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http断点续传简单实现(java)

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/* XT~]pOE;D  
**SiteFileFetch.java .V?>Jhok  
*/ H4JwgQ  
package NetFox; yDXW#q  
import java.io.*; W)fh}|.5  
import java.net.*; 3[}w#n1  
V.Qy4u7m  
Xo~kB)|,  
public class SiteFileFetch extends Thread { ,ku3;58O<  
A!fRpN  
TrmrA$5f  
SiteInfoBean siteInfoBean = null; //文件信息Bean 0%>_fMaA  
long[] nStartPos; //开始位置 <<[\ Rv  
long[] nEndPos; //结束位置 -JfO} DRI  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 A6%~+9  
long nFileLength; //文件长度 73>Hzpv0  
boolean bFirst = true; //是否第一次取文件 1n )&%r  
boolean bStop = false; //停止标志 !DNk!]|  
File tmpFile; //文件下载的临时信息 LXx`Vk>ky  
DataOutputStream output; //输出到文件的输出流 -x2&IJ!  
]8ob`F`m,  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) vC ISd   
public SiteFileFetch(SiteInfoBean bean) throws IOException *d$r`.9j  
{ `Uy'YfYF  
siteInfoBean = bean; OIdoe0JR:O  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /F7X"_(H  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); +U*:WKdI?  
if(tmpFile.exists ()) fD ?w!7f-1  
{ D}A>`6W<  
bFirst = false; rwvCp_pN.  
read_nPos(); >'|Wrz67Z  
} v.Zr,Z=eV  
else 25/OV"Z  
{ ^9A,j} >o-  
nStartPos = new long[bean.getNSplitter()]; V"R,omh  
nEndPos = new long[bean.getNSplitter()]; cHk ?$  
} Sx}61?  
40R7@Vaf  
71!'k>]h  
7) 37AKw  
} S7 WT`2  
$J)2E g  
O>kM2xw  
public void run() 0rj50$~$]  
{ T~b6Zu6  
//获得文件长度 #CTHCwYo  
//分割文件 /eNDv(g)M  
//实例FileSplitterFetch  Jyo(Etp  
//启动FileSplitterFetch线程  njg\y  
//等待子线程返回 M"|({+9eG  
try{ "%]vSr  
if(bFirst) fVx_]5jM  
{ Q2nqA1sRk  
nFileLength = getFileSize(); X6k-a;  
if(nFileLength == -1) 2r>I,TNHl  
{ W+D{4:  
System.err.println("File Length is not known!"); RLr^6+v)U  
} ?-D'xqc  
else if(nFileLength == -2) Spt;m0W90  
{ +W[NgUrGJ  
System.err.println("File is not access!"); mr\C  
} U.p"JSH L  
else wA?q/cw C  
{ N/i {j.=  
for(int i=0;i<nStartPos.length;i++) NB?y/v  
{ z{ MO~d9  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ]gG&X3jaKq  
} (H-}z`sy/@  
for(int i=0;i<nEndPos.length-1;i++) :zLeS-  
{ W:*  {7qJ  
nEndPos = nStartPos[i+1]; 66%4p%#b4  
} wTkcR^  
nEndPos[nEndPos.length-1] = nFileLength; HA0Rv#p  
} *zTEK:+_  
} qjI.Sr70  
{axMS yp;  
yy#4DYht  
//启动子线程 %m?$"<q_K  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; }Z3+z@L  
for(int i=0;i<nStartPos.length;i++) *#g[ jl4  
{ Z@ZSn0  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \:|"qk  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), @w{"6xc%a  
nStartPos,nEndPos,i); o0\d`0-el  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2V)qnMxAZJ  
fileSplitterFetch.start();  j2%?-(U  
} i*2l4  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (4oO8 aBB  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #xBh62yIuP  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", D|Raj\R  
nEndPos = " + nFileLength); QDpzIjJj  
// fileSplitterFetch[nPos.length-1].start(); q"|#KT^)  
X;%*+xQ^  
V/W{d[86G  
//等待子线程结束 )R@M~d-o  
//int count = 0; *Ph@XkhU  
//是否结束while循环 [[gfR'79{  
boolean breakWhile = false; x3]y*6  
+L\bg| ;  
!j-JMa?  
