http断点续传简单实现（java)

/* `y; s1nL  
**SiteFileFetch.java ~d :Z|8  
*/ F gM<2$h  
package NetFox;  6RV]9  
import java.io.*; o0b}:`  
import java.net.*; [H5TtsQ[  
"$KU+?  
cQ~}qE>I  
public class SiteFileFetch extends Thread { W-:gU!{*#  
oR>o/$z$)g  
[Q&{#%M  
SiteInfoBean siteInfoBean = null; //文件信息Bean B#'TF?HUEn  
long[] nStartPos; //开始位置 K^bzZa+a  
long[] nEndPos; //结束位置 JX,&im*BG  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 gNJ,Bj Pd  
long nFileLength; //文件长度 :SilQm*Pl  
boolean bFirst = true; //是否第一次取文件 _Z'j%/-4@D  
boolean bStop = false; //停止标志 Hzs]\%"  
File tmpFile; //文件下载的临时信息 vdrV)^  
DataOutputStream output; //输出到文件的输出流 /Fej)WQp  
^'Wkb7L  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） A2VN%dB  
public SiteFileFetch(SiteInfoBean bean) throws IOException +v:t  
{ Xxcv5.ug  
siteInfoBean = bean; n.]K"$230  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); `An`"$z  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); i,NU%be  
if(tmpFile.exists ()) 1UX"iOx(  
{ y6ntGrZ}$  
bFirst = false; Dk4Jg++  
read_nPos(); f^il|Obzl  
} ]YQ[ )  
else p_S8m|%  
{ hW[/{2<@  
nStartPos = new long[bean.getNSplitter()]; WbC|2!
 
nEndPos = new long[bean.getNSplitter()]; mMm_=cfv  
} '"LrGvkZ  
dABmK;  
R'f|1mt  
#4"(M9kf  
} 2C^/;z  
M7{w7}B0@  
{LfVV5
?  
public void run() mDz{8N9<FG  
{ 'F3Xb  
//获得文件长度 k"F5'Od  
//分割文件 YIo$  
//实例FileSplitterFetch d)F~)}TFM  
//启动FileSplitterFetch线程 V.5gxr3QqW  
//等待子线程返回 kx8\]'  
try{ @G< J+pm  
if(bFirst) IFNs)*  
{ /n;-f%dL  
nFileLength = getFileSize(); tr0P;}=  
if(nFileLength == -1) ,R/HT@  
{
n[ip'*2L  
System.err.println("File Length is not known!"); _]8FCO  
} ?}"$[6.  
else if(nFileLength == -2) :GXiA  
{ "mc
/fp  
System.err.println("File is not access!"); y?j#;n0  
} e9/:q"*)/  
else aP^,@RrL  
{ Y`jvza%  
for(int i=0;i<nStartPos.length;i++) 0A\OZ^P8  
{ >2tQ')%DJ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 4E]w4BG)  
} UN#XP$utY  
for(int i=0;i<nEndPos.length-1;i++) NNSHA'F,.\  
{ wYy=Tl-N  
nEndPos = nStartPos[i+1]; k4jZu?\C]  
} !'uL  
nEndPos[nEndPos.length-1] = nFileLength; eS(\E0%QI  
} gV@FT|j!i  
} Yl%1e|WV  
`s93P^%  
mn;
;wp  
//启动子线程 9I>qD  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %PozxF:  
for(int i=0;i<nStartPos.length;i++) |}N -5U  
{ vgY ) L  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9TRS#iVL+*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), l"^'uGB'  
nStartPos,nEndPos,i); S]&f+g}&w  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^
=:e9i3u  
fileSplitterFetch.start(); 7(cRm$)L  
} L+,p#w  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Bfe#,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ~t7?5b?*\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Zp@j*P  
nEndPos = " + nFileLength); R:c$f(aKv%  
// fileSplitterFetch[nPos.length-1].start(); 3V~871:-~  
e;L++D
 
