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http断点续传简单实现(java)

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/* R[/]iK+!&  
**SiteFileFetch.java  Du*O|  
*/ LM~,`#3 Ru  
package NetFox; pH'1be{K  
import java.io.*; G.}Ex!8R7_  
import java.net.*; -H;%1y$A-  
C K{.Ic^  
sY#iGEf  
public class SiteFileFetch extends Thread { :M%s:,]R  
S[_Hc$7U  
'B$ bGQ  
SiteInfoBean siteInfoBean = null; //文件信息Bean sHr!GF  
long[] nStartPos; //开始位置 * YhX6J1  
long[] nEndPos; //结束位置 R8ui LZd  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 %L^S;v3  
long nFileLength; //文件长度 m&h5u,  
boolean bFirst = true; //是否第一次取文件 @Qa)@'u  
boolean bStop = false; //停止标志 5X'com?T  
File tmpFile; //文件下载的临时信息 2qY+-yOEt  
DataOutputStream output; //输出到文件的输出流 X`QfOs#\  
 B3Yj  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) NUclF|G  
public SiteFileFetch(SiteInfoBean bean) throws IOException Ju~8C\Dd  
{ 9m:qQ1[\  
siteInfoBean = bean; 3}}#'5D  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); F%v?,`_&I  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); OFtAT@ =O  
if(tmpFile.exists ()) >;ucwLi  
{ TN=MZ{L  
bFirst = false; sT^^#$ub  
read_nPos(); ,uFdhA(i@'  
} 0k];%HV|  
else wkp|V{k  
{ hgz7dF  
nStartPos = new long[bean.getNSplitter()]; :h|nV ~  
nEndPos = new long[bean.getNSplitter()]; >#MGGCGL  
} - /s2'  
L'>t:^QTh  
]('isq,P  
|c]Y1WwDx  
}  ?2g\y@  
!7:~"kk  
n-cz xq%n  
public void run() ;56mkP  
{ mhi^zHpa  
//获得文件长度 6!A+$"  
//分割文件 -oMp@2\e  
//实例FileSplitterFetch Ch0t'  
//启动FileSplitterFetch线程 gCP f1z  
//等待子线程返回 ZQN%!2  
try{ "V>p  
if(bFirst) J5#shs[M:  
{ [eLU}4v{  
nFileLength = getFileSize(); Z` zyE P A  
if(nFileLength == -1) \sc's7  
{ >mCS`D8  
System.err.println("File Length is not known!"); #,jw! HO]  
} i7jI(VvB^  
else if(nFileLength == -2) /DE`>eJY  
{ 1MYA/l$  
System.err.println("File is not access!"); "yG*Kh7ur  
} AD@-H0Y  
else u?V Tnsu  
{ .[:2M9Rx  
for(int i=0;i<nStartPos.length;i++) bKac?y~S_  
{ v[!ZRwk4w3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #Nv)SCc  
} W</\F&  
for(int i=0;i<nEndPos.length-1;i++) +<$b6^>!$  
{ 7T/hmVi_  
nEndPos = nStartPos[i+1]; +2Wijrn  
} ATkx_1]KM-  
nEndPos[nEndPos.length-1] = nFileLength; )9~-^V0A^>  
} t_NnQ4)=  
} vE$n0bL2  
:&\^r=D  
iT,Ya-9"  
//启动子线程 " LkI'>3}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0`~#H1TK  
for(int i=0;i<nStartPos.length;i++) b3^d!#KVM  
{ v?<Tkw ^F  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), X{-901J1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), IRY/0v  
nStartPos,nEndPos,i); qt,;Yxx#^  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); p`T,VU&.  
