http断点续传简单实现（java)

/* S<88>|&n]  
**SiteFileFetch.java
G:c)e,pD  
*/ hKQT,  
package NetFox; Z)62/`C)  
import java.io.*; x?va26FV  
import java.net.*; bH3-#mw5w  
?%;7k'0"  
%Ni)^   
public class SiteFileFetch extends Thread { i?qS8h{  
9d#-;qV  
HR\yJt  
SiteInfoBean siteInfoBean = null; //文件信息Bean < I8hy$+6  
long[] nStartPos; //开始位置 {/XzIOO;b  
long[] nEndPos; //结束位置 p!|Wp  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 >Ah [uM  
long nFileLength; //文件长度 Eae]s8ek9  
boolean bFirst = true; //是否第一次取文件 N=zrY`Vd  
boolean bStop = false; //停止标志 3)atqM)i  
File tmpFile; //文件下载的临时信息 %:N5k+}  
DataOutputStream output; //输出到文件的输出流 L:XnW1(Or  
oSx]wZZ  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） _9Iz'-LgB  
public SiteFileFetch(SiteInfoBean bean) throws IOException BNQ~O^R0  
{ &=<x&4H+  
siteInfoBean = bean; (gvaYKvr  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); eMPi ho  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); xo6-Y=c8  
if(tmpFile.exists ()) Iy8Ehwejd  
{ \uQ(-ji  
bFirst = false; B3c rms['  
read_nPos(); Cbx/  
} *S:^3{.m=  
else ;pBSGr9  
{ ,kpkXK  
nStartPos = new long[bean.getNSplitter()]; Zh{Pzyp  
nEndPos = new long[bean.getNSplitter()]; yJppPIW^  
} dE
.R$SM  
flVQG@  

p#qQGJe  

#=OKY@z/  
} :nCGqg  
xl5mI~n_~  
+]Po!bN@@  
public void run() ht!o_0{~  
{ a+uSCs[C  
//获得文件长度 ",w@_}z:  
//分割文件 ['tGc{4  
//实例FileSplitterFetch 7xMvf<1P  
//启动FileSplitterFetch线程 g.SFl  
//等待子线程返回 (}V.xi  
try{ '.c[7zL  
if(bFirst) Ldf<  
{ :+bQ
PzL  
nFileLength = getFileSize(); F7Mf>."  
if(nFileLength == -1) :~~}|Eu  
{ c/^} =t(  
System.err.println("File Length is not known!"); #i%it  
} Kxn/@@z>u  
else if(nFileLength == -2) |bQKymS  
{ O B_g:T  
System.err.println("File is not access!"); Xg^`fRg =T  
} jdK~]eld=  
else )c^Rc9e/  
{ 8uP,#D<wZ  
for(int i=0;i<nStartPos.length;i++) GXr9J rs.e  
{ K#%L6=t$<  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); :p;!\4)u  
} Ew*_@hVC  
for(int i=0;i<nEndPos.length-1;i++) $k,Z)2  
{ Ckj2$c~  
nEndPos = nStartPos[i+1]; g1@zk$  
} Q]S~H+eRy  
nEndPos[nEndPos.length-1] = nFileLength; l<ag\ d  
} 2RFYnDN  
} y
lUxK{  
fFMGpibkM  
-Ds}kdxw  
//启动子线程 ['~3"lK^O  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; =kp#v  
for(int i=0;i<nStartPos.length;i++) B:\\aOEj  
{ Pv17wUB  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~pO6C*"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), yH|[K=?S[  
nStartPos,nEndPos,i); A5S9F8Q/]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (+`pEDD{X  
fileSplitterFetch.start(); %YkJA:  
} {pH{SRM)B  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /x c<&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); oM G8?p  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", R9A8)dDz  
nEndPos = " + nFileLength); ]i(tou-[i  
// fileSplitterFetch[nPos.length-1].start(); '-oS=OrZ  
:.e`w#$7  
|]1-ck!  
//等待子线程结束 ]P;uQ!  
//int count = 0; |_
"JyGR2  
//是否结束while循环 >v7fR<(%s  
boolean breakWhile = false; 5^<X:1J$  
EiQX*v  
9utiev~
3  
while(!bStop) ![h+R@_(  
{ pM],-7UM  
write_nPos(); 'r~,~AI  
Utility.sleep(500); IFcxyp  
breakWhile = true; jfP2n5X83  
\3JZ=/  
m\o<a|  
for(int i=0;i<nStartPos.length;i++) %X7R_>.   
{ 
Y~gDS^8  
if(!fileSplitterFetch.bDownOver) d[E~}Dq3#  
{ }Qyuy~-&^  
breakWhile = false; ~P8 6=Vw  
break; ^,*ED Yz  
} `Fnl<C<  
} t2skg
  