5(RFkZn4[  
//等待子线程结束 C(-wA  
//int count = 0; y%%D="  
//是否结束while循环 0Oy.&C T  
boolean breakWhile = false; }jHS  
CT5\8C  
KMC]<  
while(!bStop) lz2B,#  
{ o2M+=O@  
write_nPos(); u#(VR]u\7  
Utility.sleep(500); MLwh&I9)  
breakWhile = true; iUDNm|e  
_9yb5_  
t;005]'Mp  
for(int i=0;i<nStartPos.length;i++) n N.6?a  
{ q.sErr[zc  
if(!fileSplitterFetch.bDownOver) >h:rYEsh8V  
{ y4sKe:@2  
breakWhile = false; x!5b"  "  
break; l;{
n"F  
} SSG57N-T  
} S -$ L2N  
if(breakWhile) ED0\k $  
break; `
pr$l  
;75m 9yGo  
g7\MFertR^  
//count++; L#U-dzy\  
//if(count>4) qe. Qjq  
// siteStop(); co!o+jP  
} r'bctFsD  
0 D^d-R,  

0"l*8%g  
System.err.println("文件下载结束！"); \S#Mc  
} 581Jp'cje  
catch(Exception e){e.printStackTrace ();} z[Sq7bbYO  
} Cj{+DXT  
akR+QZ,)  
F)fCj^zL  
//获得文件长度 w:[1,rRvT  
public long getFileSize() scr`] tD  
{ >ZRCM  
int nFileLength = -1; n
^}M*#  
try{ nV`n=x  
URL url = new URL(siteInfoBean.getSSiteURL()); _8zZ.~)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w3,DsEXu  
httpConnection.setRequestProperty("User-Agent","NetFox"); GJTKqr|1O  
^YVd^<cE  
,_SE!iL  
int responseCode=httpConnection.getResponseCode(); X8(H#Ef[  
if(responseCode>=400) 9gWR djK:  
{ S
^5EG;[  
processErrorCode(responseCode); :A
2{  
return -2; //-2 represent access is error |76G#K~<X  
} op!ft/Yyb  
~vL7$-:  
|[6jf!F  
String sHeader; *\gS 2[S  
Q4~/Tl;  
o`tOnwt
  
for(int i=1;;i++) 7E0L-E=.  
{ %P3|#0yg0  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); UQX.  
//Utility.log(in.readLine()); FJI%+$]  
sHeader=httpConnection.getHeaderFieldKey(i); tr[(,kX  
if(sHeader!=null) fRcs@yZnS  
{ FCr^D$_w  
if(sHeader.equals("Content-Length")) K[,d9j`^  
{  F,hiKq*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); QaVxP1V#U  
break; kdq<)>"  
} v d{`*|x  
} hq[:U?!Tt  
else ! .q,m>?+  
break; W't?aj I|  
}
N<d0C  
} N}|<P[LW  
catch(IOException e){e.printStackTrace ();} r%:Q(|v?  
catch(Exception e){e.printStackTrace ();} \zx &5a #  
y3Z\ Y[  

