http断点续传简单实现（java)

/* ;U}lh~e11  
**SiteFileFetch.java K-_e' )22.  
*/ ='OPU5(;O  
package NetFox;  }e9:2  
import java.io.*; )+mbR_@,O6  
import java.net.*; 5oWR}qqFK  
-jFt4Q7}8  
7=mU["raz`  
public class SiteFileFetch extends Thread { |3\ mH~Bw  
{b+!0[  
](-:l6  
SiteInfoBean siteInfoBean = null; //文件信息Bean bv$)^  
long[] nStartPos; //开始位置 vVZ@/D6w  
long[] nEndPos; //结束位置 `Nu3s<O7CF  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 K}! VY`  
long nFileLength; //文件长度 ep
,kImT  
boolean bFirst = true; //是否第一次取文件 ~++y4NB8Q  
boolean bStop = false; //停止标志 H-0A&oG  
File tmpFile; //文件下载的临时信息 ,p>=WX  
DataOutputStream output; //输出到文件的输出流 .azdAq'r&\  
Y R#_<o  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） S1;#58  
public SiteFileFetch(SiteInfoBean bean) throws IOException G4MNcy  
{ PS!f&IY}[.  
siteInfoBean = bean; :)?w2'O  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); n>Q/XQXB  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); eA#J7=eC  
if(tmpFile.exists ()) AVi w}Y J  
{ EQz`o+  
bFirst = false; &kRkOjuk  
read_nPos(); +`_%U7p(  
} O^4:4tRpt  
else Z]":xl\7  
{ y$#mk3(e~t  
nStartPos = new long[bean.getNSplitter()]; HDA!;&NRS  
nEndPos = new long[bean.getNSplitter()]; I6'U[)%  
} gn#4az3@e>  
;&^S-+  
ix$?/GlL  
# TC x8]F  
} do7 [Nj  
&D>e>]E|P  
|zGwt Z  
public void run() 70a7}C\/o  
{ "+r8izB  
//获得文件长度 7oh6G  
//分割文件 lySeq^y?Q  
//实例FileSplitterFetch b 9F=}.4  
//启动FileSplitterFetch线程 .z7F58  
//等待子线程返回 >j_,3{eJ  
try{ TR5"K{WDx  
if(bFirst) :_i1)4[!  
{ j!qO[CJJ  
nFileLength = getFileSize(); ^'*9,.ltd  
if(nFileLength == -1) 70mQ{YNN  
{ B@=+Fg DD  
System.err.println("File Length is not known!"); \O^b|0zc  
} D%Hz'G0|  
else if(nFileLength == -2) u==bLl=$  
{ ;:hyW,J  
System.err.println("File is not access!"); +JB. EW/  
} 2YdMsu~  
else <IGnWAWn  
{ /Rb`^n#  
for(int i=0;i<nStartPos.length;i++) DL_2%&k/  
{ =Qp~@k=2  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); | ?~-k[|  
} |Ah26<&  
for(int i=0;i<nEndPos.length-1;i++) tB'F`HM:mq  
{ ~aNK)<Fznd  
nEndPos = nStartPos[i+1]; '|G_C%,B  
} IFH%R>={  
nEndPos[nEndPos.length-1] = nFileLength; |k{?\(h;  
} q4|TwRx
~  
} 0:@:cz=#*  
.&TJSIx$  
nUz2~z  
//启动子线程 @]Aul9.h  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;KWR/?ec  
for(int i=0;i<nStartPos.length;i++) c&e?_@}|  
{ Ef;_im  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~ 61O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ,[D
,G  
nStartPos,nEndPos,i); ^g$k4  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Aj*0nV9_  
fileSplitterFetch.start(); W r);A{  
} -z-58FLlO  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y]0
oF_ :7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \RnGKQ"4  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -:Nowb  
nEndPos = " + nFileLength); iKu[j)F  
// fileSplitterFetch[nPos.length-1].start();
hT>h
  
5-0
  
Ge8&_7  
//等待子线程结束 /Tv=BXL-  
//int count = 0; uB>NwCL
;  
//是否结束while循环 P)XkqOGpT9  
boolean breakWhile = false; C=t:0.:PJ  
-P]J:7*0?\  
M3Q#=yy$D$  
while(!bStop) !t3)j>h:  
{ 403%~  
write_nPos(); P>z k  
Utility.sleep(500); yYkk0 3  
breakWhile = true; OziG|o
@I  
d7g/s'ZHt6  
@sO*O4os>  
for(int i=0;i<nStartPos.length;i++) \5BI!<  
{
U{q6_z|c  
if(!fileSplitterFetch.bDownOver) :CV!:sUm  
{ (9CB&LZ(+E  
breakWhile = false; '""qMRCm  
break; .;u(uB;J6  
} 43W>4fsc  
} hY7Q$B<  
if(breakWhile)  (d |  
break; $h0]  
{6!Mf+Xq  
yb2*K+Kv  
//count++; 9t(B{S  
//if(count>4) ]F r+cP  
// siteStop(); |{k;pfPV  
} !u.{<51b  
zO<EbqNe!  
