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http断点续传简单实现(java)

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/* .^=I&X/P  
**SiteFileFetch.java E-Xz  
*/ c"kB@P  
package NetFox; M/.M~/ ~  
import java.io.*; 6p)&}m9!  
import java.net.*; \PT!mbB?  
\i,H1a  
]8}2  
public class SiteFileFetch extends Thread { d m"R0>  
V2?{ebx`  
U1/I( w  
SiteInfoBean siteInfoBean = null; //文件信息Bean wxK71OH  
long[] nStartPos; //开始位置 <[gN4x>'  
long[] nEndPos; //结束位置 n*AN/LBp  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [8DPZU@  
long nFileLength; //文件长度 /^si(BuC^*  
boolean bFirst = true; //是否第一次取文件 ~:0U.v_V  
boolean bStop = false; //停止标志 gz:US 77  
File tmpFile; //文件下载的临时信息 6: R1jF*eG  
DataOutputStream output; //输出到文件的输出流 qvh8~[  
c; 1 f$$>b  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) >^@~}]L  
public SiteFileFetch(SiteInfoBean bean) throws IOException 0eA |Uq~  
{ 70R_O&f-k  
siteInfoBean = bean; ^|h.B$_F,  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); |hvclEu,  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /GNm>NSK  
if(tmpFile.exists ()) C2hB7?UGN  
{ PC,I"l  
bFirst = false; zP!j {y4w  
read_nPos(); A(C0/|#V  
} ]>+ teG:4  
else (3m^@2i  
{ cGg ~+R2P  
nStartPos = new long[bean.getNSplitter()]; kf' 4C "}  
nEndPos = new long[bean.getNSplitter()]; ?O#"x{Pk  
} ; jJ%<  
{|q(4(f"Iu  
*@ S+J$  
g`=Z%{z%  
} 0bQ"s*K  
$C{-gx+:  
-0*z"a9<p8  
public void run() )*BG-nM u  
{ +4]f6Zz({  
//获得文件长度 )c0Dofhg  
//分割文件 t8#u}u  
//实例FileSplitterFetch O 0P4uq  
//启动FileSplitterFetch线程 VF:<q  
//等待子线程返回 [@$t35t~  
try{ 2J6(TrQ  
if(bFirst) $)j f  
{ s";9G^:  
nFileLength = getFileSize(); Bh q]h  
if(nFileLength == -1) K3J,f2Cn$  
{ u5P2*  
System.err.println("File Length is not known!"); M+M\3U  
} 7Y1FFw |  
else if(nFileLength == -2) 8SO(pw9  
{ /Nd`eUn  
System.err.println("File is not access!"); ^#z*   
} IKeO&]k  
else |)YN"nqg  
{ Y$eO:67;  
for(int i=0;i<nStartPos.length;i++) zhC5%R &n/  
{ yRldPk_  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @VKN6yHH  
} o;{BI Q1  
for(int i=0;i<nEndPos.length-1;i++) {} Zqaf  
{ .QM>^(o$Z  
nEndPos = nStartPos[i+1]; `z6I][Uf  
} "l-R|>6~  
nEndPos[nEndPos.length-1] = nFileLength; <3[0A;W=1  
} nW_cjYS%  
} ]9$^=z%SE  
)SWLX\b  
}Gh95HwE  
//启动子线程 JR4fJG  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; @@#h-k%k-  
for(int i=0;i<nStartPos.length;i++) p2(Z(V7*  
{ cFloaCz  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _ v3VUm#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), HV8=b"D"  
nStartPos,nEndPos,i); Amj'$G|+hj  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); t/(rB}  
fileSplitterFetch.start(); l !:kwF  
} Ws:MbZyr  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), C;XhnqWv+l  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); R b=q #  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", }\aJ%9X02  
nEndPos = " + nFileLength); klx28/]  
// fileSplitterFetch[nPos.length-1].start(); Isg\ fSK<j  
%<^j=K= 0  
#9p|aS\  
//等待子线程结束 6l& ,!fd  
//int count = 0; 4* V[^mht  
//是否结束while循环 o'|B|oZ  
boolean breakWhile = false; ]q3.^F  
:r}C&3  
ugS  
while(!bStop) @*-t.b2k  
{ #,Cz+ k*4  
write_nPos(); P$*9Z@  
Utility.sleep(500); :HkX sZ  
breakWhile = true; !p{CsR8c  
?OVje9  
f}w_]l#[G  
for(int i=0;i<nStartPos.length;i++) q:u,)6  
{ +PKd </*]  
if(!fileSplitterFetch.bDownOver) }mOo=)C!  
