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http断点续传简单实现(java)

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/* RUCPV[{b  
**SiteFileFetch.java y5= `ap  
*/ Ae^X35  
package NetFox; p <eC<dtu  
import java.io.*; @ZN^1?][  
import java.net.*; 3$vRW.c\q  
Md)zEj`\  
!KKT[28v  
public class SiteFileFetch extends Thread { 2=-utN@Z  
m6eZ_ &+u  
b1pQ`qt  
SiteInfoBean siteInfoBean = null; //文件信息Bean CV$],BM  
long[] nStartPos; //开始位置 SUWD]k>PH  
long[] nEndPos; //结束位置 6#}93Dgv4  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 L_Q#(in  
long nFileLength; //文件长度 RjJU4q  
boolean bFirst = true; //是否第一次取文件 +^rh[>W  
boolean bStop = false; //停止标志 W$JebW<z(  
File tmpFile; //文件下载的临时信息 9 7%0;a8  
DataOutputStream output; //输出到文件的输出流 z|G9,:9  
OQ :dJe6  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) j9qREf9)  
public SiteFileFetch(SiteInfoBean bean) throws IOException f:zFFpP.j@  
{ @=w<B4 L  
siteInfoBean = bean; `=#01YX[0  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); a m-b!l!q^  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); UH@a s  
if(tmpFile.exists ()) 2:}fe}  
{ QQk{\ PV  
bFirst = false; eLwTaW !C  
read_nPos(); ;E~4)^  
} r8xyd"Axy  
else * v8Ts  
{ Z'pQ^MO  
nStartPos = new long[bean.getNSplitter()]; )oo~m\`  
nEndPos = new long[bean.getNSplitter()]; e73^#O&Xt  
} d{et8N  
nmlPX7!{$  
E{=2\Wkcp  
 O#nR>1h  
} _ 7oV<  
R cY>k  
)T907I|  
public void run() 3`hUo5K  
{ >idBS  
//获得文件长度 aYL|@R5;e  
//分割文件 KDi|(  
//实例FileSplitterFetch u^I(Ny  
//启动FileSplitterFetch线程 2Zuq?1=  
//等待子线程返回 !DjvsG1x  
try{ Uu6L~iB  
if(bFirst) CZ 2`H[8  
{ 1{pmKPu  
nFileLength = getFileSize(); M_B:{%4  
if(nFileLength == -1) U]qav,^[  
{ PYB+FcR6?n  
System.err.println("File Length is not known!"); 2^~<("+w  
} (-7ZI"Ku  
else if(nFileLength == -2)  R7oj#  
{ x+? 9C  
System.err.println("File is not access!"); 1rw0sAuGy  
} W]<$0  
else  [\)oo  
{ y<W8Q<9  
for(int i=0;i<nStartPos.length;i++) +]>+a<x*%  
{ 39 e;  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); >-T`0wI  
} *, Ld/O;s  
for(int i=0;i<nEndPos.length-1;i++)  (dJI_A  
{ 'f8(#n=6qP  
nEndPos = nStartPos[i+1]; ocwG7J\W  
} N5|Rmfo1  
nEndPos[nEndPos.length-1] = nFileLength; #)+- lPe  
} 1`f_P$&Z_J  
} @ \.;b9  
^s7,_!.Pq  
!2Dy_U=  
//启动子线程 |ifHSc.j<  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; sfp,Lq`  
for(int i=0;i<nStartPos.length;i++) 9z m|Lbj  
{ [{[N(g&d  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), k0?ZYeHC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Ue5O9;y]u  
nStartPos,nEndPos,i); U IJx*  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); x9>\(-uU  
fileSplitterFetch.start(); '6Qy/R  
} qg z*'_S  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), NCeaL-y7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {!ZyCi19  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", XCB?ll*^  
nEndPos = " + nFileLength); r'/;O  
// fileSplitterFetch[nPos.length-1].start(); OL59e %X  
ofc.zwH  
,reJ(s  
//等待子线程结束 =<f-ob8,  
//int count = 0; jdut4 nFc  
//是否结束while循环 `Y?t@dd  
boolean breakWhile = false; hVoNw6fE  
$KV&\Q3\0  
<x%M3BTx  
while(!bStop) Dkw%`(Oh/,  
{ O[~x_xeW  
write_nPos(); S{F-ttS"  
Utility.sleep(500); 4Tzd; P6_  
breakWhile = true; uE_c4Hp  
xc 1A$EY  
+,'T=Ic{  
for(int i=0;i<nStartPos.length;i++) zbw7U'jk  
{ `cP <}^]  
if(!fileSplitterFetch.bDownOver) \L!uHAE2a  
{ `&7RMa4=  
breakWhile = false; A Ayv  
break; <T,A&`/  
} `ue[q!Qq  
} :bM+&EP  
if(breakWhile) `linG1mF  
break; 8"'x)y  
'3tw<k!1{.  