4+tKg*|  
Utility.log(nFileLength); i(Xz3L#(  
MbT;]Bo  
B,xohT  
return nFileLength; >$/<~j]  
} 5YV3pFz$)  
Bd++G'FZ  
sxK|0i}6  
//保存下载信息（文件指针位置） s^&Oh*SP*  
private void write_nPos() qj.>4d  
{ ^Rpy5/d  
try{ x$SxGc~4gb  
output = new DataOutputStream(new FileOutputStream(tmpFile)); n%Rl$  
output.writeInt(nStartPos.length); 8h?):e  
for(int i=0;i<nStartPos.length;i++) Yl$R$u)  
{ xs}3=&c(  
// output.writeLong(nPos); hvFXYq_[O  
output.writeLong(fileSplitterFetch.nStartPos); Z[Z3x6 6  
output.writeLong(fileSplitterFetch.nEndPos); ^ UDNp.6k  
}  %"jp':  
output.close(); 15l{gbCW  
} mVs<XnA47  
catch(IOException e){e.printStackTrace ();} :>q*#vlb  
catch(Exception e){e.printStackTrace ();} i"_@iN0N  
} f, iHM  
~+)sL1lx  
yKhN1kY  
//读取保存的下载信息（文件指针位置） m~f J_  
private void read_nPos() ]?<=DHn  
{ =i1+t"
=  
try{ L|`(u  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); xb (Cd  
int nCount = input.readInt(); w=Yc(Y:h  
nStartPos = new long[nCount]; uD0<|At/  
nEndPos = new long[nCount]; %7wNS  
for(int i=0;i<nStartPos.length;i++) \i.Yhl:O  
{ /\wm/Yx?S  
nStartPos = input.readLong(); +EOd9.X\~  
nEndPos = input.readLong(); 3 q^^Os  
}  %>z)Q  
input.close(); +oRBSAg-  
} <tn6=IV  
catch(IOException e){e.printStackTrace ();} +M{A4nYY|1  
catch(Exception e){e.printStackTrace ();} #wS/QrRE  
} (/[wM>q:r  
+?%LX4Y  
;!9-I%e  
private void processErrorCode(int nErrorCode) z#u<]] 5  
{ 3*C|"|lJ  
System.err.println("Error Code : " + nErrorCode); LDgGVl  
} )OE!vA  
-V
afN   
g5
[r!XO  
//停止文件下载 9k*1_  
public void siteStop() 6!A+$"  
{ s;Sv@=\  
bStop = true; f2]O5rXp  
for(int i=0;i<nStartPos.length;i++) 3q)y;T\yW  
fileSplitterFetch.splitterStop(); /DxeG'O  
"eH.<&  
7\<}378/^  
} ,@Aeo9}  
} LEJn 1  
//负责部分文件的抓取 8-geBlCE,  
**FileSplitterFetch.java 48g`i  
*/ %<rV~9:  
package NetFox; UC*\3:>'n  
aQ#6PO7.Z  
h7 c  
import java.io.*; }pOJM&I  
import java.net.*; 'nP;IuMP  
!wr2OxK*  
jA,|.P>  
public class FileSplitterFetch extends Thread { 7T/hmVi_  
.?dYY;P  
b75en{aDi*  
String sURL; //File URL z$b'y;k  
long nStartPos; //File Snippet Start Position T(q/$p&q  
long nEndPos; //File Snippet End Position P0O=veCf  
int nThreadID; //Thread's ID 8=DZ;]XD.  
boolean bDownOver = false; //Downing is over 0~=>:^H'`q  
boolean bStop = false; //Stop identical K
lSg0s  
FileAccessI fileAccessI = null; //File Access interface *<#$B}!{  
+WfO2V.
 
=2R0 g2n  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException x2$Y"b?vz  
{ f@aFs]xV  
this.sURL = sURL; @3W
I7q4  
this.nStartPos = nStart; DEN (pA\  
this.nEndPos = nEnd; ~(Xzm  
nThreadID = id; f6U i~  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 bc%N !d  
} -XMWN$Ah  
%=<Kb\  
Ek,$XH  
public void run() Xb\de_8!  
{ D\ kd6  
while(nStartPos < nEndPos && !bStop) Og/@w&  
{ tJ9-8ZT*  
l<dtc[  
?8TIPz J  
try{ Q'R*a(pm  
URL url = new URL(sURL); wpV)y Q^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); S0jYk(  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8%#pv
}  
String sProperty = "bytes="+nStartPos+"-"; g$9EI\a  
httpConnection.setRequestProperty("RANGE",sProperty); 9Pjw<xt  
Utility.log(sProperty); XyrQJ}WR|  
/A"UV\H`f  
L)-1( e<x  
InputStream input = httpConnection.getInputStream(); Cs?[ 
 
