http断点续传简单实现（java)

/* f0!))/rSD  
**SiteFileFetch.java 4d"r^y'  
*/ S2E8Gq9  
package NetFox; GeI-\F7b  
import java.io.*; XWnVgY s  
import java.net.*; 5CuuG<0  
X3(tuqmi  
a,Sw4yJ!Q  
public class SiteFileFetch extends Thread { |U~<3.:m:  
lVd^ ^T*fh  
84$nT>c  
SiteInfoBean siteInfoBean = null; //文件信息Bean +2(I1  
long[] nStartPos; //开始位置 iyN:%ofh  
long[] nEndPos; //结束位置 'Jiw@t<o3`  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9y6-/H ,  
long nFileLength; //文件长度 AJt+p&I[J  
boolean bFirst = true; //是否第一次取文件 `K*Q5n  
boolean bStop = false; //停止标志 w?3p';C  
File tmpFile; //文件下载的临时信息 PYiU_  
DataOutputStream output; //输出到文件的输出流 >u>5{4  
)S3\,S-.  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） "Hya6k>j  
public SiteFileFetch(SiteInfoBean bean) throws IOException >/{@C  
{ 9K.V
b1&  
siteInfoBean = bean; &]V.S7LC#  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 7Sf bx~48  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); H[m:0eF'5  
if(tmpFile.exists ()) 2uzW+D6J  
{ f0A{W/0n  
bFirst = false; 'SO %)B  
read_nPos(); WJ$bf(X*  
} i1UiNJh86  
else A8x
vo/n$  
{ v>:Ur}u!D  
nStartPos = new long[bean.getNSplitter()]; f< ia(
d  
nEndPos = new long[bean.getNSplitter()]; >q#rw  
} Ki4r<>\l{H  
F7A=GF'  
ZLc -RM  
q6@Lp^f  
} v5/~-uRL%  
RW|`nL  
9"NF/)_  
public void run() &]g}u5J!=  
{ -O1>|y2rU  
//获得文件长度 bNm#tmSt  
//分割文件 ICpAt~3[M  
//实例FileSplitterFetch jGJLSEe_  
//启动FileSplitterFetch线程 .RE:;<|w  
//等待子线程返回 2^Eg9y'  
try{ t\?ik6  
if(bFirst) mGtdO/C#B  
{ FFl!\y*0z  
nFileLength = getFileSize(); NYt&@Z}]  
if(nFileLength == -1) s0\X ^  
{ &[_g6OL  
System.err.println("File Length is not known!"); Jk&3%^P{m  
} neB\q[
k  
else if(nFileLength == -2) d.3E[AJa(  
{ eS{!)j_^  
System.err.println("File is not access!"); B%
" d~5Y  
} $}RJ,%~'x  
else !4]TXH0f  
{ O80<Z#%j`  
for(int i=0;i<nStartPos.length;i++) @>u]4Jn  
{ 6,o~\8ia  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); I*%-cA%l  
} G(Lzf(  
for(int i=0;i<nEndPos.length-1;i++) o#;b  
{ t,QyfN  
nEndPos = nStartPos[i+1]; bT\1>  
} ]}*R|1  
nEndPos[nEndPos.length-1] = nFileLength; IW>T}@ |  
} 
_?<|{O  
} 7zA'ri3w  
jDKO
} bQ  
5BWH-2HsB  
//启动子线程 a!ud{Dx  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 46$._h P  
for(int i=0;i<nStartPos.length;i++) vY4\59]P  
{ R_(tjkT  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), hwu]Er.g
n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), mi ik%7>W  
nStartPos,nEndPos,i); B,<da1(a  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %9w::hav  
fileSplitterFetch.start(); b+,';bW  
} Mxe}B'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5
G::wuxk  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ! _f9NK  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", gaQdG=G8$
 
nEndPos = " + nFileLength); 48c1gUwoP  
