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http断点续传简单实现(java)

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/* (LXYx<  
**SiteFileFetch.java HmU6:8V *Z  
*/ #D{Eq8dp  
package NetFox; ]Z=al`-  
import java.io.*; X$P(8'[9A  
import java.net.*; [[N${C  
%" l;  
o#z$LT1dY  
public class SiteFileFetch extends Thread { 8)"lCIf  
xA-?pLt "G  
i!RYrae  
SiteInfoBean siteInfoBean = null; //文件信息Bean GGhk`z  
long[] nStartPos; //开始位置 S^EAE]  
long[] nEndPos; //结束位置 ` ` Yk  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 {%y|A{}c  
long nFileLength; //文件长度 @}{uibLD\  
boolean bFirst = true; //是否第一次取文件 .O#7X  
boolean bStop = false; //停止标志 w?N>3`Jnf  
File tmpFile; //文件下载的临时信息 ,PJC FQMR  
DataOutputStream output; //输出到文件的输出流 )4:]gx#cr  
<1* \ ~CX  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) R4k+.hR  
public SiteFileFetch(SiteInfoBean bean) throws IOException Q uw|KL  
{ Vwjic2lGI  
siteInfoBean = bean; KPjAk  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /PR 4ILed  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); oj'YDQ^uj  
if(tmpFile.exists ()) O?A%  
{ 31e O2|7  
bFirst = false; ^~bd AO81  
read_nPos(); A+4Kj~`!  
} "f~OC<GdYs  
else cg9}T[A  
{ z> DQ  
nStartPos = new long[bean.getNSplitter()]; iAXGf V  
nEndPos = new long[bean.getNSplitter()]; lHTr7uF(  
} oZl%0Uy?9I  
15aPoxo>  
7kT X  
BTG_c_ ?]e  
} Hfo<EB2Y9N  
`f~$h?}3-@  
Lz:FR*  
public void run() %4YSuZg  
{ EQ :>]O  
//获得文件长度 -Xw S?*O  
//分割文件 %,ScGQE  
//实例FileSplitterFetch E m+&I  
//启动FileSplitterFetch线程 Rxlv:  
//等待子线程返回 V U5</si+  
try{ zx.SRs$  
if(bFirst) "sY}@Q7  
{ b+hN\/*]  
nFileLength = getFileSize(); @qx$b~%  
if(nFileLength == -1) DvOvtd  
{ ]gaeN2  
System.err.println("File Length is not known!"); HPt\ BK  
} d'3"A"9R7-  
else if(nFileLength == -2) 1cRF0MI  
{ C>,> _  
System.err.println("File is not access!"); ! R3P@,j  
} R?- zJ ;  
else =#<bB)59  
{ X{6a  
for(int i=0;i<nStartPos.length;i++) CY[3%7 fv  
{ $4)L~g|  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1~LfR  
} v*<rNZI  
for(int i=0;i<nEndPos.length-1;i++) koD}o^U#  
{ u!F\`Gfm_  
nEndPos = nStartPos[i+1]; r_ B.b K  
} C=cn .CX  
nEndPos[nEndPos.length-1] = nFileLength; ]?oJxW.  
} pQC|_T#u  
} s| Q1;%T j  
nXI8`7D  
c813NHW  
//启动子线程 Q&^\YgkCf  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; DxpJP,wY3  
for(int i=0;i<nStartPos.length;i++) Y3(I;~$!  
{ {Ja(+NQ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), b0@K ~O;g  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), gwXmoM5  
nStartPos,nEndPos,i); WpnP^gmX  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %f1IV(3Qc  
fileSplitterFetch.start(); 3Lq9pdM>2@  
} ux| QGT2LY  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^=1u2YdVw  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); -o!bO9vC  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", LEOa=(mN\  
nEndPos = " + nFileLength); l+hOD{F4pS  
// fileSplitterFetch[nPos.length-1].start(); k%kEW%I yG  
'd&4MA0X  
Ry xu#]s  
//等待子线程结束 t imY0fx #  
//int count = 0; yx:+Xy*N  
//是否结束while循环 ;Bzx}7A  
boolean breakWhile = false; *rHz/& ,  
_9p79S<+  
d"Wuu1tEY  
while(!bStop) -p>1:M <  
{ Q6e7Z-8  
write_nPos(); A,=> |&*  
Utility.sleep(500); 1\Pjz Lj  
breakWhile = true; /{R.   