if(breakWhile)
!~Gx@Ro  
break; :)o 4fOJ8  
O=~8+sa  
ZKy)
F-yX  
//count++; s~ ||Vv!  
//if(count>4) nr7#}pzo  
// siteStop(); Yv<'QC  
} ]L+YnZ?6  
PP)iw@9j  
RfH.WXi  
System.err.println("文件下载结束！"); ~QgyhJM_h=  
} TRP#b 7nC  
catch(Exception e){e.printStackTrace ();} q.0Evr:  
} !~Vo'ykwx'  
4<}!+X7m  
> %h7)}U  
//获得文件长度 % `Q
[?(z  
public long getFileSize() c%y(Z5  
{ iO1ir+B\  
int nFileLength = -1; ;;e\"%}@=q  
try{ \d"JYym  
URL url = new URL(siteInfoBean.getSSiteURL()); h1}U#XV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); R=&9M4  
httpConnection.setRequestProperty("User-Agent","NetFox"); p7et>;WRx  
=1Nz*
c  
aF*KY<w  
int responseCode=httpConnection.getResponseCode(); sB!#`kh  
if(responseCode>=400) L7i2is  
{ ;iT@41)
7  
processErrorCode(responseCode); v:\8  
return -2; //-2 represent access is error ffoL]u\  
} <A|X4;  
YnM&t ;TX  
w-iu/|}  
String sHeader; < z':_,  
V"Cx5#\7C  
I(^pIe-  
for(int i=1;;i++) {1?94rz  
{ U*sjv6*T  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); w`BY>Xft0
 
//Utility.log(in.readLine()); Kny0 (  
sHeader=httpConnection.getHeaderFieldKey(i); eTg8I/)%B  
if(sHeader!=null) MWdev.m:Z  
{ L& =a(  
if(sHeader.equals("Content-Length")) }9:(l  
{ d}D%%noIu  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \Ui3=8(
 