// fileSplitterFetch[nPos.length-1].start(); s2tey
m,uG  
h xSKG  
:S.9eFfa  
//等待子线程结束 ~{d$!`|a  
//int count = 0; 05z,b]>l  
//是否结束while循环 uPhK3nCGo  
boolean breakWhile = false; b$4"i XSQ  
XnDUa3  
K:!"+q  
while(!bStop) ^]7}YF2|  
{ (^s>m,h  
write_nPos(); H+1-]'g`  
Utility.sleep(500); L\Aq6q@c  
breakWhile = true; Uhe=h&e2k@  
JX-' mV`  
4y)P
>c  
for(int i=0;i<nStartPos.length;i++) 2w59^"<,  
{ mlixIW2  
if(!fileSplitterFetch.bDownOver)
E7NV ^4h  
{ XDsx3Ws  
breakWhile = false; esHg'8?U  
break; U@g4w!$r  
} !HrKXy0{  
} 'L 8n-TyL  
if(breakWhile) lm!.W5-l  
break; qo p^;~  
,ek_R)&[o  
G.rrv  
//count++; +Fuqchjq  
//if(count>4) 1|RANy  
// siteStop(); =5Q]m6-SgV  
} EwuO&q  
%{ABaeb]  
*194{ ep  
System.err.println("文件下载结束！"); jNTjSX  
} YwteZSbp6M  
catch(Exception e){e.printStackTrace ();} ZZk=E4aae  
} U[SaY0Z  
I`p+Qt  
wN`
jE0 {  
//获得文件长度
]j'p :v  
public long getFileSize() q ]M+/sl  
{ i'4B3  
int nFileLength = -1; J!0DR4=Xi  
try{ !6BW@GeF]  
URL url = new URL(siteInfoBean.getSSiteURL()); :ZTc7}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); g,}_G3[j0m  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^oVs+vC  
|s"nM<ZNZ  
$eD.W
 
int responseCode=httpConnection.getResponseCode(); qm./|#m>  
if(responseCode>=400) 'd.EC#  
{  5
V6G=H  
processErrorCode(responseCode); pNOwDJtK  
return -2; //-2 represent access is error FB
_pw!z  
} s8-<m,*  
A9f)tqbc  
uxW~uEh  
String sHeader; .P;*Dws  
KB%"bqB|  
r
YogW!  
for(int i=1;;i++) %`O
J.:k  
{ o}W%I/s  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); .Si,dc\  
//Utility.log(in.readLine()); *FC=X)_&W  
sHeader=httpConnection.getHeaderFieldKey(i); (5#nrF]
 
if(sHeader!=null) }2<r,  
{ TcIcS]w%  
if(sHeader.equals("Content-Length")) =4[v3Qx  
{ KAC6Snu1  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); IOb*GT
b  
break; :E_g"_  
} z*kutZ:6Y  
} MNC*Glj=  
else x97 j  
break; bLe<G  
} ,8:(OB|a  
} >_o}  
catch(IOException e){e.printStackTrace ();} &QDW9 Mi  
catch(Exception e){e.printStackTrace ();} E_k$W5  
'SCidN(n  
~Q?a|mV,  
Utility.log(nFileLength); |UK}  
K<pV  
hCCiD9gz  
return nFileLength; S/^"@?z,vE  
} X}tVmO?  
My<snmr2d  
&0NFb^8+  
//保存下载信息（文件指针位置） 'XZ)!1N  
private void write_nPos() GqWB{$J;"  
{ 2W/?q!t  
try{ T?
tG~  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ])L A42|  
output.writeInt(nStartPos.length); CZ(/=3,3n  
for(int i=0;i<nStartPos.length;i++) KMU4n-s"o  
{ I2 j}Am  
// output.writeLong(nPos); "ul {d(K3  
output.writeLong(fileSplitterFetch.nStartPos); ]3VI|f$$  
output.writeLong(fileSplitterFetch.nEndPos); <1FC%f/  
} E0u~i59Z  
output.close(); 29!q!g|  
} ?%`@ub$  
catch(IOException e){e.printStackTrace ();} X=hYB}}nu  
catch(Exception e){e.printStackTrace ();} BDq%'~/^  
} Fb^:V4<T  
RnhL< Ywu  
,_yhz0.  
