http断点续传简单实现（java)

/* jK!Au  
**SiteFileFetch.java JI?rL  
*/ *}
]Nf  
package NetFox; jq-p;-i  
import java.io.*; ;Yx)tWQI  
import java.net.*; 8}c$XmCM  
?{\nf7Y  
E%+Dl=  
public class SiteFileFetch extends Thread { Ky|88~}:C9  
*'OxAfa#x  
u\E?Y[1  
SiteInfoBean siteInfoBean = null; //文件信息Bean b o0^3]Z  
long[] nStartPos; //开始位置 LUG;(Fko  
long[] nEndPos; //结束位置 Gn\_+Pj$  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Fgkajig  
long nFileLength; //文件长度 [OjF[1I)u  
boolean bFirst = true; //是否第一次取文件 ?5U2D%t  
boolean bStop = false; //停止标志 @PN#p"KaT  
File tmpFile; //文件下载的临时信息 -u&6X,Oq\u  
DataOutputStream output; //输出到文件的输出流 _wC3kAO  
?Eg(Gu.J  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） (hTCK8HK  
public SiteFileFetch(SiteInfoBean bean) throws IOException x4g3rmp  
{ \,7f6:  
siteInfoBean = bean;  :l~ I  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); <:(6EKJAq}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); dA-2%uJ  
if(tmpFile.exists ()) }XZ'v_Ti  
{ iDN;m`a  
bFirst = false; l/BLUl~z  
read_nPos(); fXXr+Mor  
} g3Ec"_>P  
else t2E
Hrji~  
{ vh"R'o  
nStartPos = new long[bean.getNSplitter()]; LG-y]4a}  
nEndPos = new long[bean.getNSplitter()]; DamCF  
} 6$fHtJD:  
m*ISa(#(,  
2]I4M[|&z  
$9]m=S  
} {SwQ[$k=_  
@'YS1N<  
@L>q(Kg  
public void run() &/mA7Vf>eR  
{ nS/)
P4z  
//获得文件长度 d1T,eJ}  
//分割文件 B,M(@5
wz  
//实例FileSplitterFetch
UV5Ie!\nm  
//启动FileSplitterFetch线程 1lq(PGX)  
//等待子线程返回 %F\?R[^5  
try{ zBo1P(kek  
if(bFirst) f_[<L  
{
q:l>O5  
nFileLength = getFileSize(); t/ +=|*  
if(nFileLength == -1) -0?~  
{ 7P"| J\  
System.err.println("File Length is not known!"); c#a@n 4  
} anI
AM  
else if(nFileLength == -2) E8>Rui@9  
{ >G);j@Q  
System.err.println("File is not access!"); g1XZ5P} f  
} zEs>b(5u  
else 3l)hyVf&  
{ aT_&x@x  
for(int i=0;i<nStartPos.length;i++) 8S>&WR%jH]  
{ ([ jF4/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); `n$I]_}/%  
} :/y1y
M  
for(int i=0;i<nEndPos.length-1;i++) z."a.>fPaO  
{ 9U{a{~b  
nEndPos = nStartPos[i+1]; D-
8O+
.@  
} %TX@I$Ba  
nEndPos[nEndPos.length-1] = nFileLength; g$HwxA9Gp/  
} .}'qUPNR  
} &F\?  
Z
Piq-q  
}xBc0gr  
//启动子线程 }tsYJlh5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; "u6`m?  
for(int i=0;i<nStartPos.length;i++) y|CP;:f;  
{ @|<<H3I  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), W
.z;B<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), lCAIK  
nStartPos,nEndPos,i); QF{4/y^j{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %{YN
70/  
fileSplitterFetch.start(); ;w'D4p= P  
} `jzTm
t  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /b]oa!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); vLR~'"`F  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", q2. XoCf  
nEndPos = " + nFileLength); ?z}=B  
// fileSplitterFetch[nPos.length-1].start(); hZh9uI7.  
^
[]}R:  
f~Fm4>\(  
//等待子线程结束 x\F,SEj  
//int count = 0; -`<kCW"  
//是否结束while循环 K#*reJ}K  
boolean breakWhile = false; !lEY=1nHOJ  
>wb'QzF:  
SGh1 DB  
while(!bStop) n3}!p'-CC  
{ Of{/t1o?  
write_nPos(); KC(xb5x Y  
Utility.sleep(500); NLS
%Sq  
breakWhile = true; b`)){LR  
m_=$0m J$  
^dP KDrKxh  
for(int i=0;i<nStartPos.length;i++) *:>"q ej  
{ mocI&=EF2X  
if(!fileSplitterFetch.bDownOver) ZN!4;  
{ _u{c4U0,  
breakWhile = false; !O-C,uSm  
break; P8^hBv*  
} {T4  
} `VKf3&|<A  
if(breakWhile) {z(xFrY  
break; bA\<.d  
_Dym{!t  
^&bRX4pYo  
//count++; 6fd+Q /  
//if(count>4) xZ|Y?R5m  
// siteStop(); GytXFL3`:  
} s:p[DEj-  
/rq VB|M  
S|apw7C  
System.err.println("文件下载结束！"); RE=`  
} P`#Z9 HM4  
catch(Exception e){e.printStackTrace ();} Q2zjZC*'%  
} A3B56K  
*H?!;u=8  
bx]N>k J  
//获得文件长度 Q-MQ9'  
public long getFileSize() X>NhZ5\  
{  1WY/6[  
int nFileLength = -1; Zm=(+ f  
try{ (>`5z(X  
URL url = new URL(siteInfoBean.getSSiteURL());  `)GrwfC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2Yp7  
httpConnection.setRequestProperty("User-Agent","NetFox"); {]E+~%Va  
e&>;*$)  
)K,F]fc+O  
int responseCode=httpConnection.getResponseCode(); H2 $GIY  
if(responseCode>=400) %Eb%V($  
{ i/~
1F_  
processErrorCode(responseCode); S}$r>[t  
return -2; //-2 represent access is error ms!ref4`+  
} e*bH0';q  
(T!9SU  
BNd^qB ?  
String sHeader; \e!vj.PU  

