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http断点续传简单实现(java)

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/* BvXA9YQ3  
**SiteFileFetch.java *pu ,|  
*/ };rxpw>ms  
package NetFox; +/">]QJ  
import java.io.*; %t*_Rtz\o  
import java.net.*; L|O'X4"&_  
%/b3G*$W  
_;o)MTw|'  
public class SiteFileFetch extends Thread { Ek0zFnb[Gx  
QKj8~l(  
b4l=Bg"  
SiteInfoBean siteInfoBean = null; //文件信息Bean SGuR-$U`)  
long[] nStartPos; //开始位置 gBF2.{"^  
long[] nEndPos; //结束位置 '\v mm>  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 fjc8@S5x9j  
long nFileLength; //文件长度 z_)`='&n  
boolean bFirst = true; //是否第一次取文件 jm|x=s3}h  
boolean bStop = false; //停止标志 --(e(tvf  
File tmpFile; //文件下载的临时信息 RnvPqNs  
DataOutputStream output; //输出到文件的输出流 oCl $ 0x  
pS1f y]  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) z#$>f*b  
public SiteFileFetch(SiteInfoBean bean) throws IOException PL+j;V(<  
{ L4fM?{Ic:s  
siteInfoBean = bean; 8T:?C~"  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); x.=Np\#\G-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `y1ne x-0  
if(tmpFile.exists ()) jFa{h!  
{ '<Nhq_u{  
bFirst = false; yvPcD5s5  
read_nPos(); })I_@\q  
} !B&OK&*  
else M Y2=lT  
{ h92'~X36  
nStartPos = new long[bean.getNSplitter()]; ;IN!H@bq  
nEndPos = new long[bean.getNSplitter()]; #84<aM  
} !=C74$TH  
3#=%2\  
wt8?@lJ"/  
q9cN2|:  
} \Vc-W|e  
@ m' zm:  
byT@O:fL  
public void run() z0@{5e$#Y  
{ oWJ0>)  
//获得文件长度 ,Z2fVz~9  
//分割文件 k&|#(1CFY  
//实例FileSplitterFetch GFq,Ca~  
//启动FileSplitterFetch线程 oxs0)B  
//等待子线程返回 :\]TAQd-  
try{ T^"-;  
if(bFirst) 6c[&[L%  
{ ~,*=j~#h  
nFileLength = getFileSize(); EWI2qaSnO  
if(nFileLength == -1) \Zpg,KOT  
{ 2J>v4EWC  
System.err.println("File Length is not known!"); .(RX;.lw  
} <)D)j[  
else if(nFileLength == -2) EAPLe{qw:q  
{ td}%reH  
System.err.println("File is not access!"); LSX;|#AI  
} }^ g6Y3\  
else ws^ 7J/8  
{ !>n^ ;u  
for(int i=0;i<nStartPos.length;i++) il=:T\'U9  
{ E46+B2_~zk  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); JO|%Vpco  
} !foiGZ3g  
for(int i=0;i<nEndPos.length-1;i++) DlD;rL=  
{ m2i'$^a#  
nEndPos = nStartPos[i+1]; 1FkS$ j8:  
} e-4 Qw #cw  
nEndPos[nEndPos.length-1] = nFileLength; &bIE"ZBjt  
} LqDj4[}  
} W7\s=t\  
ji8)/  
T>$S&U  
//启动子线程 ^ UB*Q  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; &jbZL5  
for(int i=0;i<nStartPos.length;i++) (IE\}QcK  
{ *$+:Cbe-F  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ><l|&&e-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ;J]Lzh  
nStartPos,nEndPos,i); Eku+&f@RB  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I1J/de,u  
fileSplitterFetch.start(); 8p91ni'  
} bL6, fUS  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <Qx]"ZP%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Hzn6H4Rc  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", R6xJw2;_  
nEndPos = " + nFileLength); !4?QR  
// fileSplitterFetch[nPos.length-1].start(); y3^>a5z!x  
acPX2B[jJ  
 D|8Pe{`  
//等待子线程结束 r+yl{  
//int count = 0; $G,#nh2 oD  
//是否结束while循环 (8XP7c]5  
boolean breakWhile = false; x/)o'#d$|l  
U?WS\Jji3!  