{ 9i+`,r  
breakWhile = false; eR:C?v  
break; kxt/I<cs  
} p;.M .  
} t_jnp $1m  
if(breakWhile) )F,z pGG  
break; !uqp?L^;  
dK>sHUu  
C{OkbE"Vym  
//count++; KRb'kW  
//if(count>4) $) m$ c5!  
// siteStop(); #M@~8dAH}M  
} 1C(sBU"  
8T88  
j%=X ps  
System.err.println("文件下载结束!"); ^o4](l  
} USZBk0$  
catch(Exception e){e.printStackTrace ();} H:cAORLB  
} UHR%0ae  
P~s u]+  
ZP '0=  
//获得文件长度 $N\k*=  
public long getFileSize() U'@ ![Fp  
{ (#8B  
int nFileLength = -1; &cwN&XBY  
try{ -^q;e]+J  
URL url = new URL(siteInfoBean.getSSiteURL()); izs=5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); RoNE7|gF:  
httpConnection.setRequestProperty("User-Agent","NetFox"); c2-oFLNP=  
Ko0?c.l  
_ Y7 Um  
int responseCode=httpConnection.getResponseCode(); !6,rN_a@Y  
if(responseCode>=400) hDXaCift  
{ s"R5'W\U  
processErrorCode(responseCode); a(X V~o  
return -2; //-2 represent access is error 2D /bMq  
} &hih p"  
'}IGV`c  
NS-0-o|4#  
String sHeader; )!~,xl^j{}  
I51I(QF=  
dh9@3. t  
for(int i=1;;i++) ~tn$AtK  
{ GL~ Wnt  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); uh`5:V  
//Utility.log(in.readLine()); ,&y_^-|d  
sHeader=httpConnection.getHeaderFieldKey(i); ESUO I  
if(sHeader!=null) m_.9 PZ  
{ +\$c_9|C+  
if(sHeader.equals("Content-Length")) A1r%cs  
{ _]-8gr-T  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); wY ??#pS  
break; f@[)*([  
} Y>at J  
} RA?_j$  
else Jg)( F|>o  
break; 8!YQ9T[  
} :,fT^izew  
} (:F]@vT  
catch(IOException e){e.printStackTrace ();} o")"^@Zh i  
catch(Exception e){e.printStackTrace ();} ay|jq "a  
&nwS7n1eb  
zliMG=6  
Utility.log(nFileLength);  P_'{|M<?  
bDudETl  
&n6L;y-  
return nFileLength; 'IFA>}e7W  
} TspX7<6r  
v_Df+  
VrLp5?Bh  
//保存下载信息(文件指针位置) LT>_Y`5>  
private void write_nPos() A+GRTwj  
{ O2?yI8|Jn  
try{ <T;V9(66  
output = new DataOutputStream(new FileOutputStream(tmpFile)); vq.o;q /  
output.writeInt(nStartPos.length); mj'N)6ga  
for(int i=0;i<nStartPos.length;i++) tzfyS#E  
{ $MGKGWx@E  
// output.writeLong(nPos); ]*'_a@h  
output.writeLong(fileSplitterFetch.nStartPos); |d-x2M[  
output.writeLong(fileSplitterFetch.nEndPos); uF1 4;  
} Z,SV9 ~M  
output.close(); oV;sd5'LG  
} he/rt#  
catch(IOException e){e.printStackTrace ();} ]kx<aQ^  
catch(Exception e){e.printStackTrace ();} $]Ix(7@W  
} J[r_ag  
)/JVp>  
jnbR}a=fJ  
//读取保存的下载信息(文件指针位置) B~k{f}  
private void read_nPos() ;dMr2y`6  
{ X Db%-  
try{ 7O k-T10  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); G7|d$!%  
int nCount = input.readInt(); SP<Sv8Okj  
nStartPos = new long[nCount]; V6](_w!  