#M+_Lk3  
^3H:I8gRCl  
for(int i=0;i<nStartPos.length;i++) .]JIo&>5  
{ T{"Ur :p  
if(!fileSplitterFetch.bDownOver) k*\)z\f  
{ gFu,q`Vf*  
breakWhile = false; W3\E; C-g0  
break; z,2*3Be6V  
} $ Y^0l  
} ) jvI Nb  
if(breakWhile) re}PpXRC  
break; 1,Mm+_)B  
&/)B d%  
UL>2gl4s/  
//count++; >w,jaQ  
//if(count>4) M+HhTW;I=  
// siteStop(); X  u HR  
} Wi>m}^}9  
v-q-CI? B#  
!cM<&3/  
System.err.println("文件下载结束!"); "19#{yX4  
} *FZav2]-  
catch(Exception e){e.printStackTrace ();} lz36;Fp  
} 8~s0%%{,M  
|0}7/^  
?_A[E]/H  
//获得文件长度 d!Gy#<H  
public long getFileSize() ]7yxXg  
{ z\" .(fIV  
int nFileLength = -1; ;Oqf{em];  
try{ ' ]+!i a  
URL url = new URL(siteInfoBean.getSSiteURL()); CmBgay  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >P\eHR,{-  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1TR+p? "  
| B*B>P#  
lBs-u h  
int responseCode=httpConnection.getResponseCode(); ABkDOG2br  
if(responseCode>=400) YZSQOLN{  
{ B7|%N=S%/  
processErrorCode(responseCode); <j,3Dn  
return -2; //-2 represent access is error dJJq]^|  
} L=EkY O%\"  
,Tegrz&G  
gW--[  
String sHeader; >wt.)c?5  
Jvsy 6R  
C7*YZe  
for(int i=1;;i++) W;UPA~nT~  
{ !X~NL+  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 7iwck.*  
//Utility.log(in.readLine()); ?*+U[*M  
sHeader=httpConnection.getHeaderFieldKey(i); \/;c^!(<  
if(sHeader!=null) J@E]Fl  
{ ' -Cx-=  
if(sHeader.equals("Content-Length")) &ZkJ,-  
{ R LF6Bc  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); KB :JVK^<  
break; :( m, 06K  
} ]y=U"g  
} +_cigxpTc  
else &|ne!wu  
break; p5vQ.Ni*\-  
} L[Z^4l_!  
} ex1!7A!}g  
catch(IOException e){e.printStackTrace ();} N|2d9E  
catch(Exception e){e.printStackTrace ();} &oB*gGRw=7  
A:GqR;;"x>  
.PVYYhrt  
Utility.log(nFileLength); Y9<[n)>+  
+ZW>JjP*  
rg k1.0U0  
return nFileLength; d v[.u{#tP  
} Y$n+\K  
f77W{T4  
L/-SWid)  
//保存下载信息(文件指针位置) F1-"yX1B  
private void write_nPos() 7z1@XO<D  
{ LmqSxHs0Q  
try{ r0lI&25w  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Tgtym"=xd  
output.writeInt(nStartPos.length); ~K3Lbd| r  
for(int i=0;i<nStartPos.length;i++) ^\Q,ACkZb  
{ 2)|=+DN;  
// output.writeLong(nPos); Fs $FR-x  
output.writeLong(fileSplitterFetch.nStartPos); :.XlAQR~b  
output.writeLong(fileSplitterFetch.nEndPos);  ~,&8)1  
} o4EY2  
output.close(); ]w;t0Bk  
} 5 0-7L,  
catch(IOException e){e.printStackTrace ();} ?&eS}skL  
catch(Exception e){e.printStackTrace ();} 0[%{YmI{W  
} | |pOiR5  
W$SV+q(rT  
OEjX(F3=  
//读取保存的下载信息(文件指针位置) #@`c7SR  
private void read_nPos() wZ\93W-}  
{ X;6;v]  
try{ 1R~$m  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6O6B8  
int nCount = input.readInt(); L%5y@b{AR  
nStartPos = new long[nCount]; U!o  
nEndPos = new long[nCount]; .u#Hg'oP  
for(int i=0;i<nStartPos.length;i++) wUr(i*  
{ (UjaL@G  
nStartPos = input.readLong(); yGt [Qvx#  
nEndPos = input.readLong(); sGtxqnX:J  
} ?;`GCE  
input.close(); /]Y#*r8jRi  
} v@[3R7|4  
catch(IOException e){e.printStackTrace ();} i*mU<:t  
catch(Exception e){e.printStackTrace ();} _[-MyUs  
} 8\' tfHL  
hOZTD0  
$A{$$8P  
private void processErrorCode(int nErrorCode) f:~G)  
{ <|Lz#iV37  
System.err.println("Error Code : " + nErrorCode); [u K,.G  
} ,"#nJC  
hf9i%,J  
.txtt?ZF2  
//停止文件下载 6IT6EkiT  
public void siteStop() K\xM%O?  