%UO ;!&K  
while(!bStop) /x2MW5H  
{ 4ayZ.`aK  
write_nPos(); ;7 F'xz"  
Utility.sleep(500); Klv~#9Si  
breakWhile = true; JX $vz*KF  
Qf$3!O}G  
1( nK|  
for(int i=0;i<nStartPos.length;i++) oh @|*RU  
{ #mFY?Zp)  
if(!fileSplitterFetch.bDownOver) YXFUZ9a#e  
{ axpn*(yE  
breakWhile = false; ,cF $_7M  
break; JvI6+[  
} 'Cq)/}0  
} C7hJE -  
if(breakWhile) >EJ`Z7E6  
break; "QV?C  
ZD`9Ez)5  
(Y[q2b  
//count++; DO5H(a  
//if(count>4) dyyGt }}5f  
// siteStop(); k~|5TO  
} /Y7Yy jMi  
~4}'R_  
8b!-2d:*  
System.err.println("文件下载结束!"); f:!b0j  
} U~nW>WJ+.  
catch(Exception e){e.printStackTrace ();} m7n8{J1O2  
} EPn0ZwnS:M  
Ra~|;( %d  
{~=Z%Cj2Q  
//获得文件长度 BT3X7Cx  
public long getFileSize() (G#QRSXc\  
{ s2N~p^  
int nFileLength = -1; 1P '_EJ]M  
try{ 9Z_!}eY2mc  
URL url = new URL(siteInfoBean.getSSiteURL()); Dau'VtzN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); s6F^z\6  
httpConnection.setRequestProperty("User-Agent","NetFox"); O"c@x:i  
ymr#OP$<S  
 Xb'UsQ  
int responseCode=httpConnection.getResponseCode(); d8V)eZYXy~  
if(responseCode>=400) uY"Bgz:=d  
{ aEJds}eE6)  
processErrorCode(responseCode); nUy2)CL[L  
return -2; //-2 represent access is error K3xs=q]:@  
} e ab_"W   
y wf@G; fK  
~ V:@4P  
String sHeader; X v2u7T\  
Lfj]Y~*z  
JIYZ  
for(int i=1;;i++) Q9C; _Up  
{ X1J'  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 8h=Rfa9  
//Utility.log(in.readLine()); @*s7~:VQ  
sHeader=httpConnection.getHeaderFieldKey(i); '4 x uH3  
if(sHeader!=null) wFHz<i!jr&  
{ ta)'z@V@g  
if(sHeader.equals("Content-Length")) !}$,) ~<+H  
{ oDvE0"Sz  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); FsXqF&{  
break; N:]Ud(VRM  
} 3R|C$+Sc  
} l A1l  
else `VzjXJw  
break; ybNy"2Wk  
} ^|+;~3<J  
} 12bt\ h9  
catch(IOException e){e.printStackTrace ();} 6%8,OOS  
catch(Exception e){e.printStackTrace ();} `& rt>Bk /  
gb,X"ODq  
g5,Bj  
Utility.log(nFileLength); DFUW^0N  
3ug-cq  
_w\A=6=q|  
return nFileLength; =Kh1 HU.F  
} ' 6#en9{L  
Kz`g Q|S  
UrhSX!g/A>  
//保存下载信息(文件指针位置) pZA0Go2!IN  
private void write_nPos() MPxe|Wws  
{ h+<F,0  
try{ {:!CA/0Jx  
output = new DataOutputStream(new FileOutputStream(tmpFile)); nTd[-3o  
output.writeInt(nStartPos.length); wFHbz9|@I  
for(int i=0;i<nStartPos.length;i++) #y4+O;{  
{ Ki_8g  
// output.writeLong(nPos); O*%@(w6  
output.writeLong(fileSplitterFetch.nStartPos); ',g'Tl^E  
output.writeLong(fileSplitterFetch.nEndPos); <8_~60  
} pk&;5|cCD  
output.close(); 3 %'Y):  
} <JyF5  
catch(IOException e){e.printStackTrace ();} d4]9oi{}  
