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http断点续传简单实现(java)

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/*  &7L~PZ  
**SiteFileFetch.java 6?%]odI#  
*/ zQL!(2  
package NetFox; F-$Z,Q]S  
import java.io.*; 0M#N=%31  
import java.net.*; dr| | !{\  
Y H<$ +U  
X+`ddX  
public class SiteFileFetch extends Thread { -@%t"8  
PU^[HC*K  
W:VW_3  
SiteInfoBean siteInfoBean = null; //文件信息Bean *C4~}4WT\  
long[] nStartPos; //开始位置 P<>[e9|  
long[] nEndPos; //结束位置 %'{V%IXQ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 -!XrwQyk  
long nFileLength; //文件长度 :0M' =~[  
boolean bFirst = true; //是否第一次取文件 Ff[H>Lp~  
boolean bStop = false; //停止标志 u{g]gA8s  
File tmpFile; //文件下载的临时信息 ?JuX~{{. L  
DataOutputStream output; //输出到文件的输出流 ~8jThi U  
K H>Sc3p  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) "[awmZ:wo  
public SiteFileFetch(SiteInfoBean bean) throws IOException =:4 '  
{ J Z %`%rA  
siteInfoBean = bean; W.yV/fu  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); vx04h~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &e%{k@  
if(tmpFile.exists ()) t *o7,  
{ r> Fec  
bFirst = false; o{9?:*?7  
read_nPos(); Z -pyFK\  
}  AGh~8[  
else @kwLBAK}@  
{ 5+y@ ]5&g  
nStartPos = new long[bean.getNSplitter()]; )2) Zz +<  
nEndPos = new long[bean.getNSplitter()]; utq.r_  
} a;56k  
uAp -$?  
q|n97.vD  
M{*kB2jr  
} &@=u+)^-{  
TRSOO}  
h^['rmd  
public void run() 9Tqn zD  
{ (d54C(")  
//获得文件长度 HMF8;,<_w?  
//分割文件 =8O}t+U  
//实例FileSplitterFetch ov1Wr#s  
//启动FileSplitterFetch线程 La\Q'0  
//等待子线程返回 ~;}\zKQKE  
try{ UV?[d:\>'  
if(bFirst) =ZG<BG_  
{ $=\d1%_R|  
nFileLength = getFileSize(); grGhN q  
if(nFileLength == -1) )qbI{^_g  
{ ~af8p {  
System.err.println("File Length is not known!"); vB Sm=M  
} d?JAUbqy  
else if(nFileLength == -2) k& OC&  
{ $RpF xi  
System.err.println("File is not access!"); \^yXc*C  
} D=2~37CzQ1  
else <H<!ht%q3  
{ \.5F](:  
for(int i=0;i<nStartPos.length;i++) .H ,pO#{;  
{ Dp^"J85}   
nStartPos = (long)(i*(nFileLength/nStartPos.length)); &8Zeq3~  
} T0g0jr{  
for(int i=0;i<nEndPos.length-1;i++) j0AwL7  
{ }|AX_=a  
nEndPos = nStartPos[i+1]; L?C\Q^0"`G  
} |Es0[cU  
nEndPos[nEndPos.length-1] = nFileLength; U> W|(Y  
} (viWY  
} =ntft SH  
KCE=|*6::|  
5n:nZ_D  
//启动子线程 g&Z"_7L~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; N A8 sN  
for(int i=0;i<nStartPos.length;i++) S3ErH,XB.  