{ XBCHJj]k  
bStop = true; T$2A2gb `  
for(int i=0;i<nStartPos.length;i++) y< dBF[  
fileSplitterFetch.splitterStop(); ~< UYJc  
tg#jjXV\0p  
dazML|1ow  
} 6*S/frE  
} NR_3nt^h  
//负责部分文件的抓取 qtZzJ>Y  
**FileSplitterFetch.java 86-Rm  
*/ AU`z.Isf  
package NetFox; yQj J-g(.  
af>i  
Z'k?lkB2i  
import java.io.*; 2'M5+[8y8  
import java.net.*; ]3*w3Y!XK  
vW*Mf}=  
,=Wj*S)~  
public class FileSplitterFetch extends Thread { H'YKj'  
%_Lz0L64k  
z$%8'  
String sURL; //File URL FN!?o:|(  
long nStartPos; //File Snippet Start Position *lLCH,  
long nEndPos; //File Snippet End Position URm<Ji  
int nThreadID; //Thread's ID zFO0l).  
boolean bDownOver = false; //Downing is over MDIPoS3BRa  
boolean bStop = false; //Stop identical <HRPloVKo  
FileAccessI fileAccessI = null; //File Access interface ,{q#U3  
I$+=Fb'N0  
O ] !tK  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException DU"Gz!X]Jd  
{ p2b~k[  
this.sURL = sURL; <#M1I!R  
this.nStartPos = nStart; 6<S-o|Xw  
this.nEndPos = nEnd; [T7&)p  
nThreadID = id; x<!]#**;  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [&&#~gz  
} 2@Nd02v|  
~$4(|Fq/  
UYZC% $5x  
public void run() P(8Yz W  
{ vS5}OV  
while(nStartPos < nEndPos && !bStop) 6vNn;-gg.  
{ %4x0^<k~  
_$IWr)8f  
zB+e;x f|  
try{ )3e_H s+  
URL url = new URL(sURL); oupWzjo  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;rL1[qwk  
httpConnection.setRequestProperty("User-Agent","NetFox"); ceks~[rP  
String sProperty = "bytes="+nStartPos+"-"; Z P|k3   
httpConnection.setRequestProperty("RANGE",sProperty); ]Ri=*KZa  
Utility.log(sProperty); BRu}"29  
H'!OEZ  
'*Dp2Y{7  
InputStream input = httpConnection.getInputStream(); p{GO-gE@  
//logResponseHead(httpConnection); _UkBOJ:G$H  
[>p!*%m  
( EJ1g^|"  
byte[] b = new byte[1024]; x@oxIXN  
int nRead; [Nm?qY  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) r 56~s5A  
{ kkHK~(>G  
nStartPos += fileAccessI.write(b,0,nRead); KV;q}EyG  
//if(nThreadID == 1) .0U[n t6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); O zC%6;6h  
} 85|u;Fxf  
b}Im>n!  
