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http断点续传简单实现(java)

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/* `Q!|/B  
**SiteFileFetch.java bK `'zi  
*/ ]a|3"DP5  
package NetFox; V}732?Jy  
import java.io.*; G!~[+B  
import java.net.*; <wwcPe}  
3 wVN:g7  
kq6K<e4jO  
public class SiteFileFetch extends Thread { 0dhJ# [Y  
ZOl =zn  
9OB[ig  
SiteInfoBean siteInfoBean = null; //文件信息Bean 2#Fc4RR;  
long[] nStartPos; //开始位置 3=9yR* *  
long[] nEndPos; //结束位置 aK'`yuN  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]E90q/s@c  
long nFileLength; //文件长度 84[T!cDk  
boolean bFirst = true; //是否第一次取文件 X&._<2  
boolean bStop = false; //停止标志 %-@`|  
File tmpFile; //文件下载的临时信息 Wt+aW  
DataOutputStream output; //输出到文件的输出流 PezUG{q(  
>b;fhdd:4  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) E^S[8=  
public SiteFileFetch(SiteInfoBean bean) throws IOException jnFCt CB  
{ B\&;eZY'G  
siteInfoBean = bean; ~:ddTv?F  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Sc "J5^  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); H`4H(KWm  
if(tmpFile.exists ()) gkUG*Zw  
{ }9fH`C/m  
bFirst = false; gH- e0134%  
read_nPos(); 0;'kv |  
} }J t( H  
else 4cK6B)X  
{ UJkg|eu  
nStartPos = new long[bean.getNSplitter()]; #3maT*JY  
nEndPos = new long[bean.getNSplitter()]; 'UO,DFq[Fl  
} y wlN4=  
iK%<0m  
tx;DMxN!W  
Q[i/]  
} ug!DL=ZW  
BDY@&vF  
}x4,a6^  
public void run() ,J?Hdy:R  
{ ~uRG~,{rH  
//获得文件长度 <by}/lF0  
//分割文件 o[*</A }  
//实例FileSplitterFetch DsY-JBDvoz  
//启动FileSplitterFetch线程 MGIpo[  
//等待子线程返回 5,>1rd<B  
try{ e!yUA!x`u  
if(bFirst) Nd/iMV6V;  
{ kNfqdCF{P  
nFileLength = getFileSize(); DG1  >T  
if(nFileLength == -1) z<rdxn,9  
{ }gL9G  
System.err.println("File Length is not known!"); l5S (x Q  
} UwY<3ul  
else if(nFileLength == -2) 'X{cDdS^  
{ L'4ob4r{L  
System.err.println("File is not access!"); N)A?*s'v~  
} qWe1`.o  
else l(9$s4R  
{ aR.1&3fE  
for(int i=0;i<nStartPos.length;i++) 9"R]"v3BA  
{ 6\4n y0  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9}kN9u  
} BR\% aU$u  
for(int i=0;i<nEndPos.length-1;i++) +NPk9jn  
{ dC@aQi6{6  
nEndPos = nStartPos[i+1]; 9Qp39(l:  
} OxX{[|!`  
nEndPos[nEndPos.length-1] = nFileLength; rKq/=Avv  
} ?_[xpK()  
} zLXmjrC  
8WV1OIL  
Rk^Fasg"  
//启动子线程 =nOV!!  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :7p0JGd  
for(int i=0;i<nStartPos.length;i++) TCp!4-~,  
{ 49}yw3-  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2}]6~i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), AY:3o3M  
nStartPos,nEndPos,i); 8 f%@:}H  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ` 1DJwe2  
fileSplitterFetch.start(); 2;%DE<Z  
} )F&@ M;2p'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =If% m9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); C1P{4 U  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 7P9n. [  
nEndPos = " + nFileLength); 1Nw&Z0MI  
// fileSplitterFetch[nPos.length-1].start(); ?UQVmE&  
^4]#Ri=U  
d9|dHJf  
//等待子线程结束 #/@U|g  
//int count = 0; ([UuO}m-  
//是否结束while循环 AL! ^1hCF  
boolean breakWhile = false; c&)H   
Jl&bWp^3  
BDxrSq,H  
while(!bStop) Pca~V>Hd  
{ s W+YfJT  
write_nPos(); %Rr!I:[ $  
Utility.sleep(500); KgVit+4u/  
breakWhile = true; " e g`3v  
%@$h?HP  
q#v.-013r  
for(int i=0;i<nStartPos.length;i++) QRdNi 1&M  
{ $ZYEH  
if(!fileSplitterFetch.bDownOver) %0INtq  
{ 0m)["g4  
breakWhile = false; KM 4w{  
break; ~X5yHf3  
} +,7dj:0S  
} c a_N76o!  
