http断点续传简单实现（java)

/* 66*o2D\Q*G  
**SiteFileFetch.java ?MH4<7?"  
*/ "x)DE,  
package NetFox; f<wgZM  
import java.io.*; CkU=0mcY  
import java.net.*; [P/gM3*'  
P]B#i1  
J%)2,szn0  
public class SiteFileFetch extends Thread { pQNFH)=nw  
lNb\^b  
R
=PzR;8  
SiteInfoBean siteInfoBean = null; //文件信息Bean eXK`%'  
long[] nStartPos; //开始位置 T8-$[ 2  
long[] nEndPos; //结束位置 o3=kF  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 u*{ _WL[(  
long nFileLength; //文件长度
)^TQedF  
boolean bFirst = true; //是否第一次取文件 ,X^_w g  
boolean bStop = false; //停止标志 kP$gl|  
File tmpFile; //文件下载的临时信息 VaxO L61xE  
DataOutputStream output; //输出到文件的输出流 {%{GZ  
iC-ABOOu{l  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） rLxX^[Fp3  
public SiteFileFetch(SiteInfoBean bean) throws IOException W#j,{&KVn  
{ !Yu-a!  
siteInfoBean = bean; M;qL)vf  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); E,7~kd~y`  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;L2bC3
  
if(tmpFile.exists ()) $x;h[,y   
{ |@.<}/  
bFirst = false; )/"7$2Aoy  
read_nPos(); Z@!W?Ed  
} e6lOmgHn5  
else s2~dmZ_B|_  
{ .5;LL,S-  
nStartPos = new long[bean.getNSplitter()]; a}fClI-u  
nEndPos = new long[bean.getNSplitter()]; f)Q]{cb6  
} 4/?}xD|?  
gqRTv_;  
4rG 7\  
bK\WdG\;  
} sdYj'e:N  
mthl?,I|  
z\>X[yNpA  
public void run() Aq%^>YAp  
{ }Xj_Y]T  
//获得文件长度 D|j
\ nQ  
//分割文件 g ypq`F  
//实例FileSplitterFetch 
W'h0Zg  
//启动FileSplitterFetch线程 Wx$q:$h@q  
//等待子线程返回 Fx5d@WNa>  
try{ 1xAFu+
  
if(bFirst) p''"E$B/(  
{ ++DQS9b{  
nFileLength = getFileSize(); |qcFmy  
if(nFileLength == -1) _/~ ,a  
{ /1~|jmi(  
System.err.println("File Length is not known!"); -MU.Hu  
} Yc`j  
else if(nFileLength == -2) F(9 Y/UXH  
{ DnsP7k.8T  
System.err.println("File is not access!"); dyiEK)$h  
} 8<g#$(a_E  
else rn:zKTyhw  
{ o 7W Kh=  
for(int i=0;i<nStartPos.length;i++) s^YTI\L \  
{ m+2`"1IE[  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); RE $3| z  
} }?]yxa~  
for(int i=0;i<nEndPos.length-1;i++) h^+C)6(58n  
{ _b_?9b-)D  
nEndPos = nStartPos[i+1]; M'zS7=F!:  
} MiH}VfI
  
nEndPos[nEndPos.length-1] = nFileLength; =lC;^&D-0/  
} 'nWs0iH.  
} $dh4T";  
(s$u_aq77  
+6hl@Fm(  
//启动子线程 "WbVCT'i  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Kka8cG  
for(int i=0;i<nStartPos.length;i++) =v4r M0m,  
{ 6Z&u  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), AwXt @!(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),  /MqXwUbO  
nStartPos,nEndPos,i); UM( l%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >*= =wlOB  
fileSplitterFetch.start(); qfGtUkSSb  
} (#bp`Kih  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), E {KS a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); }B=qH7u.K  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", p2x1xv  
nEndPos = " + nFileLength); ,9Z2cgXwJ  
// fileSplitterFetch[nPos.length-1].start(); 8wX+ZL:9  
4W!\4Va  
<r<Dmn|\a  
//等待子线程结束 &{zwM |Q@?  