fO0(Z  
F1jglH/MF)  
for(int i=1;;i++) usEwm,b)  
{ ~_Lr=CD;4  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); R2(3>`FJ  
//Utility.log(in.readLine()); S,<EEtXQ  
sHeader=httpConnection.getHeaderFieldKey(i); UJfEC0  
if(sHeader!=null) YqP
Q%  
{ ;]gP@h/  
if(sHeader.equals("Content-Length")) oqLfesV~  
{ -RS7h  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); OCZ[D{i9@  
break; x9x E&  
} ZO4*sIw%  
} 5aln>1x>hn  
else
tZ`
z  
break; _~q?
_'kx  
} v^zu:Z*  
} p/U+0f  
catch(IOException e){e.printStackTrace ();} bYi`R)  
catch(Exception e){e.printStackTrace ();} 2RN)<\P  
&Y 4F!Rb  
^5A t?I8  
Utility.log(nFileLength); :WSDf VX  
DyQM>xw)t  
Wx~k&[&E  
return nFileLength; *+uHQgn(  
} 3&6#F"7  
M/):e$S  
?0YCpn  
//保存下载信息（文件指针位置） x.3J[=z=>  
private void write_nPos() lu#LCG-.  
{ wE@'ap#  
try{ )(tM/r4`c&  
output = new DataOutputStream(new FileOutputStream(tmpFile)); TQ`Rk;0R  
output.writeInt(nStartPos.length); LJOr!rWi  
for(int i=0;i<nStartPos.length;i++) UTf9S>HS  
{ {_Lgtu  
// output.writeLong(nPos); 'Hi: 2Wh  
output.writeLong(fileSplitterFetch.nStartPos); W-.pmU e2  
output.writeLong(fileSplitterFetch.nEndPos); :$_6SQ<?  
} H}H7lO  
output.close(); Nnk@h  
} mcn 2Wt  
catch(IOException e){e.printStackTrace ();}  ~BDu$  
catch(Exception e){e.printStackTrace ();} nPs7c %  
} /F4pb]U!*  
$2M#qkik-  
[74F6Qp  
//读取保存的下载信息（文件指针位置） H(Q.a=&4!p  
private void read_nPos() 7<jZ`qdq_  
{ /Nr*`l  
try{ OvUI@,Ef  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 'yV?*a  
int nCount = input.readInt(); b8%C*r7  
nStartPos = new long[nCount]; WBNw~|DO]  
nEndPos = new long[nCount]; >0dv+8Mn  
for(int i=0;i<nStartPos.length;i++) M/q E2L[y  
{ MY/3]g<  
nStartPos = input.readLong(); .[Ap=UYI>  
nEndPos = input.readLong(); +=]!P#  
} Hewd4k  
input.close(); ' j6gG  
} FJ %  
catch(IOException e){e.printStackTrace ();} _>=L>*  
catch(Exception e){e.printStackTrace ();} f{"8g"[[)(  
} 'Fs)Rx}\0  
KAsS[  
ovwQ2TuK  
private void processErrorCode(int nErrorCode) GEEW?8  
{ uA$<\fnz
  