break; k;5$]^x  
} 42/MBP`
\Y  
} *vy^=Yea  
else O
v$>CA  
break; |Gp!#D0b
  
} L`'#}#O l  
} OBb m?`[  
catch(IOException e){e.printStackTrace ();} z<_&4)2{  
catch(Exception e){e.printStackTrace ();} s;brs}  
nm"]q`(K  
uu7 ?,WT  
Utility.log(nFileLength); q+iG:B/Z  
wnioIpRkh  
B":9C'tip  
return nFileLength; 26M:D&|ZB  
} aE|'%72g  
TxJoN]Z.  
1`hmD1d  
//保存下载信息（文件指针位置） oX=dJJE  
private void write_nPos() v~8CpC  
{ 8F>u6Y[P  
try{
(Q5rOrA"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9sP;s^#t7U  
output.writeInt(nStartPos.length); j_I[k8z  
for(int i=0;i<nStartPos.length;i++) In[rxT~K}Q  
{ BiY-u/bH9a  
// output.writeLong(nPos); dU}Cb?]7s  
output.writeLong(fileSplitterFetch.nStartPos); m+UWvUB)  
output.writeLong(fileSplitterFetch.nEndPos); G2$<Q+UYs?  
} YD3jP}Ym  
output.close(); yj$$k~@  
} "Jahc.I  
catch(IOException e){e.printStackTrace ();} 2LfiaHO  
catch(Exception e){e.printStackTrace ();} z`"*60b  
} jgvzp  
SND@#?hiO  
@V?T'@W7D  
//读取保存的下载信息（文件指针位置） Vu`5/QDq  
private void read_nPos() gmUXh;aHc  
{ A%[e<vj9  
try{ M)F_$ ICE-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); c,2OICj  
int nCount = input.readInt(); tJG+k)EE  
nStartPos = new long[nCount]; g6 H}a  
nEndPos = new long[nCount]; mjQZ"h0  
for(int i=0;i<nStartPos.length;i++) 3S5`I9I  
{ ! k[JP+;  
nStartPos = input.readLong(); *{_N*p\{  
nEndPos = input.readLong(); ^h$^j  
} [vGkr" =  
input.close(); O~Jm<  
} u^O!5 'D%  
catch(IOException e){e.printStackTrace ();} X-=4Z
9  
catch(Exception e){e.printStackTrace ();} 3F?7oMNIh  
} 0BwxPD#6bv  
p4F%FS:`  
xH\!j  
private void processErrorCode(int nErrorCode) eJ*u]GH U  
{ KuRJo]  
System.err.println("Error Code : " + nErrorCode); /78zs-  
} ;J@U){R  
XS}-@5TI  
216`rQ}z  
//停止文件下载 2Z-[x9t  
public void siteStop() "MvSF1  
{ nt]'>eX_}  
bStop = true; DPlDuUOd  
for(int i=0;i<nStartPos.length;i++) jY2mn".N  
fileSplitterFetch.splitterStop(); {#.<hPXn  
i]#"@xQ  
Kv9$c(~#  
} 3P
jX;U|  
} "{S6iH)]8  
//负责部分文件的抓取 \#h{bnx  
**FileSplitterFetch.java s TVX/Q  
*/ ew \WV"  
package NetFox; 0HO'%'Ga*  
EI9;J-c  
x8xz33  
import java.io.*; <NEz{1Z  
import java.net.*; 85f:!p  
LOgFi%!6:  
d5>
EvK U  
public class FileSplitterFetch extends Thread { t~H0Qeb[v=  
'3w%K+eJY  
5hHLC7tT9  
String sURL; //File URL 3ey.r%n  
long nStartPos; //File Snippet Start Position cL<,]%SkE  
long nEndPos; //File Snippet End Position X }`
o9]y  
int nThreadID; //Thread's ID xnC:?d  
boolean bDownOver = false; //Downing is over @Di!~e6  
boolean bStop = false; //Stop identical Pl. y9g~  
FileAccessI fileAccessI = null; //File Access interface qSDn0^y  
V'tqsKQ
!  
q;lR|NOh  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (rc7Cp3  
{ W}y)vrL  
this.sURL = sURL; c1q;  
this.nStartPos = nStart; Gshy$'_e  
this.nEndPos = nEnd; '6kD6o_p1  
nThreadID = id; Rt5,/Q0  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 i)]f0F  
} P(s:+  
[dR#!"6t  
id588
Y78  
public void run() ]%ewxF  
{ @M OaXe  
while(nStartPos < nEndPos && !bStop) 0~z`>#W,  
{ d-
C%R9  
;[79Ewd#$  
-dWg1`;  
try{ d
iNAT`|?#  
URL url = new URL(sURL); .p]rS =#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Dpwqg3,  
httpConnection.setRequestProperty("User-Agent","NetFox"); #K`0b$
  
String sProperty = "bytes="+nStartPos+"-"; 0K6My4d{  
httpConnection.setRequestProperty("RANGE",sProperty); r7sA;Y\  
Utility.log(sProperty); Q_Br{ `c  
M KX+'p\w  
LzJ`@0RrX  
InputStream input = httpConnection.getInputStream(); sq;!5qK  
//logResponseHead(httpConnection); S[gACEZ =  
3~Lsa"/  
c5|sda{  
byte[] b = new byte[1024]; |g>
Q3E  
int nRead; )+"5($~  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) aM xd"cTzx  
{ ?K;l 5$?%  
nStartPos += fileAccessI.write(b,0,nRead); jU kxA7 }}  
//if(nThreadID == 1) Yg?BcY\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); tUuARo7
#  
} ${E^OE  
A|,qjiEJCc  
+~BP~  
Utility.log("Thread " + nThreadID + " is over!"); 7x=4P|(\}  
bDownOver = true; @)x*62r+
 
