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http断点续传简单实现(java)

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/* =#2c r:1  
**SiteFileFetch.java itg_+%^R  
*/ j(=w4Sd_W  
package NetFox; h m,{C  
import java.io.*; 0G+Q^]0  
import java.net.*; nF@**,C Q  
@|\9<S  
R9U{r.AA  
public class SiteFileFetch extends Thread { 3>KEl^1DB  
)i~AXBt}  
iApq!u,  
SiteInfoBean siteInfoBean = null; //文件信息Bean & Q3Fgj  
long[] nStartPos; //开始位置 ,AP0*Ln  
long[] nEndPos; //结束位置 eX+36VG\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 w*-42r3,'  
long nFileLength; //文件长度 U?UU] >Q  
boolean bFirst = true; //是否第一次取文件 (9Zvr4.f7  
boolean bStop = false; //停止标志 YNr"]SA@;  
File tmpFile; //文件下载的临时信息 M7TLQqaF  
DataOutputStream output; //输出到文件的输出流 2!{D~Gfl=  
fB8, )&  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) #7]Jz.S  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,U~A=bsa  
{ h3o'T=`Sm  
siteInfoBean = bean; suY47DCX)  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); zMsup4cl  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");  T Rv  
if(tmpFile.exists ()) =SJ#6uFS  
{ 0$*7lQ<a#M  
bFirst = false; "'U^8NA2  
read_nPos(); h p]J> i.  
} >Zb!?ntN`t  
else aV\i3\da  
{ Vu3DP+u|i  
nStartPos = new long[bean.getNSplitter()]; UzxL" `^7  
nEndPos = new long[bean.getNSplitter()]; YzESV Th  
} GbSCk}>  
P8eCaZg?(3  
C[L 5H  
NoiB9 8g  
} EhxpMTS  
}u_D{bz  
`HX:U3/  
public void run() 2_q/<8t  
{ rfqwxr45h  
//获得文件长度 {<42PJtPY  
//分割文件 d4| )=  
//实例FileSplitterFetch /j~~S'sw  
//启动FileSplitterFetch线程 AY /9Io-  
//等待子线程返回 .KrLvic  
try{ ?2]fE[SqY  
if(bFirst) rtj/&>  
{ 39v Bsc  
nFileLength = getFileSize(); e9{ii2M  
if(nFileLength == -1) $ VT)  
{ .C'\U[A{  
System.err.println("File Length is not known!"); -8 uS#  
} 6u, g  
else if(nFileLength == -2) 1}d F,e  
{ Va8 }JD  
System.err.println("File is not access!"); UY3)6}g6  
} jZA1fV  
else ,X|Oe@/  
{ ;/Hr ZhOE  
for(int i=0;i<nStartPos.length;i++) "*bLFORkq'  
{ K(+=V)'Dz  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); UD-+BUV  
} |{#St-!-7  
for(int i=0;i<nEndPos.length-1;i++) Ok!P~2J  
{ L]=]/>jQ6  
nEndPos = nStartPos[i+1]; YK/? mj1x  
} ?w:\0j5 ~  
nEndPos[nEndPos.length-1] = nFileLength; k4'] q  
} i]ZGq7YJ%  
} U1YqyG8  
pr<u 5  
7h\is  
//启动子线程 "Hw%@]#  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Y2L{oQ.C2  
for(int i=0;i<nStartPos.length;i++) NfoHQU <n  
{ MSCH6R"5  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \l/(L5gY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), d:'{h"M6  
nStartPos,nEndPos,i); *$A`+D9  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); hkPMu@BI  
fileSplitterFetch.start(); hi(b\ ABx  
} 5iw\F!op:  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #(tdJ<HvC|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); z4YDngf=4  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", N3u06  
nEndPos = " + nFileLength); /dCsZA  
// fileSplitterFetch[nPos.length-1].start(); ~cm4e>o  
$n<1D -0!r  
-b!?9T?}  
//等待子线程结束 RvR.t"8  
//int count = 0; #N][-i  
//是否结束while循环 #6M |T+ =  
boolean breakWhile = false; ^&;,n.X5Z  
K@p9_K8  
^]o H}lwO  
while(!bStop) n/v.U,f&l@  
{ cxR.:LD}  
