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http断点续传简单实现(java)

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/* ;vgaFc]  
**SiteFileFetch.java wUmcA~3D  
*/ mB*;>   
package NetFox; d?=r:TBU  
import java.io.*; D(M^%z2N  
import java.net.*; QeD ;GzG  
]U5/!e  
qApf\o3[0  
public class SiteFileFetch extends Thread { Oa7jLz'i  
uq@_DPA7  
4-q8:5  
SiteInfoBean siteInfoBean = null; //文件信息Bean 6/L34VH  
long[] nStartPos; //开始位置 ,}$[;$ye  
long[] nEndPos; //结束位置 wmFS+F4`2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 FJ O- p  
long nFileLength; //文件长度 2Xp?O+b#"O  
boolean bFirst = true; //是否第一次取文件 4NmLbM&C8  
boolean bStop = false; //停止标志 P64< O 5l/  
File tmpFile; //文件下载的临时信息 ((]Sy,rdk  
DataOutputStream output; //输出到文件的输出流 &+8cI^ kp  
'V:ah3 8  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) /??nO Vvt  
public SiteFileFetch(SiteInfoBean bean) throws IOException +rOd0?  
{ 6ieP` bct  
siteInfoBean = bean; 'E#Bz"T  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));  x5W. 3*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !a9/8U_>XF  
if(tmpFile.exists ()) >66v+  
{ @Yh%.#\i%  
bFirst = false; &, WQr  
read_nPos(); }%k 3  
} ~.8p8\H  
else Y kcN-  
{ O.OSLezTQ  
nStartPos = new long[bean.getNSplitter()]; &e1(|qax  
nEndPos = new long[bean.getNSplitter()]; R}\n @X*  
} z4*`K4W  
& 13#/  
zgA/B{DaC;  
9Zpd=m8dU  
} VAZ6;3@cd  
5KwT(R o  
W= $, \D+  
public void run() %n>*jFC  
{ wm_o(Z}  
//获得文件长度 dzyp:\&9  
//分割文件 WhN~R[LE_  
//实例FileSplitterFetch @wOX</_g  
//启动FileSplitterFetch线程 CqbPUcK  
//等待子线程返回 OqA#4h4^  
try{ OG}m+K&<  
if(bFirst) p*" H&xA@  
{ E=8$*YUW(g  
nFileLength = getFileSize(); [78^:q-/0  
if(nFileLength == -1) uOprA`3  
{ 63y&MaqSJ  
System.err.println("File Length is not known!"); ma(E}s  
} GJ4R f%  
else if(nFileLength == -2) OO`-{HKt  
{ haIH `S Y  
System.err.println("File is not access!"); 1A-ess\  
} R3gg{hQ  
else \v[?4 [  
{ YVB\9{H?  
for(int i=0;i<nStartPos.length;i++) ld/\`s[i  
{ UqaV9  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8!u8ZvbFG  
} mA>u6Rlc  
for(int i=0;i<nEndPos.length-1;i++) T_b$8GYfCY  
{ Dg2=;)"L  
nEndPos = nStartPos[i+1]; khtYn.eaL  
} \t\ZyPxn  
nEndPos[nEndPos.length-1] = nFileLength; uGH>|V9'c  
} fI1,L"  
} !_My]>S  
8\@&~&(y:  
nA>kJSL'$  
//启动子线程 %(y0,?*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; bClMM  
for(int i=0;i<nStartPos.length;i++) ;33LuD<h.  
{ Q,z^eMk'd:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c @~j}(A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), E8s&.:;+  
nStartPos,nEndPos,i); U<H< !NV  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yCT:U&8%F  
fileSplitterFetch.start(); 6`Af2Y_  
} [<p7'n3x  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), DKxzk~sOM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); XK t">W  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", tW |K\NL  
nEndPos = " + nFileLength); sX$EdIq  
// fileSplitterFetch[nPos.length-1].start(); _MC\\u/C/  
(r+#}z}  
'CSIC8M<j  
//等待子线程结束 (R)(%I1Oz  
//int count = 0; O4i5 fVy{  
//是否结束while循环 }+Ne)B E  
boolean breakWhile = false; jLu`DKB  
K}p!W"!o  
W4~:3 Sk  
while(!bStop) Ot#O];3  
{  iI(7{$y  
write_nPos(); 1"5-doo  
Utility.sleep(500); R"`7aa6  
breakWhile = true; ypK1 sw  
NWq>Z!x`  
l3C%`[MB  
for(int i=0;i<nStartPos.length;i++) "=97:H{!  