$NJ]2P9L  
System.err.println("文件下载结束！"); iOm~
 
} VHsuC$3W  
catch(Exception e){e.printStackTrace ();} mDC{c ?  
} >G92k76G  
m0t5oO  
WW2VW-Hk  
//获得文件长度 4f~CG r  
public long getFileSize() 46o3F"  
{ -@b&qi7&S  
int nFileLength = -1; %;(+s7  
try{ W@GcE;#-  
URL url = new URL(siteInfoBean.getSSiteURL()); Sdz!J 1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); j0L9Q|s  
httpConnection.setRequestProperty("User-Agent","NetFox"); *YZ'Uy?  
41>Bm*if  
:Qh5ZO&G0  
int responseCode=httpConnection.getResponseCode(); NDgl
se  
if(responseCode>=400) CsS0(n(x  
{ y4$UPLm
  
processErrorCode(responseCode); _tS<\zy@y  
return -2; //-2 represent access is error KOv ar0  
} , d ?4"8_  
0PE $n  
?u` ?_us  
String sHeader; Jxi>1  
-wtavv,J  
fw ._  
for(int i=1;;i++) ~j" aJ /  
{ L;I.6<K.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); _j-k*:  
//Utility.log(in.readLine()); )fP,F(  
sHeader=httpConnection.getHeaderFieldKey(i); 8X][TJG$  
if(sHeader!=null) V=Iau_  
{ B9KY$^J  
if(sHeader.equals("Content-Length")) ?q1&(g]qO  
{ "\Jq2vM  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); VV)PSodb  
break; I! {AWfp0  
} Wxkk^J9F3  
} Qf0$Z.-  
else w~afQA>  
break; k{Vc5F  
} eft-]c+*0  
} {H#1wu^]O$  
catch(IOException e){e.printStackTrace ();} YiB]}/  
catch(Exception e){e.printStackTrace ();} Qzw~\KY:  
{6^c3R[  
C_dsYuQ5R  
Utility.log(nFileLength); ~;_]U[eOL  
GeWB"(t  
E)3B)(@&P  
return nFileLength; PvBx<i}A  
} cEnkt=  
P5*:r3>  
ZZA!Y9ia2  
//保存下载信息（文件指针位置） 4%LG9hS  
private void write_nPos() L7_(K
Ch  
{ E0$UoP   
try{ 'Sppm;?  