//读取保存的下载信息（文件指针位置） kD*2~Z?;  
private void read_nPos() Ys@}3\Mc  
{ Pm lx8@D  
try{ nX(+s*Y+w  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); %;e/7`>Ma  
int nCount = input.readInt(); Bm"KOr$}-  
nStartPos = new long[nCount]; 1jy9lP=  
nEndPos = new long[nCount]; Rniq(FAx  
for(int i=0;i<nStartPos.length;i++) NbC@z9Q  
{ #Yr9AVr}K  
nStartPos = input.readLong(); T2SP W@#Z3  
nEndPos = input.readLong(); 4T!+D  
} h<Ft_#|o[  
input.close(); c8L~S/t  
} %7"X(Ts7B  
catch(IOException e){e.printStackTrace ();} cJ1#ge%4  
catch(Exception e){e.printStackTrace ();} "kMguK}c  
} wm)#[x #  
| \'rP_I>  
W6"v)Jc>_  
private void processErrorCode(int nErrorCode) KcK>%%  
{ VwOW=4`6  
System.err.println("Error Code : " + nErrorCode); Svc|0Ad&  
} t: #6sF  
Ttxqf:OMf  
GFel(cx:K  
//停止文件下载 7RUofcax  
public void siteStop() ZJwrLV  
{ JcbwDlUb  
bStop = true; -TM0]{  
for(int i=0;i<nStartPos.length;i++) |P -8HlOr  
fileSplitterFetch.splitterStop();
#$c Rkw  
%kB8'a3  
1E73i_L  
} 9[m6Li  
} :E>HE,1b+  
//负责部分文件的抓取 8"dv_`ym  
**FileSplitterFetch.java F8;dKyT?q  
*/ dl~%MWAVb  
package NetFox; e XfZ5(na  
7VMvF/ap]u  
zgs(Dt;  
import java.io.*; g>dA$h%  
import java.net.*; *M$0J'-B
Q  
c0hwc1kv-  
n@U n  
public class FileSplitterFetch extends Thread { -C<zF`jO  
(*oL+ef-C  
qe!fk?T}  
String sURL; //File URL .G+Pe'4a  
long nStartPos; //File Snippet Start Position SE),":aY  
long nEndPos; //File Snippet End Position ``OD.aY^s  
int nThreadID; //Thread's ID 'bo~%WA]n  
boolean bDownOver = false; //Downing is over XLL/4)  
boolean bStop = false; //Stop identical SQqD:{#g"  
FileAccessI fileAccessI = null; //File Access interface L{(QpgHZ  
+"8,Mh  
\ gLHi~  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #|*F1K  
{ Q($Z%1S  
this.sURL = sURL; ~-PjW#J%  
this.nStartPos = nStart; emdoA:w+   
this.nEndPos = nEnd; IRn2|  
nThreadID = id; _>9.v%5cs(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Ti'}MC+0  
} -u?S=h}  
!!Aj<*%  
|7X:TfJ  
public void run() `;)\u  
{ ik!..9aB  
while(nStartPos < nEndPos && !bStop) zxf"87
se  
{ f-5:wM&  
'Er:a?88l  
]R=,5kK3  
try{ `;>= '"O!\  
URL url = new URL(sURL); s1e:v+B]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); RLSc+kDH_  
httpConnection.setRequestProperty("User-Agent","NetFox"); oI.G-ChP  
String sProperty = "bytes="+nStartPos+"-"; l'\pk<V  
httpConnection.setRequestProperty("RANGE",sProperty); lKlU-4  
Utility.log(sProperty); PSPmO'C+  
Er{#ziN+  
:%sXO  
InputStream input = httpConnection.getInputStream(); FI
bp"~  
//logResponseHead(httpConnection); TpHfS]W-P  
F$^
Su<w5l  
6e_dJ=_  
byte[] b = new byte[1024]; (s{RnD  
int nRead; CE"JS-S?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) X`fn8~5
 
{ C&6IU8l\  
nStartPos += fileAccessI.write(b,0,nRead); 7f~Sf  
//if(nThreadID == 1) _L@2_
#h!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *P#WDXRwd  
} ?}m']4p  
Q4*fc^?u  
!}4MN:r  
Utility.log("Thread " + nThreadID + " is over!"); ,:`ND28V7  
