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http断点续传简单实现(java)

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/* tRO=k34  
**SiteFileFetch.java ' MBXk2?b  
*/ G0~Z|P  
package NetFox; %H;}+U]Z  
import java.io.*; ?@7!D8$9  
import java.net.*; ^G2M4+W|  
/.=aA~|  
jm@,Ihz=wI  
public class SiteFileFetch extends Thread { QnP?j&  
e!o\AB%d  
I$p1^8~L  
SiteInfoBean siteInfoBean = null; //文件信息Bean wGw~ F:z  
long[] nStartPos; //开始位置 D4C:%D  
long[] nEndPos; //结束位置 O9E:QN<U`*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 lC`w}0 p  
long nFileLength; //文件长度 j7QK8O$XL  
boolean bFirst = true; //是否第一次取文件 %l14K_  
boolean bStop = false; //停止标志 wu><a!3`=o  
File tmpFile; //文件下载的临时信息 ^)I}#  
DataOutputStream output; //输出到文件的输出流 D[?;+g/  
W$2 \GPJt  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) PTLlLa85<  
public SiteFileFetch(SiteInfoBean bean) throws IOException /CMgWGI  
{ ?QzL#iO }h  
siteInfoBean = bean; :CK`v6 Qs  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); MmfBFt*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); de)4)EzUP  
if(tmpFile.exists ()) Jwfb%Xge~  
{ JN4gH4ez)  
bFirst = false; /e[m;+9^&  
read_nPos(); ok0ZI>=,  
} X7AxI\h  
else c61OT@dZEA  
{ 7s3=Fa:9Q  
nStartPos = new long[bean.getNSplitter()]; '|Bk}pl7  
nEndPos = new long[bean.getNSplitter()]; p JT)X8K"  
} W]DGt|JP  
m;\nMdn  
s]O Z+^Z  
{? Y \T  
} 4x(m.u@  
/RMtCa~  
RXg\A!5GV  
public void run() A&p@iE*/  
{ TWGn: mi  
//获得文件长度 `4snTM!v&  
//分割文件 "igA^^?X1N  
//实例FileSplitterFetch  6?*Do  
//启动FileSplitterFetch线程 \8!CKnfs  
//等待子线程返回 )W>$_QxbN  
try{ Knqv|jJVx1  
if(bFirst) R!QR@*N  
{ q~ Z UtF  
nFileLength = getFileSize(); X-fWdoN @-  
if(nFileLength == -1) =X^a  
{ O/FI>RT\H  
System.err.println("File Length is not known!"); vA!IcDP"  
} Yj>4*C9  
else if(nFileLength == -2) {<@ud0A:\  
{ W_E^+Wl@  
System.err.println("File is not access!"); e)B1)c8s  
} _AX,}9  
else Hzm_o>^KC  
{ )Sb-e(sl  
for(int i=0;i<nStartPos.length;i++) YVa,?&i=N  
{ "qF/7`e[  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); VgIk'.  
} 97\K] Tr  
for(int i=0;i<nEndPos.length-1;i++) {*F =&D  
{ hZ452W  
nEndPos = nStartPos[i+1]; )1B? <4  
} }q]*aADe  
nEndPos[nEndPos.length-1] = nFileLength; 8.. |-<w  
} j3;W-c`5  
} @O'NJh{D`  
<!FcQVH+L  
P?f${ t+  
//启动子线程 / 7\q#qIm:  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]?H12xz  
for(int i=0;i<nStartPos.length;i++) YcX"Z~O6j=  
{ Jh=.}FXnjL  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )Cj1VjAg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), J-'XT_k:iM  
nStartPos,nEndPos,i); LYL_Ah'=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BXU0f%"8U  
fileSplitterFetch.start(); gAorb\iJ  
} G!sfp}qW  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4]m{^z`1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); n/(}|xYU  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", e,p*R?Y{[  
nEndPos = " + nFileLength); 5o 5DG  
// fileSplitterFetch[nPos.length-1].start(); ;z9 ,c  
aV|V C $  
B-]bhA4|:  
//等待子线程结束 =,;$d&#*h  
//int count = 0; "1^tVw|  
//是否结束while循环 _[z)%`kay  
boolean breakWhile = false; X9|*`h<  
|3E|VGm~  
Zl&ED{k<  
while(!bStop) x3FB`3y~s  
{ %G 2g @2  
write_nPos(); b j@R[!ss  
Utility.sleep(500); <";1[A%7<  
breakWhile = true; ^j${#Q  
_F[a2PE2+  
_;5zA"~c#@  
for(int i=0;i<nStartPos.length;i++) i0wBZ i?  