catch(Exception e){e.printStackTrace ();} w]ZE('3%W  
} k:JlC(^h  
&qO#EEqG]  
O 6}eV^y  
//读取保存的下载信息(文件指针位置) 2 &+Nr+P  
private void read_nPos() ^o@N.+`&<  
{ u#&ZD|  
try{ Vw~st1",[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); wm<`0}  
int nCount = input.readInt(); / ~\ I  
nStartPos = new long[nCount]; m+7/ebj{A  
nEndPos = new long[nCount]; W? ^ ?Kx  
for(int i=0;i<nStartPos.length;i++) 2U Q&n`A  
{ F=qG +T  
nStartPos = input.readLong(); 0zC mU)ng  
nEndPos = input.readLong(); l2lyi  
} 6k@(7Mw8A  
input.close(); e71dNL'$  
} btV Tt5  
catch(IOException e){e.printStackTrace ();} nR2pqaKc  
catch(Exception e){e.printStackTrace ();} lz-t+LD@ST  
} :w+2L4lGs  
]LE  
'Rg6JW\  
private void processErrorCode(int nErrorCode) " Om4P|  
{ `1T?\  
System.err.println("Error Code : " + nErrorCode); (Q/Kp*a  
} g=gWkN <  
)PNeJf|@  
i7UE9Nyl*  
//停止文件下载 AzmISm  
public void siteStop() fZH";_"1  
{ 2 u{"R  
bStop = true; {ejJI/o0  
for(int i=0;i<nStartPos.length;i++) pg4J)<t#  
fileSplitterFetch.splitterStop(); 7 z#Xf  
,8vqzI  
P`$"B0B)  
} (i"@{[IP  
} p903 *F^[,  
//负责部分文件的抓取 uoIvFcb^  
**FileSplitterFetch.java Y9K$6lz  
*/ 0bt"U=x4  
package NetFox; v p>,}nx4  
VX`E7Sf!}  
JQp::,g  
import java.io.*; fF"\$Ny  
import java.net.*; aUBGp: (  
64hl0'67y  
z'(][SB  
public class FileSplitterFetch extends Thread { Ca?:x tt  
a IA9rn  
O$2'$44HX  
String sURL; //File URL h)MU^aP  
long nStartPos; //File Snippet Start Position w[A$bqz   
long nEndPos; //File Snippet End Position @ z{E  
int nThreadID; //Thread's ID e{~3&  
boolean bDownOver = false; //Downing is over NFEF{|}BM  
boolean bStop = false; //Stop identical xjplJ'jB  
FileAccessI fileAccessI = null; //File Access interface wTL&m+xr  
6^Q Bol  
BfcpB)N&.K  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException qNH= W?T8.  
{  bK7j"  
this.sURL = sURL; CflGj0oy8  
this.nStartPos = nStart; ~Lyy7 B9  
this.nEndPos = nEnd; xw)$).yc  
nThreadID = id; h{R>L s  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :dZq!1~t  
} }! jk  
}AZ0BI,TI  
tY1M7B^~  
public void run() z^KMYvH g  
{ rfl-(_3  
while(nStartPos < nEndPos && !bStop) ^ RS?y8  
{ }i"\?M  
ZW6ZO[`6  
(sXR@Ce$  
try{ aQMUC6cPM@  
URL url = new URL(sURL); 3XCePA5z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); H\zV/1~Y  
httpConnection.setRequestProperty("User-Agent","NetFox"); wNHvYu lI  
String sProperty = "bytes="+nStartPos+"-"; P|>pm]>C  
httpConnection.setRequestProperty("RANGE",sProperty); N,iYUM?  
