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http断点续传简单实现(java)

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/* &:#"APX  
**SiteFileFetch.java @6V kNe9  
*/ X4/3vY  
package NetFox; Kza5_ 7p`L  
import java.io.*; _ uZVlu@  
import java.net.*; {cmV{ 4Yx  
{4r }jH  
OQ+kOE&  
public class SiteFileFetch extends Thread { lh-zE5;  
nQ;M@k&9eV  
G&@_,y|  
SiteInfoBean siteInfoBean = null; //文件信息Bean R:U!HE8j   
long[] nStartPos; //开始位置 U /jCM?~  
long[] nEndPos; //结束位置 -;o0) DwZ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 -932[+  
long nFileLength; //文件长度 (S8hr,%n  
boolean bFirst = true; //是否第一次取文件 mV|Z5= f  
boolean bStop = false; //停止标志 ~Hvf"bvK|  
File tmpFile; //文件下载的临时信息 K QCF "  
DataOutputStream output; //输出到文件的输出流 &X)^G#  
<AB({(  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 7upN:7D-  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,yTT,)@<  
{ v(l:N@L  
siteInfoBean = bean; j9|1G-CM  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); `t2Y IwOK  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); "cGjHy\j`  
if(tmpFile.exists ()) m]&y&oz  
{ uXVs<im  
bFirst = false; v dPb-z4  
read_nPos(); s}?QA cC  
} 8[x{]l[  
else rGQY  
{ nxs'qX(D  
nStartPos = new long[bean.getNSplitter()]; CPJ%<+4%b  
nEndPos = new long[bean.getNSplitter()]; r^`~GG!,Q  
} Z8o8>C\d9/  
"T.Qb/97@  
@UW*o&pGqL  
4d%QJ7y  
} @|fT%Rwho<  
c Sktm&SP  
5 &s<&h  
public void run() *_eY +\j  
{ [N0"mE<  
//获得文件长度 (4IH%Ez){  
//分割文件 A5,(P$@ k  
//实例FileSplitterFetch |\N))K-2D  
//启动FileSplitterFetch线程 ;& zBNj  
//等待子线程返回 ?;DzWCL~9  
try{ R!2E`^{Wl  
if(bFirst) vpoJ{TPO  
{ [q~3$mjQ  
nFileLength = getFileSize(); _aw49ag;  
if(nFileLength == -1) oI x!?,1  
{ ]>,Lw=_[_  
System.err.println("File Length is not known!"); \8]("l}ms8  
} trlZ  
else if(nFileLength == -2) ML7qrc;Rx  
{ d8VFa'|  
System.err.println("File is not access!"); b\C1qM4  
} ~/;shs<9EM  
else V(F1i%9lg  
{ _s+_M+@et  
for(int i=0;i<nStartPos.length;i++) cfL:#IM  
{ J:0`*7  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); U8 n=Ro  
} Ns.{$'ll  
for(int i=0;i<nEndPos.length-1;i++) rXVR X#Lh  
{ -!X\xA/KN  
nEndPos = nStartPos[i+1]; Ee'wsL  
} %[fZ@!B  
nEndPos[nEndPos.length-1] = nFileLength; ?A~a}bFZ  
} gk4DoOj#P  
} 6bUcrw/# p  
:CG;:( |  
}PzHtA,V  
//启动子线程 'Xg9MS&  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \/?&W[TF  
for(int i=0;i<nStartPos.length;i++) p&ZLd`[  
{ H'x_}y  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), a@N 1"O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), c6LPqPcN  
nStartPos,nEndPos,i); yS@xyW /  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0yL%Pjn6  
fileSplitterFetch.start(); #w;%{C[D  
} .>@]Im  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), xi=Qxgx0I  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Env_??xq  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", p0C|ECH  
nEndPos = " + nFileLength); @<B$LJ|jdG  
// fileSplitterFetch[nPos.length-1].start(); &\<?7Qj3U|  
jWh}cM=  
"\"sM{x  
//等待子线程结束 I1!m;5-c9k  
//int count = 0; HQV#8G#B  
//是否结束while循环 rG{,8*  
boolean breakWhile = false; pR3K~bx^  
[+b&)jN*2  
%^bN^Sq -  
while(!bStop) DaqpveKa  
{ F,JqHa9  
write_nPos(); t8t+wi!  