if(breakWhile) m{!BSl  
break; )V JAs|  
;|w &n  
z=!$3E ecr  
//count++; C!XI0d  
//if(count>4) rfYu8-  
// siteStop(); c }ivYH?`w  
} MjE.pb  
B P"PUl:  
^j';4'  
System.err.println("文件下载结束!"); l7aGo1TcIh  
} Xn"n5 =M  
catch(Exception e){e.printStackTrace ();} m0]LY-t  
} *x`z5_yfO  
FFbMG:>:  
< .$<d  
//获得文件长度 dJ?VN!B0  
public long getFileSize() Y+iC/pd  
{ G#5Cyu<r!  
int nFileLength = -1; @iUzRsl  
try{ 3`TC*  
URL url = new URL(siteInfoBean.getSSiteURL()); vQ+}rHf`[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3k;U#H  
httpConnection.setRequestProperty("User-Agent","NetFox");  vi4 1`  
/`\-.S9  
vPmP<c)cb  
int responseCode=httpConnection.getResponseCode(); h@Ea$1'e,  
if(responseCode>=400) dVVeH\o  
{ b-]E -$Uz  
processErrorCode(responseCode); oHI~-{m3)  
return -2; //-2 represent access is error XZcsx  
} #i ?@S$  
N$pwTyk  
H24g+<Tv  
String sHeader; POH >!lHu  
qS&PMQ"$  
'e3y|  
for(int i=1;;i++) FvG9PPd  
{ 8)5 n  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); l4U& CA y  
//Utility.log(in.readLine()); $2]1 3j  
sHeader=httpConnection.getHeaderFieldKey(i); MGc=TQ.  
if(sHeader!=null) @EfCNOy  
{ #H O\I7m  
if(sHeader.equals("Content-Length")) z(.$>O&6H  
{ L)8+/+  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); a[";K,  
break; @E O #Ms  
} 1a_;[.s  
} 7b+OIZB  
else H!F'I)1  
break; )FWF T:P~  
} dadOjl)S)  
}  =e$ #m;  
catch(IOException e){e.printStackTrace ();} zIF &ZYP  
catch(Exception e){e.printStackTrace ();} [w=x0J&  
bQXxb(^  
6 $ IXER  
Utility.log(nFileLength); t vk^L3=<  
JsnavI6  
bIp;$ZHy`K  
return nFileLength; `6~*kCj5  
} #Yw^n?~~  
G]P4[#5  
:U)e 8  
//保存下载信息(文件指针位置) b cM#KA  
private void write_nPos() *Z{$0K  
{ 1"/V?ArfL  
try{ + A0@# :B  
output = new DataOutputStream(new FileOutputStream(tmpFile)); qu[w_1%S  
output.writeInt(nStartPos.length); 4c2P%X( C  
for(int i=0;i<nStartPos.length;i++) &tWWb`  
{ W3<O+S&  
// output.writeLong(nPos); KNY<"b  
output.writeLong(fileSplitterFetch.nStartPos); rFx2 S  
output.writeLong(fileSplitterFetch.nEndPos); V2g$"W?3  
} LWVO%@)w  
output.close(); wW%I < M  
} !-N!8 0  
catch(IOException e){e.printStackTrace ();} iS=T/<|?  