H! r &aP  
//count++; *}b]rjsj  
//if(count>4) hP?fMW$V  
// siteStop(); ^~ =9  
} A//?6O Jx?  
l?N`{ ,1^  
>.9eBz@  
System.err.println("文件下载结束!"); _v5t<_^N  
} sOFa!bdPW  
catch(Exception e){e.printStackTrace ();} JXQPT  
} }amU[U,  
;|ub!z9GG  
>G)qns9  
//获得文件长度 dT@UK^\  
public long getFileSize() 4z4v\IpB  
{ o.:p_(|hI  
int nFileLength = -1; ~GB=Nz  
try{ 85U.wpG  
URL url = new URL(siteInfoBean.getSSiteURL()); _"f  :`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); N$aZ== $5  
httpConnection.setRequestProperty("User-Agent","NetFox"); uF(k[[qaiN  
/9ZcM]X B  
B:oF;~d/,  
int responseCode=httpConnection.getResponseCode(); I@7/jUO  
if(responseCode>=400) r((Tavn  
{ :Z`4j  
processErrorCode(responseCode); c,5n, i  
return -2; //-2 represent access is error $N+6h#  
} "X1vZwK8N  
*$,+`+  
i s"vekC  
String sHeader;  y).P=z  
V 2znU  
Rq)BssdF  
for(int i=1;;i++) R"xp%:li  
{ H3FW52pjX  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Z[#IfbYt  
//Utility.log(in.readLine()); Ueyw;Y  
sHeader=httpConnection.getHeaderFieldKey(i); n[k1np$7?6  
if(sHeader!=null) ?T*";_o,B  
{ OD9 yxN>P  
if(sHeader.equals("Content-Length")) *K!++k!Ixa  
{ I@Z)<5Zf  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); x !{   
break; 0Oxz3r%}r  
} CmC0k-%w  
} >q( 5ir  
else D!FaEN  
break; ," R>}kPli  
} KsdG(.I+ek  
} a8uYs DS  
catch(IOException e){e.printStackTrace ();} 1 p\Ak  
catch(Exception e){e.printStackTrace ();} qc8Ta"  
7[o {9Yp&  
"n?<2 wso  
Utility.log(nFileLength); 6 DP[g8  
`.BR= ['O  
UmP'L!  