//nPos = fileAccessI.write (b,0,nRead); ,a?oGi  
} 3;FV^V'  
catch(Exception e){e.printStackTrace ();} Fc80HK5R  
} dF09_nw  
} J2 /19'QE  
BG8/  
E]8uj8K3]  
//打印回应的头信息 ZW9OPwV  
public void logResponseHead(HttpURLConnection con) K@JaN/OM  
{ ahIDKvJ4  
for(int i=1;;i++) ij|>hQC5i  
{ w[D]\>QHa  
String header=con.getHeaderFieldKey(i); p!~1~q
6  
if(header!=null) R8:5N3Fx  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); j
V9oTH-  
Utility.log(header+" : "+con.getHeaderField(header)); ,v 2^Ui  
else %.D!J",\/K  
break; /D1Lh_,2  
} /Wcx%P  
} n*Dn{ 7v#z  
'l`prp3  
L&y"oAp<  
public void splitterStop() &PH:J*?C}  
{ DRR)mQBb  
bStop = true; n((A:b  
} 6D[
]Jf,9  
FF#+d~$z  
RjH68=n  
} dWQB1Y*N  
!V(r p80  
s*_fRf:  
/* dHTx^1  
**FileAccess.java -Ci&h  
*//文件访问(定位，写) ^iBIp
#  
package NetFox; fN&uat7  
import java.io.*; ~bm'i%$k  
TTFs|T6`q  
5y 5Dn!`  
public class FileAccessI implements Serializable{ Rzh.zvxTp  
\v6lcA
L-  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 i\l}M]Z#  
RandomAccessFile oSavedFile; $i6z)]rjg  
long nPos; r#2Fk&Z9  
Z~QLjv&$/r  
xp'Q>%v  
public FileAccessI() throws IOException .4U*.Rf  
{ x~R,rb   
this("",0); I#M>b:"te  
} 09anQHa  
!H)-  
nw%9Qw  
public FileAccessI(String sName,long nPos) throws IOException p/RT*?<   
{ OA=~i/n~  
oSavedFile = new RandomAccessFile(sName,"rw"); })P!7t  
this.nPos = nPos; )gSqO{Z  
oSavedFile.seek(nPos); !`RMXUV  
} V" 8 G-dK  
&Jb\}c}  
dr}PjwW%  
public synchronized int write(byte[] b,int nStart,int nLen) PZJ9f8V  
{ #=S^i[K/  
int n = -1; ;*t#:U*  
try{
-y$6gCRY  
oSavedFile.write(b,nStart,nLen); ls&H oJ7  
n = nLen; {QylNC
9  
} ~CkOiWC0  
catch(IOException e) :>;F4gGVG  
{ r~h#  
e.printStackTrace (); K)!^NT  
} +)WU:aKI  
JffaT_"\  
{4,],0bjx/  
return n; w(aHB8T  
} ;s{'cN[.  
d?J&mLQ6  
;>jEeIlT  
} o h\$u5  
%+Ze$c}X  
Iq4B%xo6G  
/* ltDohm?  
**SiteInfoBean.java \>Rfa+  
*/ [%^sl>,7  
package NetFox; uOeal^uS  
p> >H$t  
tkcs6uy  
public class SiteInfoBean { oC49c~`8  
 jF0"AA  
M1xsGa9h&  
private String sSiteURL; //Site's URL `MuX/[q  
private String sFilePath; //Saved File's Path 65qqs|&w;[  
private String sFileName; //Saved File's Name _Iav2=0Wi  
private int nSplitter; //Count of Splited Downloading File >FwK_Zd'  
|r Aot2  
zA>X+JH>iw  
public SiteInfoBean() !pw)sO~  
{//nSplitter的缺省值为5 Vi-Ph;6[  
//default value of nSplitter is 5 f+uyO7  
this("","","",5); F
c5t,P  
} 8\{z>y  
dB[4NT  
(~zu4^9w  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) )V2W:M  
{ #8"oqqYi  
sSiteURL= sURL; X1`3KqK<9  
sFilePath = sPath; X:g5;NT  
sFileName = sName; yiC7)=  
this.nSplitter = nSpiltter; .cQO?UKK  
r5S/lp+Y+N  
FUI*nkZY  
} k Alxm{  
I{g.V|+x  
|_TI/i>?'  
public String getSSiteURL() 'Tjvq%ks
 