output = new DataOutputStream(new FileOutputStream(tmpFile)); F\Q)l+c  
output.writeInt(nStartPos.length); @/l
{  
for(int i=0;i<nStartPos.length;i++) J:dF^3Y  
{ *>V6KW  
// output.writeLong(nPos); \)eHf 7H  
output.writeLong(fileSplitterFetch.nStartPos); w5gN8ZF3  
output.writeLong(fileSplitterFetch.nEndPos); 6%H8Qv  
} ,w; ~R4x  
output.close(); VQU[5C  
} C6,GgDH`  
catch(IOException e){e.printStackTrace ();} p18-yt; 1  
catch(Exception e){e.printStackTrace ();} D-9zg\\'`  
} ?aEBS
 
'Y(#Yxc  
g
P/[=:  
//读取保存的下载信息（文件指针位置） DQP#h5O  
private void read_nPos() 2!\y0*}K  
{ [6K2V:6:  
try{ >/;\{IG Wn  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); FXV=D_G}  
int nCount = input.readInt(); GK)3a 9;  
nStartPos = new long[nCount]; lyI rO"o  
nEndPos = new long[nCount]; @^a6^*X>  
for(int i=0;i<nStartPos.length;i++) gn1`ZYg  
{ O_K@\<;~  
nStartPos = input.readLong(); {R `IA|T#k  
nEndPos = input.readLong(); /_@S*=T5  
} nL5Gr:SLo  
input.close(); *=ftg&  
} `)\_  
catch(IOException e){e.printStackTrace ();} @g9j+DcU  
catch(Exception e){e.printStackTrace ();} 2`+
?s  
} yY_G;Wk  
`~UCWK  
g-E!*K  
private void processErrorCode(int nErrorCode) }oYR.UH  
{ N[^%|  
System.err.println("Error Code : " + nErrorCode); 9Re605xQ6  
} &JAQ:([:  
bv;&oc:r  
Xx[ LK  
//停止文件下载 p|,K2^?Y  
public void siteStop() auAST;"Z8  
{ 0(|R NV_  
bStop = true; F+*>q  
for(int i=0;i<nStartPos.length;i++) )wP0U{7?v  
fileSplitterFetch.splitterStop(); }r]WB)_w  
1,`-n5@J%n  
rtvuAFiH  
} ->n<9  
} W=5+k0Q
 
//负责部分文件的抓取 JmrQDO_(  
**FileSplitterFetch.java &UP@Sr0D7  
*/ VXQS~#dQj  
package NetFox; T~s/@*y9  
l<PGUm:_  
1@yXVD/  
import java.io.*; h#zx^F1  
import java.net.*; EAF<PMb  
I|RN/RVN  
=}\]i*  
public class FileSplitterFetch extends Thread { j$T2ff6  
M~I M;my  
p
o*s  
String sURL; //File URL q?[{fcNh$  
long nStartPos; //File Snippet Start Position d%1S6eYa'  
long nEndPos; //File Snippet End Position G(JvAe]r  
int nThreadID; //Thread's ID Q}^ n  
boolean bDownOver = false; //Downing is over \-GV8A2:k  
boolean bStop = false; //Stop identical C@pDX>~2=b  
FileAccessI fileAccessI = null; //File Access interface 6NbIT[LvT  
*D
~@xypy  
Id]W
KL:  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException SjKIn-  
{ 3 C=nC  
this.sURL = sURL; fdho`juFa  
this.nStartPos = nStart; ^%M!!wlUH  
this.nEndPos = nEnd; K).X=2gjY  
nThreadID = id; VPys  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 y 97QqQ^  
} $LAaG65V  
2c5>0f  
TMKemci  
public void run() 'gUHy1p  
{ vnk"0d.  
while(nStartPos < nEndPos && !bStop) p!' "hx  
{ I-kM~q_  
U'
";  
6TfL|W<  
try{ jt"p Js'  
URL url = new URL(sURL); eWqJ2Tt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bsM`C]h&  
httpConnection.setRequestProperty("User-Agent","NetFox"); Br]VCp  
String sProperty = "bytes="+nStartPos+"-"; X_HR$il  
httpConnection.setRequestProperty("RANGE",sProperty); hz Vpv,|G  
Utility.log(sProperty); PHDKx+$  
s[n
OB0  
1:My8  
InputStream input = httpConnection.getInputStream(); cIl^5eE^Pq  
//logResponseHead(httpConnection); `!qWHm6I*  
?-#w [J'6  
j0=`Jf  
byte[] b = new byte[1024]; wa<@bub  
int nRead; )#ic"UtR  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) n.$<D
[@  
{ )K@ 20Q+0K  
nStartPos += fileAccessI.write(b,0,nRead); gD=s~DgN)  
//if(nThreadID == 1) bT[Q:#GL  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @)<uQ S  
} 5PKv@Mk  
=_%:9FnQ0  
1Na CGD"  
Utility.log("Thread " + nThreadID + " is over!"); '9au
Q(2  
bDownOver = true; t@}<&{zk  
//nPos = fileAccessI.write (b,0,nRead); *Ei~2O}  
} |YZ`CN<  
catch(Exception e){e.printStackTrace ();} QV{Nq=%]  
} <FS/'[P  
} l:+tl/  
. Nog.  