Utility.sleep(500); @!%HEs!# #  
breakWhile = true; d? 4-"9Y  
Fy^MI*}BZ  
YBQ{/"v%|  
for(int i=0;i<nStartPos.length;i++) ?$%2\"wX~7  
{ #LfoG?k1K  
if(!fileSplitterFetch.bDownOver) D*!9K8<o  
{ %Sw hNn  
breakWhile = false; DTC OhUIV  
break; m]/s R3yF  
} =xM:8 hm  
} vp`s< ;CA  
if(breakWhile) YI),yj  
break; #80M+m  
nfS.0\z  
K7]QgfpSZ  
//count++; +P;&/z8i*g  
//if(count>4) dU#} Tk  
// siteStop(); ,5P tB]8&3  
} ^(1S`z$  
U$j?2|v-x  
B#[.c$  
System.err.println("文件下载结束!"); LRv[,]b  
} P#qQde/y  
catch(Exception e){e.printStackTrace ();} '~[JV>5  
} <xr\1VjA  
N m@UM*D  
/t_AiM,(  
//获得文件长度 xRm~a-rp  
public long getFileSize() B^"1V{M  
{ z460a[Wl  
int nFileLength = -1; Mtq^6`JJ'  
try{ 2Z*^)ZQB  
URL url = new URL(siteInfoBean.getSSiteURL()); KNqs=:i  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); X>ck.}F  
httpConnection.setRequestProperty("User-Agent","NetFox"); '%[r9 w  
^"EK:|Y4%K  
yn.f?[G2  
int responseCode=httpConnection.getResponseCode(); <{1=4PA  
if(responseCode>=400) VU \{<j{  
{ X&cm)o%5Fe  
processErrorCode(responseCode); g)^g_4  
return -2; //-2 represent access is error 4i(?5p>f  
} #\gx.2W7  
t? [8k&Z  
Y]H,rO  
String sHeader; ?=%#lZ &?  
0R}F( tjw  
nBGcf(BE.$  
for(int i=1;;i++) _#T bO fu  
{ .@3bz  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9AHxa  
//Utility.log(in.readLine()); Ae>:i7.V  
sHeader=httpConnection.getHeaderFieldKey(i); x^/453Lk  
if(sHeader!=null) ?m dGMf)  
{ 5ii:93Hlj  
if(sHeader.equals("Content-Length")) h"On9  
{ ')1p  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); yo_;j@BGR  
break; (GbZt{.  
} x4;ndck%U  
} *&~wl(+O=  
else < /9@RO  
break; 0i/!nke.  
} {Zrf>ST  
} e\' =#Hw  
catch(IOException e){e.printStackTrace ();} ^ /7L(  
catch(Exception e){e.printStackTrace ();} )G@/E^ySM  
70yM]C^  
peGh-  
Utility.log(nFileLength); ;@V1*7y  
d^^EfWU  
Z'o'd_g>I+  
return nFileLength; e~NF}9#A  
} ]TIBy "3  
]$i~;f 8I  
=Bb/Y`Q  
//保存下载信息(文件指针位置) TqTz  
private void write_nPos() n$y@a? al  
{ C^nTLw;K  
try{ ($[)Tcq*~  
output = new DataOutputStream(new FileOutputStream(tmpFile)); s.XLC43Rs  
output.writeInt(nStartPos.length); |oV_7%mlu  
for(int i=0;i<nStartPos.length;i++) 9O\N K:2  
{ )9z3T>QW  
// output.writeLong(nPos); .|<+-Rsj  
output.writeLong(fileSplitterFetch.nStartPos); _X]S`e1F  
output.writeLong(fileSplitterFetch.nEndPos); |ZJ<N\\h-  
} ?qR11A};tG  
output.close(); 'uU{.bq  
} _ e94  
catch(IOException e){e.printStackTrace ();} 41NVF_R6J  
catch(Exception e){e.printStackTrace ();} %mMPALN]{  
} w}r~Wk^dLI  
S F&EVRv  
Kzrt%DA  
//读取保存的下载信息(文件指针位置) L5A?9zum/!  