nEndPos = new long[nCount]; jD"nEp-  
for(int i=0;i<nStartPos.length;i++) F):kF_ho  
{ <*z'sUh+}  
nStartPos = input.readLong(); H)E,([   
nEndPos = input.readLong(); "%+||IyW  
} D</?|;J#/  
input.close(); xu"-Uj1  
} 0sKo NzE  
catch(IOException e){e.printStackTrace ();} m <z?6VC  
catch(Exception e){e.printStackTrace ();} Z.Z31yF:f  
} Lg,ObVt!  
.#Z'CZO|  
[.Md_  
private void processErrorCode(int nErrorCode) E&z^E2  
{ a6ryyt 5  
System.err.println("Error Code : " + nErrorCode); z1,#ma}.  
} J Q*~le*  
tj0 0xYY  
+}( ]7du  
//停止文件下载 Gw-{`<CxE  
public void siteStop() ~H?v L c;>  
{ @XL49D12c  
bStop = true; /Us+>vg!  
for(int i=0;i<nStartPos.length;i++) >wb*kyO7(#  
fileSplitterFetch.splitterStop(); QD^=;!  
psx_gv,  
d^$cx(2$D  
} {Fyw<0 [@  
} ! @Vj&>mH$  
//负责部分文件的抓取 u 1}dHMoX~  
**FileSplitterFetch.java I Gb'ii=A  
*/ bzZdj6>kX  
package NetFox; X=6L-^ o)  
,g?M[(wtc  
;UX9Em  
import java.io.*; j+/EG^*/  
import java.net.*; OEbZs-:  
#3?"#),q  
P&5vVA6K7  
public class FileSplitterFetch extends Thread { F3Da-6T@  
9S'\&mRl  
HP3%CB  
String sURL; //File URL n Zx^ej\  
long nStartPos; //File Snippet Start Position C5Fq%y{$.  
long nEndPos; //File Snippet End Position S*3$1BTl  
int nThreadID; //Thread's ID MfLus40;n  
boolean bDownOver = false; //Downing is over p"cY/2w:j  
boolean bStop = false; //Stop identical {"|GV~  
FileAccessI fileAccessI = null; //File Access interface (lit^v,9  
:t+Lu H g  
5/m*Lc+r  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException c No)LF  
{ |?' gT" #  
this.sURL = sURL; T~}g{q,tR  
this.nStartPos = nStart; zn*i  
this.nEndPos = nEnd; \4*i;a.kU  
nThreadID = id; mn{R>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 F>@z&a}(  
} ;%u)~3B$JK  
1 EV0Y]T1  
Uf[Gs/!NV  
public void run() &j{I G`Trl  
{ }LZz"b<aw  
while(nStartPos < nEndPos && !bStop) j z&=8  
{ 6X VJ/qZ  
DshRH>7s8  
1b!5h  
try{ e7U9"pk  
URL url = new URL(sURL);  _8z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9'p pb  
httpConnection.setRequestProperty("User-Agent","NetFox"); \ $9n `  
String sProperty = "bytes="+nStartPos+"-"; T5 BoOVgO  
httpConnection.setRequestProperty("RANGE",sProperty); 1;MUemnx`  
Utility.log(sProperty); 3e^'mT  
+xtR`Y"  
*YY:JLe  
InputStream input = httpConnection.getInputStream(); &+t,fwlM  
//logResponseHead(httpConnection); G;pxB,4s5  
l4Y}<j\;  
c=HL 6v<  
byte[] b = new byte[1024]; ;H8A"$%n~  
int nRead; M3dNG]3E  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) r&ex<(I{  
{ }mw31=2bD  
nStartPos += fileAccessI.write(b,0,nRead); "eal Yveu  
//if(nThreadID == 1) f8 M=P.jz  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mYzq[p_|j  
} cB7=4:U  
eq\{*r"DCK  
C '}8  
Utility.log("Thread " + nThreadID + " is over!"); GVp2| \-L  
bDownOver = true; Ye_)~,{,p  
//nPos = fileAccessI.write (b,0,nRead); P A9 ]L  
} z|SLH<~  
catch(Exception e){e.printStackTrace ();} b-+iL  
} wLC|mByq  
} 8a1G0HRQ  
l$Y7CIH  
dDy9yw%f?  