Utility.log(sProperty); YH0=Y mU#X  
yBd#*3K1  
th$?#4SbR  
InputStream input = httpConnection.getInputStream(); yJ\K\\]  
//logResponseHead(httpConnection); {hS9FdWA;  
q&j4PR{  
yXuF<+CJ  
byte[] b = new byte[1024]; 0Y%u[i/  
int nRead; %Km^_JM  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qmWK8}F.cE  
{ D*Cn!v$  
nStartPos += fileAccessI.write(b,0,nRead); #6'x-Z_  
//if(nThreadID == 1) |>/T*zk<  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r#% e$  
} @w8MOT$  
w^_[(9 `  
2|LgUA?<  
Utility.log("Thread " + nThreadID + " is over!"); |#y+iXTJ   
bDownOver = true; cc*xHv^  
//nPos = fileAccessI.write (b,0,nRead); }mZ sK>  
} zA~aiX  
catch(Exception e){e.printStackTrace ();} :`pgdn  
} ]vFtByqn  
} 6X2~30pdE  
\:'|4D]'I  
%ut^ O  
//打印回应的头信息 0R#T3K}  
public void logResponseHead(HttpURLConnection con) qu}&4_`%:V  
{ &Z.zem?n  
for(int i=1;;i++) P?.j wI  
{ #QWG5  
String header=con.getHeaderFieldKey(i); "_g3{[es!  
if(header!=null) Id<3'ky<N  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ?qdZ]M4e  
Utility.log(header+" : "+con.getHeaderField(header)); |#87|XIJ&~  
else SR+<v=i  
break; \Y>!vh X  
} %[ Z[  
} i*T>, z  
&fyT}M A  
j06Xz\c  
public void splitterStop() &!adW@y  
{ ggy 7p44  
bStop = true; |JR;E$  
} f&n6;N  
p^E}%0#  
-F]0Py8(  
} JfrPK/Vn  
,X&(BQj h  
#fuc`X3:HL  
/* 4!I;U>b b  
**FileAccess.java SEL7,8 Hm  
*//文件访问(定位,写) jn+M L&  
package NetFox; h=1cD\^|qw  
import java.io.*; kOQq+_Y  
"I7 Sed7  
x}c%8dO#J  
public class FileAccessI implements Serializable{ _w'N&#  
",pN.<F9O  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 UTThl2=+  
RandomAccessFile oSavedFile; {eQ')f  
long nPos; Q)H1\  
PCx] >&  
Xyf7sHQ  
public FileAccessI() throws IOException ^EG@tB $<  
{ .t7mTpi  
this("",0); h/AL `$  
} ]h`<E~  
Wl4T}j  
_ i-(` 5  
public FileAccessI(String sName,long nPos) throws IOException s-z*Lq*  
{ L, k\`9bQ  
oSavedFile = new RandomAccessFile(sName,"rw"); p?#cn   
this.nPos = nPos; }'FNGn.~#  
oSavedFile.seek(nPos); .ZB/!WiF  
} jW?siQO^  
b')Lj]%;k  
p{sbf;-x}  
public synchronized int write(byte[] b,int nStart,int nLen) Ga%x(1U[&  
{ '%D$|)  
int n = -1; Qxvj`Ge  
try{ +yh-HYo`  
oSavedFile.write(b,nStart,nLen); pO;BX5(x  
n = nLen; y'a(>s(  
} WC?}a^ 8  
catch(IOException e) !JkH$~  
{ 0UHX Li47Y  
e.printStackTrace (); :=0XT`iY  
} :*{>=BD  
x+L G4++  
R m{\ R  
return n; 2Sq+w;/  
} LPOZA`  
$p} /&  
s`bC?wr5h  
} 49BLJ|:P?  