4I:Jb;k>  
//打印回应的头信息 (`3Bi]7  
public void logResponseHead(HttpURLConnection con) SwC
,=S  
{ *sAoYx  
for(int i=1;;i++) wjS3ItB  
{ l-t:7`=|  
String header=con.getHeaderFieldKey(i); &`@,mUi{Ac  
if(header!=null) !!2~lG<]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ug_zyfr  
Utility.log(header+" : "+con.getHeaderField(header)); &JfyXM[]  
else mWmDH74  
break; <+_OgF1G  
} B'
yN &3  
} )/ s9ty  
rxP^L(q0*  
5uDQ*nJ|  
public void splitterStop() S`0@fieOf  
{ jq.@<<j|$  
bStop = true; bXJ,L$q  
} C!qW:H  
xBB:b\  
gl]{mUZz}  
} c0Q`S"o+  
.]r[0U  
_ esFx  
/* aMv  
**FileAccess.java aEZl ICpU7  
*//文件访问(定位，写) Aba6/  
package NetFox; XHN?pVZ7  
import java.io.*; R#1m_6I  
Hd;>k$B  
,j&o H$mW  
public class FileAccessI implements Serializable{ !m_'<=)B4~  
HkEp}R  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 vf5[x!4  
RandomAccessFile oSavedFile; Em4TEv  
long nPos; xFg=Tyq:  
%}j/G l5  
[c>X Q  
public FileAccessI() throws IOException Onot<}K  
{ -(:BkA  
this("",0); c (\-7*En  
} OmU.9PDg-  
_BR>- :Jr  
L0+@{GP?  
public FileAccessI(String sName,long nPos) throws IOException xg3G  
{ $#t&W&  
oSavedFile = new RandomAccessFile(sName,"rw"); dr9I+c7
u  
this.nPos = nPos; l l&iMj]  
oSavedFile.seek(nPos); >S
t  
} bzUc;&WDz  
YJ
3970c/M  
T*YdGIFO  
public synchronized int write(byte[] b,int nStart,int nLen) X-n'?=  
{ "B+M5B0Z  
int n = -1; -$e\m] }Z  
try{ ig?]kZ  
oSavedFile.write(b,nStart,nLen); bZ3CJ f&mE  
n = nLen; |$1j;#h  
} (%I`EAR  
catch(IOException e) Lo;T\C
N  
{ Bb-x1{t  
e.printStackTrace (); ,{E'k
+  
} Xc Pn  
ENqJ9%sk7  
f3yZx!K_Br  
return n; {{2ZWK 6|  
} $]Fe9E?   
t$Qav>D  
i ;X'1TN(y  
} ,j5fzA  
Q^mJ_~  
/jS  
/* Cs*u{O  
**SiteInfoBean.java \UNw43EL  
*/ Dm4\Rld{  
package NetFox; 8dL(cC  
A1YIPrav(  
bZtjg  
public class SiteInfoBean { {a(YV\^y|H  
u9VJ{F  
/D~z}\k  
private String sSiteURL; //Site's URL $9hOWti  
private String sFilePath; //Saved File's Path lHP[WO  
private String sFileName; //Saved File's Name cT.1oaAM0  
private int nSplitter; //Count of Splited Downloading File 6J&L5E  
=&}dP%3LC)  
"I+wU`AIek  
public SiteInfoBean() kyY tL_SD  
{//nSplitter的缺省值为5 RYvS,hf6z  
//default value of nSplitter is 5 IClnh1=  
this("","","",5); ri
\r%x  
} lT$A;7
[  
U)c,ZxE  
ql8CgL  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) hg\$>W~2  
{ S{ *RF)  
sSiteURL= sURL; q$H'u[KQ06  
sFilePath = sPath; iLS'47  
sFileName = sName; zeR!Y yt!  
this.nSplitter = nSpiltter; w/Q'T&>b/  
gy*N)iv%  
((t8  
} BQw#PXp3  
9nd'"$  
eOLS  
public String getSSiteURL() nk6xavQji  
{ [QL)6Xr  
return sSiteURL; vT[%*)
`  
} D+"5R5J",  
\9D '7/$I,  
8|i&Gbw+  
public void setSSiteURL(String value) &WsDYov?  