1qn/*9W}=  
Utility.log("Thread " + nThreadID + " is over!"); X.#9[3U+  
bDownOver = true; FPK=Tr:b  
//nPos = fileAccessI.write (b,0,nRead); F)eP55C6  
} V[WZ#u-p  
catch(Exception e){e.printStackTrace ();} 0k\,z(e  
} kP('X/  
} M+ <SSi"  
^5~x*=_  
.e3@fq  
//打印回应的头信息 q$v0sTk0Y  
public void logResponseHead(HttpURLConnection con) .,S`VNU  
{ k-^^Ao*@  
for(int i=1;;i++) NF |[j=?  
{ 4,QA {v  
String header=con.getHeaderFieldKey(i); yCkc3s|DA;  
if(header!=null) -9+$z|K  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); a $'U?%  
Utility.log(header+" : "+con.getHeaderField(header)); p8.JJt^  
else 525^/d6v  
break; N|)e {|k  
} N&k\X]U  
} n'pJl  
jYAm}_?No  
ZWuNl!l>  
public void splitterStop() INk|NEX  
{ Snmv  
bStop = true; 3My}u>  
} yNwSiZE X  
j8?! J^TC  
h 1 "#  
} oIj/V|ByK  
-3d`e2^&}  
:si&A;k  
/* ^oq|^O  
**FileAccess.java L?8OWLjRy  
*//文件访问(定位,写) DTi^* Wj  
package NetFox; vYLspZ;S  
import java.io.*; w0sy@OF  
9'|k@i:  
n?q+:P  
public class FileAccessI implements Serializable{ s` , g4ce`  
{s6#h#U  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 rWO#h{  
RandomAccessFile oSavedFile; zU0JwZi  
long nPos; 86qQ"=v  
dn42'(p@G  
$'!n4}$}  
public FileAccessI() throws IOException a.O"I3{?h  
{ (<OmYnm  
this("",0); T51oNO%^  
} q]!FFi{w;  
&DtI+ )[|  
6y`FW[  
public FileAccessI(String sName,long nPos) throws IOException dR,a0+!  
{ K!>3`[:I"  
oSavedFile = new RandomAccessFile(sName,"rw"); }7fzEo`g  
this.nPos = nPos; b/#<::D `  
oSavedFile.seek(nPos); ib]<;t  
} L4u.cH J}0  
-s0J8b  
/ )[\+Nc  
public synchronized int write(byte[] b,int nStart,int nLen) @LU[po1I  
{ e2nZwPH  
int n = -1; ? )IH#kL  
try{ vu*{+YpH  
oSavedFile.write(b,nStart,nLen); Q3t%JP>;g  
n = nLen; =''*'a-P  
} Y<@_d  
catch(IOException e) l:#'i`;   
{ slr>6o%W`  
e.printStackTrace (); U&$I!80.  
} <A\g*ld  
P6v@ Sn  
s1%2({wP  
return n; [P)](8nR[  
} 5*B'e{C  
mkBQ TQGT  
.rDao]K  
} 8|hi2Qeu,c  
"4*QA0As  
&s\,+d0  
/* ^b.fci{1m  
**SiteInfoBean.java <X97W\  
*/ +@@( C9  
package NetFox; iN@|08  
<P Vmr2Jp"  
q}g0-Da  
public class SiteInfoBean { VF7H0XR/k5  
wmP[\^c%$j  
3] U/^f3  
private String sSiteURL; //Site's URL aH500  
private String sFilePath; //Saved File's Path LzB*d  
private String sFileName; //Saved File's Name jM'Fb.>~  
private int nSplitter; //Count of Splited Downloading File D2:ShyYAS  
%a-fxV[  
r"5\\qf5*  
public SiteInfoBean() RC/& dB  
{//nSplitter的缺省值为5 +fMW B  
//default value of nSplitter is 5 yN#]Q}4  
this("","","",5); , d4i0;2}+  
} !E *IktAI  
r9-)+R J  
`E>o:tff  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) cf_X=;yaqy  
{ qNkX:|j  
sSiteURL= sURL; yW_goS0  
sFilePath = sPath; M|$A)D1  
sFileName = sName; D@iS#+22  
this.nSplitter = nSpiltter; b0/[+OY   
=D 5!Xq'|  
Zk gj_  
} 2+LvlS)C  
U4e9[=q`'  
z-S8s2.Fd  
public String getSSiteURL() `3UvKqe  
{ v[m1R'  
return sSiteURL; xz/G$7q7  
} mj2sbRiSR=  
 ck`$ `  
q1%xk =8  
public void setSSiteURL(String value) u,@x7a,z  
{ X=JAyxY  
sSiteURL = value; KH[Oqd  
} J8`vk#5  
V}G; oz&>)  
.ityudT<  
public String getSFilePath() &gvX<X4e  
{ mgEZiAV?  