fileSplitterFetch.start(); P+(q38f[  
} jImw_Q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N}X7g0>hV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %WO4uOi:@  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #4wia%}u  
nEndPos = " + nFileLength); ]]!&>tOlI  
// fileSplitterFetch[nPos.length-1].start(); !Jk|ha~r  
Wo, "$Z6B  
K;P<c,9X/  
//等待子线程结束 N*6lyFcg  
//int count = 0; -XMWN$Ah  
//是否结束while循环 ^w+)A;?W  
boolean breakWhile = false; DUlvlQW  
=BVBCh  
P{[@t_  
while(!bStop) Ns5'K^  
{ \\v1 \  
write_nPos(); vQsI^p  
Utility.sleep(500); Gid6,J  
breakWhile = true; WOR H4h9  
wpV)y Q^  
bP HtP\)  
for(int i=0;i<nStartPos.length;i++) ~F^7L5d}C  
{ BaXf=RsZ  
if(!fileSplitterFetch.bDownOver) ]>H'CM4JR  
{ [*W l=  
breakWhile = false; OTV$8{  
break; I*OJPFZ^4  
} L`n Ma   
} bY!1t}ALh  
if(breakWhile) 6  5>}Q.p  
break; I6.}r2?;A  
-0:Equ?pz  
%}1v-z  
//count++; 4#Id0['  
//if(count>4) 'FN+BvD  
// siteStop(); u~\l~v^mj  
} a~Nh6 x  
~xakz BE  
`2PvE4]%p  
System.err.println("文件下载结束!"); M#o'hc  
} :~4 M9  
catch(Exception e){e.printStackTrace ();} T.GB *  
} AH'4k(-  
j@C*kj;-  
b5t:" >wC  
//获得文件长度 )L/o|%r!  
public long getFileSize() D'Y=}I)8Dn  
{ xG~7kj3  
int nFileLength = -1; Rr"D)|Y;C(  
try{ *z6m644H  
URL url = new URL(siteInfoBean.getSSiteURL()); `ZZq Sc4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0.lOSAq  
httpConnection.setRequestProperty("User-Agent","NetFox"); #{x4s?   
pL pBP+i  
I`4k5KB;  
int responseCode=httpConnection.getResponseCode(); m'YYkq(5%Z  
if(responseCode>=400) u7}C):@H  
{ ]m@p? A$  
processErrorCode(responseCode); s8|F e_  
return -2; //-2 represent access is error d[$YTw  
} =L9;8THY  
f0]`TjY  
r0j+P%  
String sHeader; _>4Qh#6K  
@zi_@B  
HsRQiai*  
for(int i=1;;i++) &09g0K66  
{ C[s='v~}  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); C*&FApG  
//Utility.log(in.readLine()); S?e*<s9k  
sHeader=httpConnection.getHeaderFieldKey(i); k\A[p\  
if(sHeader!=null) M$MFUGS'  
{ 7kq6VS;p  
if(sHeader.equals("Content-Length")) [&K"OQ^\2h  
{ N= {0A  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ZP;WXB`  
break; t^SND{[WcM  
} mt*/%>@7R  
} G[ gfD\  
else Zt"3g6S  
break; %W,V~kb  
} {bMOT*X=A  
} uG{/yJeU  
catch(IOException e){e.printStackTrace ();} 4$MV]ldUI  
catch(Exception e){e.printStackTrace ();} ,@r 0-gL  
'q, L*  
!B:wzb_  
Utility.log(nFileLength); 7xoq:oP-}N  
K} TSwY  
9f_Qs4  
return nFileLength; qJYEsI2M  
} 3&"+)*/ m  
r(DW,xoK0  
3iBUIv  
//保存下载信息(文件指针位置) ;noZmPa  
private void write_nPos() *!&,)''  
{ J[jzkzSu`  
try{ `| f1^C^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); $.T\dm-  
output.writeInt(nStartPos.length); }-2U,Xg[  
for(int i=0;i<nStartPos.length;i++) [s&0O<Wv  
{ Ah Rvyj  
// output.writeLong(nPos); >@?`n}r|  
output.writeLong(fileSplitterFetch.nStartPos); B'!I{LC  
output.writeLong(fileSplitterFetch.nEndPos); C[Nh>V7=  
} \3 M%vJ  
output.close(); 26[m7\O  
} JYO("f  
catch(IOException e){e.printStackTrace ();} :BpXi|n;  
catch(Exception e){e.printStackTrace ();} v/~Lfi  
} FN"Ye*d  
N`rz>6,k1  
6<{XwmM  
//读取保存的下载信息(文件指针位置) $i"IOp  
private void read_nPos() h}yfL@  
{ ;I!Vba  
try{ Cm~z0c|T  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 7O\Qxc\  
int nCount = input.readInt(); CjZIBMGc  
nStartPos = new long[nCount]; F@rx/3 [  
nEndPos = new long[nCount]; $J!WuOz4^i  
for(int i=0;i<nStartPos.length;i++) j+NsNIJq  
{ -mqL[ h,  
nStartPos = input.readLong(); 9/$Cq  
nEndPos = input.readLong(); l }WvO]  
}  re@;6o  
input.close(); EN;4EC7tE  
} "eZ~]m}L0  
catch(IOException e){e.printStackTrace ();} UB3hC`N\  
catch(Exception e){e.printStackTrace ();} O2N~&<^  
} cs0rz= ZdH  
3eR c>^wh  
` 3h,Cy^  
private void processErrorCode(int nErrorCode) `=19iAp.  