q$;'Fy%oy  
L 1fK  
/* Od>^yhn  
**SiteInfoBean.java CD]2a@j {  
*/ ic"n*SZa  
package NetFox; ) LA^j|Y}  
Qe~2'Hw#9  
Rv ]?qJL  
public class SiteInfoBean { ]wMp`}$b@L  
%Ps DS  
~okIiC]#  
private String sSiteURL; //Site's URL `%2e?"OOJ  
private String sFilePath; //Saved File's Path x bG'![OX  
private String sFileName; //Saved File's Name ^GXy:S$  
private int nSplitter; //Count of Splited Downloading File ZU vA`   
3b_tK^|'  
J.`z;0]op  
public SiteInfoBean() !eoN  
{//nSplitter的缺省值为5 S;o U'KOY  
//default value of nSplitter is 5 E0nR Vg  
this("","","",5); cU y,q]PO  
} /nK)esB1L  
*>=vSRL0_  
n 0X_m@  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) nP9@yI*7  
{ }OeEv@^  
sSiteURL= sURL; Tl#Jf3XY}  
sFilePath = sPath; C?n3J  
sFileName = sName; 2$D *~~  
this.nSplitter = nSpiltter; WC!bB  
Y$^x.^dT,  
)shzJ9G  
} -R!qDA"  
SL;\S74  
lu^ c^p;  
public String getSSiteURL() lN,8(n?g  
{ *yuw8  
return sSiteURL; GHHErXT\a  
} 2Yx6.e<  
o7feH 6Sh  
/j]r?KAzw  
public void setSSiteURL(String value)  qO  
{ %h** L'~``  
sSiteURL = value; =&*:)  
} ]JX0:'x^  
Q6y883>9  
<zN  
public String getSFilePath() k]<  
{ 3G9YpA_}X  
return sFilePath; ?~rF3M.=|  
} }DTpl?l  
3,j)PKf ;  
^4Ra$<  
public void setSFilePath(String value) 'sJ=h0d_[V  
{ (Rvke!"B  
sFilePath = value; (NUk{MTX  
} w,NK]<dU@  
pb`F_->uq  
rt%.IQdY  
public String getSFileName() XG"&\FL{T  
{ >9W ;u`  
return sFileName; C #ng`7 q  
} @<--5HbX  
/%Bc*k=ox  
"U34D1I )#  
public void setSFileName(String value) ]Ff"o7gT  
{ SMaC{RPQ  
sFileName = value; euM7> $`  
} Qi|jL*mj&  
Vg/{;uLAe  
s+>""yi  
public int getNSplitter() /-<S FT`  
{ 2%N$Y]  
return nSplitter; SF61rm  
} qUSImgg  
I#Ay)+D  
KzZ! CB\  
public void setNSplitter(int nCount) Y((s<]7  
{ x^}kG[s  
nSplitter = nCount; w4pU^&O  
} L,.Ae i9  
} DF'-dh</*  
AJSe +1  
!<]%V]5[_  
/* Mw@T!)(  
**Utility.java oju7<b9Ez  
*/ ^AMcZ6!\  
package NetFox; 0\%/:2   
8Cz_LyL  
+T=Z!2L  
public class Utility { ?U~C= F?K  
?hvPPEJf  
9_[TYzpB!  
public Utility() c|u{(E58  
{ (E59)z -  
bLGgu#  
/HgdTyR)  
} 4&)*PKq  
%TdZ_  
//线程睡眠 31 4PcSc  
public static void sleep(int nSecond) =v=a:e  
{ :L&Bbw(  
try{ V(1Ldl'a  
Thread.sleep(nSecond); !HL7a]PB  
} k_#ra7zP  
catch(Exception e) gxpR#/(E~  
{ \-N 4G1  
e.printStackTrace (); P %f],f  
} eX7Ev'(H  
} <",4O  
[sp=nG7i&  
//日志 .2/(G{}U  
public static void log(String sMsg) L=3^A'|  
{ "0 \U>h  
System.err.println(sMsg); T j9;".  
} X{\>TOk   
6c>t|=Ss(  
R K#e7  
public static void log(int sMsg) P!:Y<p{=>  
{ o0&jel1a  
System.err.println(sMsg); 5:E7nqsNhq  
} @FIR9XJ  
} |1X^@  
]78I  
x0@J~ _0  
/* "12.Bi.O"[  
**TestMethod.java /ZHuT=j1  
*/ HT)b3Ws~M8  
package NetFox; ;H /*%2  
7g}4gX's  
xcwyn\93)  
public class TestMethod { hL~@Ah5&t  
T5.1qrL  
_ $PZID  
public TestMethod() @|(mR-Jj  
{ ///xx/weblogic60b2_win.exe frbKi _1  
try{ u*Z>&]W_  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); H`C DfTy  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); BusD}9QqB  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ~'KymarPU  
fileFetch.start(); [?iA`#^d  
} /cF 6{0XS9  
catch(Exception e){e.printStackTrace ();} 2MQgTFM9  
&!]$#  
5s_7 P"&H  
} _Sy-&}c+ +  
z:-a7_   
Ac'[(  
public static void main(String[] args) wv<D%nF2|  
{ D% } ?l  
new TestMethod(); )9MmL-7K  
} (xpj?zlmM  
} >[B}eS>  
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