System.err.println("Error Code : " + nErrorCode); m85WA # `  
} ?x+Z)`w_  
O/.Uh`T`6  
*dvDap|8W  
//停止文件下载 8a_[B~  
public void siteStop() xB@|LtdO9;  
{ M@3"<[g  
bStop = true; @JvPx0  
for(int i=0;i<nStartPos.length;i++) @h*fFiY&{  
fileSplitterFetch.splitterStop(); HLBkR>e  
?%VI{[y#>  
Ov#=]t5  
} jS;J:$>^  
} /s-A?lw^2  
//负责部分文件的抓取 >yXN,5d[  
**FileSplitterFetch.java 2P]L9'N{Y  
*/ CH fVQ|!\  
package NetFox; `'\t$nU  
`xz<>g9e  
/ }Rz=&  
import java.io.*; }lK3-2Pk  
import java.net.*; gJ;_$`  
Wd0[%`dq  
Yp0/Ab(v  
public class FileSplitterFetch extends Thread { %0 #XPc("  
r?CI)Y;  
0QvT
 
String sURL; //File URL ~GuMlV8  
long nStartPos; //File Snippet Start Position "+zCS|   
long nEndPos; //File Snippet End Position 4QIE8f Y  
int nThreadID; //Thread's ID *=
fr8  
boolean bDownOver = false; //Downing is over DAwqo.m  
boolean bStop = false; //Stop identical U`o^mtW.  
FileAccessI fileAccessI = null; //File Access interface MWNPPYww  
(_4;') 9  
oG7q_4+&  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException wBQF~WY  
{ * ,v|y6  
this.sURL = sURL; jqH3J2L  
this.nStartPos = nStart; `]LSbS  
this.nEndPos = nEnd; {QbvR*gv  
nThreadID = id; 4CQ"8k(S"  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 wnTV|^Q  
} lNv".Y=l  
$7QoMV8V  
zE)~0v
4  
public void run() Fb/XC:AD  
{ QI]Ih  
while(nStartPos < nEndPos && !bStop) tTN?r8  
{ 'TTUN=y  
~2d:Q6  
.[u>V  
try{ g~BoFc.V2~  
URL url = new URL(sURL); c8Q]!p+Yp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?<Y+peu  
httpConnection.setRequestProperty("User-Agent","NetFox"); *cTO7$\[  
String sProperty = "bytes="+nStartPos+"-"; U$H@ jJ*  
httpConnection.setRequestProperty("RANGE",sProperty); #wc \T  
Utility.log(sProperty); ^FZ^6*
 