while(!bStop) Egr'IbB  
{ )W.Y{\D0  
write_nPos(); 32Jl|@8,g  
Utility.sleep(500); S1G3xY$0  
breakWhile = true; 1./iF>*A  
0V5{:mzA  
S1D;Xv@  
for(int i=0;i<nStartPos.length;i++) 'e5,%"5(c  
{ Z|IFT1K  
if(!fileSplitterFetch.bDownOver) o]O  
{ sm96Ye{O{  
breakWhile = false; jhkNi`E7  
break; j O6yZt  
} \\i$zRi  
} UgAG2  
if(breakWhile) vQhi2J'  
break; ruK, Z,3Q  
fgEMn;  
;/|3U7{c  
//count++; >C"QV `+  
//if(count>4) /{HK0fd  
// siteStop(); > J>|+W  
} V07? sc<  
B#Z-kFn@  
'Bb@K[=s  
System.err.println("文件下载结束!"); /woC{J)4p  
} <N}*|z7=b  
catch(Exception e){e.printStackTrace ();} to"[r  
} a-Ef$(i_  
$mZpX:7/u8  
CY i{WV(:  
//获得文件长度 bf&k:.v'8  
public long getFileSize() Cv;\cI"&  
{ ga+Z6|t  
int nFileLength = -1; [$P.ek<  
try{ \jGvom.  
URL url = new URL(siteInfoBean.getSSiteURL()); tF=Y3W+L  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h(H b+7g  
httpConnection.setRequestProperty("User-Agent","NetFox"); +KKx\m*  
K}1eQS&$a  
Sw^-@w=!U5  
int responseCode=httpConnection.getResponseCode(); 9 &p;2/H  
if(responseCode>=400) *&sXC@^@^  
{ T_1p1Sg  
processErrorCode(responseCode); gg}^@h&?  
return -2; //-2 represent access is error {_<,5)c  
} }$T!qMst{  
?~#{3b  
'p:L"L}Q?  
String sHeader; aq<QKn U  
P|{Et=R`1  
[tY+P7j9)  
for(int i=1;;i++) GYM6 `  
{ [5O`  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); k>;a5'S  
//Utility.log(in.readLine()); z3>oUq{  
sHeader=httpConnection.getHeaderFieldKey(i); /'g"Ys?3  
if(sHeader!=null) y.m;4((  
{ UOtrq=y  
if(sHeader.equals("Content-Length")) {%Ujp9i  
{ I'%(f@u~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Q1(6U6L  
break; Vuu_Sd  
} 5xF R7%_&  
} 6*r3T:u3  
else `.8#q^  
break; 2lm{:tS  
} *N|s+  
} Gaxa~?ek  
catch(IOException e){e.printStackTrace ();} a{%]X(';  
catch(Exception e){e.printStackTrace ();} Y^P'slY{%  
Up|>)WFw"  
| *J-9  
Utility.log(nFileLength); ;UB$Uqs6  
}4M4D/=  
j*05!j<'  
return nFileLength; 8NS1*\z  
} v'zj<|2  
`GD>3-   
WCPl}7>  
//保存下载信息(文件指针位置) aA/.EAc7  
private void write_nPos() byUz  
{ m&X6a C'[  
try{ o I6o$C  
output = new DataOutputStream(new FileOutputStream(tmpFile)); gQ=g,X4  
output.writeInt(nStartPos.length); FTfejk!  
for(int i=0;i<nStartPos.length;i++) U%,N"]`  
{ o) hQ]d  
// output.writeLong(nPos); 2AZ)|dM'`  
output.writeLong(fileSplitterFetch.nStartPos); G,J~Ed  
output.writeLong(fileSplitterFetch.nEndPos); zrJ/Fs+s  
} u/2!v(  
output.close(); s*0PJ\E2  
} t%f6P  
catch(IOException e){e.printStackTrace ();} wWNHZ v&  
catch(Exception e){e.printStackTrace ();} U'tfsf/V  
} 0 w#[?.  