{ @]#[TbNo  
if(!fileSplitterFetch.bDownOver) h%u!UHA  
{ &l ]F&-  
breakWhile = false; 9-{+U,3)  
break; dl8f]y#Q  
} ;`pIq-=  
} k6z ]-XG  
if(breakWhile) +,YK}?e  
break; -f ~1Id  
am3.Dt2\  
k3t]lG p  
//count++; C.#Ha-@uz  
//if(count>4) R'tvF$3=i  
// siteStop(); ZG1TR F "  
} PPV T2;9  
P3W3+pwq  
6(7{|iY  
System.err.println("文件下载结束!"); &L?]w=*  
} W0mvwYON[  
catch(Exception e){e.printStackTrace ();} $Bc3| `K1v  
} `u_MdB}<x;  
.YvIVQ  
U_'M9g{,<  
//获得文件长度 X,G"#j^  
public long getFileSize() ,.2qh|Ol  
{ X=f%!  
int nFileLength = -1; ._j?1Fw`  
try{ 0Cf'\2  
URL url = new URL(siteInfoBean.getSSiteURL()); Q.jThP`p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $Lbamg->E  
httpConnection.setRequestProperty("User-Agent","NetFox"); C :sgT6  
?MSwr_eZH  
NpM;vO  
int responseCode=httpConnection.getResponseCode(); `_1fa7,z  
if(responseCode>=400) >h~ik/|*  
{ /CyFe<t  
processErrorCode(responseCode); p`\>GWuT!  
return -2; //-2 represent access is error R#y"SxD()  
} 9^H.[t  
ADOA&r[  
jHE^d<=O^  
String sHeader; tK uJ &I~  
l+&DBw[  
iT| 7**+3  
for(int i=1;;i++) j -"34  
{ vN_ 8qzWk  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); V'dw=W17V  
//Utility.log(in.readLine()); m}D;=>2$  
sHeader=httpConnection.getHeaderFieldKey(i); NhTJB7  
if(sHeader!=null) -e0[$v  
{ 6!itr"  
if(sHeader.equals("Content-Length")) FAc^[~E  
{ ojm IEzsz  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); a @3s71  
break; 0:I<TJ~P  
} IaO R%B g  
} stW G`>X  
else K8 [Um!(  
break; #U w X~  
} [742s]j  
} >)diXe}j  
catch(IOException e){e.printStackTrace ();} A1Uy|Dl  
catch(Exception e){e.printStackTrace ();} 2)0J@r'  
l. cp[  
:HrFbq  
Utility.log(nFileLength); ?>V>6cDQ  
!kb:g]X  
I][&*V1  
return nFileLength; Np$&8v+en  
} 1 \aTA,  
zv;xxAX  
Y}2Sr-@u  
//保存下载信息(文件指针位置) [kxOv7a  
private void write_nPos() ^LB]  
{ Z'!ORn#M  
try{ :IJ<Mmb  
output = new DataOutputStream(new FileOutputStream(tmpFile)); O8" t.W  
output.writeInt(nStartPos.length); t18j2P>`  
for(int i=0;i<nStartPos.length;i++) ;&}z L.!jo  
{ ),Yk53G6c  
// output.writeLong(nPos); uHmvHA~/c8  
output.writeLong(fileSplitterFetch.nStartPos); W|zPV`  
output.writeLong(fileSplitterFetch.nEndPos); E11C@%  
} Dic|n@_Fy  
output.close(); MXEI/mDYK  
} EN/t5d  
catch(IOException e){e.printStackTrace ();} =6=:OId  
catch(Exception e){e.printStackTrace ();} ?Y8hy|`  
} B B69U  
BgdUG:;&  
^=5y;  
//读取保存的下载信息(文件指针位置) =23@"ji@D  
private void read_nPos() 4J(-~  
{ =0PGE#d{t  
try{ 7 wEv`5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); VMJaL}J]  
int nCount = input.readInt(); T KAs@X,t  
nStartPos = new long[nCount]; I''n1v?N  
nEndPos = new long[nCount]; m]fUV8U  
for(int i=0;i<nStartPos.length;i++) aL90:,V  
{ {~Jk(c~I  
nStartPos = input.readLong(); h2Th)&Fb>  
nEndPos = input.readLong(); X?< L<:.  