{ `a-Bji?  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |4=ihB9+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), gRHtgR)T3  
nStartPos,nEndPos,i); ? 'Cb-C_  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); { AFf:[G  
fileSplitterFetch.start(); 'CgV0&@  
} V>6QPA^  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), B<Ol+)@,}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); qbH %Hx  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", U4]30B{;H  
nEndPos = " + nFileLength); i)=m7i  
// fileSplitterFetch[nPos.length-1].start(); X|,["Az 8  
Pv~:gP  
YDW|-HIF  
//等待子线程结束 x9h?e`  
//int count = 0; tbg*_ZQO u  
//是否结束while循环 )u<eO FI+  
boolean breakWhile = false; ]}.0el{  
WX LK89ev\  
E!uJ6\  
while(!bStop) [8.-(-/;  
{ I4ebkPgf  
write_nPos(); 7aV$YuL)X~  
Utility.sleep(500); $_wo6/J5+D  
breakWhile = true; ,}KwP*:Z  
-U7,k\g  
l(#1mY5!q8  
for(int i=0;i<nStartPos.length;i++) grc:Y  
{ >}CEN  
if(!fileSplitterFetch.bDownOver) M%3Wy"YQ,n  
{ GKCM|Y  
breakWhile = false; _p0)vT  
break; f$vwuW  
} ?HV}mS[t  
} ndqckT@93  
if(breakWhile) eIsT!V" 7  
break; Z0 aUHWms  
wE?CvL  
7N| AA^I  
//count++; B@"J]S  
//if(count>4) -A}zJBcR  
// siteStop(); "w9`cz9a~J  
} Y KY2Cw  
yWNOG 2qAP  
&f"T,4Oh  
System.err.println("文件下载结束!"); 7|Xe&o<n  
} g>_OuQ|c  
catch(Exception e){e.printStackTrace ();} b;*c:{W)  
} _H8*ReFG  
Zb"jB$58  
PYu$1o9+N  
//获得文件长度 a_MFQf&KV  
public long getFileSize() 1\y@E  
{ w763 zi{  
int nFileLength = -1; Od-Ax+Hp  
try{ W tVf wC_  
URL url = new URL(siteInfoBean.getSSiteURL()); /9Z!p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M1EOnq4-  
httpConnection.setRequestProperty("User-Agent","NetFox"); Jr]gEBX  
*!w25t  
2$ tQ @r  
int responseCode=httpConnection.getResponseCode(); yyjw?#\8  
if(responseCode>=400) F{\=PCZ>7  
{ @y5=J`@=  
processErrorCode(responseCode); =DC 3a3&%  
return -2; //-2 represent access is error ~;8I5Sge  
} NJm-%K  
ioWo ]  
\sITwPA[z  
String sHeader; ' Rc#^U*n  
Z%OW5]q  
e}e6r3faz  
for(int i=1;;i++) {yS;NU`2  
{ WFem#hq   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 7E\g &R.  
//Utility.log(in.readLine()); 8ljuc5,J  
sHeader=httpConnection.getHeaderFieldKey(i); uFo/s&6K  
if(sHeader!=null) lm*g Gy1i  
{ 2T?TM! \Q  
if(sHeader.equals("Content-Length")) 0<Q*7aY  
{ z&F5mp@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )b0];&hw]  
break; 7h`^N5H.q  
} H99xZxHZ{  
} Bzw19S6y  
else ?A&%Cwj  
break; G|*G9nQ  
} 7&foEJ3q  
} xNIGO/uI~  
catch(IOException e){e.printStackTrace ();} #A )Ab%r8"  
catch(Exception e){e.printStackTrace ();} K{2h9 ]VF  
#)]E8=}  
WqQU@sA  
Utility.log(nFileLength); #w|5 jN?  
ke]Yfwk  
G?ig1PB"#  
return nFileLength; wDKELQ(y H  
} >vAN(3Idu  
0X>T+A[E  
~b6GrY"vB  
//保存下载信息(文件指针位置) ? |VysJ  
private void write_nPos() TF2KZL#A|  
{ pV=@sz,G  
try{ 0>FE%  
output = new DataOutputStream(new FileOutputStream(tmpFile)); RX>2~^  
output.writeInt(nStartPos.length); &a6,ln:P  
for(int i=0;i<nStartPos.length;i++) ?Oc -aa  
{ RG1\=J$:E  
// output.writeLong(nPos); X!c?CL  
output.writeLong(fileSplitterFetch.nStartPos); w.^yP7:  
output.writeLong(fileSplitterFetch.nEndPos); +?AW>&68y  
} $8g42LR'  
output.close(); p9iu:MucD<  
} V;;#/$oU:4  
catch(IOException e){e.printStackTrace ();} U=QA  e  
catch(Exception e){e.printStackTrace ();} w & P&7  
} ]\dHU.i  
NzlAC  
Ao"C<.gUYP  
//读取保存的下载信息(文件指针位置) 2y%R:Mu  
private void read_nPos() ]r959+\$  
{ Dr+Ps  
try{ 12OlrU  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ShGp^xVj  
int nCount = input.readInt(); oY.\)eJ~>  
nStartPos = new long[nCount]; ]0-<>  
nEndPos = new long[nCount]; vQHpf>o  
for(int i=0;i<nStartPos.length;i++) {SdO9Yy?@7  
{ FmD +8=  
nStartPos = input.readLong(); VB"(9O]  
nEndPos = input.readLong(); iRve)   
} ix*muVBj.  