//logResponseHead(httpConnection); 
u[+/WFH  
XTS%:S  
;^9y#muk  
byte[] b = new byte[1024]; U%H6jVE  
int nRead; zA%$l&QN]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Ers8J V  
{ 0o_wy1O1,  
nStartPos += fileAccessI.write(b,0,nRead); 7>!Rg~M  
//if(nThreadID == 1) *di}rQHm  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j@C*kj;-  
} &8M^E/#.^;  
y6`zd
B  
MVXy)9q  
Utility.log("Thread " + nThreadID + " is over!"); =VvQ2Y0h8  
bDownOver = true; 1vUW$)?X  
//nPos = fileAccessI.write (b,0,nRead); P{%R*hb]  
} fYUbr"Oe  
catch(Exception e){e.printStackTrace ();} SU>cJ*  
} -EIfuh  
} / &#b*46  
T)tf!v3v  
mz?1J4rt  
//打印回应的头信息 @8"c
T-  
public void logResponseHead(HttpURLConnection con) rUWC=?Q  
{ ]JvZ{fA%*  
for(int i=1;;i++) e%EE|  
{ o7 1f<&1  
String header=con.getHeaderFieldKey(i); Dh.pH1ZY3n  
if(header!=null) WeE1 \  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); gSt'<v  
Utility.log(header+" : "+con.getHeaderField(header)); VK3e(7b  
else 1,Ji|&Pwf  
break; :!<U"AC  
} _&}z+(Ug  
} ]B=2r^fn  
8c5%~}kG  
|jJ9dTD8/  
public void splitterStop() CN!~(1v  
{ HrH! 'bd  
bStop = true; n2;Vrs,<1&  
} 'q, L*  
-cs$E2 -  
\oy8)o/Gb  
} %hV]vm
  
v%!'vhf_K  
U2kl-E:  
/* |7@@~|A  
**FileAccess.java y.+!+4Mg|  
*//文件访问(定位，写) <g'0q*qE  
package NetFox; #Pe|}!)u  
import java.io.*; IXof-I%8  

