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http断点续传简单实现(java)

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/* P !f{U;B  
**SiteFileFetch.java @_"cMU!  
*/ > }f!. i  
package NetFox; o]tfvGvU*  
import java.io.*; W8QP6^lY  
import java.net.*; R\ 8[6H  
##''d||u  
_R(ZvsOZ  
public class SiteFileFetch extends Thread { .lj5pmD  
Y[)mHs2  
nHeJ20  
SiteInfoBean siteInfoBean = null; //文件信息Bean h8O\sKn  
long[] nStartPos; //开始位置 u(3 uZ:  
long[] nEndPos; //结束位置 XK\nOHLS  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !pU^?Hy=  
long nFileLength; //文件长度 l'4<^q  
boolean bFirst = true; //是否第一次取文件 >Z*b0j  
boolean bStop = false; //停止标志 I}u\ov_Su  
File tmpFile; //文件下载的临时信息 0`.&U^dG  
DataOutputStream output; //输出到文件的输出流 |WS@q'  
i 1w ]j  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) evZP*N~G  
public SiteFileFetch(SiteInfoBean bean) throws IOException p#w8$Qjp  
{ l"JM%LV  
siteInfoBean = bean; @ NDcO,]  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); K:-jn}i?/  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~D5FnN9  
if(tmpFile.exists ()) {hN\=_6*EW  
{ m4h)Wq  
bFirst = false; M 2| k.  
read_nPos(); b=S"o )>  
} zQ:nL*X'Z"  
else &a'mG=(K_c  
{ !BW!!/U  
nStartPos = new long[bean.getNSplitter()]; qF^P\cD  
nEndPos = new long[bean.getNSplitter()]; HOu$14g  
} k@%5P-e}  
$-]G6r  
k(tB+k!vH\  
!21G $ [H  
} (rJ-S"^u  
3}g>/F ~  
6d8)]  
public void run() L"vk ^>E6  
{ N/WtQSl  
//获得文件长度 }@6yROy.  
//分割文件 Q)4[zStR#  
//实例FileSplitterFetch GQ?FUFuIoW  
//启动FileSplitterFetch线程 !wE% <Fh  
//等待子线程返回 >pZ _  
try{ %"c;kvw  
if(bFirst) Mu:zWLM*M  
{ Ep;?%o,G  
nFileLength = getFileSize(); 0LC]%x+"  
if(nFileLength == -1) indbg d  
{ @I1*b>X~<  
System.err.println("File Length is not known!"); Cp!9 "J:  
} :(OV{ u  
else if(nFileLength == -2) VJ'-"8tY&  
{ &FRf-6/  
System.err.println("File is not access!"); }8l+Jd3"  
} s \3]0n9  
else C$q-WoTM(  
{ +W1l9n*  
for(int i=0;i<nStartPos.length;i++) dk1q9Tx  
{ d< XY"Y%  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); .$d:c61X  
} `0W"[BY  
for(int i=0;i<nEndPos.length-1;i++) `lm'_~=`&  
{ ":T"Y;  
nEndPos = nStartPos[i+1]; MY\mo,#  
} aBQ--Sz  
nEndPos[nEndPos.length-1] = nFileLength; &<#1G u_  
} ,0HID:&  
} ;W+1 H !  
:#sBNy  
kz1Z K  
//启动子线程 qooTRqc#,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; n&]J-^Tx  
for(int i=0;i<nStartPos.length;i++) Z>w@3$\z  
{ B ( h`~pb  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), hC{2LLu;n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), E{-pkqx  
nStartPos,nEndPos,i); f]2gjQHM  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zN9@.!?X2  
fileSplitterFetch.start(); MwD+'5   
} ~ cu+QR)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c uAp,!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); K4NzI9@  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", liB~vdqj  
nEndPos = " + nFileLength); ^cW{%R>XY  
// fileSplitterFetch[nPos.length-1].start(); .'+JA:3R  
b)XGr?  