w'X]M#Q><  
oo=#XZkk  
InputStream input = httpConnection.getInputStream(); *_ +7ni  
//logResponseHead(httpConnection); Gn)y> AN  
"lNzGi-H  
]I/Vbs  
byte[] b = new byte[1024]; Qm8)4?FZ  
int nRead; N~g:Wf!  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) SEl#FWR  
{ u*7Z~R  
nStartPos += fileAccessI.write(b,0,nRead); !GW,\y  
//if(nThreadID == 1) aZKOY  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r-kMLw/)  
} GHF_R,7  
o$C|J]%  
?R-9W+U%f  
Utility.log("Thread " + nThreadID + " is over!"); qzFQEepso  
bDownOver = true; NNG}M(/V  
//nPos = fileAccessI.write (b,0,nRead); T@%m7|P  
} e4I^!5)N  
catch(Exception e){e.printStackTrace ();} O+=vEp(  
} -Q;#sJ?  
} +>7$4`Nb2  
Y${l!+q  
O[9-:,B{w  
//打印回应的头信息 }j1!j&&  
public void logResponseHead(HttpURLConnection con) +Z!;P Z6  
{ =2y8CgLj  
for(int i=1;;i++) \n9A^v`F/  
{ F8e<}v&7R  
String header=con.getHeaderFieldKey(i); i#X!#vyc  
if(header!=null) ^MD;"A<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 8hA^`Y  
Utility.log(header+" : "+con.getHeaderField(header)); Fg/dS6=n`?  
else wA`"\MWm  
break; kl1Y] ?z}  
} E3a_8@ZB7  
} WxbsD S;  
6|J'>)  
a;$P:C{gj?  
public void splitterStop() &V7>1kD3  
{ *QM~O'WhD  
bStop = true; 69kJC/1+l  
} w:o-klKXY  
iRG?# "  
bg?"I
Lpk  
} I\\QS.2  
FVF-:C
 
8*g ^o\M  
/* t ]c{c#N/  
**FileAccess.java Io2mWvu?5  
*//文件访问(定位，写) E?PGu!&u  
package NetFox;  .Qt4&B  
import java.io.*; PiLJZBUv  
5/m$)wE  
g^kx(p<u`  
public class FileAccessI implements Serializable{ !C:rb  
:f'&z47  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 '#O_}|ZN  
RandomAccessFile oSavedFile; "`A:(<x  
long nPos; !c<wSQ,  
=He.fEy  
pz_e=xr  
public FileAccessI() throws IOException 0;~yZ?6_F  
{ dMl+ko  
this("",0);
YEYY}/YX  
} Qq0l*)mX  
oJ*1>7[J  
0MIUI<;j  
public FileAccessI(String sName,long nPos) throws IOException |'HLz=5\  
{
AB.(CS=i  
oSavedFile = new RandomAccessFile(sName,"rw"); .g\6g~n  
this.nPos = nPos; 
Gie@JX  
oSavedFile.seek(nPos); <64HveJ  
} %
U`xu.  
~3
WL)%  
Q |i9aE  
public synchronized int write(byte[] b,int nStart,int nLen) `GQ{*_-  
{ RE46k`44  
int n = -1; *QE<zt  
try{ Z&!!]"I  
oSavedFile.write(b,nStart,nLen); j?(!^ _!m  
n = nLen; 0?bA$y  
} 9w;?-  
catch(IOException e) Zu<]bv  
{ s[3fqdLP&  
e.printStackTrace (); ,[48Mspp  
} H!IDV}dn  
%4>x!{jwV  
~hN~>0O  
return n; i6no;}j  
} nl/UdgI  
 ~krS#\  
+6W(z3($  
} c^I0y!  
#]KgUc5B  
8IY19>4'5J  
/* ,8K'
F  
**SiteInfoBean.java 3" Vd==oK~  
*/ e(\I_  
package NetFox; 'Am-vhpm  
;q#]-^  
fu\s`W6f&  
public class SiteInfoBean { iL?iz?+.%@  
(fk5'  
"-i#BjZl/  
private String sSiteURL; //Site's URL }HZ{(?  
private String sFilePath; //Saved File's Path 5vZ#b\;#V  
private String sFileName; //Saved File's Name EO"C8z'al  
private int nSplitter; //Count of Splited Downloading File p6 xPheD  
v"1Po_`  
=fG:A(v%}  
public SiteInfoBean() zQuM !.  
{//nSplitter的缺省值为5 2:v<qX  
//default value of nSplitter is 5 4L:>4X[T  
this("","","",5); [ x>  
} z?.(3oLT  
^)\+l%M  
P2k7M(I_&  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) CJw$j`k  
{ L`K;IV%;  
sSiteURL= sURL; VQ |^   
sFilePath = sPath; p!"(s/=  
sFileName = sName; 9R]](g#  
this.nSplitter = nSpiltter; $iMC/Kym  
+g
\;bLT  
o'UHStk
 