[s&0O<Wv  
r l>e~i  
public class FileAccessI implements Serializable{ t)^18 z  
KAR **Mp+  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |rwx;+  
RandomAccessFile oSavedFile; >o|.0aw<  
long nPos;
[[' (,,r  
NNn sq@?6  
/j;HM[  
public FileAccessI() throws IOException u?lbC9}$  
{ Y:4/06I  
this("",0); iNv"!'|  
} prO
~g  
rhj_cw  
+ 3c (CTz  
public FileAccessI(String sName,long nPos) throws IOException ]y~"M  
{ 9Z lfY1=  
oSavedFile = new RandomAccessFile(sName,"rw"); _l{_n2D-  
this.nPos = nPos; \CVrLn;}  
oSavedFile.seek(nPos); 4v;KtD;M  
} 0^mCj<g  
KSxZ
4Y  
`=19iAp.  
public synchronized int write(byte[] b,int nStart,int nLen) cxc-|Xori  
{ ]3I@5}5%  
int n = -1; W
WN2  
try{ 6h{>U*N"&d  
oSavedFile.write(b,nStart,nLen); "`Y.5
.  
n = nLen; *:8,w?Nt  
} ?#Y1E~N  
catch(IOException e) NQIbav^5  
{ 3B?7h/f  
e.printStackTrace (); mt}3/d  
} /A1qTG=Br  
`[F[0fY-  
2|$G<f  
return n; \vF*n Z5/  
} %&pd`A/  
g![?P"i^t  
5m9;'SF  
} ~vB
dq Yj  
uy8mhB+]  
`P?!2\/  
/* grTwo  
**SiteInfoBean.java sPRo=LB  
*/ DH!_UV  
package NetFox; qv)%)n  
3.w &e0Es  
!n|4w$t"V  
public class SiteInfoBean { U~O*9  
H'%#71  
`Tc"a_p9t  
private String sSiteURL; //Site's URL tG*HUN?*  
private String sFilePath; //Saved File's Path Y;#H0v>E  
private String sFileName; //Saved File's Name "Zu>cbE  
private int nSplitter; //Count of Splited Downloading File rFhi:uRV  
$Qcr8~+a  
#BwOWra  
public SiteInfoBean() k FCdGl  
{//nSplitter的缺省值为5 FZx.Yuv  
//default value of nSplitter is 5 jh"YHe/X  
this("","","",5); Bj
* M W  
} iHlee=}od  
hFMT@Gy  
%:yVjb,Yf  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^ wb9n  
{ `qhZZ{s)1U  
sSiteURL= sURL; )}1S `*J/O  
sFilePath = sPath; #PQhgli  
sFileName = sName; s_cur-  
this.nSplitter = nSpiltter; |[X-i["y  
@waY+sqt=  
$Go)Zs-bL?  
} d'[]  
Zb$P`~(%  
ZG8Xr"  
public String getSSiteURL() I
\@`AU  
{ M?QX'fia  
return sSiteURL; A>%mJ3M  
} #A=ER[[  
\-CL}Z}S  
b=XHE1^rM  
public void setSSiteURL(String value) 4ZtsLMwLD  
{ fr
<V])  
sSiteURL = value; (lt{$0   
} 4rUOk"li  
-;iCe7|Twf  
Y7<
(_
p7  
public String getSFilePath() G<Y}QhFU  
{ Z4369  
return sFilePath; *{dMo,.eI  
} +^ `n- m  
`_!R;f  
b{}ao  
public void setSFilePath(String value) DVjwY_nG7  
{ PLRMW2  
sFilePath = value; fT.MglJcb  
} !7Nz_d~n  
LL+PAvMg  
HM
&"2c  
public String getSFileName() lH/7m;M  
{ mq+<2 S  
return sFileName; \{;3'<  
} @k)[p+)E  
f0+vk'Z  
]|_+lik#  
public void setSFileName(String value) +!$]a^3l  
{ Z31a4O  
sFileName = value; |>KOlwh5n  
} ,1>n8f77]  
d[oHjWk  
wicW9^ik  
public int getNSplitter() >tE6^7B*  
{ f0 kz:sZ9  
return nSplitter; ^u> fW["[  
} *M'/z=V?%  
{_UOS8j7  
^Vg-fO]V  
public void setNSplitter(int nCount) d fSj= 4  
{ +P<#6<gR  
nSplitter = nCount; fT{%zJU  
} ~L:H]_8F l  
} }!N/?A5  
8wMwS6s:  
j+("4b'  
/* BbhC0q"J  
**Utility.java yiMqe^zy  
*/ Hz j%G>  
package NetFox; 'oF XNO  
Qcn;:6_&W  
h_6c9VI  
public class Utility { -Eoq#ULvR  
* 'Bu-
1{  
TT={>R[B  
public Utility() Ll, U>yo  
{ dUv(Pu(.#  
yz=aJ v; H  
1vdG\$  
} ^O,r8K{1n  
d;i@9+  
//线程睡眠 YT6dI"48  
public static void sleep(int nSecond) EAlLxXDDh  
{ 0+/ew8~$  
try{ O=oIkvg  
Thread.sleep(nSecond); 1rON8=E  
} ~ 1~|/WG  
catch(Exception e) ZE9
.r`  
{ tac\Ki?  
e.printStackTrace (); a\}` f=T  
} 9 dK`  
} KbMan~Pb6  
Q 3/J@MC  
//日志 nH B  
public static void log(String sMsg) /@&#U bN\  
{ e xkPu-[W  
System.err.println(sMsg); D"exI]  
} }ld^zyL  
7&u$^c S(  
k"6&&  
public static void log(int sMsg) yW&ka3j
\  
{ A9MTAm{  
System.err.println(sMsg); -q\Rbb5M  
} 1x8wQ/p|  
} t%StBq(q  
tG~[E,/`  
%M:$ML6b<  
/* {C0Y8:"`  
**TestMethod.java kn/xt  
*/ 0{  
package NetFox; BN~ndWRK  
y+KAL{AGK  
kK/XYC 0D  
public class TestMethod { >`p?
CE  
:(@P *"j  
|a%Wd  
public TestMethod() F x^X(!)~]  
{ ///xx/weblogic60b2_win.exe 3O;"{E= <  
try{ Mmg~Fn  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); wD4[UU?  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $Ggnn#  
SiteFileFetch fileFetch = new SiteFileFetch(bean); _3.rPS,s  
fileFetch.start(); xsiJI1/68  
} *F!1xyg  
catch(Exception e){e.printStackTrace ();} k SgE_W)  
*eX/ZCn  
|(AFU3~  
} V7.g,  
JW)f'r_f  
J5';Hb)  
public static void main(String[] args) uP(t+}dQ+3  
{ ,HI%ym  
new TestMethod(); `5!AHQ/  
} @DF7j|]tV  
} C|h Uyo  
点击下载更多相关资料