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http断点续传简单实现(java)

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/* !30BR|K*  
**SiteFileFetch.java D"8?4+  
*/ ;%!]C0 ?  
package NetFox; ?XB[awTD~  
import java.io.*; n>W*y|UJ  
import java.net.*; CJe~>4BT  
m*~Iu<5L  
Eh&-b6:  
public class SiteFileFetch extends Thread { v`Yj)  
SYwB #|  
R?iC"s!  
SiteInfoBean siteInfoBean = null; //文件信息Bean +jb<=ERV[  
long[] nStartPos; //开始位置 o,'Fz?[T%  
long[] nEndPos; //结束位置 ,Bl_6ZaL  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7GRPPh<4  
long nFileLength; //文件长度 nnCz!:9p  
boolean bFirst = true; //是否第一次取文件 hfpis==  
boolean bStop = false; //停止标志 6S^JmYq  
File tmpFile; //文件下载的临时信息 bycnh  
DataOutputStream output; //输出到文件的输出流 f1 `E-  
~YXkAS:  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) "Fz1:VV&  
public SiteFileFetch(SiteInfoBean bean) throws IOException DJ`xCs!R  
{ zGa V^X  
siteInfoBean = bean; aVp-Ps|r  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =nv/ r  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .@psW0T%  
if(tmpFile.exists ()) o@ @|4 F  
{ LeYI<a@n@$  
bFirst = false; )B"E+Q'h{7  
read_nPos(); 3g5D[>J'  
} &3:<WU:U  
else V^_U=Ed@M  
{ zA| )9Dq  
nStartPos = new long[bean.getNSplitter()]; 0B"_St}3D  
nEndPos = new long[bean.getNSplitter()]; 1V-sibE  
} Dlz1"|SF  
5:%`&B\  
Y)7\h:LIg  
?L6wky{  
} ( ; _AP.  
7V&ly{</  
+@~e9ZG%a  
public void run() bd[iD?epD]  
{ k=9k4l  
//获得文件长度 S7j U:CLJ  
//分割文件 s`=&l  
//实例FileSplitterFetch )*&61  
//启动FileSplitterFetch线程 on 4 $n7  
//等待子线程返回 #v*3-) 8  
try{ oz7=1;r  
if(bFirst) %- Ga  ^[  
{ {FR+a**  
nFileLength = getFileSize(); rVwW%&  
if(nFileLength == -1) ~Xc1y!"9*  
{ =KHX_ib  
System.err.println("File Length is not known!"); #wJ^:r-c`  
} izLB4pk$  
else if(nFileLength == -2) |][PbN D  
{ E5\>mf ,;u  
System.err.println("File is not access!"); ={50>WXE  
} (/7cXd@\6  
else N!<X% Ym  
{ y:k7eE"  
for(int i=0;i<nStartPos.length;i++) (^m~UN2@~m  
{ t-Ble  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); AR c  
} C|]Zpn#{K  
for(int i=0;i<nEndPos.length-1;i++) ?gCP"~  
{ B^.:dn  
nEndPos = nStartPos[i+1]; d"S\j@  
} # S0N`V  
nEndPos[nEndPos.length-1] = nFileLength; :0p$r pJP  
} 1";s #Jq  
} ]'Gz~Z%>F  
[@NW  
D8`SI2 1P  
//启动子线程 0CI\Yd=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; .f|)od[  
for(int i=0;i<nStartPos.length;i++) k<RaC=   
{ KK4rVb:-  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \)W Z D  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), cDz^jC   
nStartPos,nEndPos,i); rpEN\S%7P  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &&C'\,ZK5  
fileSplitterFetch.start(); @2 SL$0!QA  
} %'dsb7n  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), G""=`@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); VF9-&HuC  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", td2bL4  
nEndPos = " + nFileLength); ,q Bu5t  
// fileSplitterFetch[nPos.length-1].start(); yn{U/+  
' @j8tK  
Oin:5K)4-  
//等待子线程结束 r}t%DH  
//int count = 0; 23`pog{n  
//是否结束while循环 Js !Zk\O  
boolean breakWhile = false; Pu!%sGjD  
;'|t>'0_  
glWa?#1  
while(!bStop) v=+>ids  
{ *\[GfTL  
write_nPos(); OH~I+=}.  