write_nPos(); .rBU"Rbo  
Utility.sleep(500); KpGx<+0p  
breakWhile = true; ;-3&yQ7N)  
X5o*8Bg4M  
q7CLxv &QG  
for(int i=0;i<nStartPos.length;i++) pLu5x<  
{ aVR!~hvFs  
if(!fileSplitterFetch.bDownOver) "~VKUvDu  
{ T={!/y+  
breakWhile = false; k~ )CJ6}  
break; !60U^\  
} >~,~X9   
} X@kgc&`0  
if(breakWhile) 1tY+0R  
break; Tf#Op v)  
./I?|ih  
u0W6u} 4;  
//count++; eBa#Z1Z  
//if(count>4) )xVf3l pQ  
// siteStop(); lW"0fZ_x'E  
} ~C{:G;Iy0  
VP!4Nob  
,#XXwm ^I  
System.err.println("文件下载结束!"); f}yRTR GJv  
} @G;9eh0$  
catch(Exception e){e.printStackTrace ();} ZY<R Nwu  
} jTS8 qu  
k;cIEEdZD  
iY>P7Uvvz  
//获得文件长度 >)D=PvGlmp  
public long getFileSize() ?$`kT..j,u  
{ \dQc!)&C9  
int nFileLength = -1; Yz;7g8HI  
try{ 3D6&0xTq  
URL url = new URL(siteInfoBean.getSSiteURL()); 53hX%{3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &B5&:ib1D  
httpConnection.setRequestProperty("User-Agent","NetFox"); `a52{Wa  
R?1Z[N  
v{$?Ow T/u  
int responseCode=httpConnection.getResponseCode(); TFOx=_.%i  
if(responseCode>=400) a=W%x{  
{ '`;=d<'  
processErrorCode(responseCode); Z'A 3\f   
return -2; //-2 represent access is error qMEd R;o  
} 0to`=;JI  
u"zR_CzYc  
%KVmpWku  
String sHeader; ]-t>F  
xbi\KT`~  
1>[#./@  
for(int i=1;;i++) RL&0?OT  
{ mxEe -q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); .<vXj QE  
//Utility.log(in.readLine()); _# Hd2h  
sHeader=httpConnection.getHeaderFieldKey(i); >NPK;Vu  
if(sHeader!=null) .,6o):  
{ HT/!+#W .  
if(sHeader.equals("Content-Length")) ,8zJD&HMx  
{ i%!<9D~n  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [ PN2^  
break; 6&]Z'nW0k  
} eV%{XR?y  
} auGK2i  
else BEax[=&W  
break; \s[L=^!  
} r<kgYU`  
} *A`ZcO=   
catch(IOException e){e.printStackTrace ();} UU(Pg{DA 6  
catch(Exception e){e.printStackTrace ();} db_Qt'>  
}Tk:?U{  
:YRHO|  
Utility.log(nFileLength); NL:dyV }  
&*o4~6pQ#  
,FP0n  
return nFileLength; ` Ft-1eE  
} b5MU$}:  
N?t*4Y  
pq]z%\$u  
//保存下载信息(文件指针位置) W\-`}{B_/  
private void write_nPos() ]gX8z#*k  
{ 3~R,)fO;  
try{ /$clk=  
output = new DataOutputStream(new FileOutputStream(tmpFile)); :' 5J[]J  
output.writeInt(nStartPos.length); J0vQqTaT  
for(int i=0;i<nStartPos.length;i++) P(yLRc  
{ Wgs6}1b g  
// output.writeLong(nPos); sMAj?]hI$  
output.writeLong(fileSplitterFetch.nStartPos); Q7e4MKy7  
output.writeLong(fileSplitterFetch.nEndPos); LK4NNZf7  
} ">!pos`<C  
output.close(); uO]|YF  
} vn*K\,  
catch(IOException e){e.printStackTrace ();} J|hVD  
catch(Exception e){e.printStackTrace ();} `3jwjy| 5  
} wZ0bD&B  
YJ6:O{AL1  
wEq&O|Vj  
//读取保存的下载信息(文件指针位置) #5h_{q4l  
private void read_nPos() L8n?F#q  
{ @r[SqGa:  
try{ mW{uChHP  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $,O8SW.O$  
int nCount = input.readInt(); &\ca ? #  
nStartPos = new long[nCount]; Z,AY<[/C  
nEndPos = new long[nCount]; lO|LvJyx  
for(int i=0;i<nStartPos.length;i++) y+Nw>\|S  
{ Q }^Ip7T  
nStartPos = input.readLong(); 1p5'.~J+Q  
nEndPos = input.readLong(); \: F$7 *Ne  
} &HLG<ISw  
input.close(); D1+1j:m  
} c2Z !Vtd  
catch(IOException e){e.printStackTrace ();} F,)+9/S&  
catch(Exception e){e.printStackTrace ();} [z\baL|  
} &,8Qe;  
117lhx].'  
