLen; TBCp L]QT  
} w(U:U-MNe  
catch(IOException e) ESTM$k}X  
{ }7ehF6  
e.printStackTrace (); zI^]esX!2_  
} kA4@`YCl  
,2L$G&?  
X32C}4-B  
return n; +r]zs
^'  
} {tw+#}T a  
\'Ssn(s  
wN97_Y=`n  
}  fRB5U'  
+m)q%I>  
&]F3#^!^  
/* @MiH(.Dq  
**SiteInfoBean.java dRW$T5dac  
*/ nv0#~UgE#a  
package NetFox; l30Y8t~d  
Qd]we$G  
UMU2^$\iS  
public class SiteInfoBean { :ofBzTNwZ  
?A?F.n`  
=Mj0:rW  
private String sSiteURL; //Site's URL =dZHYO^
Cv  
private String sFilePath; //Saved File's Path ***a2Z/(  
private String sFileName; //Saved File's Name IXpc,l `  
private int nSplitter; //Count of Splited Downloading File jq-l5})h  
eF~dQ4RZ  
;W]\rft[  
public SiteInfoBean() +lE90y  
{//nSplitter的缺省值为5 *$,:m  
//default value of nSplitter is 5 m&*JMA;^  
this("","","",5); :"Y*<=x#2  
} I|9 SiZ0  
~g6 3qs  
g^7MM
lY%  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) o*5U:'=5}  
{
`JB?c  
sSiteURL= sURL; q_V0+
qH  
sFilePath = sPath; PLX>-7@  
sFileName = sName; =-"c*^$]  
this.nSplitter = nSpiltter; n
hT-Ido  
jQ\zGJ3  
M}O}:1Par  
} wSEWwU[  
0hY{<^"Y  
`d\r;cE%lm  
public String getSSiteURL() W$0^(FH[  
{ W3H+.E  
return sSiteURL; HCWNo  
} Y}s@WJ  
[
sF(#Y:I  
G2Vv i[c  
public void setSSiteURL(String value) P 43P]M2  
{ 0[Ht_qxb  
sSiteURL = value; rx0~`cVV:  
} -' g*^  
au7.4ln>Y  
v&a4^s  
public String getSFilePath() W,XTF  
{ up>c$jJ  
return sFilePath; asHxL!  
} :,B7-kBw  
X]%itA  
*v ?m6R=)h  
public void setSFilePath(String value) A A^{B  
{ 2ZcKK8X;7  
sFilePath = value; zK|i='XSf  
} PjKECN  
^r6!l.  
;&V s4  
public String getSFileName() >J9oH=S6  
{ }%7NF*  
return sFileName; #Tw@wfaq)  
} c;?fMX  
f>`dF?^6  
1y#D?R=E  
public void setSFileName(String value) 3cdTed-MIh  
{ $5x ,6[&  
sFileName = value; eI45PMP  
} rf~Y
6U?7  
8N&+7FK  
21hv%CF\9  
public int getNSplitter() ^9Qy/Er'  
{ =X\^J  
return nSplitter; GZI`jS"lU  
} >NYW{(j  
s\!>"J bAQ  
3?2 FP|G8  
public void setNSplitter(int nCount) oND@:>QBF
 
{ `F<jLU^3  
nSplitter = nCount; Guz"wY  
} KlRr8G!Z  
} h/?l4iR*  
;X*cCb`h  
/ 0 O=(  
/* '3zc|eJt&  
**Utility.java (hiyNMC
  
*/ <sK4#!K  
package NetFox; >leU:7  
4=<tWa|@9  
1`ayc|9BR  
public class Utility { 'AN>`\mR$  
=[b)1FUp  
RuII!
}*  
public Utility() /1Ue?)g  
{ ck?YI]q|  
dXF^(y]l  
p w8 s8?  
} `tP7ncky  
_S>JKz  
//线程睡眠 I(S`j[U  
public static void sleep(int nSecond) '>r7V  
{ EoK~S\dS  
try{ '!/<P"5t  
Thread.sleep(nSecond); KQB
3m"  
} 0c}  }Q  
catch(Exception e) y
KO`rtP  
{ +
$g}4  
e.printStackTrace (); %CK^Si%+  
} ^fZ&QK  
} (sh)TBb5  
?@E!u|]K  
//日志 E?_Z`*h  
public static void log(String sMsg) PLK3v4kVM!  
{ dqN5]Sb2B  
System.err.println(sMsg); RzWXKBI\E]  
} 0#nPbe,Lj  
YW7b)uYf  
>0"+4<72  
public static void log(int sMsg) T}8Y6N<\m  
{ C=eF.FB;'  
System.err.println(sMsg); I:mr}mv=i  
} C.FI~Z  
} ."9];)2rx  
B)0i:"q  
U&?v:&c#&n  
/* w@{=nD4p  
**TestMethod.java =3L;Z[^9  
*/ x QIq^/F0  
package NetFox; @)fd}tV  
ouuuc9x]  
J:Qa5MTWp  
public class TestMethod { 
Z'\h  
cXKjrL[b  
p,eTY[k?  
public TestMethod() Ft&]7dT{W  
{ ///xx/weblogic60b2_win.exe `\}v#2VJ
  
try{ ))"6ern  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [n:<8ho  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); zx)z/
1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +mn,F};  
fileFetch.start(); Le\?+h42>  
} PpAu!2lt9  
catch(Exception e){e.printStackTrace ();} "hsb8-  
<i&_ooX  
@0/+_2MH-  
} P
K`D8)=u  
t+!$[K0/  
hpD!2 K3>  
public static void main(String[] args) 'h,VR=e<  
{ NA~V
g8  
new TestMethod(); "$YJX1u3  
} [D\k^h  
} ]GW]dM  
点击下载更多相关资料