{ Ld}?daPj  
return sSiteURL; Fb]+h)on  
} S \]O8#OX  
3PU_STSix  
/"?DOsJ.  
public void setSSiteURL(String value) >bf.T7wy  
{ mW%8`$rVEO  
sSiteURL = value; F6[F~^9D  
} uW!XzX['  
zFExYYd   
Ph[MXb:*  
public String getSFilePath() D/."0 #q  
{ vnvpb! @Q  
return sFilePath; .5G`Y  
} jjj<B
'zt  
;(/go\m tB  
:IS?si5|  
public void setSFilePath(String value) p lnH  
{ +mVAmG@  
sFilePath = value; ~#3{5* M  
} b`#YJpA  
,7&\jET5^0  
(V6bX]<  
public String getSFileName() H u;"TG  
{ G9Uc }z  
return sFileName; Z\CvaX  
} Ie. on)  
<C'_:&M  
/"gRyv  
public void setSFileName(String value)  80@\e  
{ /#Aw7F$Ey  
sFileName = value; ~TRC-H  
} uH9Vj<E$K  
O0qG 6a  
[G|.  
public int getNSplitter() ``WTg4C(Y  
{ I </P_:4G  
return nSplitter; f $Agcy  
} "i;.>  
xO )c23Z)]  
4<#ItQ(  
public void setNSplitter(int nCount)  9BtGzI\  
{ b}R_@_<u  
nSplitter = nCount; 8{G!OBxc\.  
} N^rpPq  
} OX;(Mg|  
.pUB.l$)  
lw9jk`7^  
/* Z
xnPSA@%  
**Utility.java 'lZlfS:Z8  
*/ -iDs:J4Iq  
package NetFox; p2gdAJ  
N# }w1]  
_k2R^/9Ct%  
public class Utility { $?PI>9g!  
?l9sj]^w  
XZ |L D#  
public Utility() :.+w'SEn4M  
{ {:gx*4}q8  
HqWWWCWal  
6m;>R%S_  
} *m"9F'(Sd  
9xK>fM&u  
//线程睡眠 b\(f
>
g[  
public static void sleep(int nSecond)
PuP"( M  
{ `nyz,  
try{ .4CDQ&B0K  
Thread.sleep(nSecond); }gv'r ";  
} 7p.8{zQ*  
catch(Exception e) !.j{vvQ/  
{ Z{^!z  
e.printStackTrace (); ]20:8l'  
} *LB-V%{|'  
} S5hc@^|0Z  
arm_SyL0  
//日志 K]m#~J3d>  
public static void log(String sMsg) n{4iW_/D  
{ zq</(5H  
System.err.println(sMsg); ]"T157F  
} K:U=Y$x  
b;QgL_w  
8`*5[ L~~/  
public static void log(int sMsg) $Lstq_x+  
{ ejV`W7U  
System.err.println(sMsg); 0cHcBxdF  
} Eg`~mE+a  
} M$EF 8  
UmVn:a  
N9/k`ZGC  
/* F7=9> ,  
**TestMethod.java vX }iA|`#  
*/ ^`yhN  
package NetFox; @sn:%/x_  
"Y+VNS  
%DiQTg7V,  
public class TestMethod { i 7]o[  
AJ/Hw>>$?m  
4xW~@meNB  
public TestMethod() _K9PA[m5~  
{ ///xx/weblogic60b2_win.exe 3J"`mQ  
try{ uN<=v&]q  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); (>0`e8v!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); HHx:s2G  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^ZsIQ4@`  
fileFetch.start(); k$%{w\?Jf  
} [1(eSH  
catch(Exception e){e.printStackTrace ();} ti+e U$  
c
Y!Y?O  
m%J?5rR3  
} aZ~e;}w.Zq  
rwDLBpk  
N#M>2b<A/T  
public static void main(String[] args) EN`JzLjP  
{ Mt4]\pMUb  
new TestMethod(); HCOsVTl,  
} =~O3j:<6  
} "T5jz#H#/  
点击下载更多相关资料