UrciCOQf  
private void processErrorCode(int nErrorCode) Bx\ o8k  
{ ugXDnM[S%  
System.err.println("Error Code : " + nErrorCode); OcWKK!A  
} \ :s%;s51  
0\"#Xa+}8  
<uBRLe`)  
//停止文件下载 huA?*fat   
public void siteStop() x6JV@wA&  
{ A@_>9;   
bStop = true; ~9APc{"A  
for(int i=0;i<nStartPos.length;i++) jP/Vqe%%8  
fileSplitterFetch.splitterStop(); ;=IJHk1&  
5m'AT]5Tn_  
d3\?:}o,  
} %^E 7Iqc  
} _(?`eWo  
//负责部分文件的抓取 Z5oDj|&l}  
**FileSplitterFetch.java _#v"sGmN  
*/ l]D $QT3  
package NetFox; 'bLP#TAzf  
j&/+/s9N  
lijT L-3  
import java.io.*; (Nz`w  
import java.net.*; *k#"@  
[ *It' J^  
z.SKawm6T  
public class FileSplitterFetch extends Thread { *-fd$l.  
ha;fxM]  
4x-,l1NMR  
String sURL; //File URL GPGP teC  
long nStartPos; //File Snippet Start Position e<{ d{  
long nEndPos; //File Snippet End Position V,VL?J\  
int nThreadID; //Thread's ID 9XQE5^  
boolean bDownOver = false; //Downing is over bJ 6ivz  
boolean bStop = false; //Stop identical 6&'kN 2  
FileAccessI fileAccessI = null; //File Access interface P-[})Z=  
JW><&hY$"  
XZ8rM4 ]  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException U!Zj%H1XQ0  
{ B*}]'  
this.sURL = sURL; `WCL-OoZc5  
this.nStartPos = nStart; H;_Ce'oU(  
this.nEndPos = nEnd; 6W1+@ q  
nThreadID = id; 12L`Gi  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 z]hRc8 g}d  
} {E(2.'d  
#r"|%nOfY  
( sl{Rgxe*  
public void run() u/|@iWK:  
{ !hfpa_5  
while(nStartPos < nEndPos && !bStop) NBasf n  
{ :+>7m  
;*zLf 9i  
Hc<@T_h+2  
try{ 8Uh|V&  
URL url = new URL(sURL); 6Hb a@Q1`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); z__t8yc3  
httpConnection.setRequestProperty("User-Agent","NetFox"); -Wmb M]Z  
String sProperty = "bytes="+nStartPos+"-"; a%HNz_ro  
httpConnection.setRequestProperty("RANGE",sProperty); vOCaru?~h  
Utility.log(sProperty); S]%,g%6i  
R!/JZ@au<  
4P)#\$d:  
InputStream input = httpConnection.getInputStream(); hTO 2+F*  
//logResponseHead(httpConnection); *re?V9  
j3%Wrt  
A)!W VT&2A  
byte[] b = new byte[1024]; RAhDSDf  
int nRead; V D7^wd9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) i Pr(X  
{ VfJ{);   
nStartPos += fileAccessI.write(b,0,nRead); ,0AS&xs$  
//if(nThreadID == 1) [S]q'c)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3  ;F  
} F[O147&C  
,)d`_AD+5  
";&PtLe  
Utility.log("Thread " + nThreadID + " is over!"); YwY?tOxBe  
bDownOver = true; 0e#PN@  
//nPos = fileAccessI.write (b,0,nRead); Z/:yYSq  
} E Lq1   
catch(Exception e){e.printStackTrace ();} ;c]O*\/  
} 6W3oIt  
} ]Oo!>iTQi  
:epB:r  
p`7d9MV^  
//打印回应的头信息 0&| M/  
public void logResponseHead(HttpURLConnection con) [ R8BcO(  
{ r9bAbE bI  
for(int i=1;;i++) C_ d|2C6  
{ W[`ybGR<  
String header=con.getHeaderFieldKey(i); (>u1O V  
if(header!=null) ND?"1/s  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); E]&N'+T  
Utility.log(header+" : "+con.getHeaderField(header)); C^'r>0  
else /<[_V/g[t?  