ZA_~o#0%  
//等待子线程结束 p+Bvfn  
//int count = 0; >>R)?24,<  
//是否结束while循环  ;1,#rTs  
boolean breakWhile = false; +LWgby4q  
# 6?2 2Os  
GQ.akA_(  
while(!bStop) KVoi>?a   
{ YP"%z6N@v  
write_nPos(); u0+<[Ia'q  
Utility.sleep(500); )('{q}JxV  
breakWhile = true; T3)m{gv0`  
`+KLE(]vyH  
?|2m0~%V=  
for(int i=0;i<nStartPos.length;i++) m^0*k|9+G  
{ ?~}8^~3  
if(!fileSplitterFetch.bDownOver) A1zV5-E/  
{ o'P[uB/  
breakWhile = false; JP]4* l  
break; w+%p4VkA<r  
} Y\1&  Uk  
} rY6bc\?`x  
if(breakWhile) Oh`Pf;.z%  
break; z;YX 2G/{  
Y'6P ~C;v  
u4=ulgi  
//count++; hoPh#? G  
//if(count>4) .b*-GWx  
// siteStop(); JK XIxw>q  
} _#P5j#  
eBECY(QMQ  
CS"k0V44}  
System.err.println("文件下载结束!"); 1*@Q~f:Uk  
} wE <PXBl\b  
catch(Exception e){e.printStackTrace ();} M@.?l=1X  
} :e_yOT}}  
T5-'|+  
|>I4(''}  
//获得文件长度 %s%e5hU  
public long getFileSize() QmPHf*w[  
{ 5FNf)F   
int nFileLength = -1; p_3VFKq>0  
try{  mxvV~X %  
URL url = new URL(siteInfoBean.getSSiteURL()); a5g1.6hF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 79lG~BGE  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?0E-Lac=  
/8(t:  
IP 1{gMG  
int responseCode=httpConnection.getResponseCode(); Ce3  
if(responseCode>=400) !.{{QwZ  
{ i6h0_q8 >  
processErrorCode(responseCode); 6ozBU^n  
return -2; //-2 represent access is error w$I$xup  
} ? v@q&  
);F /P0P  
\l;H !y[  
String sHeader; D>q?My  
[;INVUwG^  
MES|iB  
for(int i=1;;i++) E"H> [E  
{ ;{>-K8=>$  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); U &W}c^#  
//Utility.log(in.readLine()); Cd'SPaR  
sHeader=httpConnection.getHeaderFieldKey(i); dG]s_lb9H  
if(sHeader!=null) kmL~H1qd  
{ Vuo 8[h>  
if(sHeader.equals("Content-Length")) {[B`q  
{ iuq%Q\0@w  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); pK2n'4 C  
break; _UeIzdV9  
} nr9c G/"  
} k{$Mlt?&-  
else 6sRKbp|r7  
break; Uw_z9ZL  
} T/l2B1  
} .mS'c#~5Y  
catch(IOException e){e.printStackTrace ();} #T)gKp  
catch(Exception e){e.printStackTrace ();} Ne,u\q3f  
x~O_v  
{~d8_%:b  
Utility.log(nFileLength); }NJ? .Y  
Vt," 5c  
I:#Es.  