//int count = 0; Wm)-zvNY;  
//是否结束while循环 jF2[bzY4  
boolean breakWhile = false; Zj1ZU[BEcL  
au~]  
X
LZ j  
while(!bStop) <mZrR3v'D  
{ M'umoZmW0  
write_nPos(); %6A-O
F  
Utility.sleep(500); fW.GNX8
 
breakWhile = true;
ik2- OM  
Ht|",1yr+  
%2Epgh4?  
for(int i=0;i<nStartPos.length;i++) L\b]k,Ksf  
{ -BA"3 S  
if(!fileSplitterFetch.bDownOver) 731h ~x!u  
{ b/sOfQ  
breakWhile = false; XogvtK*  
break; "xvtqi,R  
} x.b; +p}=  
} H>
?:U]  
if(breakWhile) Opv1B2  
break; 8 7RHA $?  
;Z ]<S_#-  
e0f":Vct  
//count++;  3L%WVCB  
//if(count>4) (8CCesy&  
// siteStop(); 5<89Af&&K8  
} X
zT78  
`$S^E !=  
cz2,",+~  
System.err.println("文件下载结束！"); @Q;i.u{V  
} /Q?~Q0{)es  
catch(Exception e){e.printStackTrace ();} GAv)QZyV$  
} dh&W;zs  
nVxq72o@  
[{`)j  
//获得文件长度 LGIalf*7  
public long getFileSize() Yeqvv  
{ 7}Bj|]b)~  
int nFileLength = -1; oW^k7#<e}  
try{ !w q4EV  
URL url = new URL(siteInfoBean.getSSiteURL()); .i$,}wtw  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bE?'C h  
httpConnection.setRequestProperty("User-Agent","NetFox"); /xcJo g~F,  
qAqoZMpI|;  
7))\'\  
int responseCode=httpConnection.getResponseCode(); T^~)
jpkw  
if(responseCode>=400) oEJaH  
{ B&?fM~J  
processErrorCode(responseCode); 7_DG 5nT  
return -2; //-2 represent access is error 2B-.}OJ  
} )s7bJjT0=X  
4E
2yH6l  
F\5X7ditD  
String sHeader; 4otl_l(`yv  
%y>+1hakkX  
,eDD:#)$}  
for(int i=1;;i++) !\^jt%e&  
{ n@ 4@,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +'|{1gB  
//Utility.log(in.readLine()); AYcgi  
sHeader=httpConnection.getHeaderFieldKey(i); 6B#('gxO  
if(sHeader!=null) 1Ao6y.S  
{ 8h|M!/&2  
if(sHeader.equals("Content-Length")) OkpwhkPL5  
{ 7{pIPmJ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !tU'J"Zy  
break; JWWYVl VC  
} T7{<arL$  
} thuRNYv<  
else S ZlC4=6c  
break; y;nvR6)  
} Ry z?v<)h  
} ?6f7ld5  
catch(IOException e){e.printStackTrace ();} w$j{Hp6m  
catch(Exception e){e.printStackTrace ();} D+sQPymI  
XA)'=L!^  
yl$F~e1W  
Utility.log(nFileLength); llq*T"
7  
'.(~  
edijfhn  
return nFileLength; CvK3H\.&;k  
} abi[jxCG  
U\jb"  
t<638`{kk  
//保存下载信息（文件指针位置） )JhT1j
Qc  
private void write_nPos() *%\mZ,s"  
{ #6=MKpR  
try{ ]78!!G[`  
output = new DataOutputStream(new FileOutputStream(tmpFile)); cJDd0(tD!  
output.writeInt(nStartPos.length); ~~nqU pK?v  
for(int i=0;i<nStartPos.length;i++) NvJV</l6A  
{ I{ ryD -!  