{ E5 uk<e_  
System.err.println("Error Code : " + nErrorCode); :@K~>^+U  
} $_Q]3"U  
a|kEza,]  
gRg8D{  
//停止文件下载 Q 1[E iM3  
public void siteStop() "`Y.5.  
{ Y?xc#'  
bStop = true; UIK4]cYC'  
for(int i=0;i<nStartPos.length;i++) AGK{t+`  
fileSplitterFetch.splitterStop(); Z:.*fs5  
bD<hzOa  
*IIuGtS  
} (Ky$(Ubb#6  
} .'zcD^  
//负责部分文件的抓取 `[F[0fY-  
**FileSplitterFetch.java QR {>]I  
*/ ,| ~Pa  
package NetFox; :YM1p&|fS  
cg_j.=M-  
m e2$ R>@  
import java.io.*; CMC9%uq  
import java.net.*; $mcq/W   
(gjCm0#_%  
h1Logm+m  
public class FileSplitterFetch extends Thread { O>[B"mM t  
Z!*k0 <Z  
rH9[x8e  
String sURL; //File URL Z=zD~ka  
long nStartPos; //File Snippet Start Position ?$~5ti#\  
long nEndPos; //File Snippet End Position Q&8epO|J  
int nThreadID; //Thread's ID 5;X3{$y  
boolean bDownOver = false; //Downing is over qv)%)n  
boolean bStop = false; //Stop identical g [c ^7  
FileAccessI fileAccessI = null; //File Access interface {"mb)zr  
>N-l2?rE  
".sRi  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException kS< 9cy[O  
{ nJcY>Rp?  
this.sURL = sURL; `Tc"a_p9t  
this.nStartPos = nStart; Y%Tm `$^V  
this.nEndPos = nEnd; j6#Vwcr  
nThreadID = id; To =JE}jzo  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 =PYS5\k  
} CSlPrx2\  
e|eWV{Dsz  
$ Qcr8~+a  
public void run() q*7:L  
{ z, c=."<z  
while(nStartPos < nEndPos && !bStop) uQiW{Kja2  
{ R/jHH{T3  
pP^5y{  
Y3bZ&G)  
try{ *&tv(+P  
URL url = new URL(sURL); T4h&ly5 f  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); oD=+  
httpConnection.setRequestProperty("User-Agent","NetFox"); lD6PKZ\RIj  
String sProperty = "bytes="+nStartPos+"-"; mO&zE;/[  
httpConnection.setRequestProperty("RANGE",sProperty); n7pjj  
Utility.log(sProperty); ]:.9:RmEV  
x\5v^$  
0`Y"xN`'i  
InputStream input = httpConnection.getInputStream(); @o>3 Bv.  