return nFileLength; nR~L$Wu5_a  
} (hX}O>  
_\xd]~ELj  
xSHeP`P^X  
//保存下载信息(文件指针位置) [R[Suf  
private void write_nPos() F{aM6I  
{ GwVSRI:[N  
try{ AfW9;{j&I  
output = new DataOutputStream(new FileOutputStream(tmpFile)); }h)[>I(  
output.writeInt(nStartPos.length); bQM_rqjJGw  
for(int i=0;i<nStartPos.length;i++) | [lM2  
{ 3~!PJI1  
// output.writeLong(nPos); R'r^v  
output.writeLong(fileSplitterFetch.nStartPos); \=/^H  
output.writeLong(fileSplitterFetch.nEndPos); Me*]Bh  
} KI Ua  
output.close(); vl}uHdeP9  
} pn~$u  
catch(IOException e){e.printStackTrace ();} Y|iALrx  
catch(Exception e){e.printStackTrace ();} PUViTb  
} rj].bGQ,+  
#nh;KlI 0  
^^Tu/YC9x  
//读取保存的下载信息(文件指针位置) pb5'5X+  
private void read_nPos() N^. !l_  
{ rx#\Dc}  
try{ 3l@={Ts  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0zAj.iG  
int nCount = input.readInt(); L);kwx7{LW  
nStartPos = new long[nCount]; \YBY"J  
nEndPos = new long[nCount]; q,a|lH  
for(int i=0;i<nStartPos.length;i++) f[/E $r99J  
{ #_bSWV4  
nStartPos = input.readLong(); `cr.C|RT:  
nEndPos = input.readLong(); S)*eAON9  
} Qy@r&  
input.close(); o5FBqt  
} obE_`u l#  
catch(IOException e){e.printStackTrace ();} q|%(47}z  
catch(Exception e){e.printStackTrace ();} ^\<1Y''  
} GZ]; U] _  
(HkMubnqg  
A %s"WSx,  
private void processErrorCode(int nErrorCode) 7Jm9,4]  
{ BI]%$rq  
System.err.println("Error Code : " + nErrorCode); eS jXaZh  
} *lIK?"mo  
f13%[RA9N  
3RP}lb  
//停止文件下载 YDyi6x,  
public void siteStop() %!HmtpS  
{ r,x;q  
bStop = true; *qE[Y0Cd  
for(int i=0;i<nStartPos.length;i++) f&Bu_r  
fileSplitterFetch.splitterStop(); of ^N4  
; . c]0  
bd2"k;H<o  
} `1KZ14K  
} .;n<k  
//负责部分文件的抓取 T%xB|^lf  
**FileSplitterFetch.java |:tFQ.Z'2  
*/ h2Z Gh  
package NetFox; 08S|$_  
f[!Q R  
SL/ FMYdd  
import java.io.*; O(otI-Lc  
import java.net.*; j%KLp4J/e  
SA|f1R2uS  
16YJQ ue  
public class FileSplitterFetch extends Thread { QP?Z+P<  
.Tdl'y:..  
y@G5I>v  
String sURL; //File URL ,bCPO` 45  
long nStartPos; //File Snippet Start Position mMw&{7b:  
long nEndPos; //File Snippet End Position U&/Jh^Yy  
int nThreadID; //Thread's ID 9\i,3:Qc  
boolean bDownOver = false; //Downing is over B" wk:\zC  
boolean bStop = false; //Stop identical UGPD5wX?  
FileAccessI fileAccessI = null; //File Access interface It4J \S  
Kl$!_$  
pVw)"\S%  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Q<r O5 -K  
{ b#.hw2?a`  
this.sURL = sURL; - iS\3P.  
this.nStartPos = nStart; u[^(s_  
this.nEndPos = nEnd; oZ@_o3VG  
nThreadID = id; Y2w 9]:J  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 gBq,So  
} %?C{0(Z{  
gRKmfJ*u  
kO\(6f2|x  
public void run() JF_\A)<ki  
{ 5sx-u!7  
while(nStartPos < nEndPos && !bStop) t_WNEZW7f  
{ l0b Y  
R{+ Rvk  
1DGVAIcD  
try{ ~/h P6*  
URL url = new URL(sURL); Ni GK| Z   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1z$;>+g<  
httpConnection.setRequestProperty("User-Agent","NetFox"); "S^;X @#v  
String sProperty = "bytes="+nStartPos+"-"; h]c-x(+  