{ OPsg3pW!]  
if(!fileSplitterFetch.bDownOver) =Vm"2g,aA  
{ T2^0Q9E?  
breakWhile = false; ) ]x/3J@  
break; N1O.U"L;  
} xVn"xk  
} qvH7otA  
if(breakWhile) U*s QYt<?g  
break; 9OnH3  
ZfYva(zP{Q  
O8drR4 Pt  
//count++; SuU_psF  
//if(count>4) `pzXh0}|  
// siteStop(); rL /e  
} 8I`t`C/4  
|3A/Og  
a*Oc:$  
System.err.println("文件下载结束!"); xF4>D!T%8  
} tgPx!5U  
catch(Exception e){e.printStackTrace ();} Y]SX2kk(2  
} 8(EK17rE `  
2HemPth  
8- U1Y  
//获得文件长度 X<<hb  
public long getFileSize() D< h+r?  
{ hS}d vZa  
int nFileLength = -1; feH|sz`e  
try{ }Ra'`;D$  
URL url = new URL(siteInfoBean.getSSiteURL()); }yfSF|\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !F_BLHig  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9$u'2TV  
?!:$Z4G  
_*SA_.0  
int responseCode=httpConnection.getResponseCode(); Gw/imXL  
if(responseCode>=400) !6UtwCVR  
{ 5g{F-  
processErrorCode(responseCode); :bhpYEUMx  
return -2; //-2 represent access is error ^K#PcPF-j  
} t'@qb~sf  
!u0qF!/W  
lo%:$2*'p  
String sHeader; $]Vvu{  
5zqlK-$  
X(Wd  
for(int i=1;;i++) _rz*7-ks=  
{ ]}~[2k.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); El}."}l&  
//Utility.log(in.readLine()); =D2jJk?AX  
sHeader=httpConnection.getHeaderFieldKey(i); .9<  i  
if(sHeader!=null) 9,4Lb]  
{ LXIQpD,M  
if(sHeader.equals("Content-Length")) cnUYhxE+s  
{ %$)[qa3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); FM)Es&p&  
break; YB^[HE\#y  
} #Tjv(O[&  
} %)Pn<! L  
else [=63xPxs.  
break; {q[l4_  
} `Eijy3>h  
} Ez*9*]O*+  
catch(IOException e){e.printStackTrace ();} /WlpRf%  
catch(Exception e){e.printStackTrace ();} yH'vhtop  
*h`%u8/{  
2&f] v`|M|  
Utility.log(nFileLength); l.#iMi(@p~  
]5+db0  
lm?1 K:+[  
return nFileLength; yj6o533o  
} 4+Sq[Rv0  
+$hqwNh@Z@  
y7;i4::A\  
//保存下载信息(文件指针位置) ;<JyA3i^V,  
private void write_nPos() nty^De%  
{ meHnT9a^  
try{ c Bl F  
output = new DataOutputStream(new FileOutputStream(tmpFile)); o Q!56\R  
output.writeInt(nStartPos.length); D{]t50a.  
for(int i=0;i<nStartPos.length;i++) &vf%E@<  
{ GvL)SVv?  
// output.writeLong(nPos); E,F'k2yU  
output.writeLong(fileSplitterFetch.nStartPos); 1 h.=c  
output.writeLong(fileSplitterFetch.nEndPos); \a|Fh hI  
} P,2FH2Eyj  
output.close(); RJo"yB$1e6  
} ~VRt 6C  
catch(IOException e){e.printStackTrace ();} j{i3lGaN  
catch(Exception e){e.printStackTrace ();} .o(XnY)cgJ  
} C6=P(%y  
_Ra$"j  
Hl,.6 >F?  