Utility.sleep(500); m*TJ@gI*t  
breakWhile = true; k12mxR/  
$h'>Zvf  
GoKMi[b  
for(int i=0;i<nStartPos.length;i++) ?s: 2~Qlu  
{ |7G=f9V  
if(!fileSplitterFetch.bDownOver) " gi 1{  
{ 5LxzET"P  
breakWhile = false; cUr'mb  
break; ]F,v#6qi  
} LD}ZuCp!  
} O.P:~  
if(breakWhile) LpSd/_^b  
break; <' b%  
u|E9X[%  
[Uu!:SZ  
//count++; *:V"C\`^n  
//if(count>4) aAkO>X%[  
// siteStop(); 1He'\/#  
} RIxGwMi%  
@Tf5YZ*  
XZ&q5]PJI  
System.err.println("文件下载结束!"); zDof e*  
} ;+]GyDgVq  
catch(Exception e){e.printStackTrace ();} JxLD}$I  
} Nc:>]  
\9dC z;  
9#niMv9  
//获得文件长度 (g]J hG  
public long getFileSize() uEkUK|  
{ gkNvvuQXc  
int nFileLength = -1; $+ ?A[{JG  
try{ }\!38{&  
URL url = new URL(siteInfoBean.getSSiteURL()); C$$lJ=>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [z`m`9Aq  
httpConnection.setRequestProperty("User-Agent","NetFox"); }c*6|B@f  
vc(6lN9>  
q9c:,k  
int responseCode=httpConnection.getResponseCode(); b 7bbrR8  
if(responseCode>=400) N{6Lvq[8  
{ Y>[u(q&09O  
processErrorCode(responseCode); AW:WDNQh8n  
return -2; //-2 represent access is error mEe JK3D[  
} R%N&Y~zH  
d.uJ}=|  
O hcPlr  
String sHeader; geu8$^  
bI~(<-S~K  
O486:tF  
for(int i=1;;i++) Af>Ho"i  
{ `$D2w|  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); X6]eQ PN2  
//Utility.log(in.readLine()); gyW##M@{  
sHeader=httpConnection.getHeaderFieldKey(i); n/5)}( }K  
if(sHeader!=null) HLcK d`$/  
{ &Q"Ox{~W  
if(sHeader.equals("Content-Length")) '\X<+Sm'  
{ ef=LPCi?  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); VZ8HnNAbX  
break; Ni[2 p  
} s9Aq-N  
} YS5Pt)?  
else 29E9ZjSK  
break; Iz\IQa  
} PO[ AP%;  
} M[R\URu8  
catch(IOException e){e.printStackTrace ();} !fcr3x|Y~M  
catch(Exception e){e.printStackTrace ();} 1[vmK,N=E  
%vO b"K$X  
w%[ `'_[  
Utility.log(nFileLength); T7=~l)I  
agFWye  
D'Gmua]I  
return nFileLength; L.z`>1  
} ,#42ebGHR  
~cSOni`  
s:y=X$&M  
//保存下载信息(文件指针位置) f|1GlUA{t  
private void write_nPos() Svo gvn  
{ u;Q'xuo3  
try{ b;O|-2AR  
output = new DataOutputStream(new FileOutputStream(tmpFile)); nx >PZb  
output.writeInt(nStartPos.length); +SSF=]4+  
for(int i=0;i<nStartPos.length;i++) Y|=/*?o}  
{ t F<|Eja *  
// output.writeLong(nPos); q|. X[~e|  
output.writeLong(fileSplitterFetch.nStartPos); FU|c[u|z  
output.writeLong(fileSplitterFetch.nEndPos);  `Up Zk?k  
} {g *kr1JM  
output.close(); ~',<7eW  
} W|@/<K$V  
catch(IOException e){e.printStackTrace ();} {Ah\-{]  
catch(Exception e){e.printStackTrace ();} r~uWr'}a}  
} GyOo$FW  
Cu0N/hBT  
3!0Eh8ncI  
//读取保存的下载信息(文件指针位置) F~dq7 AS  
private void read_nPos() ~)#JwY  
{ gNO<`9q  
try{ 0FF x  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Oi=>Usd  
int nCount = input.readInt(); YN ~ 7nOw  
nStartPos = new long[nCount]; k 4+F  
nEndPos = new long[nCount]; >*v^E9Y  
for(int i=0;i<nStartPos.length;i++) m1X0stFRs"  
{ H1'`* }V  
nStartPos = input.readLong(); ~bCn%r2  
nEndPos = input.readLong(); L "L@4 B  
} zhI} p.  