httpConnection.setRequestProperty("RANGE",sProperty); >ea<6&!Ee  
Utility.log(sProperty); ~-6Kl3Y  
A[!Fg0X0  
Hi9;i/  
InputStream input = httpConnection.getInputStream(); RIM"MR9qe=  
//logResponseHead(httpConnection); |]]Xee]  
Zi2NgVF  
N Q{ X IN~  
byte[] b = new byte[1024]; p/'C v  
int nRead; w=3@IW  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) \p.Byso,  
{ D C mNxN  
nStartPos += fileAccessI.write(b,0,nRead); ID5?x8o#k  
//if(nThreadID == 1) * KFsO1j  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >NW /0'/  
} M\8FjJ>9  
+8Zt<snG  
q=}Lm;r  
Utility.log("Thread " + nThreadID + " is over!"); :j vx-jQ  
bDownOver = true; ?ae:9ZcH  
//nPos = fileAccessI.write (b,0,nRead); 2:/'  
} M&y!w   
catch(Exception e){e.printStackTrace ();} #=b_!~:%  
} 6U7z8NV&[  
} I [0od+K  
F1)Q#ThF\  
,$sq]_t  
//打印回应的头信息 Sy'/%[+goJ  
public void logResponseHead(HttpURLConnection con) ev#d1s|<S  
{ M{:gc7%  
for(int i=1;;i++) W UdKj  
{ *6q8kQsz^1  
String header=con.getHeaderFieldKey(i); \y: 0+s/  
if(header!=null) QO7 > XHn  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Yq#I# 2RD  
Utility.log(header+" : "+con.getHeaderField(header)); y^hpmTB3"  
else 9ToM5oQ  
break; J~DP*}~XK  
} 7~eo^/Pb S  
} -Z<e`iFQS  
n@5pS3qZ  
KcfW+> W3  
public void splitterStop() )~O{jd  
{ wQp,RpM  
bStop = true; JXGIVH?Rpu  
} iX.=8 ~3  
Rmn|"ZK  
X!CLOHVA a  
} Q{H88g^=J  
\h :Rw|  
X`:(-3T  
/* xp1 +C{  
**FileAccess.java *WfOB2rU  
*//文件访问(定位,写) -t?S:9 [w  
package NetFox; g;\zD_":l  
import java.io.*; e&7GW9FSg  
x7l)i!/$  
\"_;rJ{!aE  
public class FileAccessI implements Serializable{ 5cxA,T  
iyu%o9_0  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @*q\$Eg}2  
RandomAccessFile oSavedFile; Gc4N)oq)}b  
long nPos; A! <R?  
9 o-T#~i  
H4KwbTT"+  
public FileAccessI() throws IOException E[nWB"pxE  
{ =9YyUAJZ  
this("",0); lV`y6{o#T  
} !o:RIwS3  
}^?dK3~q  
68Wm=j.m  
public FileAccessI(String sName,long nPos) throws IOException 6H VS0  
{ v=i[s  
oSavedFile = new RandomAccessFile(sName,"rw"); 7SXi#{  
this.nPos = nPos; |j^>6nE  
oSavedFile.seek(nPos); (Y, @-V  
} t{!}^{ "5  
emw3cQ  
/.$n>:XR  
public synchronized int write(byte[] b,int nStart,int nLen) @6 gA4h  
{ !F;W#Gc  
int n = -1; 0$}+tq+  
try{ uc=-+*D'I  
oSavedFile.write(b,nStart,nLen); 0l.+yr}PE  
n = nLen; W5_t/_EWD  
} 4'Vuhqk  
catch(IOException e) #rzxFMA"  
{ R7x4v  
e.printStackTrace (); *J8j_-i,R  
} 2y ~]Uo  
eAu3,qoM  
#R305  
return n; 3r+vpyu  
} =o{zw+|% %  
Z?XE~6aP>  
vj[ .`fY  
} $62ospR^Y  
V`S6cmwdc\  
GZXUB0W\@)  
/* l K}('7\  
**SiteInfoBean.java L;fhJ~ r  
*/ +X cB5S>  
package NetFox; q^( [ & +  
K}`.?6O  
kIrME:  
public class SiteInfoBean { qK.8^{b  
jf*M}Q1jHE  
zg)Z2?K|;u  
private String sSiteURL; //Site's URL t \DS}3pv  
private String sFilePath; //Saved File's Path V2i*PK X  
private String sFileName; //Saved File's Name U,[vfSDGr  
private int nSplitter; //Count of Splited Downloading File rbO9NRg>  
9"=:\PE  