private void read_nPos() Rg~F[j$N  
{ m! _*Q  
try{ A7=k 9|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); <K  GYwLk  
int nCount = input.readInt(); d{:0R9  
nStartPos = new long[nCount]; aF%V  
nEndPos = new long[nCount]; 7V-'><)gI  
for(int i=0;i<nStartPos.length;i++) !7jVKI80  
{ dI) 9@UL  
nStartPos = input.readLong(); X^9eCj;c  
nEndPos = input.readLong(); &M*f4PeXb  
} ^Bu55q  
input.close(); m$}Jw<.W  
} \cW9"e'  
catch(IOException e){e.printStackTrace ();} ) |j?aVqZ  
catch(Exception e){e.printStackTrace ();} %3mh'Z -[f  
} iuS*Vw  
)T!3du:M  
l&oc/$&|[  
private void processErrorCode(int nErrorCode) POt 8G  
{ vbSycZ2M7  
System.err.println("Error Code : " + nErrorCode); o2W^!#]=  
} eGj[%pk  
5Za%EaW%G  
g~]?6;uu  
//停止文件下载 k07pI<a?  
public void siteStop() <_~e/+_.  
{ F7IZ;4cp  
bStop = true; Q+a"Z^Z|  
for(int i=0;i<nStartPos.length;i++) [ %6(1$Ih  
fileSplitterFetch.splitterStop(); D2MWrX  
nV3I6  
a+P Vi  
} K| '`w.  
} W+u-M>Cj6  
//负责部分文件的抓取 Y[Eq;a132  
**FileSplitterFetch.java IHcR/\mz  
*/ Uc d~-D  
package NetFox; Qkb=KS%z  
55Ag<\7  
}b=Cv?Zg$m  
import java.io.*; _q=ua;I&  
import java.net.*; p}K.-S`MQ  
%hCd*[Z}j  
$c}-/U 8  
public class FileSplitterFetch extends Thread { #8@o%%F d  
2+cpNk$  
a<CACWsN.T  
String sURL; //File URL 5`p>BJ+n  
long nStartPos; //File Snippet Start Position f_'8l2jK1i  
long nEndPos; //File Snippet End Position <#~n5W{l  
int nThreadID; //Thread's ID *^[j6  
boolean bDownOver = false; //Downing is over /a?qtRw  
boolean bStop = false; //Stop identical -~v1@  
FileAccessI fileAccessI = null; //File Access interface &AP`k  
*I9O+/,  
dq^vK  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +a0` ,Jc  
{ *=zv:!  
this.sURL = sURL; jzd)jJ0M  
this.nStartPos = nStart; M<'He.n  
this.nEndPos = nEnd; ! q5qA*  
nThreadID = id; X}B ]0z>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;bRyk#  
} >p 9~'  
Nx=rw h  
]_43U` [#  
public void run() ~Aw.=Yi=  
{ OZ, Xu&N  
while(nStartPos < nEndPos && !bStop) AA<QI'6  
{ JasA w7  
.X34[AXd  
;"|QW?>$D  
try{ -rlCE-S  
URL url = new URL(sURL); C1o^$Q|j  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); cG,zO-H  
httpConnection.setRequestProperty("User-Agent","NetFox"); R'Uf#.  