break; ZHeue_~x4  
} dn])6Xl;i  
} 0Qeda@J  
S?i^ ~  
O \o@]  
public void splitterStop() x4g6Qze  
{ yyu-y0_  
bStop = true; cf>lY  
} By!u*vSev  
FVP,$  
+&f_k@+  
} ,Iz9!i J"  
Yyd}>+|<,  
!~F oy F  
/* S{2;PaK  
**FileAccess.java 8'3&z-  
*//文件访问(定位,写) =z9,=rR4  
package NetFox; [X@{xF^vBQ  
import java.io.*; }0 H<G0   
S3U]AH)C  
@%u}|iF|  
public class FileAccessI implements Serializable{ ?uTuO  
ph(LsPT-  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 q0>9T  
RandomAccessFile oSavedFile; `l?MmIJ  
long nPos; |8k^jq  
F:<+}{Av  
>#mKM%T2MJ  
public FileAccessI() throws IOException RYC%;h  
{ Ym ]g0a  
this("",0); &e).l<B  
} buzpmRoN)  
W"#<r  
RB""(<  
public FileAccessI(String sName,long nPos) throws IOException <T.R%Jys  
{ <)O#Y76s  
oSavedFile = new RandomAccessFile(sName,"rw"); q\!"FDOl4  
this.nPos = nPos; n@bkZ/G  
oSavedFile.seek(nPos); +J|LfXgB  
} 5"U5^6:T  
/M]P&Zb |  
{*CG&-k2D  
public synchronized int write(byte[] b,int nStart,int nLen) BBX/&d8n  
{ suhnA(T{  
int n = -1; .':17 $c`H  
try{ c"`HKfL  
oSavedFile.write(b,nStart,nLen); RmKbnS $*q  
n = nLen; Z9% u,Cb  
} Pk5\v0vkg  
catch(IOException e) >yVrIko  
{ ^56D)A=  
e.printStackTrace (); 3#udz C  
} d1^5r 31  
^"/TWl>jB  
*CF80DJ  
return n; ;VCFDE{K=  
} F [-D +Nka  
O7Jp ;  
=r`E%P:  
} AoxORPp'  
4TU\SP8sM  
?_S);  
/* {ByKTx &  
**SiteInfoBean.java #|:q"l9  
*/ #X!seQ7a  
package NetFox; *}(B"FSO  
r_'];  
1T~`$zS7  
public class SiteInfoBean { 4^Ks!S>K{8  
BUh(pS:  
1,Pg^Xu  
private String sSiteURL; //Site's URL "GqasbX  
private String sFilePath; //Saved File's Path *E|3Vy{4  
private String sFileName; //Saved File's Name l!j=em@  
private int nSplitter; //Count of Splited Downloading File 7X$pgNRx/a  
DBvozTsF~  
ep48 r>  
public SiteInfoBean() | z}VP-L  
{//nSplitter的缺省值为5 8rU| Oh  
//default value of nSplitter is 5 2Z^p)  
this("","","",5); Gh{9nM_\"  
} ?5pZp~  
KV{  
#f=41d%  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 0!:%Ge_  
{ 9dp4&&Z+F  
sSiteURL= sURL; 2ss*&BR.  
sFilePath = sPath; ` -f\6r|:)  
sFileName = sName; vf?m6CMU !  