B\KvKT|\  
public SiteInfoBean() , YTuZS  
{//nSplitter的缺省值为5 `Kpn@Xg  
//default value of nSplitter is 5 Sw%=/g  
this("","","",5); Xy_+L_h^  
} Z7K ;~*  
vs7Hg )F  
C[&  \Xq  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) EtcAU}9  
{ _;v4 ]MU  
sSiteURL= sURL; k/j]*~"  
sFilePath = sPath; r<UZ\d -  
sFileName = sName; x}AWWmXv  
this.nSplitter = nSpiltter; y*vs}G'W  
HS="t3  
TN.mNl%  
} A$;U*7TJuO  
eMPi ho  
xo6-Y=c8  
public String getSSiteURL() p r(:99~3  
{ tL 3]9qfj  
return sSiteURL; 2e/ JFhA  
} DFVaZN?~  
^7Z)/c`"  
jU@qQ@|  
public void setSSiteURL(String value) $ze%! C  
{ -PB m@}*  
sSiteURL = value; ,m8l /wG  
} xs.>+(@|;  
Br`Xw^S  
&]ts*qCEL  
public String getSFilePath() ]6GdB3?UVM  
{ &Jk0SUk MP  
return sFilePath; 8JJqEkQ  
} s34{\/'D+  
Gi6sl_"q  
h-<('w:A  
public void setSFilePath(String value) 5^ARC^v  
{ ^UEI`_HO0  
sFilePath = value; t}c ymX~  
} i"0^Gr  
% E3  
Owo2DsT t  
public String getSFileName() |k^'}n  
{ =v:vc~G6  
return sFileName; ht (RX  
} =n cu# T]  
8l~] }2LAs  
L1VUfEG-  
public void setSFileName(String value) Ha[Bf*  
{ d2Z5HFtY  
sFileName = value; 4sP0oe[h  
} PL@hsZty~c  
)c^Rc9e/  
8uP,#D<wZ  
public int getNSplitter() K;k_MA310  
{ /$|C s  
return nSplitter; 4;<?ec(dc  
} W.r0W2))(  
z4HIDb  
eY-W5TgU  
public void setNSplitter(int nCount) Xjw> Qws  
{ &-:ZM0Fl  
nSplitter = nCount; WUvrC  
} Mi%i_T^i  
} r? nvJHP  
@mSdksB/L  
X#EMmB!  
/* T&oY:1D,g  
**Utility.java [ %cW ?@  
*/ s{(aW5$!s  
package NetFox; cV\(Z6u  
3=RVJb  
|F=!0Id<  
public class Utility { YiJnh47  
({v$!AAv  
^ |z|kc  
public Utility() O:IU|INq8  
{ ai)S:2  
Ew5(U`]  
j1Fy'os"!  
} uUB,OmLN  
umaF}}-Q{  
//线程睡眠 Dq/_^a/1  
public static void sleep(int nSecond) )a AKO`  
{ -*~ = 4m<  
try{ |]1-ck!  
Thread.sleep(nSecond); i,r O3J n  
} z#ab V1 Xi  
catch(Exception e) P"Lk(gY  
{ wzVx16Rvc  
e.printStackTrace (); B 7zyMh   
} 4nK\gXz19  
} {;4Y5kj  
)e(Rf!P{  
//日志 UbNA|`H  
public static void log(String sMsg) jfP2n5X83  
{ \3JZ =/  
System.err.println(sMsg); m \o<a|  
} %X7R_>.   
Y~gDS^8  
d[E~}Dq3#  
public static void log(int sMsg) }Qyuy~-&^  
{ ~P8 6=Vw  
System.err.println(sMsg); ^,*ED Yz  
} ` Fnl<C<  
} t2skg  
!~Gx@Ro  
:)o 4fOJ8  
/* O=~8+sa  
**TestMethod.java ZKy)F-yX  
*/ s~ ||Vv!  
package NetFox; nr7#}pzo  
Yv<' QC  
]L+YnZ?6  
public class TestMethod { PP)iw@9j  
RfH.WXi  
~QgyhJM_h=  
public TestMethod() TRP#b 7nC  
{ ///xx/weblogic60b2_win.exe q.0Evr:  
try{ !~Vo'ykwx'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);  ;wo  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); POvxZU  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8=QOp[w   
fileFetch.start(); x93h{K f  
} Zk,` Iq  
catch(Exception e){e.printStackTrace ();} kt`_n+G  
BIGln`;,f  
mN^w?R41m  
} jz,Mm,Gi  
`_%U K=m  
_gU:!:}  
public static void main(String[] args) 8Na.H::cZ  
{ !%MI9Ok  
new TestMethod(); V`P8oIOh]  
} ]Z\Z_t  
} f@S n1c,Mk  
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