// output.writeLong(nPos); 1u~ MXGF  
output.writeLong(fileSplitterFetch.nStartPos); R,t$"bOd  
output.writeLong(fileSplitterFetch.nEndPos); @g-G =Ba  
} pJBg?D  
output.close(); /=)L_  
} `G!M>h@  
catch(IOException e){e.printStackTrace ();} XF*.Jg]  
catch(Exception e){e.printStackTrace ();} c2 Aps  
} Gb2L }  
q0&$7GH4  
m#e*c[*G  
//读取保存的下载信息（文件指针位置） Pbn!KX~F~  
private void read_nPos() pKT2^Q}-h  
{ M`7y>Ud  
try{ 6na^]t~ncm  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 8Pmdk1 ~  
int nCount = input.readInt(); v.&>Ih/L
 
nStartPos = new long[nCount]; YoKs:e2/:  
nEndPos = new long[nCount]; Xg7|JS!  
for(int i=0;i<nStartPos.length;i++) < zOi4v0  
{ 65TfFcQ<S  
nStartPos = input.readLong(); 7 oQ[FdRn*  
nEndPos = input.readLong(); PuL<^aJ  
} <a(}kk}  
input.close(); H8{ol6wc)6  
} Y32 "N[yw  
catch(IOException e){e.printStackTrace ();} //f  
catch(Exception e){e.printStackTrace ();} u92^(|  
} h-#1U
3d  
P7.'kX9  
hK|j6xf.o  
private void processErrorCode(int nErrorCode) x,n,Qlb  
{ r'GP$0rr9!  
System.err.println("Error Code : " + nErrorCode); ?6^|ZtB  
} rl08R  
3g~'5Ao  
c{3wk7  
//停止文件下载 )e|=mtp  
public void siteStop() 9X$ma/P[  
{ Wb}c=hZv  
bStop = true; eE GfM0  
for(int i=0;i<nStartPos.length;i++) fHRMu:q  
fileSplitterFetch.splitterStop(); oU*45B`"  
*{ {b~$  
#OO>rm$  
} 457\&  
} c0&Rg#  
//负责部分文件的抓取 QX4ai3v  
**FileSplitterFetch.java 4JGtI*%5lq  
*/ (QoI<j""  
package NetFox; EJ@p-}I!  
u&mS8i}  
c2t=_aAIPQ  
import java.io.*; ?i
I4x%y  
import java.net.*; jRSUp E8  
o%9*B%HO/  
i.D
3'l  
public class FileSplitterFetch extends Thread { scLn=  
u_(VEfs4  
#P l~R  
String sURL; //File URL J_x13EaV0  
long nStartPos; //File Snippet Start Position .qMOGbd?  
long nEndPos; //File Snippet End Position u!"t!2I  
int nThreadID; //Thread's ID ~cTN~<{dq  
boolean bDownOver = false; //Downing is over R}^~^#  
boolean bStop = false; //Stop identical QnZcBXI8  
FileAccessI fileAccessI = null; //File Access interface a,2'+Tlo  
V=:'SL*3|  
QUU;g2k  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException e/0
<[s*#Q  
{ =R*qP;#  
this.sURL = sURL; ]o cWt3|  
this.nStartPos = nStart; P"B0_EuR<T  
this.nEndPos = nEnd; }:X*7 n(&  
nThreadID = id; ^*P%=>zO  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 K+;e4_\  
} rM'=_nmi  
_%5Ro6  
f7m%|v!  
public void run() v?KC%  
{ ;\f gF@  
while(nStartPos < nEndPos && !bStop) S30?VG9U0f  
{ U2bjFLd"  
>}+/{(K"E|  
:yUEkm8  
try{ /YZr~|65  
URL url = new URL(sURL); -$\+' \  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .zi_[  
httpConnection.setRequestProperty("User-Agent","NetFox"); "?V0$-DR  
String sProperty = "bytes="+nStartPos+"-"; 0aG ni|  
httpConnection.setRequestProperty("RANGE",sProperty); Ney/[3 A  
Utility.log(sProperty); q@[QjGj@  
Kx>qz.wwI?  