30Z RKrW"~  
&R "Q  
//读取保存的下载信息(文件指针位置) A+Xk=k5<  
private void read_nPos() #=hI}%n  
{ $SmmrM  
try{ =1}Umn|ZLS  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 7>`VZ?  
int nCount = input.readInt(); g, %xGQ4+  
nStartPos = new long[nCount]; HX3R@^vo  
nEndPos = new long[nCount]; Ka"Z,\T   
for(int i=0;i<nStartPos.length;i++) o?$B<Cb"  
{ &4ScwK:  
nStartPos = input.readLong(); QQwD) WG  
nEndPos = input.readLong(); WhR j@y  
} 0H-~-z8Y  
input.close(); ~e!b81  
} 02~+$R]L  
catch(IOException e){e.printStackTrace ();} d* 6 lJT  
catch(Exception e){e.printStackTrace ();} lbtVQW0V;o  
} kr C4O2Fkj  
@ !:~gQ  
l`vb  
private void processErrorCode(int nErrorCode) De(\ <H#  
{ Hi 1@  
System.err.println("Error Code : " + nErrorCode); domaD"C  
} -K_p? l  
&l=%*`On  
M=hH:[6 &  
//停止文件下载 >7VO ytc  
public void siteStop() y2U^7VrO  
{ wf<=r W'  
bStop = true; v{}i`|~J  
for(int i=0;i<nStartPos.length;i++) aJC,  
fileSplitterFetch.splitterStop(); L]goHs  
%\ i 7  
gqje]Zc<  
} aF9p%HPDw  
} DUk&`BSJ  
//负责部分文件的抓取 4X@ <PX5  
**FileSplitterFetch.java `!.)"BI/s  
*/ DB'd9<  
package NetFox; "Z&-:1tP{9  
#S/]=D  
0Jh^((i*  
import java.io.*; 1 XAXokxj  
import java.net.*; :D>afC8,  
(hB&OP5Fne  
9U_uw Rv2  
public class FileSplitterFetch extends Thread { 2Qqk?;^ 1  
}hralef #N  
UvSvgDMl  
String sURL; //File URL (RR:{4I  
long nStartPos; //File Snippet Start Position Awo H d7M  
long nEndPos; //File Snippet End Position Zr0bVe+h  
int nThreadID; //Thread's ID B>3joe}  
boolean bDownOver = false; //Downing is over |&+0Tg~ZE  
boolean bStop = false; //Stop identical Fq6sl}b(On  
FileAccessI fileAccessI = null; //File Access interface y\DR,$Py  
9 wun$!>&  
=kz(1Pb  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException El;\#la  
{ BULf@8~(  
this.sURL = sURL; (cX;a/BR  
this.nStartPos = nStart; k !S0-/ h  
this.nEndPos = nEnd; <n4T*  
nThreadID = id; 2nW:|*:/p6  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 =l_B58wrx  
} )uvs%hK  
_;G. QwHr  
#,0PLU3%  
public void run() YRXXutm  
{ +/tN d2  
while(nStartPos < nEndPos && !bStop) @)A)cBv#  
{ 42a.@JbLQ  
j@xerY  
]Q Y:t:-  
try{ !o+Y" * /  
URL url = new URL(sURL); g\CRx^s  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~C1lbn b  
httpConnection.setRequestProperty("User-Agent","NetFox"); i`3h\ku  
String sProperty = "bytes="+nStartPos+"-"; [Bn C_^[W  
httpConnection.setRequestProperty("RANGE",sProperty); UQ;ymTqdc  
Utility.log(sProperty); ,m| :U  
V _(L/6  
9qUc{ydt  
InputStream input = httpConnection.getInputStream(); |H`}w2U[j  
//logResponseHead(httpConnection); "|?zQ?E  
OOzk@j^  
v=kQ / h  
byte[] b = new byte[1024]; -}u=tiNG  
int nRead; :.863_/  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)  L|hdV\  
{ H ?Vo#/  
nStartPos += fileAccessI.write(b,0,nRead); sN`2"t/s  
//if(nThreadID == 1) k e'aSD  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); e6E{l  
} v~f_~v5J!  