return nFileLength; 2R@%Y/  
} 9U<Hf32  
&TT":FPR  
V/y=6wUiSl  
//保存下载信息(文件指针位置) 9{eBgdC  
private void write_nPos() cH"@d^"+q|  
{ gbGTG(:1S  
try{ "EPD2,%S  
output = new DataOutputStream(new FileOutputStream(tmpFile)); HhSjR%6HY;  
output.writeInt(nStartPos.length); }p'8w\C$  
for(int i=0;i<nStartPos.length;i++) =7jEz+w#  
{ l1-HO  
// output.writeLong(nPos); qi=3L  
output.writeLong(fileSplitterFetch.nStartPos); :c4kBl%gJ  
output.writeLong(fileSplitterFetch.nEndPos); pCt}66k}  
} #)74X% 4(  
output.close(); !IA KVQ  
} DX@}!6|T  
catch(IOException e){e.printStackTrace ();} FBY ODw  
catch(Exception e){e.printStackTrace ();} B=zMYi  
} Q=+8/b  
nR'#s%Kj  
*SZ>upg  
//读取保存的下载信息(文件指针位置) - V=arm\#z  
private void read_nPos() M\UWWb&%\  
{ "{F;M{h$},  
try{ 'Z7P  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9*pG?3*I  
int nCount = input.readInt(); 3%IWGmye4  
nStartPos = new long[nCount]; z\}!RBOq  
nEndPos = new long[nCount]; { /<4'B  
for(int i=0;i<nStartPos.length;i++) _T~H[&Hl  
{ =lrN'$z?%  
nStartPos = input.readLong(); |~NeB"l{  
nEndPos = input.readLong(); X <xqT  
} 878tI3-  
input.close(); h)o]TV  
} u2lmwE  
catch(IOException e){e.printStackTrace ();} *Q/E~4AW|t  
catch(Exception e){e.printStackTrace ();} .BL:h&h|y  
} raQYn?[  
Nmf#`+7gCI  
<nA3Sd"QfV  
private void processErrorCode(int nErrorCode) AQ}l%  
{ 3wNN<R  
System.err.println("Error Code : " + nErrorCode); 4(m3c<'P  
} *|'}v[{v^9  
^<9)"9)m_  
"jGe^+9uT  
//停止文件下载 ? ).(fP  
public void siteStop() MZ^Ch   
{ E& ]_U$  
bStop = true; >sV Bj(f  
for(int i=0;i<nStartPos.length;i++) r}@< K  
fileSplitterFetch.splitterStop(); ~ 7BX@?  
Qa?Q bHc  
vs*I7<  
} ;U7t  
} M9g1d7%  
//负责部分文件的抓取 AI fk"2  
**FileSplitterFetch.java w:R]!e_6\9  
*/ V'yxqI?  
package NetFox; oZvG3_H4.  
m/N(%oMWB=  
,CW%JIM  
import java.io.*; L&HzN{K  
import java.net.*; m?vAyi  
~y%7w5%Un  
Ja=N@&Z#  
public class FileSplitterFetch extends Thread { 3mA/Nu_  
Ib(,P3  
-9Xw]I#QR  
String sURL; //File URL p,^>*/O>  
long nStartPos; //File Snippet Start Position dh,7iQ s  
long nEndPos; //File Snippet End Position |ZuDX87  
int nThreadID; //Thread's ID | VRq$^g  
boolean bDownOver = false; //Downing is over *EE|?vn  
boolean bStop = false; //Stop identical bgXc_>T6_y  
FileAccessI fileAccessI = null; //File Access interface 2^ kn5  
s.e y!ew  
cFxSDTR  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [r~~=b7*[  
{  RA~_]Hk  
this.sURL = sURL; F~P/*FFK  
this.nStartPos = nStart; c$.T<r)Z  
this.nEndPos = nEnd; P#9-bYNU  
nThreadID = id; &`5 :G LV  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 lc-*8eS  
} +{bh  
gU*I;s>  
[ 1D)$"  
public void run() A'(k Yc  
{ vev8l\  
while(nStartPos < nEndPos && !bStop) ,XP@ pi  
{ '|+=B u  
 m"1 ?  
p!V) 55J*  
try{ @@xF#3   
URL url = new URL(sURL); `}n0=E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1 pYsjo~  
httpConnection.setRequestProperty("User-Agent","NetFox"); th;]Vo  
String sProperty = "bytes="+nStartPos+"-"; F6h/0i  
httpConnection.setRequestProperty("RANGE",sProperty); -y<rM0"NE  
Utility.log(sProperty); GYTbeY  
q .)^B@}_  
"N]WL5$i  
InputStream input = httpConnection.getInputStream(); 6q!7i%fK?  