//读取保存的下载信息(文件指针位置) H8V${&!ho  
private void read_nPos() _%M5 T  
{ 7fVlA"x  
try{ hP=^JH  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6^vMJ82U  
int nCount = input.readInt(); JF%eC}[d  
nStartPos = new long[nCount]; I.[2-~yf  
nEndPos = new long[nCount]; D;pfogK @  
for(int i=0;i<nStartPos.length;i++) DS@ZE Q`F  
{ lG\6z"K  
nStartPos = input.readLong(); tSr.0'CE  
nEndPos = input.readLong(); )%4%Uo_Xm  
} 6*] g)m  
input.close(); -R^OYgF  
} u~| D;e  
catch(IOException e){e.printStackTrace ();} x<m{B@3T  
catch(Exception e){e.printStackTrace ();} xQ[~ c1  
} ZfPWH'P  
U>bmCK2  
)575JY `6K  
private void processErrorCode(int nErrorCode) i?.7o*w8  
{ i`]-rM%J#  
System.err.println("Error Code : " + nErrorCode); _vQtV]  
} %SG**7  
z|w@eQ",  
uM!$`JN  
//停止文件下载 F~;G [6}  
public void siteStop() 39xAh*}G]  
{ )ZU)$dJ>V  
bStop = true; K3uNR w  
for(int i=0;i<nStartPos.length;i++) ~i)m(65:  
fileSplitterFetch.splitterStop(); {*gO1TZt9  
N$8do?  
3ErW3Ac Ou  
} I<v1S  
} [Yo3=(7J  
//负责部分文件的抓取 j.? '*?P  
**FileSplitterFetch.java AY{-Hf&  
*/ *SW.K{{  
package NetFox; E8[{U8)[;5  
|\yVnk!c  
9n#Q1Xq  
import java.io.*; q .[hwm  
import java.net.*; %^e~;i=2  
s*"Yi~  
O~E6"v Q  
public class FileSplitterFetch extends Thread { [D8u.8q  
y\=(;]S'  
V'kCd4  
String sURL; //File URL D(EY"s37  
long nStartPos; //File Snippet Start Position sFd"VRAV~E  
long nEndPos; //File Snippet End Position !H,_*u.  
int nThreadID; //Thread's ID vdwh59W  
boolean bDownOver = false; //Downing is over 5_bIc=L1  
boolean bStop = false; //Stop identical svt%UE|_:$  
FileAccessI fileAccessI = null; //File Access interface 2E V M*^A  
bPaE;?m  
;.Lf9XJ   
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException p$>e{-u  
{ _/@VV5Mq  
this.sURL = sURL; G+k[.  
this.nStartPos = nStart; mN5`Fct*A>  
this.nEndPos = nEnd; pF)}<<C  
nThreadID = id; e(;1XqLM  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 z:RclDm  
} t<_Jx<{2  
:lF[k`S T  
/i$-ws-  
public void run() _cz&f%qr  
{ f.V1  
while(nStartPos < nEndPos && !bStop) wYZ"fusT  
{ N|Cx";,|FZ  
<AZ21"oR/  
G#V}9l8 Q  
try{ 64qm  
URL url = new URL(sURL); W/z\j/Rgc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); oV4+w_rrLc  
httpConnection.setRequestProperty("User-Agent","NetFox"); S >E|A %  
String sProperty = "bytes="+nStartPos+"-"; 1b4aY> Z  
httpConnection.setRequestProperty("RANGE",sProperty); "`b"PQ<x  
Utility.log(sProperty); n5nV4 61U  
@,Je*5$o"  
Irk@#,{<  
InputStream input = httpConnection.getInputStream(); HPc7Vo(  
//logResponseHead(httpConnection); 4nC`DJ;V  
KfC8~{O-  
xM ]IU <  
byte[] b = new byte[1024]; a&>Tk%  
int nRead; q3+G  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 2k\i/i/Y  
{ : K%{?y  
nStartPos += fileAccessI.write(b,0,nRead); 9fk@C/$  
//if(nThreadID == 1) #[.vfG  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 'qGKS:8  
} w]Q0}Z  
czMu<@c [  
bFivHms  
Utility.log("Thread " + nThreadID + " is over!"); x/nlIoT  
bDownOver = true; ]ne&`uO  
//nPos = fileAccessI.write (b,0,nRead); adHZX  
} <+MNv#1:w  
catch(Exception e){e.printStackTrace ();} {@T8i ^EI  
} GCN(  
} Qt+|s&HGt  
./_o+~\e'  
W)3IS&;P  
//打印回应的头信息 @agW{%R:.  