#k %$A}9  
s}8(__|  
Utility.log("Thread " + nThreadID + " is over!"); /5qeNjI+2  
bDownOver = true; !~+"TI}_%w  
//nPos = fileAccessI.write (b,0,nRead); 'R&Y pR  
} Aofk<O!M  
catch(Exception e){e.printStackTrace ();} f tS^|%p  
} @>Y.s6a  
} : +Na8\d  
DQC=f8  
G:$Ta6=  
//打印回应的头信息 Lnin;0~{  
public void logResponseHead(HttpURLConnection con) T r|B:)X  
{ ~HWH2g  
for(int i=1;;i++) Y>Oh]?  
{ nQe^Bn  
String header=con.getHeaderFieldKey(i); ~#z8Q{!O  
if(header!=null) b@GL*Z  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Af~>}-`a  
Utility.log(header+" : "+con.getHeaderField(header)); ObK-<kGcB  
else ]mDsd*1  
break; {+`'ZU6C  
} v2OK/W,0  
} V}?*kx~T2C  
+m|S7yr'  
^|u7+b'|t  
public void splitterStop() 8+HXGqcv  
{ HPz9Er  
bStop = true; Z>0a?=1[  
} &J>XKO nl  
lD`@{A  
5 )tDgm  
} >3{#S:  
q1rBSlzN  
DRp h?V\  
/* ~ IPel  
**FileAccess.java iLQFce7d|&  
*//文件访问(定位,写) L#t^:%   
package NetFox; (u/-ud1p  
import java.io.*; <c` + f PW  
1~J:hjKQ  
R,]J~TfPK  
public class FileAccessI implements Serializable{ x;Qs_"t];3  
I},]Y~Y3  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 R^v-%mG9  
RandomAccessFile oSavedFile; uu5AW=j  
long nPos; MR=dQc  
gLm ]*  
9%{V?r]k  
public FileAccessI() throws IOException %y7&~me  
{ .A(QqL>  
this("",0);  Ptt  
} (d9G`  
54X=58Q  
'?j[hhfB-  
public FileAccessI(String sName,long nPos) throws IOException ;k W+  
{ F0 .Rv):  
oSavedFile = new RandomAccessFile(sName,"rw"); WruSL|4iH  
this.nPos = nPos; 8C,}nh  
oSavedFile.seek(nPos); .|$:%"O&X  
} Fe r&X  
=1kE2u  
Hnq$d6F  
public synchronized int write(byte[] b,int nStart,int nLen) A_8UPGh8  
{ P\jnht  
int n = -1; z%FBHj  
try{ Z<P?P`  
oSavedFile.write(b,nStart,nLen); |M8FMH[_  
n = nLen; ;u:A:Y4V  
} ~J~@mE2ks  
catch(IOException e) xE$>;30b_  
{ L=7Y~aL=  
e.printStackTrace (); y cT@ D/  
} nj90`O.K  
Z.^DJ9E<1  
";kwh8wB  
return n; g6AEMer  
} PZ#\O  
+#;t.&\80N  
Z=[qaJ{]  
} r$8(Q'  
V4["+Y  
n]3Lqe;  
/* g-C)y 06  
**SiteInfoBean.java M]5)u=}S-  
*/ ;hf{B7  
package NetFox; !7rk>YrY  
#F|q->2`o  
zl]Ic' _i  
public class SiteInfoBean { (WCczXm)  
-`f 1l8LD2  
n_ 3g  
private String sSiteURL; //Site's URL =<BPoGs5  
private String sFilePath; //Saved File's Path S9 p*rk ~  
private String sFileName; //Saved File's Name ' ?4 \  
private int nSplitter; //Count of Splited Downloading File dmB _`R  
KUV(vAY,  
pW7#&@AR  
public SiteInfoBean() 5bj9S  
{//nSplitter的缺省值为5  Zra P\?  