//logResponseHead(httpConnection); 8^NE=)cb7w  
fjG/dhr  
{S# 5g2  
byte[] b = new byte[1024]; OQ 0b$qw  
int nRead; $M%}Oz3*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 2}1!WIin  
{ |oB]6VS`  
nStartPos += fileAccessI.write(b,0,nRead); 34^Q5B~^J  
//if(nThreadID == 1) SwQOFE/Dv~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @V*au:  
} U@MOvW)  
$Jt8d|UP  
cbY3mSfn*  
Utility.log("Thread " + nThreadID + " is over!");  &s_}u%iC  
bDownOver = true; 96k(X LR  
//nPos = fileAccessI.write (b,0,nRead); ~c'\IM  
} + >Fv*lux  
catch(Exception e){e.printStackTrace ();} j= p|'`  
} DDZTqsws  
} qRWJ-T:!F  
)Ep@$Gv|S  
-1dIZy  
//打印回应的头信息 yzODF>KJ  
public void logResponseHead(HttpURLConnection con) :  ,|=Q}  
{ (u$!\fE-et  
for(int i=1;;i++) c lq <$-  
{ 8VKb*  
String header=con.getHeaderFieldKey(i); bK6, saN>  
if(header!=null) !$4Q]@ }  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9,}fx+^  
Utility.log(header+" : "+con.getHeaderField(header)); G;Pt|F?c  
else PP~CZ2Fze  
break; yRSy(/L^+  
} /<G yg7o0  
} WIhIEU7/  
_q2`m  
3BuD/bs  
public void splitterStop() =2Pz$q*ub  
{ }"!6Xm  
bStop = true; i@sCMCu6  
} B>c[Zg1  
](idf(j  
99=[>Ck)G  
} \Or]5ogT'  
6uv'r;U]  
X:iG[iU*  
/* %l0_PhAB  
**FileAccess.java Z%(Df3~gmm  
*//文件访问(定位,写) j TGS6{E  
package NetFox; !:R^}pMhIk  
import java.io.*; U]1>?,Nk'3  
N GX-'w  
 'lSnyW{  
public class FileAccessI implements Serializable{ G=+!d&mbg  
R|d^M&K,  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 <<~lV5  
RandomAccessFile oSavedFile; ^*j[&:d  
long nPos; j58Dki->.  
PkZf(=-X  
6T5A31 Q  
public FileAccessI() throws IOException %`8KG(F^  
{ AiR%MD  
this("",0); c=uBT K*  
} j X^&4f  
!c3Qcva  
vgd}09y  
public FileAccessI(String sName,long nPos) throws IOException loAfFK>g  
{ (dw3'W  
oSavedFile = new RandomAccessFile(sName,"rw"); OoA5!HEh  
this.nPos = nPos; ?}!gLp  
oSavedFile.seek(nPos); e\+~  
} wt3Z?Pb  
T/X?ZK(T  
I3F6-gH  
public synchronized int write(byte[] b,int nStart,int nLen) 6jQ&dN{=qB  
{ ; +#za?w  
int n = -1; M,=@|U/B  
try{ 4OB~h]Vc  
oSavedFile.write(b,nStart,nLen); ;RTrRh0v  
n = nLen; 0|qx/xo|-  
} ]-+.lR%vd9  
catch(IOException e) &9GR2GY  
{ ]y$V/Ij=qK  
e.printStackTrace (); C>\h?<s  
} GhchfI.  
D|8sjp4  
uH~ TugQ~  
return n; +A.a~Stt  
} @8x6#|D  
3e!a>Gl*  
6kmZ!9w0|  
} jQw`*Y/,  
0|*UeM  
519:yt   
/* l%Fse&4\  
**SiteInfoBean.java D+@/x{wX2  
*/ 7o 83|s.Bm  
package NetFox; W6!4Qyn  
Ra15d^  
o 0cc+  
public class SiteInfoBean { (,)vak&t  
N";dG 3  
e-duZ o  
private String sSiteURL; //Site's URL DftGy:Ah3  
private String sFilePath; //Saved File's Path 0wa!pE"  
private String sFileName; //Saved File's Name Ot8S'cB1,$  
private int nSplitter; //Count of Splited Downloading File %o _0M^3W  
g)| ++?  