public void logResponseHead(HttpURLConnection con) uZsm=('ww  
{ UlBg6   
for(int i=1;;i++) 8&15k A  
{ . &dh7` l  
String header=con.getHeaderFieldKey(i); 2o0.ttBAqZ  
if(header!=null) 0\ G`AO;D  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); V=<OV]0  
Utility.log(header+" : "+con.getHeaderField(header)); Pn)^mt  
else ^;J@]&[ ~  
break; l0c ws`V  
} zCrDbGvqF`  
} @@L@r6  
(p1y/"Xh  
ahagt9[,:F  
public void splitterStop() (!h%) _?.l  
{ sOc<'):TK  
bStop = true; 7U#`^Q}  
} f_`gUMf  
)9~1XiS,  
OrX x0Hn  
} 7%p[n;-o&  
i ! wzID  
=^. f)  
/* tw. 2h'D  
**FileAccess.java >QwZt  
*//文件访问(定位,写) pfj%AP:  
package NetFox; d*%-r2K  
import java.io.*; yZf+*j/a7  
(<ybst6+I  
;Qpp`  
public class FileAccessI implements Serializable{ S~WsGLF s  
[ m*=Q  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 n\v\<mVTb7  
RandomAccessFile oSavedFile; :Jp$_T&E  
long nPos; z7+y{-{Z  
#(o 'G4T  
!!Tk'=t9"3  
public FileAccessI() throws IOException 0 S3~IeJ  
{ Ndj9B|s_  
this("",0); 7g(,$5  
} ;6N@raP7  
lk $S"OH!  
A1xY8?#?~c  
public FileAccessI(String sName,long nPos) throws IOException )A]E:]2  
{ Fs q=u-= :  
oSavedFile = new RandomAccessFile(sName,"rw"); QJFx/zU  
this.nPos = nPos; {7^7)^@  
oSavedFile.seek(nPos); yteJHaq  
} rvT7 5dV0  
MpbH!2J  
.pNPC|XU  
public synchronized int write(byte[] b,int nStart,int nLen) `Q2 `":  
{ 6l|pTyb1  
int n = -1; Wc4K?3 ZM  
try{ $M\[^g(q  
oSavedFile.write(b,nStart,nLen); uMm/$#E  
n = nLen; - #]?3*NO  
} jEBZ"Jvb  
catch(IOException e) o[AQS`  
{ /p~Wk4'  
e.printStackTrace (); 8" Z!: =A  
} csTX',c  
x Z2 }1D  
[3`T/Wm  
return n; {Y{*(5YV  
} k[oU}~*U+  
A(y^1Nm  
<Sn5ME<*  
} azMrY<  
}G$rr.G  
zGFo -C  
/* }a@ZFk_>  
**SiteInfoBean.java [V`j@dV  
*/ qX{m7  
package NetFox; ehEXC  
Ij>x3L\-  
>j1\]uo  
public class SiteInfoBean { i][7S mN  
SJ1 1LF3)  
[T', ZLR|  
private String sSiteURL; //Site's URL ;czMsHu0X  
private String sFilePath; //Saved File's Path iqCKVo7:M  
private String sFileName; //Saved File's Name w5"C<5^  
private int nSplitter; //Count of Splited Downloading File jqHg'Fq  
X#mm Z;P  
Z(AI]wk3<  
public SiteInfoBean() 11}fPWK  
{//nSplitter的缺省值为5 ToIvyeFr  
//default value of nSplitter is 5 a pqzf  
this("","","",5);  $3](6  
} }fw;{&s{z  
>'eOzMBn  
b?h9G3J_a  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) WSfla~-'F  
{ ^=Rqa \;  
sSiteURL= sURL; .)^@[yrkz  
sFilePath = sPath; 5J1A|qII  
sFileName = sName; b7>^w<ki  
this.nSplitter = nSpiltter; E)|_7x<u  
<^VZ4$j  
SymSAq0$F  
} j(G}4dib  
0 3L"W^gc  