input.close(); 3 n/U4fn_  
} 2!/_Xh  
catch(IOException e){e.printStackTrace ();} ;9pOtr  
catch(Exception e){e.printStackTrace ();} ~B%=g)w  
} VrA9}"1x~*  
\ qc 8;"@  
33_YZOy^j  
private void processErrorCode(int nErrorCode) 6<+R55  
{ Oc;0*v[I  
System.err.println("Error Code : " + nErrorCode); /YWoDHL  
} h*f=  
-bK#&o,  
h:3`e`J<h  
//停止文件下载 HPAd@5d(  
public void siteStop() ) w.cCDL c  
{ N?H;fK4v  
bStop = true; /I3#WUc;![  
for(int i=0;i<nStartPos.length;i++) kn_%'7  
fileSplitterFetch.splitterStop(); m-lUgx7  
Cyxt EzPp  
1o7 pMp=  
} #e0tT+  
} !6ZkLE[XJ<  
//负责部分文件的抓取 3VbQDPG  
**FileSplitterFetch.java ip4:px-  
*/ C26PQGo#$  
package NetFox; ^.F@yo2}  
g83!il\  
]BU,*YaB  
import java.io.*; AG2iLictv  
import java.net.*; ,qak_bP  
&E$jAqc  
d{@X-4k :  
public class FileSplitterFetch extends Thread { ` !HGM>  
LMWcF'l  
9}Tf9>qP>M  
String sURL; //File URL '2a}1?  
long nStartPos; //File Snippet Start Position o_p//S#q  
long nEndPos; //File Snippet End Position qn#\ro1H  
int nThreadID; //Thread's ID _JA.~edqM  
boolean bDownOver = false; //Downing is over \Nu(+G?e  
boolean bStop = false; //Stop identical  gM20n^  
FileAccessI fileAccessI = null; //File Access interface 2As 4}  
W|3XD-v@  
qtTys gv  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException '8~7Ru\KyX  
{ . zv F!!z  
this.sURL = sURL; Pv{ {zyc  
this.nStartPos = nStart; =*qu:f\y  
this.nEndPos = nEnd; 6#O n .Q  
nThreadID = id; ="RDcf/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Dg/&m*Yl  
} L@w|2  
AZxx%6  
A"k6n\!n;  
public void run() Aj.TX%}`h  
{ nI%0u<=d  
while(nStartPos < nEndPos && !bStop) ;Br8\2=$  
{ kssS,Ogf\_  
zv!%u=49  
:k075Zr/#D  
try{ y@'8vOh`  
URL url = new URL(sURL); {IJV(%E   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +/7UM x1  
httpConnection.setRequestProperty("User-Agent","NetFox"); {%@zQ|OO0  
String sProperty = "bytes="+nStartPos+"-"; ZPn`.Qc  
httpConnection.setRequestProperty("RANGE",sProperty); 8Vv"'CU#  
Utility.log(sProperty); H=z@!rJc.  