3 MI) E  
public SiteInfoBean() EY[Q%  
{//nSplitter的缺省值为5 Bb2r95h}^  
//default value of nSplitter is 5 aZ`_W|  
this("","","",5); olQ8s *  
} AD4L`0D  
 6@Z'fT4  
s5Bmv\e.i5  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 4jyr\=42F'  
{ wshp{ y  
sSiteURL= sURL; qyG636i  
sFilePath = sPath; %NAFU /&  
sFileName = sName; X6"^:)&1M  
this.nSplitter = nSpiltter; yADN_  
(w@MlMk  
eL$U M  
} Kr}M>hF+|  
c#4L*$ViF  
B$[%pm`'2  
public String getSSiteURL() CFS3);'<|  
{ G:6$P%.  
return sSiteURL; %JA&O  
} >[P7Zlwv4  
ws=9u-  
GVHfN5bTqn  
public void setSSiteURL(String value) 2ZzD^:V[}  
{ +hvIJv ?  
sSiteURL = value; "!_ 4%z-  
} 94k)a8-!  
'|A5a+[  
xvz5\s|b  
public String getSFilePath() ; K 6Fe)  
{ Z!=Pc$?  
return sFilePath; A%czhF  
} yU8Y{o;:  
+]~w ?^h  
8UY=}R2C  
public void setSFilePath(String value) pQ-^T.'  
{ LK-6z w5=(  
sFilePath = value; kI[O{<kQ  
} p31rhe   
SAo \H  
I3rnCd(  
public String getSFileName() I~5fz4Q  
{ O[(HE 8E  
return sFileName; /5'<w(  
} vaCdfO&  
x_iy;\s1  
5\kZgXWIh  
public void setSFileName(String value) bZlLivi  
{ 1S.e5{  
sFileName = value; 2Q'XB  
} 08n%% F  
P)j9\ muc  
zhm!sMlO  
public int getNSplitter() MfpWow-#{  
{ C.e|VzQa  
return nSplitter; O> ^~SO  
} D>#v 6XI  
iYQy#kO  
f;XsShxr  
public void setNSplitter(int nCount) \t(r@q q  
{ a=T7w;\h  
nSplitter = nCount; 0}7Rm>  
} jl0Eg  
} ~Z/`W`  
~JRu MP  
8sjHQ)<  
/* 6l]?%0[*  
**Utility.java Jz3<yQ-  
*/ x^#{2}4u  
package NetFox; I%b:Z  
.dLX'84fY  
e2o9)=y  
public class Utility { DW%K'+@M  
?9okjLp1n  
BG?2PO{  
public Utility() h _7;UQH  
{ KA{DN!  
GvtI-\h]  
V5@[7ncVf  
} <l s/3!  
>W]"a3E  
//线程睡眠 -:p1gg&  
public static void sleep(int nSecond) +PXfr~ 4  
{ 86 /i~s  
try{ CZ%"Pqy&1L  
Thread.sleep(nSecond); whZ],R*u  
} GZ[h`FJg/  
catch(Exception e) E=~WQ13Q  
{ 4k?JxA)  
e.printStackTrace (); >s?;2T2"yx  
} 1Kf t?g  
} lGBdQc]IL  
ITqigGan%  
//日志 LmdV@gR  
public static void log(String sMsg) mb`}sTU).  
{ w8#>xV^~  
System.err.println(sMsg); \R6T" U  
} R M+K":p  
Nl)jQ  
AS"|r  
public static void log(int sMsg) [>9"RzEl  
{ !4.^@^L|\  
System.err.println(sMsg); "8dnFrE  
} (s*Uz3 sq  
} 5)NfZN# &  
 y] r~v  
>5:e1a?9  
/* /,%o<Ql9  
**TestMethod.java 6}lEeMRW  
*/ Q>g$)-8  
package NetFox; R* G>)YH  
/Z_ [)PTH  
dY` J,s  
public class TestMethod { Ijro;rsEKM  
(lsod#wEMg  
7TY"{? ~O5  
public TestMethod() kV9NFo22  
{ ///xx/weblogic60b2_win.exe /j\TmcnU^  
try{ v86`\K*0Y  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); x&b-Na3Xi  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); '=Y~Ir+  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3o/ a8  
fileFetch.start(); |i}g7  
} B&j+fi  
catch(Exception e){e.printStackTrace ();} .[85<"C  
k6XmBBIj-  
!@1!ld  
} Mo|5)8_  
*n ?:)(  
6T_c#G5  
public static void main(String[] args) nW*Oo|p~=  
{ zb)SlR  
new TestMethod(); ]J]p:Y>NL  
} 4c@F.I  
} 'E8Qi'g  
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