catch(Exception e){e.printStackTrace ();} 30DpIkf  
} P? 9CBhN  
EHzZ9zH\  
"VT5WFj  
//读取保存的下载信息(文件指针位置) P*aD2("Z  
private void read_nPos() EAY9~b6~c  
{ {q}: w{x9u  
try{ >E]*5jqU  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ]m4LY.SQ  
int nCount = input.readInt(); *r-Bt1  
nStartPos = new long[nCount]; uXhp+q\  
nEndPos = new long[nCount]; +B8Ut{l  
for(int i=0;i<nStartPos.length;i++) e\yj>tQJg  
{ UD9h5PgT  
nStartPos = input.readLong(); s|,]Nb=z/  
nEndPos = input.readLong(); ZM|>Va/X  
} b%oma{I=.c  
input.close(); G x,D'H'  
} 1c}'o*K_%  
catch(IOException e){e.printStackTrace ();} +Og O<P  
catch(Exception e){e.printStackTrace ();} 20fCWVw}?}  
} {;p /V\   
8ZIv:nO$  
(XW#,=rYk  
private void processErrorCode(int nErrorCode) spl*[ d  
{ qb"!  
System.err.println("Error Code : " + nErrorCode); `Mjm/9+18  
} Rp@u.C <  
htF&VeIte  
y:,{U*49  
//停止文件下载  R(zsn;  
public void siteStop() &1Y+ q]  
{ \]9;c6(  
bStop = true; 3/[=  
for(int i=0;i<nStartPos.length;i++) KDXo9FzF  
fileSplitterFetch.splitterStop(); iEU(1?m2-  
Etl7V  
'@fk(~|  
} 26Yg?:kP  
} >)N#n`  
//负责部分文件的抓取 Xs!eV  
**FileSplitterFetch.java TM"-X\e~{  
*/ ^-ACtA)  
package NetFox; iF%q 6R  
SHGO;  
.Z^g 7 *s  
import java.io.*; B}MJ?uvA  
import java.net.*; %]R#}amW  
`Ch6"= t  
P\M+Z A ;  
public class FileSplitterFetch extends Thread { 8odVdivh  
HhpP}9P;  
$(NfHIX  
String sURL; //File URL ~Fx[YPO,  
long nStartPos; //File Snippet Start Position q6ikJ8E8b  
long nEndPos; //File Snippet End Position kl={L{r  
int nThreadID; //Thread's ID - a=yi d  
boolean bDownOver = false; //Downing is over %bimcRX#W  
boolean bStop = false; //Stop identical q@\_q!  
FileAccessI fileAccessI = null; //File Access interface sbs"26IE  
xv*mK1e  
Y{O&- 5H^|  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ex| kD*=  
{ b9Y pUm7#  
this.sURL = sURL; +p[~hM6?  
this.nStartPos = nStart; gO/(/e>P  
this.nEndPos = nEnd; JxvwquI  
nThreadID = id; =3T?U_u@  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 1y@-  
} H,I}R  
z=fag'fzM  
kDz.{Ih  
public void run() h49Q2`  
{ {jVFlKP>  
while(nStartPos < nEndPos && !bStop) C=]3NB>Jc  
{ M ?3N  
w %zw+E  
6,7omYof  
try{ U=t'>;(g  
URL url = new URL(sURL); VsmL#@E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +sI.GWQ_:  
httpConnection.setRequestProperty("User-Agent","NetFox"); a(7ryl~c=  
String sProperty = "bytes="+nStartPos+"-"; xC{NIOYn'  
httpConnection.setRequestProperty("RANGE",sProperty); x3P@AC$\  
Utility.log(sProperty); esHiWHAC  
xL BG}C  
q)~qd$yMS  
InputStream input = httpConnection.getInputStream(); 6+FON$8  
//logResponseHead(httpConnection); b1#=q0Zl  
t#q> U%!  
Ocb2XEF  
byte[] b = new byte[1024]; "h2Ny#  
int nRead; |]q=D1/A  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) saT9%?4-  
{ %C)JmaQ{9  
nStartPos += fileAccessI.write(b,0,nRead); p3S c4  
//if(nThreadID == 1) [s/@z*,M1  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); cDx^}N!  