{ jQ7RH/?_  
sSiteURL = value; *=r,V  
} v?Y9z!M  
1Rwk}wL  
tR2IjvmsX  
public String getSFilePath() lm@
<i4%$F  
{ ^#"!uCq]gM  
return sFilePath; <EpP;  
} (u$Q  
m2VF}% EIr  
`Jz"rh-M  
public void setSFilePath(String value) 9~>;sjJk  
{ S W  
sFilePath = value; Af*^u|#  
} u^V`Ucd"R  
vp-)$f&  
ZEHz/Y%  
public String getSFileName() 7G2TTa  
{ l} h<2  
return sFileName; YMJjO0  
} Oja)J-QXb  
2:2rwH }e  
G~YV6??  
public void setSFileName(String value) HH[?LKd<  
{ 3pq&TYQU  
sFileName = value; \!s0VEE  
} cV)C:!W2  
)/f,.Z$  
}4ta#T Ea  
public int getNSplitter() O7q-MeMM  
{ tS`fG;  
return nSplitter; w,JB`jS)/  
} eGnc6)x@C  
3LX<&."z  
9<-AukK m  
public void setNSplitter(int nCount) 875V{fvPBU  
{ xOD;pRZQ  
nSplitter = nCount; H VG'v>s@  
} nvpdu)q<  
} v)J
6}H}e  
8ae]tX5$  
`<+D<x)(3  
/* !]5F2~"v  
**Utility.java %,>> <8  
*/ 9k2HP]8=[{  
package NetFox; N.BD]_C  
g8}/Ln*W'  
aI+:rk^  
public class Utility { K3'`!Ka*  
lXL\e(ow  
Qh)@-r3  
public Utility() #).om*Xh  
{ l0[jepmpiT  
w.J2pvyB  
-\AB!#fh  
} PS(9?rX#+  
1 dI  
//线程睡眠 ma?569Z8~0  
public static void sleep(int nSecond) vF3>nN(]  
{ ZK3?"|vhC  
try{ Y( D d7`c  
Thread.sleep(nSecond); )!p=0&z@{  
} &RpQ2*4n  
catch(Exception e) L=4?vs  
{ KdYT5VUM/  
e.printStackTrace (); y|iZuHS}  
} ;z)$wH0xc  
} x\;`x$3t  
S #&HB  
//日志 M_$pqVm  
public static void log(String sMsg) LQNu]2  
{ Zdj~B1  
System.err.println(sMsg); @QVAsNW:O  
} [$9sr=3:  
{HvR24
#  
-5kq9Dy\,  
public static void log(int sMsg) sVaWg?=qs'  
{ <`*6;j.&  
System.err.println(sMsg); bHWy9-  
} <w.V!"!  
} ,t61IU3"  
j$&k;S  
9BNAj-Xa  
/* [WX+/pm7>  
**TestMethod.java 7:{4'Wr@6|  
*/ :14O=C  
package NetFox; c{rX7+bN  
zO9|s}J8q  
WO^smCk  
public class TestMethod { ./J.OU1  
Y\sLwLLlG  
J0mY=vX  
public TestMethod() w0^(jMQe^  
{ ///xx/weblogic60b2_win.exe *G>V`||RW  
try{ Q gDjc'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); PFUb\AY  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); .Eh~$wm  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 1Qhx$If~  
fileFetch.start(); JR'Q Th:z  
} \TC&/'7}  
catch(Exception e){e.printStackTrace ();} XV). cW|.a  
I2YQIY+  
zu^?9k  
} ?ti7iBz?  
}9<aX Y,  
eV1O#FLbi  
public static void main(String[] args) 06 K8|K  
{ 4#;rv$ {  
new TestMethod(); T!(I\wz;Bo  
} >OZ+k(saL  
} roj/GZAy"  
点击下载更多相关资料