V5UF3'3;}  
InputStream input = httpConnection.getInputStream(); a(l29>  
//logResponseHead(httpConnection); ;M)QwF1  
Zl^\Q=*s  
Tj:B!>>  
byte[] b = new byte[1024]; 3B84^>U<  
int nRead; '.:z&gSqx0  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 7pe\M/kl  
{ < jJ  
nStartPos += fileAccessI.write(b,0,nRead); "N`[r iq{  
//if(nThreadID == 1) wOU_*uY@6'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jPUwSIP  
} }H^+A77v  
E=nIRG|g  
<J)]mh dm  
Utility.log("Thread " + nThreadID + " is over!"); #d6)#:uss  
bDownOver = true; h&KO<
>  
//nPos = fileAccessI.write (b,0,nRead); 5>[u `  
} gEy?s8_,  
catch(Exception e){e.printStackTrace ();} N sXHO  
} 45@^L's  
} >T^;MS  
I>W=x'PkLn  
\NPmym_6J  
//打印回应的头信息 hgPa
6Kd  
public void logResponseHead(HttpURLConnection con) {*G9|#[/@  
{ Ayxkv)%:@)  
for(int i=1;;i++) b,7k)ND1F  
{ T&6l$1J  
String header=con.getHeaderFieldKey(i); `dq,>HdW  
if(header!=null) k\5c|Wq|g  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >;e~WF>+K  
Utility.log(header+" : "+con.getHeaderField(header)); H#,W5EJzM  
else 'jWr<]3  
break; *4\:8  
} TM%|'^)  
} akp-zn&je  
]d$8f  
+$ 'Zf0U  
public void splitterStop() p`olCp'  
{ $V-~Bu-  
bStop = true; BC^ :=  
} rV` #[d  
11Q1AN  
~Y^+M*  
} fK>L!=Q  
xQ7l~O b  
R@1xt@?  
/* ,LHn90S  
**FileAccess.java \V;F/Zy(  
*//文件访问(定位，写) P)Jgs  
package NetFox; - YEZ]:"  
import java.io.*; ,0M_Bk"  
WlOmJtt4)  
*7uH-u"5d  
public class FileAccessI implements Serializable{ g];!&R-  
W=~~5jFX  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 .]8ZwAs=&  
RandomAccessFile oSavedFile; Cj
n#00  
long nPos; qU \w=  
Vr3Zu{&2  
k =>oO9
`  
public FileAccessI() throws IOException ?g_3 [Fk  
{ {:/#Nc$5  
this("",0); j`{?OYD  
} $o+j El>  
E^B'4  
N=V==Dbu-  
public FileAccessI(String sName,long nPos) throws IOException /2&c$9=1  
{ )v'WWwXY>  
oSavedFile = new RandomAccessFile(sName,"rw"); ahusta  
this.nPos = nPos; )*$lp'~7N  
oSavedFile.seek(nPos); ^ gdaa>L  
} /!0=
{G  
/p/]t,-j2  
mVj9,q0  
public synchronized int write(byte[] b,int nStart,int nLen) 3/P1!:g9  
{ aS>u,=C  
int n = -1; ]_)yIi"  
try{ " s,1%Ltt  
oSavedFile.write(b,nStart,nLen); x`mG<Yt
 
n = nLen; l|u>Tb|V  
}  CT&|QH{  
catch(IOException e) Pd8![Z3  
{ {B~QQMEow  
e.printStackTrace (); 4VHn \  
} kXViWOXU^  
0Fq} N  
,Co|-DYf}  
return n; Usvl}{L[  
} jVi) Efy  
TP*hd  
b1cy$I  
} 5%"V[lDx@  
H8=N@l  
"MeVE#O  
/* hDDn,uzpd  
**SiteInfoBean.java /'SNw?&  
*/ }PlRx6r@  
package NetFox; 7g^]:3f!
 
[NTzcSN.  
cZ,b?I"Q%  
public class SiteInfoBean { ./Xz}<($8  
3l~^06D  
{p2!|A&a  
private String sSiteURL; //Site's URL g _9C*  
private String sFilePath; //Saved File's Path X0HZH?V+  
private String sFileName; //Saved File's Name D\v+wp.  