} (&v|,.c^)1  
input.close(); 4L{]!dox  
} kMnG1K  
catch(IOException e){e.printStackTrace ();} ^_P?EJ,)`  
catch(Exception e){e.printStackTrace ();} cRbA+0m>  
} &Q}%b7  
2@z.ory.  
~a`  xI  
private void processErrorCode(int nErrorCode) u'_}4qhCC;  
{ [v*q%Mi_  
System.err.println("Error Code : " + nErrorCode); ##xvuLy-6  
} 6g" h}p\{S  
\**j \m   
U Xpp1/d|e  
//停止文件下载 u SQ#Y^V_  
public void siteStop() wik<# ke  
{ +YW;63"o  
bStop = true; BQg3+w:>  
for(int i=0;i<nStartPos.length;i++) `G`R|B  
fileSplitterFetch.splitterStop(); mR XR uK  
&V <f;PF(I  
Mz2TwU_  
} L)F4)VL  
} {GnZ@Q:F  
//负责部分文件的抓取 g\.$4N  
**FileSplitterFetch.java (g X8iKl  
*/ URbB2 Bi  
package NetFox; |D/a}Av>B  
ysIhUpd  
G&1bhi52  
import java.io.*; +>!nqp  
import java.net.*; Fc\]*  
*kqC^2t  
OM\1TD/-  
public class FileSplitterFetch extends Thread { =IQ}Y_xr  
zN]%p>,)HB  
V8B4e4F  
String sURL; //File URL a <?~1pWtc  
long nStartPos; //File Snippet Start Position vVa|E# [  
long nEndPos; //File Snippet End Position W~D_+[P|_  
int nThreadID; //Thread's ID sr&W+4T  
boolean bDownOver = false; //Downing is over 0D@$  
boolean bStop = false; //Stop identical AzXLlQ  
FileAccessI fileAccessI = null; //File Access interface wDW%v@  
[*zg? ur  
>Q=^X3to  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [NO4Wzc  
{ 23L>)Q  
this.sURL = sURL; ^ `Ozw^~  
this.nStartPos = nStart; !^su=c  
this.nEndPos = nEnd; 7(.Z8AO  
nThreadID = id; H#;*kc a4  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 x@rQ7K>  
} b=:ud[h  
wv{ Qx^  
o|z@h][(l(  
public void run() 4l %W]'  
{ \b(&-=(  
while(nStartPos < nEndPos && !bStop) Wmcd{MOS  
{ '0q$qN  
QE[<Y3M  
mWaij]1>  
try{ Y 2ANt w@  
URL url = new URL(sURL); XxmWj-=qO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); OR~ui[w  
httpConnection.setRequestProperty("User-Agent","NetFox"); IV. })8  
String sProperty = "bytes="+nStartPos+"-"; {E Ay~lo  
httpConnection.setRequestProperty("RANGE",sProperty); 7mMGH(  
Utility.log(sProperty); S5TVfV5LI  
 MYy58N  
NC-K`)  
InputStream input = httpConnection.getInputStream(); >;c);|'}q  
//logResponseHead(httpConnection); Y#68_%[  
%CiF;wJ  
%w65)BFQ  
byte[] b = new byte[1024]; k"i3$^v8  
int nRead; ANu>*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) iVZ}+Ct<"  
{ .@OQ$ D<  
nStartPos += fileAccessI.write(b,0,nRead); *%KIq/V  
//if(nThreadID == 1) {ac$4#Bp[B  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :\"0jQ.y|  
} BkXv4|UE  
{HEWU<5  
8~C}0H  
Utility.log("Thread " + nThreadID + " is over!"); l6HtZ(  
bDownOver = true; ?{f6su@rW  
//nPos = fileAccessI.write (b,0,nRead); `X@\Zv=}  
} jC>ZMy8U)4  
catch(Exception e){e.printStackTrace ();} N { oVz],  
} St%x\[D  
} [6mK<A,/  
q\o#<'F1J  
-@w,tbc$  
//打印回应的头信息 ~+4lmslR  
public void logResponseHead(HttpURLConnection con) 06.%9R{  
{ f~mwDkf?L  
for(int i=1;;i++) qK%N{ro[{?  
