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http断点续传简单实现(java)

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/* ikxSWO_Y=  
**SiteFileFetch.java QY^ y(I49  
*/ _8S).*  
package NetFox; o<g (%ncr  
import java.io.*; vW4 f3(/  
import java.net.*; 94a _ W9  
&pmJ:WO,h  
+QHhAA$  
public class SiteFileFetch extends Thread { d->b9  
ZR#UoYjupb  
V!Joh5=a  
SiteInfoBean siteInfoBean = null; //文件信息Bean b uhxC5i%  
long[] nStartPos; //开始位置 &c\8` # 6  
long[] nEndPos; //结束位置 N9*$'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [2FXs52  
long nFileLength; //文件长度 }>OE"#si  
boolean bFirst = true; //是否第一次取文件 []Fy[G.)H  
boolean bStop = false; //停止标志 | 'z)RFqj  
File tmpFile; //文件下载的临时信息 t*<c+Ixu  
DataOutputStream output; //输出到文件的输出流 XSxya .1  
R1 wd Q8q  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ,2cw9?<  
public SiteFileFetch(SiteInfoBean bean) throws IOException *Z0}0< D@Z  
{ $jzk4V  
siteInfoBean = bean; brVT  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6@$[x* V  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); xj~6,;83xR  
if(tmpFile.exists ()) y7w>/7q  
{ TxiJ?sDh*  
bFirst = false; %kUJ:lg;d  
read_nPos(); S4(IYnwN  
} J\{)qJ*jp  
else  I&v B\A  
{ e-s@@k  
nStartPos = new long[bean.getNSplitter()]; ^Uf`w7"iY  
nEndPos = new long[bean.getNSplitter()]; \.{JS>!  
} F-R`'{ ka  
%sq=lW5R{b  
 h43k   
>2|#b  
} F?dTCa  
k]JLk"K  
Q\r qG  
public void run() i3~!ofTb  
{ zZRqb/20  
//获得文件长度 cn#a/Hx  
//分割文件 tb i;X=5  
//实例FileSplitterFetch F;ZLoG*U  
//启动FileSplitterFetch线程 z6!X+`&  
//等待子线程返回 0N}5sF  
try{ QZfPd\Q5  
if(bFirst) Kzm_AHA)  
{ ::R^ w"  
nFileLength = getFileSize(); b'&pJ1]]}  
if(nFileLength == -1) i" )_M|   
{ ! Q#b4f  
System.err.println("File Length is not known!"); :X!(^ a;]  
} u7;A`  
else if(nFileLength == -2) ?1{`~)"  
{ =UV?Pi*M>  
System.err.println("File is not access!"); 4 hj2rK'y  
} U %4g:s  
else V ": BAn  
{ dbLX}>  
for(int i=0;i<nStartPos.length;i++) GBQb({  
{ kgIWgk%  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); l=oVC6C  
} k@~-|\ooG  
for(int i=0;i<nEndPos.length-1;i++) {7wvC)WW  
{ 79V5{2Y*U  
nEndPos = nStartPos[i+1]; sV6A& Aw  
} *"5a5.`%,  
nEndPos[nEndPos.length-1] = nFileLength; d5%*^nMpY  
} W(8g3  
} "tark'  
NWg\{a  
w?*KO?K  
//启动子线程 WU4i-@Bm8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; GKSy|z  
for(int i=0;i<nStartPos.length;i++) qh'BrYu*  
{ K4yYNlY  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +E:(-$"R  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [0LqZ<\5  
nStartPos,nEndPos,i); 10rGA=x'(  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); g?VME]:  
fileSplitterFetch.start(); YUb,5Y0  
} 'k67$H  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^;3rdBprm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 5{a( +'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", a7|&Tbv  
nEndPos = " + nFileLength); gB(W`:[  
// fileSplitterFetch[nPos.length-1].start(); t/1NTa  
\k=Qq(=  
Yel(}Ny  
//等待子线程结束 IpJv\zH7  
//int count = 0; %MJ7u}  
//是否结束while循环 !S!03|  
boolean breakWhile = false; K)+l6Q  
F"H!CJJu&  
#}(Df&  
while(!bStop) j*u9+.   