//打印回应的头信息 CtA0W\9w5a  
public void logResponseHead(HttpURLConnection con) kqA`d  
{ {E`f(9r:  
for(int i=1;;i++) p_ QL{gn  
{ S-:l 60.  
String header=con.getHeaderFieldKey(i); @Tzh3,F2  
if(header!=null) BfF$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); W%.Kr-[?`o  
Utility.log(header+" : "+con.getHeaderField(header)); ]#[ R^t  
else ]pr;ME<M{  
break; avk0pY(n  
} F,`y_71<  
} qGgT<Rd~1  
*B`wQhB%  
Wel-a< e  
public void splitterStop() *A O/$K@Ma  
{ 5o2;26c  
bStop = true; r/fLm8+  
} Ohnd:8E  
eEQ 4L\d  
$} 7/mS@c  
}  #IyxH$  
q!9SANTx  
q?{wRBVVB  
/* {cKKTDN  
**FileAccess.java 5B@+$D[0?3  
*//文件访问(定位,写) +dk}$w[ g  
package NetFox; 9#.nNv*z3  
import java.io.*; izow=}  
=\?KC)F*e  
{(A Ys*5  
public class FileAccessI implements Serializable{ zN {'@B  
c:4M|t=  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Sim\+SL{#  
RandomAccessFile oSavedFile; Q'&oSPXSDd  
long nPos; DnP>ed"M!  
X4lz?Y:*  
NI \jGR.  
public FileAccessI() throws IOException kc\^xq~  
{ 4WZ:zr N  
this("",0); :03w k)  
} `\P#TBM  
sME3s-  
B_anO{3$4  
public FileAccessI(String sName,long nPos) throws IOException ]i)m   
{ 34Q l7LQp[  
oSavedFile = new RandomAccessFile(sName,"rw"); gN Xg  
this.nPos = nPos; OW\r }  
oSavedFile.seek(nPos); %vDN{%h8  
} <V#9a83JP  
K 38e,O  
htj:Z:C`  
public synchronized int write(byte[] b,int nStart,int nLen) <T+)~&g$  
{ h W6og)x  
int n = -1; #HpF\{{v  
try{ i<l_z&  
oSavedFile.write(b,nStart,nLen); (;;%B=  
n = nLen; k*d0ws#<l  
} 9aFu51  
catch(IOException e) Eq=~SO%  
{ \wEHYz  
e.printStackTrace (); P3UU~w+s  
} L\)ssO uh  
 eme7y  
'/%]B@!  
return n; ?zGx]?1P1<  
} ?55t0  
7v3'JG1r-  
y_boJ  
} AI0YK"c?  
ce@1#}*  
82l$]W4  
/* Y S/x;  
**SiteInfoBean.java ;c p*]  
*/ A?i ~*#wE  
package NetFox; 4zyN>f|  
h|qTMwPr  
4&%0%  
public class SiteInfoBean { V>D8l @  
j5\z7  
hOZ:r =%  
private String sSiteURL; //Site's URL ;Z^\$v9?  
private String sFilePath; //Saved File's Path C.qN Bl*  
private String sFileName; //Saved File's Name s^f7w  
private int nSplitter; //Count of Splited Downloading File  2%4u/  
rlxZ,]ul  
Qw>~] d,Z  
public SiteInfoBean() <@:RS$" i  
{//nSplitter的缺省值为5 by07l5  
//default value of nSplitter is 5 ]R%[cr  
this("","","",5); pmda9V4  
} ^UU@7cSi|G  
KU$:p^0l;*  
8XfhXm>~  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) uuHg=8(  
{ mok94XuK)  
sSiteURL= sURL; X1DE   
sFilePath = sPath; ^IQtXae6M  
sFileName = sName; ^mH:8_=(.  