private int nSplitter; //Count of Splited Downloading File Z-%\ <zT  
"nynl'Ryk  
#\{l"-  
public SiteInfoBean() 'ms-*c&  
{//nSplitter的缺省值为5 VD*6g%p  
//default value of nSplitter is 5 ~12EQacOT  
this("","","",5); fgTg7 m  
} bL`TySX  
|d2SIyUc  
j^sg6.Z*  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) J3V= 46Yc  
{ tAd%#:K  
sSiteURL= sURL; h8q[1"a:  
sFilePath = sPath; 5vQHhwO50k  
sFileName = sName; au(D66VO  
this.nSplitter = nSpiltter; n&4N[Qlv,  
ZDJ`qJ8V  
#lo6c;*m5  
} U+jOTq8M  
 4\N;2N  
=j_4S<  
public String getSSiteURL() lN)C2
2  
{ F~vuM$+d  
return sSiteURL; C[AqFo  
} "S]0  
!?jrf] A@  
2RX;Ob_  
public void setSSiteURL(String value) *KF#'wi  
{ ]jQutlg|  
sSiteURL = value; .hb:s,0mP  
} hh%-(HaLX3  
ub0.J#j@  
Vm(y7}Aq{  
public String getSFilePath() H2 {+)  
{ SHxNr(wJ<Q  
return sFilePath; Y]_ruDIW  
} H|<[YYk  
:S83vE81WK  
:pY/-Cgv  
public void setSFilePath(String value) ^)S;xb9  
{  DPxM'7  
sFilePath = value;
2wg5#i  
} :r,pqnH_  
{]!mrAjD  
mDABH@R  
public String getSFileName() IPKbMlV#d  
{ XEp{VC@=  
return sFileName; lv<*7BCp  
} ek\ xx  
u%KTNa0  
~H_/zK6e  
public void setSFileName(String value)
b5I 
I/Y  
{ 7IH@oMvE  
sFileName = value; 2#]#sZmk  
} l/GGCnO/  
k,6f &#x  
@V sG'  
public int getNSplitter() ]@c+]{  
{ =[{i{x|Qz  
return nSplitter; iN\4gQ!  
} LgU_LcoM*  
hbDXo:  
{X+3;&@  
public void setNSplitter(int nCount) %P/Jq#FE.  
{ TDKki(o=~  
nSplitter = nCount; G@\1E+Ip  
} ]=I@1B;_m  
} (O?.)jEW(.  
sN*N&XG  
.Iw AK/QS  
/* WIT>!|w_  
**Utility.java m+R[#GE8#  
*/ YeL#jtC  
package NetFox; &MQmu,4  
F?*-4I-  
Q7\w+ANf0  
public class Utility { $E~`\o%Ev  
gIa+5\qYY  
 .-c4wm}  
public Utility() XGWSdPJLr  
{ Y|f[bw  
W?
R6ZAn  
gMmaK0uhS  
} /GN<\_o=q  
,t?B+$E  
//线程睡眠 Y0@"fU35  
public static void sleep(int nSecond) C.yQ=\U2  
{ uAJx.>$b  
try{ jyUjlYAAv`  
Thread.sleep(nSecond); @[<><uTH  
} `l ^9/_g'6  
catch(Exception e) jh%Eq+#S  
{ z6=Z\P+  
e.printStackTrace (); Uw. `7b>B  
} O7m(o:t x3  
} /<=u\e'rE  
/wEhVR`=  
//日志 W
0@n/U  
public static void log(String sMsg) x7&B$.>3  
{ (AaoCa[  
System.err.println(sMsg); EzM ?Nft  
} XK3tgaH  
ghG**3xr  
s4y73-J^.v  
public static void log(int sMsg) B$fPgW-  
{ ?W?c1>  
System.err.println(sMsg); kWMl  
} !Y0Vid  
} x;P_1J%Q  
mZS >O_E  
XH4  
/* 0WW2i{7`U  
**TestMethod.java A5I)^B<(  
*/ O>bC2;+s  
package NetFox; ifMRryN4  
kzQ+j8.,U  
]___M  
public class TestMethod { |}s*E_/[  
NqazpB*  
ar!R|zmf  
public TestMethod() }_M~2L?i  
{ ///xx/weblogic60b2_win.exe #C74z$  
try{ taHJ ub  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); n`?aC|P2s  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ]b:Lo  
SiteFileFetch fileFetch = new SiteFileFetch(bean); {Qf=G|Ah  
fileFetch.start(); Pe_W;q.  
} GbY7_N  
catch(Exception e){e.printStackTrace ();} Y1W1=Uc uk  
F3[T.sf  
J@HtoTDO3  
} YNyk1cE  
ky,(xT4  
O_muD\  
public static void main(String[] args) [\98$BN  
{ Tj`,Z5vy  
new TestMethod(); (?1y4M  
} 4<w.8rR:A  
} {=9,n\85#  
点击下载更多相关资料