this.nSplitter = nSpiltter; Jl6biJx  
11fV|b%  
mv*M2NuhT  
} Ve"M8-{oKk  
=7~;*Ts  
#.}&6ZP  
public String getSSiteURL() *a(GG  
{ [Q8vS;.  
return sSiteURL; <1~_nt~(*  
} [*ug:PG  
K7qR  
6k37RpgH  
public void setSSiteURL(String value) Y|-&=  
{ {ueDwnZ  
sSiteURL = value; rXGaav9  
} ldaT: er9  
J}@.f-W\j  
VjiwW%UOM  
public String getSFilePath() ?%Pi#%P  
{ XzBl }4s  
return sFilePath; 56Lt "Z F  
} RtaMrG=D  
\:Hh'-77q  
3Z}m5f`t  
public void setSFilePath(String value) mI;\ UOh'  
{ NeewV=[%  
sFilePath = value; (I1^nrDP.  
} H,!yG5yF  
K1- 3!G  
sa"!ckh  
public String getSFileName() Ob|tA  
{ xCu\jc)2  
return sFileName; ~!Rf5QA85  
} b|.<rV'BTt  
B-$ps=G+z  
/5f=a  
public void setSFileName(String value) cdL0<J b,  
{ |Yi_|']#  
sFileName = value; &c= 3BEh  
} "t>H B6^  
+5Y;JL<%/  
>+[{m<Eq  
public int getNSplitter() ge{%B~x  
{ $cO-+Mr-~  
return nSplitter; j  W -K  
} clT[ ?8*  
'L%)B-,n  
[hiV #  
public void setNSplitter(int nCount) - l0X]&Ex  
{ <Um5w1  
nSplitter = nCount; cw~-%%/  
} Ige*tOv2  
} dhr-tw  
llpgi,-=  
r)dXcus  
/* zwlz zqV  
**Utility.java *W4~.peoE  
*/ o<Rrr,  
package NetFox; XE:bYzH  
xZMAX}8v  
)EsFy6K:  
public class Utility { _E^ !, Wz  
*Y ?&N2@c  
,Mn?h\  
public Utility() 2cv=7!K4Uv  
{ )aX#RM? N  
~/Kqkhq+c  
*nY$YwHB  
} S^SF!k=  
`{nzw$  
//线程睡眠 :1!k*5  
public static void sleep(int nSecond) Rdy-6  
{ B,{Q[  
try{ [g lhru=+  
Thread.sleep(nSecond); 3=^B &AB  
} v *@R U  
catch(Exception e) 6"o@d8>v  
{ )!l1   
e.printStackTrace (); i uoZk5O  
} -$f$z(h  
} G>+iisb%  
 11-?M  
//日志 !4+@b s  
public static void log(String sMsg) w `>g^_xsg  
{ S\A9r!2  
System.err.println(sMsg); JjBlje  
} =K6{AmG$  
YM +4:P2  
D^H4]7wG@  
public static void log(int sMsg) SrvC34<7  
{ ia%U;M  
System.err.println(sMsg); n'<F'1SWv  
} b5UIX Kim  
} g;</|Z  
pIvr*UzY  
I oC}0C7  
/* _I #a `G  
**TestMethod.java yJHFo[wGMJ  
*/ (!diPwcv  
package NetFox; D~f[Rg  
(fC U+  
h_xzqElZu  
public class TestMethod { FmtV[C #  
5[rA>g~  
M}!E :bv'  
public TestMethod() S>EO6z#   
{ ///xx/weblogic60b2_win.exe 0d #jiG  
try{ 0/b3]{skK  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _n!W4zwi  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); jsIT{a*]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 1(m[L=H5>  
fileFetch.start(); Nvj KB)J  
} .^!uazPE0  
catch(Exception e){e.printStackTrace ();} ]*yUb-xY  
j{H,{x  
 u~j&g  
} aumM\rY  
N5@l[F7I  
ey) 8q.5  
public static void main(String[] args) $ud\CU:r  
{ (p}N cn.  
new TestMethod(); N/eFwv.Er  
} z%[^-l-  
} 5^GrG|~  
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