this.nSplitter = nSpiltter; df\^uyD;  
i~Qnw-^B  
p1F{ v^  
} l,fwF ua  
>]{{5oOQ>  
88x2Hf5I  
public String getSSiteURL() 79&=MTM  
{ osM[Xv  
return sSiteURL; F\u]X  
} ;t~Y>,  
-HwqR Y s  
/,d]`N!  
public void setSSiteURL(String value) f;D(X/"f]  
{ [_T6  
sSiteURL = value; xs 1V?0  
} .R^R32ln  
u+lNcyp"MW  
.(^%M 2:6  
public String getSFilePath() 4Sz2 9\X  
{ (N6=+dNY  
return sFilePath; ilRPV'S^  
} 8B?*?,n5  
~%eZQgqA*  
t/lQSUip  
public void setSFilePath(String value) g es-nG-  
{ ? KDg|d  
sFilePath = value; g-pEt#  
} :jAsm[  
QVF561Yz  
! FVD_8  
public String getSFileName() I p<~Y  
{ ep6V2R  
return sFileName; J``5;%TJp  
} WN $KS"b6}  
wwNkJ+  
`z^50Vh|  
public void setSFileName(String value) fh*7VuAc  
{ :IO"' b  
sFileName = value; _b`/QSL  
} ki'<qa  
>]HvXEdNZ|  
%CZGV7JdA  
public int getNSplitter() bzaweA H  
{ _VB;fH$  
return nSplitter; SmS6B5j\R  
} -k  }LW4  
D;hJK-Y  
%(S!/(LWW  
public void setNSplitter(int nCount) ]5Q)mWF  
{ tb>Q#QB&u  
nSplitter = nCount; "!Nu A  
} *Z+U}QhHD6  
} </B:Zjn  
- i{1h"  
R|k!w]  
/* /g1;`F(MS/  
**Utility.java  T4J WZ  
*/ 9&HaEAme  
package NetFox; L*P*^I^1  
NA YwuE-`  
<vzU}JA\  
public class Utility { S^N{=*  
|}: D_TX  
ZftucD|ZY/  
public Utility() Gx|/ Jq  
{ 1lsg|iVz  
Snq0OxS[v  
,!^g8zO  
} R0yp9icS  
:4>LtfA  
//线程睡眠 Qqd+=mgc  
public static void sleep(int nSecond) QbYNL9%  
{ EkOn Rm_hn  
try{ ZC&~InN  
Thread.sleep(nSecond); 2{G7ignv  
} q#0yu"<  
catch(Exception e) :io~{a#.2\  
{ BO 3z$c1yU  
e.printStackTrace (); ZV!*ZpTe~  
} km}E&ao  
} "-Uqv@  
?aZ\D g{  
//日志 s ~i,R  
public static void log(String sMsg) c- [IgX e  
{ ?o d*"M  
System.err.println(sMsg); OQ<NB7'n0A  
} E;r~8^9)  
MENrP5AL  
U6M&7 l8  
public static void log(int sMsg) PR>%@-Vgj  
{ <h~_7Dn  
System.err.println(sMsg); 6o GF6C  
} XOzZtt  
} 1gH>B5`  
%U$%x  
o&E2ds3  
/* o&HFlDZ5jO  
**TestMethod.java \fC}l Ll  
*/ }}v28"\TA  
package NetFox; H.TPKdVX  
YfH+kDT  
Y.o-e)zX  
public class TestMethod { 4!<[5+.  
J]Qbg7|  
jF%l\$)/  
public TestMethod() v&u8Ks  
{ ///xx/weblogic60b2_win.exe UyOoyyd.  
try{ t-w4rXvF   
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); a~;`&Uj  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); CA ,0Fe3  
SiteFileFetch fileFetch = new SiteFileFetch(bean); O0> ^?dsL  
fileFetch.start(); _qhYG1t  
} V: ivnx*  
catch(Exception e){e.printStackTrace ();} 24/ ^_Td  
iLG~_Ob:  
TWJ%? /d  
} <7sGA{  
SN|:{Am  
54, (;  
public static void main(String[] args) L-(.v*  
{ T=->~@5  
new TestMethod(); c*x5t"{  
} W%cJ#R[o  
} mw&)j R$&  
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