//default value of nSplitter is 5 pu"m(9  
this("","","",5); U } K]W>Z  
} M?gc&2 Y  
G7qB   
pdw;SIoC  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Ii.?| u  
{ PHxU6UPqy  
sSiteURL= sURL; FQlYCb  
sFilePath = sPath; -$2B!#]3  
sFileName = sName; e{Y8m Xu  
this.nSplitter = nSpiltter; Jan~R ran  
hZwbYvu  
4[XiD*  *  
} Fkvf[!Ci  
ZRy'lW  
>)j`Q1Qc\  
public String getSSiteURL() rOo |.4w  
{ s7Z+--I)L  
return sSiteURL; _{C =d3  
} n40&4n  
P\rA>ZY  
F97HFt6{  
public void setSSiteURL(String value) )c<X.4  
{ 3oQ?VP  
sSiteURL = value; NMvNw?]  
} d#U~>wr  
UhX)?'J  
Zk+c9,q  
public String getSFilePath() `9`T,uJe  
{ _'}Mg7,V  
return sFilePath; q; ?Kmk  
} />X"' G  
2:jWO_V@  
6JB* brO  
public void setSFilePath(String value) E4cPCQyeH  
{ lzbAx  
sFilePath = value; lJJ`aYDp  
} !+)5?o  
v.!e1ke8D*  
Q/%]%d  
public String getSFileName() x4N*P  
{ =JGL~t?  
return sFileName; @c -| Sl  
} 0F-%C>&g  
EEp~\^ -  
PNB E  
public void setSFileName(String value) gWGh:.*T  
{ W @]t  
sFileName = value; K[^BRn  
} h|{DIG3  
Vpe\Okt:  
'E)g )@^  
public int getNSplitter() :>*0./hG  
{ 08qM?{z o^  
return nSplitter; ]j+J^g  
} ,382O$C  
le150;7  
^JY,K  
public void setNSplitter(int nCount) pmuT7*<19  
{ DmiZ"A  
nSplitter = nCount; =`OnFdI  
} Ca}V5O  
} l_i&8*=Px  
J,D^fVIw  
QIC? `hk1  
/* fA"9eUu  
**Utility.java %hVI*p3  
*/ ~[Z,:=z  
package NetFox; mO0}Go8  
.YlhK=d4  
X<<FS%:+  
public class Utility { $g!iy'4n*  
{:TOm0eK  
7srq~;j3  
public Utility() gXvE^fE  
{ H Xb_k1n  
k9!eu j&  
1'!%$D  
} sP@7%p>wt  
(2(y9r*1  
//线程睡眠 %fIYWu`X  
public static void sleep(int nSecond) ` 1v Dp.  
{ BV)) #D9  
try{ vEc<|t  
Thread.sleep(nSecond); c+ukVn`r  
} Y(;u)uN_  
catch(Exception e) E[Bj+mX9  
{ $Ned1@%[  
e.printStackTrace (); c@x6<S%*  
} }q=tg9  
} $QnsP#ePN  
6 2LLfD  
//日志 UgTgva>?  
public static void log(String sMsg) 9dwLkr  
{ .s%dP.P:i1  
System.err.println(sMsg); i$6o>V6  
} 8<=]4-X@  
IqCh4y3  
]2rC n};  
public static void log(int sMsg) 6T6UIq  
{ 8|~M!<  
System.err.println(sMsg); d Z}|G-:  
} nk"nSXm3SR  
} 'kHa_  
Q#lFt,.y  
"%ZAL\x  
/* MogIQ  
**TestMethod.java KtcuGI/A  
*/ 3oM&#a  
package NetFox; b!T-{Ns6  
&*; Z(ul&9  
nq:'jdY5|  
public class TestMethod { A2''v3-h8  
59H~qE1Md  
&F.L*M  
public TestMethod() oA+'9/UY  
{ ///xx/weblogic60b2_win.exe ut^6UdJ+`  
try{ scPvuHzl  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); a)' P/P  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); kd OIL2T  
SiteFileFetch fileFetch = new SiteFileFetch(bean); N>IkK*v  
fileFetch.start(); BeFXC5-qat  
} _xGC0f (  
catch(Exception e){e.printStackTrace ();} +J3Y}A4W3X  
]RxWypA`  
T/?C_i  
} 3il/{bgM  
B:6VD /qC  
0,wmEV!)  
public static void main(String[] args) X nB-1{a1  
{ %FJB9?9=|  
new TestMethod(); I+rLKGZC  
} fv:&?gc  
} h]WW?.   
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