{ u9S*2'  
String header=con.getHeaderFieldKey(i); "H(3pl.  
if(header!=null) ]w6 F%d  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); pwfQqPC#_  
Utility.log(header+" : "+con.getHeaderField(header)); x&;AY  
else Z. gb'  
break; &EV%g6  
} c2g[w;0"  
} cwzkA,e@  
D|ze0A@  
u/j\pDl.  
public void splitterStop() -"nkC  
{ .Bl:hk\  
bStop = true; 1w7tRw  
} (}X5*BB&  
I*a@_EO  
,byc!P  
} /K li C\  
R5=J:o  
-r cEG!  
/* =_k  
**FileAccess.java [ft6xI  
*//文件访问(定位,写) 3\m !  
package NetFox; Ql5bjlQdO  
import java.io.*; 9)t b=  
Xf&YcHo  
p)B /(%  
public class FileAccessI implements Serializable{ QO;Dyef7b  
O"~[njwkE  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 s&nat4{B  
RandomAccessFile oSavedFile; m^L!_~  
long nPos; bQ3<>e\%B  
kfas4mkc  
Q9OCf"n$  
public FileAccessI() throws IOException h!SsIy(  
{ &l2xh~L  
this("",0); [G8EX3  
} A-4;$ QSm  
l GYW[0dy  
:|V650/  
public FileAccessI(String sName,long nPos) throws IOException yrEh5v:  
{ X9?)P5h=  
oSavedFile = new RandomAccessFile(sName,"rw"); ] hK}ASC  
this.nPos = nPos; 5;KJ0N*-  
oSavedFile.seek(nPos); _s@PL59,  
} $#f_p-N  
^*fD  
.:&`PaMt  
public synchronized int write(byte[] b,int nStart,int nLen) n yPeN?-  
{ A^).i_&#  
int n = -1; c6i7f:'-0  
try{ MkMDI)Y|  
oSavedFile.write(b,nStart,nLen); | U0s1f  
n = nLen; -B-G$ii  
} t!3s@  
catch(IOException e) lv/im/]v  
{ X>`03?L  
e.printStackTrace (); qZF&^pCF}  
} mmJnE  
1A'eH:$  
;8PO}{rD  
return n; zB0*KgAn{  
} bDl#806PL  
9NwUX h(:(  
F<{,W-my `  
} |HT7m5tu4  
BNJ0D  
cdkEK  
/* + Fo^NT  
**SiteInfoBean.java t[+bZUS$~  
*/ pnSKIn  
package NetFox; kiJ=C2'&  
Lqxh y s  
rM.Pc?Z  
public class SiteInfoBean { uz+ WVmb  
kCD] &  
PP$2s]{  
private String sSiteURL; //Site's URL \h3HaNC  
private String sFilePath; //Saved File's Path P\K#q%8  
private String sFileName; //Saved File's Name Pa0W|q#?X  
private int nSplitter; //Count of Splited Downloading File !0hyp |F:>  
>6yQuB  
py7Zh%k  
public SiteInfoBean() ppn  8  
{//nSplitter的缺省值为5 tn Ufi8\ob  
//default value of nSplitter is 5 Vx.c`/  
this("","","",5); ,gNZHKNq  
} \:Tq0|]Px  
^_3Ey  
` Ny(S2  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) b#N P*L&  
{ AJ>E\DK0]  
sSiteURL= sURL; \( V1-,  
sFilePath = sPath; +`wr{kB$~  
sFileName = sName; m%u`#67oK  
this.nSplitter = nSpiltter; >b"@{MZ@t  
Xj+_"0 #  
\^,Jh|T  
} |MKR&%Na  
QyL]-zNg  
d+)LK~  
public String getSSiteURL() $!. [R}  
{ 3<<wHK;)  
return sSiteURL; IY6Ll6OK  
} !VIxEu^ke  
Zs/-/C|  
Dti-*LB1  
public void setSSiteURL(String value) %8I^&~E1  
{ 0vLx={i  
sSiteURL = value; -w2^26 ax  
} XGR63hXND  
M:OZWYQ  
{@L{l1|0  
public String getSFilePath() T_2'=7  
{  mY"Dw^)  
return sFilePath; yx`@f8Kr  
} i#YDdz  
gNxv.6Pp=  
Q (N'Oj:J  
public void setSFilePath(String value) (9( xJ)  
{ "UD)3_R  
sFilePath = value; 5YPIv-  
} %LC)sSq{H  
q*R~gEi#yk  
FEhBhv|m  
public String getSFileName() w7~]c,$y.  