} Wk|z\OR(  
w=`z!x![/  
O)Qz$  
Utility.log("Thread " + nThreadID + " is over!"); @( t:E`8  
bDownOver = true; z(WpOD   
//nPos = fileAccessI.write (b,0,nRead); e ?YbG.(E9  
} y#0w\/<  
catch(Exception e){e.printStackTrace ();} uaKB   
} LnDj   
} QdTe!f|  
AH`15k_i  
</X"*G't  
//打印回应的头信息 .#@Dn(  
public void logResponseHead(HttpURLConnection con) m\f_u*  
{ (*ng$z Z$  
for(int i=1;;i++) V\"5<>+O  
{ [!le 9aNg  
String header=con.getHeaderFieldKey(i); jE#8&P~  
if(header!=null) CwvNxH#LVu  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /RM-+D:Y  
Utility.log(header+" : "+con.getHeaderField(header)); W,~1KUTc  
else s2v*  
break; b8>9mKs  
} ddP,_.0  
} h7$!wf!I  
`$H   
M@kZ(Rkv  
public void splitterStop() qJA.+q.e$e  
{ CiuN26>  
bStop = true; }#8uXA  
} ? st#6=M  
0I((UA/7Zs  
kKM%    
} b..$5  
Z-|C{1}A  
\DqxS=o;  
/* vI'>$  
**FileAccess.java ~-`02  
*//文件访问(定位,写) Bs?F*,zDJ  
package NetFox; |esjhf}H>v  
import java.io.*; fO^6q1a  
u`@f ~QP0  
zfb _ )  
public class FileAccessI implements Serializable{ c0&'rxi( B  
v|@n8ED|@K  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 C8:"+;  
RandomAccessFile oSavedFile; }qhK.e  
long nPos; 5$U>M  
kW&Z%k  
qD*\}b]9I  
public FileAccessI() throws IOException sK0VT"7K  
{ F5+_p@ !i  
this("",0); gi'agB^  
} A#S:_d  
<UJJ],)^1A  
7[BL 1HI*  
public FileAccessI(String sName,long nPos) throws IOException |nN/x<v  
{ 3|Sy'J0'K  
oSavedFile = new RandomAccessFile(sName,"rw"); Uob|Q=MQ  
this.nPos = nPos; NCnId}BT  
oSavedFile.seek(nPos); %uVJL z  
} _a$DY ,;  
U!:!]DX(  
;J-Ogt@d7  
public synchronized int write(byte[] b,int nStart,int nLen) ]t)M}^w  
{ rJZs 5g`  
int n = -1; ZT8J i?_n  
try{ Lzx$"R-  
oSavedFile.write(b,nStart,nLen); 'S7@+kJ  
n = nLen; \Z20fh2  
} 3D{4vMm X  
catch(IOException e) M#]|$\v(  
{ n/oipiYx  
e.printStackTrace (); d[e:}1  
} |$w={N^4  
jne9=Als5  
6BU0hV  
return n; mqk(UOK`  
} ' P`p.5nH  
yj'' \  
` .(S#!gw  
} \h7J/es^p!  
Mp"ci+Iu  
=+}}Sv2  
/* BrH;(*H)8  
**SiteInfoBean.java I.+)sB?5  
*/ ClMtl59  
package NetFox; *C@[5#CA2z  
iW1ih Q X  
8;g.3Qv  
public class SiteInfoBean { e=o{Zo?H=  
mERrcYY{  
h2"|tTm,a  
private String sSiteURL; //Site's URL %C`'>,t>  
private String sFilePath; //Saved File's Path GGc_9?h  
private String sFileName; //Saved File's Name "Dl9<EZ  
private int nSplitter; //Count of Splited Downloading File ?ey&Un"  
MAe<.DHY  
`x$}~rP&)!  
public SiteInfoBean() BQ9`DYIb  
{//nSplitter的缺省值为5 bI]UO)  
//default value of nSplitter is 5 \As oeeF  
this("","","",5); HS6Imi  
} NnLhJPh  
.aismc`=  
y|;8:b32  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?FV7|)f  
{ #EmffVtY  
sSiteURL= sURL; R_>TEYZ  
sFilePath = sPath; hG~]~ )  
sFileName = sName; cxD}t'T  
this.nSplitter = nSpiltter; Stw+Dm\!  
ok3  
a|P~LMPM  
} B2G5h baA  
Z0"&  
Naf`hE9  
public String getSSiteURL() !*?(Q6  
{ O:,2OMB}B`  
return sSiteURL; a\&(Ua  
} Ukx/jNyYv  
c[h'`KXJf-  
c. TB8Ol  
public void setSSiteURL(String value) /;<e.  