//logResponseHead(httpConnection); #PQhgli  
ky I~  
>Do P2]  
byte[] b = new byte[1024]; _[,7DA.qc  
int nRead; xP $\ }  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) %H3 M0J2L  
{ 7.bPPr&  
nStartPos += fileAccessI.write(b,0,nRead); [WO>}rGw4  
//if(nThreadID == 1) x,UP7=6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V=)' CCi{  
} /A93mY[  
*Ke\Yb  
Uf#9y182*c  
Utility.log("Thread " + nThreadID + " is over!"); #Q$+AdY|  
bDownOver = true; }ZJ*N Y  
//nPos = fileAccessI.write (b,0,nRead); wVkRrFJ  
} +Sak_*fq  
catch(Exception e){e.printStackTrace ();} &;[e  
} PGhYkj2  
} lS/l iI'Y  
h I7ur  
0N):8`dY  
//打印回应的头信息 s3y"y_u  
public void logResponseHead(HttpURLConnection con) S@cKo&^  
{ (lt{$0   
for(int i=1;;i++) ?wREX[Tqs  
{ o ^""=Z  
String header=con.getHeaderFieldKey(i); 30{WGc@l#  
if(header!=null) ~2[mZias  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :(#5%6F  
Utility.log(header+" : "+con.getHeaderField(header)); B}^l'p_u  
else Z4369  
break; 2X6L'!=  
} 4D sHUc6  
} LN`Y`G|op  
`&i\q=u+  
b{}ao  
public void splitterStop() uA~?z :~=  
{ m.Ki4NUm  
bStop = true; G(gZL%M6  
} bp>M&1^KY  
d0 ;<Cw~Tl  
Zu|qN*N4  
} 6rMNp"!  
o8fY!C)  
 }A&I@2d  
/* %PC8}++  
**FileAccess.java =)nJ'}x  
*//文件访问(定位,写) G{gc]7\=Cd  
package NetFox; $^`@lyr  
import java.io.*; P.- `[  
(: @7IWZf@  
5=/j  
public class FileAccessI implements Serializable{ w#{S=^`}  
iC~ll!FA!  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Kiq[PK  
RandomAccessFile oSavedFile; cFr `9A\-n  
long nPos; _kdt0Vr,L  
F h+g@ u6  
>tE6^7B*  
public FileAccessI() throws IOException #,9#x]U#v  
{ =Y5_@}\0  
this("",0); xM![  
} 6 tl#AJ-  
%|'VucLx  
rDv`E^\  
public FileAccessI(String sName,long nPos) throws IOException Z u/w>  
{ sBLOrbo  
oSavedFile = new RandomAccessFile(sName,"rw"); {'yr)(:2M  
this.nPos = nPos; H7}f[4S%  
oSavedFile.seek(nPos); ^9 ^DA!'  
} ! =*k+gpF  
:M8y 2f h  
{43 J'WsJ  
public synchronized int write(byte[] b,int nStart,int nLen) VcLzv{  
{ \i3)/sZ?l  
int n = -1; j+("4b'  
try{ ;cGY  
oSavedFile.write(b,nStart,nLen); >1$Vh=\OI  
n = nLen; 'cA(-ghY/E  
} .JV y}^Q\  
catch(IOException e) Rd[^)q4d$w  
{ Y(=A HmR  
e.printStackTrace (); w%-S5#  
} h !?rk|  
|IDZMd0  
r! ~6.  
return n; eIQ@){lJ-]  
} @a,} k<@E  
 vUR gR  
Xn02p,,  
} pO)5NbU  
kAq#cLprG  
}8'b}7!  
/* !\!j?z=O8  
**SiteInfoBean.java u}89v1._Jn  
*/ b-RuUfUn0  
package NetFox; m .R**g  
0+/ew8~$  
a}X. ewg  
public class SiteInfoBean { t \-|J SZ  
D9!$H!T _  
?hYWxWW  
private String sSiteURL; //Site's URL J3$@: S'  
private String sFilePath; //Saved File's Path tGF3Hw^mS  
private String sFileName; //Saved File's Name tac\Ki?  
private int nSplitter; //Count of Splited Downloading File 6G{ Q@  
 F |aLF{  
gv1y%(`|n(  
public SiteInfoBean() FM7`q7d  
{//nSplitter的缺省值为5 /!fJ`pu!  