input.close(); x0<^<D&Q  
} 0T9. M(  
catch(IOException e){e.printStackTrace ();} " " %#cDR  
catch(Exception e){e.printStackTrace ();} LGVlc@0'  
} 1-o V-K  
`D2Mss$!  
ArXl=s';s4  
private void processErrorCode(int nErrorCode) ti2  
{ n&d/?aJ7a\  
System.err.println("Error Code : " + nErrorCode); Nog(VN4I&  
} X<euD9?  
mb{q(WEPP  
YgimJsm  
//停止文件下载 N RSU+D-z  
public void siteStop() P }Te"Y  
{ Uk'U?9O  
bStop = true; vpLMhf`  
for(int i=0;i<nStartPos.length;i++) R=$Ls6z  
fileSplitterFetch.splitterStop(); Qxq-Mpx{  
[r9d<Zi}{  
nzuF]vo  
} xS+rHC  
} eY}V9*.v  
//负责部分文件的抓取 wS$46M<  
**FileSplitterFetch.java u"FjwF?  
*/ UA(;fZ@  
package NetFox; ]w[ThHRJ  
A*i_|]Q  
sE9Ckc5  
import java.io.*; *eGM7o*\X  
import java.net.*; 8x{Hg9  
h(N=V|0  
%5Rq1$D  
public class FileSplitterFetch extends Thread { M-Sv1ZLh  
:Q- F9o J  
XU9'Rfp  
String sURL; //File URL 9o_- =>(  
long nStartPos; //File Snippet Start Position yL&/m~{s  
long nEndPos; //File Snippet End Position ] .5O X84  
int nThreadID; //Thread's ID '[f Zt#  
boolean bDownOver = false; //Downing is over ~L'nz quF  
boolean bStop = false; //Stop identical f#OQ (WTJE  
FileAccessI fileAccessI = null; //File Access interface ZqK]jT6V/X  
% rcFT_  
T4GW1NP  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException N`1r;%5  
{ ( 3;`bvYH"  
this.sURL = sURL; P']Y( !L  
this.nStartPos = nStart; *rf$>8~$n  
this.nEndPos = nEnd; 6N3@!xtpi  
nThreadID = id; *Hunp Y  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \ja `c)x  
} &HL{LnLP@/  
_]o5R7[MQ  
/s`;9)G]9  
public void run() .$wLLE^*  
{ @a(oB.i  
while(nStartPos < nEndPos && !bStop) 784;]wdy\  
{ ?D=8{!R3  
gp/YjUH7k8  
|M E{gy`5  
try{ w1i?# !|  
URL url = new URL(sURL); )eR$:uO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); dtTlIhh1V  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~6d5zI4\  
String sProperty = "bytes="+nStartPos+"-"; 3cThu43c  
httpConnection.setRequestProperty("RANGE",sProperty); .Dx2 ;lj  
Utility.log(sProperty); }cW#045es  
T2|:nC)@  
ML= z<u+  
InputStream input = httpConnection.getInputStream(); ^:z7E1 ~  
//logResponseHead(httpConnection); Y iZx{5  
) b:4uK A  
sykFSPy`'  
byte[] b = new byte[1024]; sN]Z #7  
int nRead; rPO}6lsc  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >EIrw$V$  
{ x'i0KF   
nStartPos += fileAccessI.write(b,0,nRead); bl.EIyG>  
//if(nThreadID == 1) wPH+n-&e  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U~/ID  
} VDiOO  
DL4iXULNY  
?Aw3lH#:  
Utility.log("Thread " + nThreadID + " is over!"); Qlh?iA  
bDownOver = true; !Uy>eji}  
//nPos = fileAccessI.write (b,0,nRead); )!,@m>0v{  
} j38 6gL  
catch(Exception e){e.printStackTrace ();} +c?ie4   
} 7K:FeW'N  
} -tyaE  
yVYkuO  
>76 |:Nq  
//打印回应的头信息 <Uwwux<v  
public void logResponseHead(HttpURLConnection con) U>A6eWhH  
{ TQ-KkH}y  
for(int i=1;;i++) jL_5]pzJ  
{ a8QfkOe  
String header=con.getHeaderFieldKey(i); G_(ct5:_"!  