return sFilePath; =Ajw(I[56  
} Cz4l  
M""X_~&I"  
OgyHX>}bH  
public void setSFilePath(String value) D_I_=0qNd  
{ 8GT{vW9  
sFilePath = value; jATN):8W  
} 4+0:(=>[%  
B|BJkY'  
& =vi]z:[  
public String getSFileName() z#olKBs  
{ DTx>^<Tk  
return sFileName; O@KAh5EB  
} A Rjox`  
IAbH_+7O  
FBI^}^#_  
public void setSFileName(String value) a^9}ceu?   
{ &R}2/Mt  
sFileName = value; Z9PG7h  
} ]<E\J+5K  
k5GJrK+  
`"E<%$|ZQy  
public int getNSplitter() xTdh/}  
{ ZCkwK  
return nSplitter; MqswYK-s  
} Y<`uq'V  
Yg")/*!H  
gM Z `  
public void setNSplitter(int nCount) [ Q20c<,  
{ 2ISnWzq;  
nSplitter = nCount; locf6%2g~  
} e%&/K7I"?  
} qznd '^[  
? $X1X`@  
6imQjtI  
/* e_CgZ  
**Utility.java y+a]?`2  
*/ ;jpsH?3g  
package NetFox; .AHww7  
T$9tO{  
x-s]3'!L  
public class Utility { Y-:{a1/RKo  
ucC'SS  
Ps7Bt(/  
public Utility() t{ScK%S6  
{ ]1n =O"vE  
mE_?E&T`|  
rM(2RI4O`0  
} -*C+z!?BP  
i!EN/Bd  
//线程睡眠 x AR9* <-  
public static void sleep(int nSecond) '|l1-yD_  
{ 4P}<86xk  
try{ #a"gW,/K  
Thread.sleep(nSecond); IG~d7rh"  
} XQL]I$?  
catch(Exception e) Q68q76  
{ !XS ;&s7[*  
e.printStackTrace (); go$zi5{h#  
} SdBo sB3v>  
} Q+'QJ7fw'|  
,v+~vXO&\  
//日志 JN-wToOF  
public static void log(String sMsg) E h>qUa  
{ k9?fE  
System.err.println(sMsg); D>Dch0{H,:  
} 1-60gI1)  
8!{F6DG  
$17utJ 58  
public static void log(int sMsg) J(\f(jh/  
{ elf2!  
System.err.println(sMsg); F&x9.  
} %B'*eBj~fw  
} -5t .1/  
DkGC+Dw  
!Wz%Hy:ZK  
/* [1{uK&$e  
**TestMethod.java ^X/[x]UOT@  
*/ E)w^odwMU  
package NetFox; INj2B@_  
*XZlnO  
4r'f/s8"#  
public class TestMethod { Dy_Za.N2  
y0D="2)  
k&PxhDf  
public TestMethod() qXJBLIG  
{ ///xx/weblogic60b2_win.exe &}G2;O}3  
try{ )a%kAUNj  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 2pEr s|r  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Wp<4F 6C$@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); gIfl}Jat  
fileFetch.start(); "eiZZSz  
} %;|^*?!J0  
catch(Exception e){e.printStackTrace ();} B&E qd  
h{&}p-X&[  
qZ6Mk9@M  
} MjW g  
8QN#PaY  
=)GhrWeVi4  
public static void main(String[] args) m:,S1V_jl  
{ t  Tky  
new TestMethod(); ErNL^Se1  
} |i7j }i  
} b xT|  
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