{ _7=pw5[  
sSiteURL = value; iVKbGgA  
} yF/< :  
-.b Io  
HTUYvU*-  
public String getSFilePath() W7*_T]  
{ ^3WIl ]  
return sFilePath; %on9C`/  
} 9xK4!~5V  
D]pK=247  
Tw`c6^%^y  
public void setSFilePath(String value) g<2lPH  
{ I(^jOgYU  
sFilePath = value; E+m]aYu"  
} I|F~HUzA"  
]{AOh2Z.hv  
JA?,0S  
public String getSFileName() e7XsyL'|p  
{ _H4$$  
return sFileName; 6+Wr6'kuH  
} vZ[ $H  
l:zU_J6  
(>rS _#^  
public void setSFileName(String value) P~Te+ -jX}  
{ 2fkIdy#n@  
sFileName = value; h/ LR+XX!  
} O1x0[sy  
z-KrQx2  
+  ZR(  
public int getNSplitter() 3 x"@**(Q  
{ =2RhPD  
return nSplitter; ,J~,ga~  
} F!OOrW]p0  
/S7+B ]  
]z-']R;  
public void setNSplitter(int nCount) l zfD)TWb  
{ ' "ZRD_"  
nSplitter = nCount; )l+XDI  
} #&^ZQs<  
} H$~M`Y9I~  
|8&-66pX  
!X5o7b)  
/* \LIy:$`8  
**Utility.java ~In{lQ[QX  
*/ S2J#b"Y  
package NetFox; CrnB{Z4L  
G$;>ueM  
QD$}-D[  
public class Utility { [c&2i`C  
x @1px&^  
tWpl`HH  
public Utility() KI E k/]<H  
{ gCv"9j<j  
Dk)@>l:gI,  
gB(9vhj $  
} Eyr5jXt%;  
-Bo86t)F  
//线程睡眠 *'Z-OY<V  
public static void sleep(int nSecond) wrH7 pd  
{ jZXVsd  
try{ -M"IVyy@  
Thread.sleep(nSecond); t{_!Z(Rt5)  
} "DVt3E  
catch(Exception e) 25xcD1*  
{ wn &$C0  
e.printStackTrace (); HA$Y1}  
} r#LnDseW  
} HzP.aw4  
90Xt_$_}s  
//日志 CdX`PQ  
public static void log(String sMsg) B }6Kd  
{ ~_ *H)|  
System.err.println(sMsg); 9aTL22U?  
} %lXbCE:[  
7< ^'DO s  
n`P`yb\f$  
public static void log(int sMsg) y7CWBTH0>  
{ 5B}3GBA  
System.err.println(sMsg); ( FM4 ^#6  
} @q,)fBZq  
} Q 2*/`L}m\  
N1PECLS?  
O x{Q.l  
/* |kId8WtA  
**TestMethod.java ;!'qtw"CB  
*/ m'd^?Qc  
package NetFox; ;xL67e%?  
h]qT1( I  
F vj{@B!  
public class TestMethod { + Qt[1Xq  
]x1p!TSU  
^rL ,&rk  
public TestMethod() v#zPH5xo  
{ ///xx/weblogic60b2_win.exe d{W}p~UbH  
try{ TW>?h=.z  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); "hW(S  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); iDZrK%f l  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ]x2Jpk99a  
fileFetch.start(); e{5,'(1]  
} xFOBF")  
catch(Exception e){e.printStackTrace ();} :#WEx_]  
.%_)*NUZ  
4&|C}  
} )B81i! q  
d5Qd'  
\ [cH/{nt  
public static void main(String[] args) 26M~<Ic  
{ q&Q/?g>f  
new TestMethod(); VO9XkA7  
} [KMS<4t'  
} V7P6zAJy  
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