if(header!=null) )7AM3%z1?  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Efr3x{ j  
Utility.log(header+" : "+con.getHeaderField(header)); 4Py3I9  
else D|TR!  
break; b1)\Zi  
} v, 0<9!'v  
} 7d9Z/J@>  
(hsZ  
]]y[t|6  
public void splitterStop() **HrWM%?8o  
{ L*^ V5^-  
bStop = true; .vaJ Avg  
} 5!h<b3u>]  
bd{\{[^S!  
K?YEoz'y[  
} {aIZFe}B  
dEET}s\  
y@ .b 4  
/* FfSI n3  
**FileAccess.java r=\P!`{5  
*//文件访问(定位,写) Z@oKz:U  
package NetFox; BA*&N>a  
import java.io.*; z Lw(@&  
8!4[#y<  
DaDUK?  
public class FileAccessI implements Serializable{ O! (85rp/  
JZw^ W{  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 DaCblX  
RandomAccessFile oSavedFile; nX 8B;*p6b  
long nPos; g]4y AV<2  
M:(&n@e  
)f[C[Rd  
public FileAccessI() throws IOException +C5#$5];  
{ XHNkQe  
this("",0); ==`Pb  
} %ET # z!  
?RJdn]`4j  
07Y_^d  
public FileAccessI(String sName,long nPos) throws IOException X TM$a9)  
{ y9ip[Xn-$:  
oSavedFile = new RandomAccessFile(sName,"rw"); kwc*is  
this.nPos = nPos; 23k)X"5  
oSavedFile.seek(nPos); ]_\AHnJ  
} pU@YiwP"]x  
L6x B`E9  
AoU_;B\b%  
public synchronized int write(byte[] b,int nStart,int nLen) q#m!/wod  
{ J@gm@ jLc  
int n = -1; "u5KbJW  
try{ PY\W  
oSavedFile.write(b,nStart,nLen); T+(M8 qb  
n = nLen; +K&?)?/=  
} *?p ^6vO  
catch(IOException e) [9J:bD  
{ r;'i<t{P  
e.printStackTrace (); 6"%@ L{UQ  
} Z,SY N?@  
(H2ylMpQt  
bl`D+/V   
return n; i)[kubM  
} YQx?* gZS  
1]Lhk?4t  
%rw}u"3T  
} HM 90Sb  
~;!BDLMC6  
V07VwVD  
/* @"0uM?_)-  
**SiteInfoBean.java #)FDl70S8  
*/ 73VQ@J n  
package NetFox; Ej{+U  
!. p  
hAlPl<BO#V  
public class SiteInfoBean { m|lM.]2_  
]  ~'9  
aU4R+.M7@  
private String sSiteURL; //Site's URL brj[c>ID  
private String sFilePath; //Saved File's Path aj?2jU~Pq  
private String sFileName; //Saved File's Name 8<Xq=*J+  
private int nSplitter; //Count of Splited Downloading File }a' cm!"  