String sProperty = "bytes="+nStartPos+"-"; fi  [4F  
httpConnection.setRequestProperty("RANGE",sProperty); %jn)=;\  
Utility.log(sProperty); \gR%PN  
v"-K-AQjB  
<h%I-e6  
InputStream input = httpConnection.getInputStream(); 0t7vg#v|  
//logResponseHead(httpConnection); Z7p!YTA  
8\Bb7*  
K/M2L&C  
byte[] b = new byte[1024]; A\<W x/  
int nRead; pD;fFLvN  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) W_lXY Z<  
{ N5.B"l  
nStartPos += fileAccessI.write(b,0,nRead); sW@_' Lw  
//if(nThreadID == 1) `G`y A%  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bX>R9i$  
} ZdgzPs"  
xSq{pxX  
Z):Nd9  
Utility.log("Thread " + nThreadID + " is over!"); }CL7h;5N 3  
bDownOver = true; oS^KC}X  
//nPos = fileAccessI.write (b,0,nRead); 1$H<Kjsm  
} n j2=}6  
catch(Exception e){e.printStackTrace ();} -ARks_\  
} i!)\m0Wm  
} oI-,6G}  
**JBZ\'  
sO{TGk]*  
//打印回应的头信息 iFnD`l 6)  
public void logResponseHead(HttpURLConnection con) BhhFij4  
{ xZA.<Yd^r  
for(int i=1;;i++) 1Eb2X}XC  
{ b8E7/~<z3  
String header=con.getHeaderFieldKey(i); Bk[C=<X  
if(header!=null) 0+e  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); e, fZ>EJ  
Utility.log(header+" : "+con.getHeaderField(header)); sLUOs]cj  
else  hLj7i?  
break; +QNsI2t;r  
} V!/9GeIF  
} */2nh%>$  
3OFI> x,h  
bEln.)  
public void splitterStop() o59b#9  
{ }(7TiCwd  
bStop = true; \440gH`  
} h"nhDART<  
R3%%;`c=  
*wx95?H0Z  
} ERia5HnoD,  
 ?tA%A  
f-p$4%(  
/* -iKoQkHt  
**FileAccess.java _ s*p$/V\  
*//文件访问(定位,写) .><-XJ  
package NetFox; -Aojk8tc  
import java.io.*; Y&H<8ez  
hZlHY9[t?  
B<i(Y1n[  
public class FileAccessI implements Serializable{ &gKDw!al  
qw1W }+~g  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 #k?.dWZ!  
RandomAccessFile oSavedFile; \&b 9  
long nPos; `QtkC>[  
+P8CC fPu  
)ZI#F]  
public FileAccessI() throws IOException Em !%3C1r  
{ U.X` z3q  
this("",0); +abb[  
} $JUkw sc  
ja9=b?]0,  
Wf^ sl  
public FileAccessI(String sName,long nPos) throws IOException `mA;1S  
{ ]6M,s0  
oSavedFile = new RandomAccessFile(sName,"rw"); @yo6w}3+-  
this.nPos = nPos; 4EmdQn  
oSavedFile.seek(nPos); zc$}4o  
} N`?|~g3  
3dlY_z=0  
NGJst_  
public synchronized int write(byte[] b,int nStart,int nLen) (T%?@'\  
{ eL~3CAV{  
int n = -1; )[oP `Z  
try{ b.v +5=)B  
oSavedFile.write(b,nStart,nLen); tDRo)z  
n = nLen; d%.|MAE  
} E- [Eg  
catch(IOException e) eh> |m> JY  
{ r}es_9*~Z  
e.printStackTrace (); YC')vv3o(  
} H6{Bx2J1*  
'&e8;X  
FvY=!U06  
return n; ^RO<r}B u  
} } C:i0Q  
`hdff0  
1YQYZ^11  
} AwjXY,2  
FzcXSKHV %  
zyhM*eM.7  
/* oyr b.lu/  
**SiteInfoBean.java jXLd#6  
*/ o$eCd{HuX  
package NetFox; ;mT}Q;F#  
q/@+.q  
Vjs'|%P7  
public class SiteInfoBean {  V?1[R  
=yz"xWH  
#:+F  
private String sSiteURL; //Site's URL 1Y*k"[?dW  
private String sFilePath; //Saved File's Path yQMwt|C4  
private String sFileName; //Saved File's Name Zp^O1&\SK?  