{ S7/v ,E  
write_nPos(); ug,|'<G+  
Utility.sleep(500); 1^#Q/J,  
breakWhile = true; 5#)<rK  
,rI |+  
-C}59G8  
for(int i=0;i<nStartPos.length;i++) uW~ ,H}E  
{ E`n`#=xKR  
if(!fileSplitterFetch.bDownOver) ~ p.W*skD  
{ \,gZNe&Vv  
breakWhile = false; ('-}"3  
break; U_;J.{n  
} <57l|}8  
} Wky STc  
if(breakWhile) w%dIe!sV  
break; K=?F3tX^  
W+ '}O<  
}!<cph  
//count++; F` 5/9?;|  
//if(count>4) 25c!-.5D  
// siteStop(); xO-U]%oq  
} ;T{/;  
So *Wk "  
P&3/nL$9N  
System.err.println("文件下载结束!"); >DUE8hp ;<  
} KBRg95E~]l  
catch(Exception e){e.printStackTrace ();} nl9Cdi]o  
} \seG2vw$  
AV 5\W}  
,e FQ}&^A  
//获得文件长度 lhA s!\F  
public long getFileSize() ObyuhAR  
{ >_aio4j}r  
int nFileLength = -1; tP Efz+1N  
try{ +F~0\#d  
URL url = new URL(siteInfoBean.getSSiteURL()); ^GrkIh0nL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); z2Y_L8u2  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?)[zLnxc&  
zt[4_;2Y  
dHq )vs,L  
int responseCode=httpConnection.getResponseCode(); PWk ?8dL-  
if(responseCode>=400) hHc^ZA  
{ blfE9Oy  
processErrorCode(responseCode); TjUZv1(L  
return -2; //-2 represent access is error [Ql?Y$QB`4  
} =tc`:!$  
[%84L@:h  
:#\B {)(  
String sHeader; YNg\"XjJM<  
du'}+rC  
wyrI8UY  
for(int i=1;;i++) EID)o[<  
{ (~7m"?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); gR;8ht(pd(  
//Utility.log(in.readLine()); &:DCtjK  
sHeader=httpConnection.getHeaderFieldKey(i); [-E{}FL|  
if(sHeader!=null) (K*/Vp  
{ DrCWvpudd  
if(sHeader.equals("Content-Length")) f3zfRhkIk  
{ V5u}C-o  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Ld\LKwo  
break; 8|5Gv  
} :kb1}Wu  
} AB2mt:^  
else ]g>m?\'n  
break; t+3   
} ]_ejDN\>{V  
} Mhv1K|4s  
catch(IOException e){e.printStackTrace ();} hJw |@V  
catch(Exception e){e.printStackTrace ();} {d 1N&  
%tzN@  
U] V3DDN  
Utility.log(nFileLength); bkr~13S{+  
0'yG1qG  
lh,ylh  
return nFileLength; c<=`<!FS[  
} 4|> rwQ~t  
YN,y0t/cQ  
r,2Xu  
//保存下载信息(文件指针位置) ,DQGv_  
private void write_nPos() dGbU{#"3s  
{ a=J@y K  
try{ KInUe(g<9M  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ZnvEv;P  
output.writeInt(nStartPos.length); r5MxjuOB1  
for(int i=0;i<nStartPos.length;i++) k^H0b\hYY  
{ l|08  
// output.writeLong(nPos); IajD;V  
output.writeLong(fileSplitterFetch.nStartPos); ^M`>YOU2+  
output.writeLong(fileSplitterFetch.nEndPos); R'Kt=.s<  
} 2d-TU_JqX  
output.close(); y z[%MXI  
} Qg'c?[~W@  
catch(IOException e){e.printStackTrace ();} + ,@ FxZl  
catch(Exception e){e.printStackTrace ();} FU_fCL8yA  
} Op`I;Q #%d  
Sm$p\ORa  
;_mgiKHg  
//读取保存的下载信息(文件指针位置) WGH%92  
private void read_nPos() b8rp8'M)  
{ F>(qOH.I  
try{ E% <w5d.lq  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :PgF  
int nCount = input.readInt(); VZ\O9lD  
nStartPos = new long[nCount]; Z5((1J9  
nEndPos = new long[nCount]; PT3>E5`Nu  
for(int i=0;i<nStartPos.length;i++) Oo FgQEr@  
{ (C,e6r Y  
nStartPos = input.readLong(); # v{Y=$L  
nEndPos = input.readLong(); `TUZZz  
} Rw{$L~\  
input.close(); hHcJN  
} u3U4UK  
catch(IOException e){e.printStackTrace ();} ?nQ_w0j  
catch(Exception e){e.printStackTrace ();} )VNM/o%Q  