-!(  
public String getSSiteURL() *W q{ :k  
{ K^AX=B  
return sSiteURL; XtfO;`   
} 9&5\L  
@YmD 79  
ann!"s_  
public void setSSiteURL(String value) 'Omi3LXfDT  
{ ^\ &:'$f+8  
sSiteURL = value; ]H7_bix  
} 8Dpf{9Y-E  
ABEC{3fWpu  
zcItZP  
public String getSFilePath() W5?F?Dp!v  
{ z<rdxn,9  
return sFilePath; pmXx2T#=  
} wzB*M}3  
S4kGy}{+i  
9z 5K  -s  
public void setSFilePath(String value) $DW3H1iW  
{ fXMVl\ <  
sFilePath = value; QOIi/flK  
} 9@C3jZ+9`H  
o9M[Zr1@k  
''!pvxA  
public String getSFileName() *!UY;InanX  
{ 5=Mm=HyI2  
return sFileName; |jm|/{lc  
} 3ydOBeY  
70&v`"  
13Ga #  
public void setSFileName(String value) eN{[T PPCq  
{ yyh L]Uq"=  
sFileName = value; u8 14ZN}  
} %*P59%  
o#E 3{zM  
mnL \c'  
public int getNSplitter() 1Nx.aji  
{ qEKTSet?  
return nSplitter; HyXw^ +tsj  
} "!XeK|Wi  
_Jj/"?  
qie7iE`o  
public void setNSplitter(int nCount) YE&"IH]lF  
{ La? q>  
nSplitter = nCount; c;e-[F7  
} 2;%DE<Z  
} )F&@ M;2p'  
=If% m9  
C1P{4 U  
/* 7P9n. [  
**Utility.java 1Nw&Z0MI  
*/ I"@X~Y7}  
package NetFox; y|q4d(P.  
d9|dHJf  
#/@U|g  
public class Utility { gBHev1^y  
xBU\$ToC  
;OmmXygl  
public Utility() Jl&bWp^3  
{ j11\t  
,Ihuo5>/z  
( gO?-0  
} PC/fb-J  
#})Oz| c  
//线程睡眠 ]>/YU*\  
public static void sleep(int nSecond) !`\W8JT+  
{ Dqe)8 r  
try{ ?LgR8/Io@5  
Thread.sleep(nSecond); l9 )iLOj  
} j>eL&.d  
catch(Exception e) ~j 3B'  
{ Yqmx]7Y4  
e.printStackTrace (); #NNj#  
} >joGG T  
} 5. :To2  
3/:O8H  
//日志 0~A<AF*t  
public static void log(String sMsg) UA{sUj+?  
{ # j*$ `W;  
System.err.println(sMsg); [V{JuG;s  
} KoiU\r  
Ql%7wrK  
F^_d8=67h  
public static void log(int sMsg) /V~L:0%  
{ P~ _CDh.N  
System.err.println(sMsg); 0{ v?  
} {b^naE  
} [ar:zl V8  
4DEsB)%X  
cGkl=-oQ'  
/* R%aH{UhE`  
**TestMethod.java b@^M|h.Va  
*/ lZ0+:DaP2  
package NetFox; 52m^jT Sx  
?Li^XONz  
a%tm[Re  
public class TestMethod { `NXyzT`:K  
dpZ7eJ   
sxgR;gf6  
public TestMethod() _XXK1H x  
{ ///xx/weblogic60b2_win.exe 7E Y~5U/4  
try{ YC&iH>jO3  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 7;;W{W%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,M7sOp6}  
SiteFileFetch fileFetch = new SiteFileFetch(bean); f Otrn  
fileFetch.start(); |C'w] QYm  
} POH >!lHu  
catch(Exception e){e.printStackTrace ();} qS&PMQ"$  
rZu_"bcJ  
x~s>  
} H; TmG<S  
34YYw@?}Y  
$2]1 3j  
public static void main(String[] args) MGc=TQ.  
{ @EfCNOy  
new TestMethod(); #H O\I7m  
} z(.$>O&6H  
} L)8+/+  
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