private int nSplitter; //Count of Splited Downloading File v/9DD%An  
fLqjBG]<  
T.3{}230<  
public SiteInfoBean() tsL ; wT_  
{//nSplitter的缺省值为5 l _%<U  
//default value of nSplitter is 5 1O< 6=oH  
this("","","",5); g4b#U\D@)/  
} IdN3Ea]  
/ Ws>;0  
mvK^')  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) y: x<`E=  
{ W#~7X  
sSiteURL= sURL; kl]MP}wc  
sFilePath = sPath; h x&"fe  
sFileName = sName; |T@SlNi]  
this.nSplitter = nSpiltter; ,}&TZkN{-  
v@tEHRadz  
:;.^r,QAI  
} D\b$$z]q  
51b%uz  
Y|><Ls6Q  
public String getSSiteURL() *U,J Q  
{ NS2vA>n8R  
return sSiteURL; xYCJO(&  
} Yi?bY  
g i6s+2  
L7;~4_M9.V  
public void setSSiteURL(String value) oe]* Q  
{ :`zO%h  
sSiteURL = value; P%lD9<jED  
} s{R ,- \_  
vhbHt_!u&  
3a.!9R>  
public String getSFilePath() `DF49YP"~  
{ /0H}-i  
return sFilePath; Gmi? xGn  
} J)Y`G4l2@  
e)n ,Y  
y ;Cs#eo  
public void setSFilePath(String value) F`m}RL]g  
{ babL.Ua8o  
sFilePath = value; :\P@c(c{^C  
} 8 E\zjT!#\  
PVp>L*|BZ;  
:Q>e54]'&  
public String getSFileName() p$9Aadi]  
{ / Qd` ?  
return sFileName; U,#x\[3!Jt  
} lQ`=PFh  
:>{!%-1Z  
H^*AaA9-   
public void setSFileName(String value) A6]X aF  
{ ~q}L13^k  
sFileName = value; (g@\QdH`|  
} mdEJ'];AH  
0|Fx Sc  
'Og@<~/Xy  
public int getNSplitter() e O\72? K  
{ fV|uKs(W  
return nSplitter; 6!"wiM"]  
} ,{HQKHg  
k3qQU)  
vvv'!\'#  
public void setNSplitter(int nCount) v,ZYh w  
{ d-B+s%>D  
nSplitter = nCount; m6mGcbpn  
} __'4Qt   
} uL^; i""  
xj;:B( i  
K<*6E@+i  
/* Q}@t'  
**Utility.java KhfADqji|  
*/ bpwA|H%{M  
package NetFox; O|,9EOrP  
p?y2j  
o13jd NQ-  
public class Utility { ")No t$8  
|T""v_q  
'JMW.;Lh?X  
public Utility() ]5"k%v|  
{ t<Yi!6  
"jum*<QZz  
PiKP.  
} o@zxzZWg  
Gy/w #4xj  
//线程睡眠 z qq  
public static void sleep(int nSecond) FSA%,b; U  
{ \uOM,98xS  
try{ '_G\_h}5  
Thread.sleep(nSecond); q k^FyZ<  
} sWo`dZ\6WB  
catch(Exception e) |ZH(Z}m  
{ '-%1ILK$3r  
e.printStackTrace (); .@,t}:lD  
} UmWXv#q\l  
} /%&  d:  
dR]-R/1|  
//日志 kP%hgZ  
public static void log(String sMsg) UA8hYWRP  
{ losqc *|  
System.err.println(sMsg); [ @eA o>  
} pz /[ ${X  
7?=^0?a  
XG.[C>  
public static void log(int sMsg) V+"%BrM  
{ '%rT]u3U  
System.err.println(sMsg); p3U)J&]c6  
} Rsfb?${0G  
} M9W zsWM  
8<C*D".T$  
VhkM{O  
/* MT&aH~YB  
**TestMethod.java |X8?B =  
*/ k)n b<JW|r  
package NetFox; 6#+&/ "*  
| ky40[C  
~JXz  
public class TestMethod { 2xLtJR4L  
1X2j%q I&  
?.VKVTX^  
public TestMethod() 4[$:KGh3  
{ ///xx/weblogic60b2_win.exe _U^[h!  
try{ ~9+01UU^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); d^}p#7mB\  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); tS2 &S 6u  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (kLaXayn  
fileFetch.start(); @-)?uYw:r  
} UN.;w3`Oc  
catch(Exception e){e.printStackTrace ();} * hs&^G  
(+|+ELfqW  
5I2,za&e  
} src9EeiV  
oFU:]+.+D  
27D*FItc  
public static void main(String[] args) g3$'G hf  
{ !{jw!bB  
new TestMethod(); [Y](Y3/.N  
} )*BZo>"  
} @JbxGi  
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