{ b?0WA.[{  
return sFileName; BeRs;^r+  
} NM9ViYm>P  
qDswFs(  
"fNv(> -7s  
public void setSFileName(String value) YRZw|H{>t  
{ 6flO;d/v  
sFileName = value; h\#4[/  
} 5[zr(FuE  
`4@` G:6BL  
S|u5RU8*"|  
public int getNSplitter() </<z7V,{  
{ q{*[uJ}Xc"  
return nSplitter; fU.hb%m)Q\  
} "o;%em*Bc  
sdXchVC  
P >0S ZP  
public void setNSplitter(int nCount) yT3K 2A  
{ Qh3+4nLFtb  
nSplitter = nCount; ;/m>c{  
} ~:!& }e5  
} UBM8l  
L}8 }Pns?&  
&C,]c#-+  
/* /s)It  
**Utility.java Ca"i<[8  
*/ 3s:)CXO  
package NetFox; hhjsg?4uL  
]]V=\.y  
,V4pFQzL  
public class Utility { &U.y):  
Z+J~moW `  
,aWfGh#$  
public Utility() _["97>q  
{ g5Hsz,x  
&xlOsr/n  
0Z%<H\Z  
} OK}8BY  
; zy;M5l5.  
//线程睡眠 A]V<K[9:b  
public static void sleep(int nSecond) dnPr2oI?I  
{ ^eYJ7&t  
try{ WWTJ%Rd|  
Thread.sleep(nSecond); Z[j-.,Qu  
} 8{Svax(  
catch(Exception e) ~>$(5 s2  
{ N) z] F9Kg  
e.printStackTrace ();  [7)#3  
} |4Q><6"G  
} Z3T26Uk  
{24Pv#ZG#^  
//日志 ^h|'\-d\  
public static void log(String sMsg) s3T 6"%S`  
{ :\1&5Pm]  
System.err.println(sMsg); :(x 90;DW  
} X_|} b[b  
U(qM( E  
 })w5`?Y  
public static void log(int sMsg) Y!s/uvRI  
{ qdu:kA:]  
System.err.println(sMsg); 9zd)[4%=  
} ln!KL'T]  
} *XzUqK  
I`KN8ll  
Z#W`0G>'  
/* .g&BA15<F6  
**TestMethod.java 7y`~T+  
*/ `0 F"zu  
package NetFox; o_$r*Z|HG  
!p9F'7;Y<  
uTJ?@ ^nq  
public class TestMethod { QU4'x4YS  
Yc5$915  
KoXXNJax  
public TestMethod() MDCf(LhEH  
{ ///xx/weblogic60b2_win.exe bFx?HM.AGW  
try{ W]*wxzf!5z  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);  3i$AR  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 2Uk8{d  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ,[hJi3xM  
fileFetch.start(); >) :d38M  
} XKK*RVs#  
catch(Exception e){e.printStackTrace ();} },L[bDOV07  
]V]o%onW  
?^+|V,<  
} +1623E  
xO@OkCue  
jH G(d$h  
public static void main(String[] args) ^~I  
{ 4%{m7CK}  
new TestMethod(); *ZEs5`x  
} MdfkC6P  
} 8ksDXf`.  
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