} AT"!{Y "H  
oFWt(r   
{}V$`L8  
private void processErrorCode(int nErrorCode) DW#Bfo  
{ ]JH64~a  
System.err.println("Error Code : " + nErrorCode); 1Fv8T'  
} lK0s=4c{  
@&;(D!_&  
Nwgu P  
//停止文件下载 M|d={o9Hp  
public void siteStop() y<TOqn  
{ ~e{H#*f&1/  
bStop = true; =4eUAeH {w  
for(int i=0;i<nStartPos.length;i++) :4|M jn  
fileSplitterFetch.splitterStop(); |+98h&U~  
1!vPc93 $$  
2gt+l?O<PS  
} ~8TF*3[}[  
} UVrQV$g!  
//负责部分文件的抓取 zxkM'8JC  
**FileSplitterFetch.java 9CB\n  
*/ ]fZ<`w8u}  
package NetFox; 5y]io Jc9-  
%Uy%kN_&  
%,/lqcFo  
import java.io.*; G8eD7%{b:)  
import java.net.*; BWh }^3?l  
pV7N byb4  
/Y,r@D  
public class FileSplitterFetch extends Thread { (ew} gJ  
) V36t{  
Z0$] tS  
String sURL; //File URL i\)3l%AK]T  
long nStartPos; //File Snippet Start Position gw^'{b  
long nEndPos; //File Snippet End Position m[spn@SF  
int nThreadID; //Thread's ID ~h! 13!  
boolean bDownOver = false; //Downing is over b HE7yv [  
boolean bStop = false; //Stop identical #jBN?Z#  
FileAccessI fileAccessI = null; //File Access interface \:Za[6  
*t(4 $  
Zsj`F9*e  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException XV>@B $hu  
{ _\\ -md:  
this.sURL = sURL; 9cG<hX9`F  
this.nStartPos = nStart; ,(N[*)G  
this.nEndPos = nEnd; *)'Vvu<  
nThreadID = id; v*z(@<Y  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 dY!u)M;~~  
} "UG K8x  
jAC78n,Fi@  
^2S# Uk  
public void run() o5!f#Y  
{ r8[T&z@_  
while(nStartPos < nEndPos && !bStop) dz-y}J11  
{ 7&U&E|  
irKIy  
O("Uq../3  
try{ XN;&qR^j  
URL url = new URL(sURL); 19t{|w<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); S_ b/DO  
httpConnection.setRequestProperty("User-Agent","NetFox"); @0NJ{  
String sProperty = "bytes="+nStartPos+"-"; 0 )}$^TV  
httpConnection.setRequestProperty("RANGE",sProperty);  )h_8vO2  
Utility.log(sProperty); ?mv:neh  
MsOs{2 )2  
jVWK0Zba  
InputStream input = httpConnection.getInputStream(); hH>``gK  
//logResponseHead(httpConnection); (=u'sn:s  
wRvb8F 0  
.c+9P<VmC}  
byte[] b = new byte[1024]; Q.Aa{d9e  
int nRead; 28I^$> [  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @Jn!0Y1_3  
{ cn`iX(ZgR  
nStartPos += fileAccessI.write(b,0,nRead); np9dM  
//if(nThreadID == 1) ' cIEc1y  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [ f/I2  
} {tiKH=&J  
>IfV\ w32  
:"1|AJo)  
Utility.log("Thread " + nThreadID + " is over!"); Bc5+ss  
bDownOver = true; h6:#!Rg  
//nPos = fileAccessI.write (b,0,nRead); `A@w7J'  
} B?bW1  
catch(Exception e){e.printStackTrace ();} pG3k   
} /F)H\*  
} 3Q^fVn$tk  
I/6)3 su%  
x;s0j"`Jb  
//打印回应的头信息 UL$}{2N,_  
public void logResponseHead(HttpURLConnection con) d+eZub94U  
{ W?woNt'n  
for(int i=1;;i++) w_tJ7pz8T  
{ \ 0W!4D  
String header=con.getHeaderFieldKey(i); tq1CwzRX  
if(header!=null) zi@]83SS#  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); C1kYl0 zR[  
Utility.log(header+" : "+con.getHeaderField(header)); V!_71x\-Q  
else $sHP\{  
break; QS[L~97m2M  
} 942lSyix  
} n2B){~vE  
NoE*/!Sr  
q?qC  
public void splitterStop() B;>{0 s  
{ ED>prE0  
bStop = true; uo%P+om_}  
}  {^a36i  
-VKS~{  
}@ Z56  
} Mn1Pt|_@!  