bV&/)eqv  
m,$oV?y>j  
InputStream input = httpConnection.getInputStream(); uh%%MhTjv  
//logResponseHead(httpConnection); (1fE^KF@f  
|&3m'"(  
PkQuN;a  
byte[] b = new byte[1024]; m;lwMrY\7>  
int nRead; TS)p2#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Vp\BNq_!s  
{ D|,d_W  
nStartPos += fileAccessI.write(b,0,nRead); V{@<Z8sW#  
//if(nThreadID == 1) xZjD(e'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |Rw0$he  
} C 7YZ;{t  
tQbDP!,A*=  
?C//UN;  
Utility.log("Thread " + nThreadID + " is over!"); Y.3]vno?X  
bDownOver = true; ~!&WK,k6  
//nPos = fileAccessI.write (b,0,nRead); ]]Ypi=<'  
} aG8}R~wH&  
catch(Exception e){e.printStackTrace ();} 3Tg  
} 6gJy<a3  
} @3c5"  
]nhLv!Co  
"wmQ,=  
//打印回应的头信息 41mg:xW(J  
public void logResponseHead(HttpURLConnection con) b[? 6/#N  
{ /d9I2~}B  
for(int i=1;;i++) kWc%u-_  
{ !v<r=u  
String header=con.getHeaderFieldKey(i); )?joF)  
if(header!=null) <w(UDZ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;#P@(ZVT  
Utility.log(header+" : "+con.getHeaderField(header)); a Umcs!@  
else AtYe\_9$C  
break; EE#4,d`J  
} gfw,S;  
} dY68wW>d|  
"3LOL/7f  
Xz4!#,z/  
public void splitterStop() 1`r 4  
{ [Pi8gj*  
bStop = true; W`^'hka  
} bv5,Yk  
;&37mO/T  
2)h i(  
} 49^;T;'v  
#+|{l*>  
!>Db  
/* SfyZ,0  
**FileAccess.java )TFaG[tj  
*//文件访问(定位,写) 2PE|4zG  
package NetFox; 'W3>lAPx!  
import java.io.*; _)O1v%]"4  
9xyj,;P>  
! pR&&uG  
public class FileAccessI implements Serializable{ {=PO`1H  
)&+j#:  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 UGj!I  
RandomAccessFile oSavedFile; }|%dN*',  
long nPos; [94A?pn[z  
;U<;R  
Q}d6+C  
public FileAccessI() throws IOException $Lv,e\]  
{ 7f#e#_sM;  
this("",0); fQ=Yf?b  
} E#v}//  
z4b2t}  
w<<>XIL  
public FileAccessI(String sName,long nPos) throws IOException n'9Wl'  
{ )~v`dwKj;  
oSavedFile = new RandomAccessFile(sName,"rw"); 57*z0<  
this.nPos = nPos; #Gx%PQ`  
oSavedFile.seek(nPos); QxH%4 )?  
} R22YKXU  
7/a[;`i*!  
d }=fJ  
public synchronized int write(byte[] b,int nStart,int nLen) *%7[{Loz  
{  gPh;  
int n = -1; *9y)B|P^  
try{ #wK {G)J  
oSavedFile.write(b,nStart,nLen); vP`Sz}FU  
n = nLen; a$yAF4HR<  
} q.U` mtS  
catch(IOException e) s]50Y-C  
{ -;20|US)u  
e.printStackTrace (); ? [l[y$9  
} 6X~.J4  
z85%2Apd  
x2=Bu#Y  
return n; }pdn-#  
} H<#M)8  
8om6wALXB  
7n9&@D3 :P  
} ,dhJ\cQ~  
L15?\|':Y  
nICc}U?k  
/* B>rz<bPT  
**SiteInfoBean.java <k!M+}a 9V  
*/ #<s6L"Z-  
package NetFox; 2 -72 8  
ukpbx;O:hc  
[Ul"I-K  
public class SiteInfoBean { H C(Vu  
C-E~z{  
)' +" y~  
private String sSiteURL; //Site's URL 83K)j"!<X  
private String sFilePath; //Saved File's Path ]$Pl[Vegy  
private String sFileName; //Saved File's Name x? tC2L  
private int nSplitter; //Count of Splited Downloading File 1DgR V7  
WvR-0>E  
\(2w/~  
public SiteInfoBean() (hNTr(z  
{//nSplitter的缺省值为5 `qnp   
//default value of nSplitter is 5 {L~j;p_G&  
this("","","",5); +wc8rE6+W  
} 0gO_dyB  
mivb}cKM  
rV84?75( Y  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <}t~^E,  
{ 7'Z-VO  
sSiteURL= sURL; YbtsJ <w  
sFilePath = sPath; g xY6M4  
sFileName = sName; 3}dTbr4y  
this.nSplitter = nSpiltter; J{;XNf =  
k-IL%+U  
p[R4!if2  
} Q,R>dkS  
(VD Y]Q)  
yJQ>u  
public String getSSiteURL() :No`+X[Kq  
{ 2(LF @xb  
return sSiteURL; ~hD!{([  
} n2} (Pt.  