.Jptj  
gU+ss  
public SiteInfoBean() WqR7uiCi  
{//nSplitter的缺省值为5 el}hcAY/RP  
//default value of nSplitter is 5 X:U=MWc>  
this("","","",5); tg3zXJ4k_  
} [z^Od  
!ZX&r{pJp  
o>.AdZby  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 2G ZF/9}  
{ K[e`t%2_  
sSiteURL= sURL; xUIvLH=  
sFilePath = sPath; `t%|.=R  
sFileName = sName; e~3]/BL  
this.nSplitter = nSpiltter; @`5QG2  
KM5jl9Vv  
<>VID E  
} Qg[heND  
?vMK'"  
/q T E  
public String getSSiteURL() b-2pzcK{#  
{ q)vK`\Y  
return sSiteURL; )sRN!~  
} (v]P<3%  
U&`6&$]  
v: giZxR  
public void setSSiteURL(String value) !;TR2Zcn  
{  ccRlql(  
sSiteURL = value; 9U&~(;  
} !X%S)VSMU  
K4_~ruhr  
N`f!D>b:dn  
public String getSFilePath() Rq"VB.ef&{  
{ dJloH)uJZ>  
return sFilePath; 0 4P.p6  
}  c^rC8E  
*U :VM'a  
GahaZ F  
public void setSFilePath(String value) oN_S}o  
{ #,t2*tM  
sFilePath = value; @<|6{N<  
} sf fV.cC`  
"v@);\-V  
6euR'd^Qi  
public String getSFileName() R_t~UTfI;  
{ "tfn?n0  
return sFileName; 4tbw*H5!5  
} Um/CR!  
 o1 jk=  
bh{E&1sLh  
public void setSFileName(String value) [SK2x4  
{ G}182"#4  
sFileName = value; C\y[&egww  
} 2=jd;2~  
kZJt ~}  
eH ;Wfs2f  
public int getNSplitter() f#*h^91x  
{ f;e_04K  
return nSplitter; :x8Jy4L  
} Ga]47pQ"F  
d#E(~t(^  
-K:yU4V  
public void setNSplitter(int nCount) Qk?jGXB>^  
{  AqKHjCI  
nSplitter = nCount; Cw6>^  
} n>u.3w L  
} wYZy e^7  
V+Y|4Y&  
R 4DM_ u  
/* XPar_8I  
**Utility.java d^ 2u}^kG  
*/ s>LA3kT  
package NetFox; uCY(:;[<  
F~tm`n8Z  
@~JB\j9  
public class Utility { P]|J?$1K  
y2oB]^z&n  
1[26w_B3  
public Utility() >`<Ued  
{ Mr$# e  
 aeEw#  
OG0r4^6Ly  
} &mX5&e  
Is4%}J!8  
//线程睡眠 :Tlf4y:/w  
public static void sleep(int nSecond) *>E I2HX  
{ 8dV.nO  
try{ l\q*%'Pe  
Thread.sleep(nSecond); s@[C&v  
} f 1sy9nQs  
catch(Exception e) sjkWz2]S  
{ w%>aR_G  
e.printStackTrace (); 5x:Ift *  
} p>2||  
} j)g_*\tQ  
i58ZV`Rk`  
//日志 5W*7qD[m  
public static void log(String sMsg) O<}ep)mr  
{ }wvwZ`5t  
System.err.println(sMsg); hubfK~  
} K<$wz/\  
It#hp,@e  
!F=|*j  
public static void log(int sMsg) `'z(--J}`  
{ \hjk$Gq  
System.err.println(sMsg); s-QM 6*  
} nAQyxP%  
} 3!i. Fmo  
Gg 7Wm L  
jA20c(O  
/* y0/WA4,  
**TestMethod.java "6NFe!/Y$*  
*/ Dj-\))L  
package NetFox; o0zc}mm  
08<k'Oi]  
F{#N6,T  
public class TestMethod { !yoSMI-  
)e4WAlg8c  
O"_erH\nk  
public TestMethod() 2rK-X_}  
{ ///xx/weblogic60b2_win.exe h Jfa_  
try{ .8u$z`j  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `_NnQ%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $=e&q  
SiteFileFetch fileFetch = new SiteFileFetch(bean); u=p ;A1oy  
fileFetch.start(); ]_^"|RJ  
} \_m\U.*  
catch(Exception e){e.printStackTrace ();} .V5q$5j  
ib5;f0Qa  
oV0LJ%  
} ga4/,   
e%P+KX  
6F|Hg2tpz  
public static void main(String[] args) DFt=%aV[  
{ _hAj2%SL  
new TestMethod(); 0EL\Hd  
} Y9IJ   
} K7 t&fDI  
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