Hmt^h(*/2  
:}8Z@H!KkY  
/* H %JaZ?(  
**FileAccess.java }o4N<%/+  
*//文件访问(定位,写) &Mq~T_S  
package NetFox; y$FW$Ka  
import java.io.*; e}/Lk5q!  
MTg:dR_  
NX`*%K  
public class FileAccessI implements Serializable{ ^z1&8k"[^  
LEMfG~Czq  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -}O1dEn.  
RandomAccessFile oSavedFile; *4+3ObA  
long nPos; u0aJu  
"k*PA\U  
$vC1 K5sLk  
public FileAccessI() throws IOException MYJg8 '[j  
{ m8'C_U^89  
this("",0); \$0F-=w`8  
} j 8*ZF  
 ]#7zk9  
A+6 n#  
public FileAccessI(String sName,long nPos) throws IOException 1) ta  
{ '!l 1=cZD  
oSavedFile = new RandomAccessFile(sName,"rw"); ?]D"k4  
this.nPos = nPos; il|1a8M2~  
oSavedFile.seek(nPos); ee%fqVQ8P  
} ;};wq&b#  
?\C"YG69T  
6qcO?U  
public synchronized int write(byte[] b,int nStart,int nLen) ono4U.C9  
{ a=M\MZK>  
int n = -1; fP.F`V_Y  
try{ qM#R0ZUIe\  
oSavedFile.write(b,nStart,nLen); Y3Vlp/"rB"  
n = nLen;  r.4LU  
} 3nZo{p:E  
catch(IOException e) 0-~\ W(  
{ aW>6NDq(  
e.printStackTrace (); ^i:`ZfA#  
} ZPbpp@,  
B}PIRk@a1  
LpR3BP@At  
return n; 0eK*9S]  
} ]\7]%(  
)M)7"PC  
jDQZQ NS  
} rn<PR*  
[IK  )  
jBegh9KHq  
/* `uC@nJ  
**SiteInfoBean.java Mbjvh2z  
*/ `w]s;G[  
package NetFox; OKoan$#sn  
d/i`l*  
lsJnI|  
public class SiteInfoBean { !Q#{o^{Y~  
s`0QA!G{-  
8MSC.0   
private String sSiteURL; //Site's URL J>/w5$h5  
private String sFilePath; //Saved File's Path OF\rgz  
private String sFileName; //Saved File's Name 9uGrk^<t  
private int nSplitter; //Count of Splited Downloading File aG^4BpIP  
wXsmn1w9  
fMOU$0]$<  
public SiteInfoBean() /iX+R@  
{//nSplitter的缺省值为5 U\Z?taXB  
//default value of nSplitter is 5 -;'1^  
this("","","",5); je!-J8{  
} U~pV)J  
~JaAii{  
92EWIHEWZ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) V3"=w&2]K  
{ rb|U;)C  
sSiteURL= sURL; eM+!Y>8Y  
sFilePath = sPath; Dc_yM  
sFileName = sName; y~FV2$  
this.nSplitter = nSpiltter; }I :OsAw  
m}X`> aD/  
nJo`B4'U  
} |9B.mBoX  
Sv +IS  
*NG+L)g  
public String getSSiteURL() ll C#1  
{ uXKERzg  
return sSiteURL; #W|'1 OX4  
} 5=Di<!a;  
!1ED~3 /X  
B#M5}QT|2  
public void setSSiteURL(String value) t]YC"%[S  
{ ; d J1  
sSiteURL = value; T3^GCX|!@  
} k3uit+ge }  
*FMMjz  
QDhOhGK  
public String getSFilePath() uH(f$A  