//default value of nSplitter is 5 zbjV>5  
this("","","",5); nH B  
} ?}#Iu-IA  
y-{?0mLq  
?in)kL  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) h4Xz"i{z  
{ PJ\k|  
sSiteURL= sURL; *,28@_EwY  
sFilePath = sPath; 6Ad=#MM  
sFileName = sName; L%+mD$@u  
this.nSplitter = nSpiltter; dSe d 6  
""*g\  
@2;cv?i)  
} -d^'-s  
N_/+B]r }T  
{nw.bKq 7  
public String getSSiteURL() =_CH$F!U  
{ W}#n.c4+  
return sSiteURL; wF3 MzN=%  
} r"|.`$:B  
C[5dhFZ  
^PUB~P/  
public void setSSiteURL(String value) OY2u,LF9H  
{ Jhfw$DF  
sSiteURL = value; E6z&pM8<8  
} .y lvJ$  
[s{[ .0P]+  
'V &Tlw|  
public String getSFilePath() d{"@<0i?  
{ '_5|9 }  
return sFilePath; RT${7=  
} ~/XDA:nfL:  
XlnSh<e  
v]Aop<KLX  
public void setSFilePath(String value) lB.n5G  
{ RhC|x,E  
sFilePath = value; `3`.usw  
} 8H|ac[hXK2  
`YqXF=-  
F)v  
public String getSFileName() .R l7,1\  
{ Pm,.[5uc  
return sFileName; x2'pl (^  
} 4-I7"pW5  
".2d{B  
7O:g;UI#  
public void setSFileName(String value) N,l"9>CF  
{ M8/:PmR<  
sFileName = value; XUnw*3tPJ  
} T#wG]DH;  
pRd'\+  
vPc*x5w-  
public int getNSplitter() $HtGB]  
{ 9Q!Z9n"8~)  
return nSplitter; tzv4uD]  
} _GrifGU\  
vn!3Z!dm(  
jw`05rw:  
public void setNSplitter(int nCount) sG)aw`_j  
{ jOzi89  
nSplitter = nCount; ^bP`Iv  
} zWH)\>X59  
} x,zYNNx5g  
@b,6W wc  
lQBE q"7$  
/* 7?{y&sf  
**Utility.java @$'pMg  
*/ TiF+rA{t  
package NetFox; 3+(lKd  
k>7bPR5Mw  
n1PBpM9!  
public class Utility { +vxOCN4}v  
53gLz_ee  
7mf&`.C np  
public Utility() V )1.)XC  
{ !zllv tK4  
,aa 4Kh  
?~4x/d%  
} W)J MV  
;Rpib[m  
//线程睡眠 3W]gn8  
public static void sleep(int nSecond) f*xr0l  
{ :0QDV~bs  
try{ T\g+w\N  
Thread.sleep(nSecond); CWocb=E  
} 3u&,3:  
catch(Exception e) GC'e  
{ |xg_z&dX  
e.printStackTrace (); =5Nh}o(l?  
} O ;[Mi  
} GM?s8yZ<  
aKWxLe  
//日志 RRV%g!  
public static void log(String sMsg) k!}(a0h  
{ 8A.7q  
System.err.println(sMsg); EmR82^_:  
} d~QM@<SV  
C=]<R< Xy  
MkL2I+*  
public static void log(int sMsg) _> x}MW+  
{ \"))P1  
System.err.println(sMsg); `GdH ,:S>  
} q6w)zTpJGJ  
} %ut 8/T  
|R _rfJh  
Tjq1[Wq  
/* 3Ovx)qKxd  
**TestMethod.java ,[zSz8R  
*/ T!ZjgCY}  
package NetFox;  WZY+c  
(RV#piM  
>}%#s`3W1_  
public class TestMethod { AvB=/p@]  
`[g$EXX  
ES AX}uF  
public TestMethod() 2xflRks  
{ ///xx/weblogic60b2_win.exe ybw\^t  
try{ pGjwI3_K  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); , ?U)mYhI  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); NsP=l]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); <kPNe>-f  
fileFetch.start(); !Q15qvRS  
} t!*[nfR  
catch(Exception e){e.printStackTrace ();} 1n[)({OQ  
8.n#@%  
T3@2e0u )  
} _:=\h5}8  
HbI{Xf[6LP  
,;Wm>V)o  
public static void main(String[] args) `bfUP s  
{ wjwCs`  
new TestMethod(); U4fv$gV  
} R[j?\#  
} Z4Dx:m-  
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