} ubGs/Vzye  
cx(2jk}6  

LM,fwAX  
public String getSSiteURL() INNAYQ  
{ f]_mzF=&  
return sSiteURL; w7Dt1axB  
} F1u)i  
#\FT EY!  
Q-('5a19J  
public void setSSiteURL(String value) pt!'v$G/*  
{ 3IyZunFT  
sSiteURL = value; Pz~q%J  
} H7e /  
Cd~LsdKE5  
v}`1)BUeF
 
public String getSFilePath() 9m!7|(QV  
{ #EwK"S~  
return sFilePath; 9O;vUy)  
} G=$}5; t  
3V-6)V{KaE  
CIQwl 6H9  
public void setSFilePath(String value) sJ6a7A8)  
{ {e9Y !oFg  
sFilePath = value; ,YlQK;  
} L+R>%d s  
vfbe$4mH  
TA)LPBG  
public String getSFileName() k^*$^;z  
{ yh!B!v'  
return sFileName; ks:{TA27  
} d.\PS9l  
_t.FL@3e  
`p|[rS>  
public void setSFileName(String value) %cj58zO|y  
{ |\{Nfm=:%  
sFileName = value; OOLe[P3J3  
} pG28M]\  
>UN vkQ:  
hWxT!  
public int getNSplitter() 84Zgo=P}  
{ 5; f\0<-  
return nSplitter; Yw^ Gti'<  
} kIM C~Z  
tR O IBq|  
 1ZNNsB  
public void setNSplitter(int nCount) Z3`2-r_=  
{ C1ZyB"{
 
nSplitter = nCount; {Q<0\`A  
} 1*c>I@I;  
} 4?]ZV_BD  
<ge}9pU)o^  
wT%"5:  
/* A;t zRe  
**Utility.java ~
,Mr0  
*/ xppkLoPK  
package NetFox; ;+9(;  
EE9v
k*[@C  
3{q[q#"  
public class Utility { `oPLl0  
aH^{Vv$]M@  
tQf
!|]#J  
public Utility() j@SYXKL~  
{ 4tnjXP8  
;_p fwa4  
{g@A>  
} C
2.W[T  
jMqx   
//线程睡眠 F,.Q|.nN  
public static void sleep(int nSecond) *I/A,#4r  
{ gPp(e j7  
try{ /.)2d8,  
Thread.sleep(nSecond); u#!GMZJN  
} H9:%6sds  
catch(Exception e) ;"SZ}  
{ `$f2eB&   
e.printStackTrace (); ##2`5i-x  
} "B?R| Xg  
} ~zj"OG"zOw  
S|) J{~QH  
//日志 @Q3, bj  
public static void log(String sMsg) %xpd(&)n  
{ Yg|"-  
System.err.println(sMsg); \Nyr=<c  
} AtT"RG-6  
9nO(xJ"e4  
'tut4SwC  
public static void log(int sMsg) :r-.r"[m-  
{ H}a)^90_  
System.err.println(sMsg);  )Oo2<:"  
} 1V0sl0i4  
} A{1 \f*  
Ri[S<GOMii  
e@yx}:]h  
/* )5'rw<:="  
**TestMethod.java ]*a@*0=  
*/ _ flgQ  
package NetFox; MyqiBGTb  
XUf7yD  
mDlCt_h  
public class TestMethod { W0U`Kt&~a  
/t$*W\PL@  
e6o/q)9#  
public TestMethod() hi0XVC95  
{ ///xx/weblogic60b2_win.exe B#Qpd7E+*  
try{ r:
.6"VQu}  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); U(P:Je  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Z$1.^H.Db  
SiteFileFetch fileFetch = new SiteFileFetch(bean); )ph30B  
fileFetch.start(); C~{xL>I  
} K,G,di  
catch(Exception e){e.printStackTrace ();} *^ey]),f54  
/ Z1Wy-Z  
'%);%y@v  
} dA|Lufy#  
!2#\| NJk  
~ t"n%SgY  
public static void main(String[] args) )G^p1o;\  
{ '1Y<RD>x  
new TestMethod(); &+,:u*%  
} P:>'   
} (y 3~[  
点击下载更多相关资料