{ Wr( y)D<y}  
return sFilePath; ](s'L8 (x  
} WS`qVL]^&  
#H :7@  
\Rp-;.I@6  
public void setSFilePath(String value) `tn{ei  
{ m8o(J\]  
sFilePath = value; H(Z88.OM  
} sPR1?:0:  
u4/kR  
lb3]$Da  
public String getSFileName() !Y[lQXv  
{ &MCbYph,  
return sFileName; +w+} b^4  
} z& fwE$Nm  
4/wa+Y+=vt  
f>N!wgo[  
public void setSFileName(String value) J%,*is EL  
{ e8GEoD  
sFileName = value; SgS~ {4Zx*  
} CW,Wx:Y  
U4b0*`o  
)3>hhuaa  
public int getNSplitter() Uk6HQQ  
{ D"a~ #^  
return nSplitter; ~x ]jB  
} PEW=@xj2y  
&FF"nE*  
#~<0t(3Q  
public void setNSplitter(int nCount) a+%6B_|\  
{ "$2 y-|  
nSplitter = nCount; !0vG|C ;'  
} pLLGus+W  
} lc~%=  
y9>ZwYN  
rV T{90,  
/* 1f":HnLRM  
**Utility.java *q-['"f  
*/ F;7dt@5;  
package NetFox; Z|lq b=  
N-e @j4WU  
6jC`8l:  
public class Utility { osX8eX]\  
.P7"e5g e  
}x07^4$j  
public Utility() 1$p2}Bf {n  
{ RT.D"WvT  
=AEBeiz  
i;_tI#:A  
} 8n*.).33  
T^Ze3L]  
//线程睡眠 z <##g  
public static void sleep(int nSecond) -T[lx\}  
{ -bSSP!f  
try{ JNJ=e,O,  
Thread.sleep(nSecond); \uza=e  
} br":y>=,  
catch(Exception e) 5a hVeY  
{ 9 mmCp&~Z  
e.printStackTrace (); hKT  
} <c qbUL  
} 98uV6b~g  
'gTbA?+@5  
//日志 >VN5`Zlw\C  
public static void log(String sMsg) 4'!c*@Y  
{ q@nP}Pv&5  
System.err.println(sMsg); ?6fnpGX@a  
} :uK? 4  
=A!@6Nw  
=Q+= f  
public static void log(int sMsg) y*tZ !m2Gg  
{ O4^8jK}  
System.err.println(sMsg); s3R(vd  
} p%*%n3bw  
} jO1r)hw N>  
nysUZB  
O"c;|zCc>  
/* 06N}k<10O  
**TestMethod.java vfE6Ggz  
*/ < F`>,Pm  
package NetFox; &'}RrW-s  
TTt#a6eJ  
6u7?dG'4  
public class TestMethod { or';A'k  
Zy(W^~NT  
1M 781  
public TestMethod() ] 0B2# d  
{ ///xx/weblogic60b2_win.exe Z3& _  
try{ ~nG(5:A5g/  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); I.94v #r  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5Drq9B9;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ;bL EL"x%  
fileFetch.start(); }9W4"e2)  
} ~R26  
catch(Exception e){e.printStackTrace ();} +L9Eqll  
Gq }U|Z  
'zGo?a  
} I$0)Px%z  
/x[jQM\  
k+8q{5>A<  
public static void main(String[] args) m/y2WlcRx  
{ "0cID3A$  
new TestMethod(); 86mp=6@  
} ?`#/ 8PN  
} \8 h;K>=h  
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