>*s_)IH2  
EP,j+^RVf  
public void setSSiteURL(String value) X3e&c  
{ 2[~|#0x  
sSiteURL = value; W*S}^6ZT`  
} "| Oj!&0  
_PT5  
?M!Mb-C[  
public String getSFilePath() 94^)Ar~O  
{ JguPXHa0  
return sFilePath; 9gq+,g>E_  
} J,4,#2M8  
QO2@K1Y  
(xpt_]Q!H  
public void setSFilePath(String value) J^<Gi/:*^  
{ Drm#z05i[g  
sFilePath = value; RO+ jVY~H-  
} Y TpiOPf  
PAng(tubl  
8tfM,.]_i  
public String getSFileName() '41'Gn  
{ .3 >"qv  
return sFileName; GuK3EM*_  
} P5Lb)9_Jw  
Zt_~Zxn3  
(4o<U%3kGq  
public void setSFileName(String value) &!P' M  
{ X*cDn.(I  
sFileName = value; H9;0$Y(e-  
} ;~D$ rT  
yFoPCA86y  
$%BI8_  
public int getNSplitter() U!d|5W.{Q  
{ zh{,.c  
return nSplitter; {wy{L-X  
} U#V&=~-  
cWtuI(.  
/!Ay12lKE}  
public void setNSplitter(int nCount) i<0_sxfUD  
{ m)7Ql!l  
nSplitter = nCount; vB74r]'F  
} r>: ~!o*  
} y1{TVpN  
>``sM=Wat  
BG|m5f  
/* \?v?%}x  
**Utility.java W4;/;[/L  
*/ GCf,Gfmr  
package NetFox; vA3wn><  
BP4xXdG  
@C-03`JWuK  
public class Utility { NSawD.9mV  
pfBe24q  
rjffpU  
public Utility() nw4 I<Q  
{ BLN|QaZ  
3 Fb9\2<H  
lArKfs/   
} +7\d78U  
'-U&S  
//线程睡眠 ]p8 zT|bv  
public static void sleep(int nSecond) * N]^(+/A  
{ .k:heN2-x  
try{ ">._&8KkE0  
Thread.sleep(nSecond); !4-4i  
} X+1Mv  
catch(Exception e) d-3.7nJ:  
{ /#WvC;B  
e.printStackTrace (); V7b;qC'  
} Rk,'ujc  
} beaSvhPU  
%afN&T  
//日志 hkb&]XWi[  
public static void log(String sMsg) 9tX+n{i  
{ Zg$S% 1(Q  
System.err.println(sMsg); i;rcg d  
} H;R~d%!b  
6hMKAk  
#f [}a  
public static void log(int sMsg) t"zi'9$t  
{ e)= " Fq!  
System.err.println(sMsg); ZNVrja*  
} Sn S$5o  
} z&cM8w:  
SRtw  
T|8:_4/l  
/* SJ91(K  
**TestMethod.java Q^;:Kl.b  
*/ ua"2nVxK_K  
package NetFox; s+~GQcj<T  
)=#e*1!b  
Esu {c9,  
public class TestMethod { 2eHVl.C5  
qu1+.z=|  
=z;]FauR!  
public TestMethod() RL:B.Lv/W  
{ ///xx/weblogic60b2_win.exe O6/:J#X%  
try{ NVghkd  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); CY*o"@-o5)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $*VZa3B\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 06O_!"GD}  
fileFetch.start(); |h }4J  
} "u]&~$  
catch(Exception e){e.printStackTrace ();} GeDI\-  
C{,^4Eh3r  
:hT.L3n,  
} e!PB3I  
%ufh  
"={*0P  
public static void main(String[] args) F^$;hMh%  
{ n$N$OFuO  
new TestMethod(); {nXygg J  
} Cdy,8*   
} O/|))H?C  
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