bDownOver = true; &NSY9'N,  
//nPos = fileAccessI.write (b,0,nRead); Fr%d}g  
} #(1j#\  
catch(Exception e){e.printStackTrace ();} b*FC\:\  
} Le*.*\  
} c7M%xGrP  
cKn`/\.H  
`\m*+Bk[5  
//打印回应的头信息 :OW;?{ ~j  
public void logResponseHead(HttpURLConnection con) Bf$_XG3  
{ #?XQ7Im  
for(int i=1;;i++) l2&`J_"  
{ (XXheC  
String header=con.getHeaderFieldKey(i); P9S2?Q  
if(header!=null) |QMhMGjV  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); V=lfl1Ev0J  
Utility.log(header+" : "+con.getHeaderField(header)); I8QjKI (  
else l983vKr  
break; %/>Y/!;  
} 9JWa$iBH@  
} =&},;VOh  
\4AM*lZ  
?_ dIIQ  
public void splitterStop() !H2QjW  
{ +Y V|ij  
bStop = true; o,xxh  
} h(F<h_  
=i(?deR  
hRq3C1mR  
} !wWJ^Oz=  
]r-C1bKD`  
?X5]i#j[  
/* z.CywME<)t  
**FileAccess.java YG8>czC  
*//文件访问(定位，写) %eJGte-  
package NetFox; CT\;xt,S  
import java.io.*; B}eA\O4}I  
UK{irU|\  
j+^
oz'q  
public class FileAccessI implements Serializable{ 4]/7 )x?R  
p2N:;lXM  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 I(S)n+E  
RandomAccessFile oSavedFile; Cn_$l>  
long nPos; Iu{kPyx  
XTd3|Pm  
I"1;|`L~:  
public FileAccessI() throws IOException @&"Pci+-|  
{ jM&r{^(  
this("",0); i[ $0
a4  
} >5wx+n)/)  
fi+R2p~vs  
~h"/Tce  
public FileAccessI(String sName,long nPos) throws IOException 4Td{;Y="yF  
{ :aG#~-Q  
oSavedFile = new RandomAccessFile(sName,"rw"); 5'Q|EIL  
this.nPos = nPos; .>(Q)"v  
oSavedFile.seek(nPos); 1RKW2RCaW_  
} :0/q5_t  
siTX_`0  
c,Euv>*`  
public synchronized int write(byte[] b,int nStart,int nLen) vm'5s]kdh
 
{ @w>zF/  
int n = -1; WsFk:h'r  
try{ up2+s#  
oSavedFile.write(b,nStart,nLen); (Z}>1WRju  
n = nLen; nkv(~ej(  
} @vMA=v7a  
catch(IOException e) kqb0>rYa   
{ 9 C{;h  
e.printStackTrace (); 4G@nZn  
} \j2;4O?`  
hb/]8mR  
NjE</Empb%  
return n; v?c 0[+?  
} g}f9dB,F  
Bk}><H  
dtPoo\@  
} "Pl9nE  
>3gi yeJ  
GdVhK:<>  
/* `]v[5E  
**SiteInfoBean.java )>7%pz  
*/ o&hIHfZri  
package NetFox; Jd,)a#<j  
f1PN|  
>\ u<&>i  
public class SiteInfoBean { }YOL"<,:o  
~Z ~v  
1 ^g t1o  
private String sSiteURL; //Site's URL |+U<S~  
private String sFilePath; //Saved File's Path HP.E3yYK  
private String sFileName; //Saved File's Name +Ug/rtK4  
private int nSplitter; //Count of Splited Downloading File gq"k<C0  
iU+nqY'  
aS}1Q?cU  
public SiteInfoBean() &t(0E:^TRU  
{//nSplitter的缺省值为5 #tdf>?  
//default value of nSplitter is 5 ^+SkCO  
this("","","",5); PS S?|Vk  
} 'O6]0l  
Gq#~vr  
,uz ]V1  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) U6[ang'l  
{ ?4G|+yby  
sSiteURL= sURL; Zs2-u^3&  
sFilePath = sPath; I =Wc&1g  
sFileName = sName; %g]vxm5?  
this.nSplitter = nSpiltter; qpJ{2Q  
t!1$$e?`r  
7*wVI+  
} $XBAZ<"hd  
}%TSGC4{  
OndhL
Lz  
public String getSSiteURL() `N/RHb%  
{ 6+K_Z\  
return sSiteURL; ]
=73-ywn]  
} d
{2  
mgZf3?,)  
1x~U*vbhQ  
public void setSSiteURL(String value) zVv04_:  
{ jy2IZ o  
sSiteURL = value; /cFzotr"9  
} Fk=}iB#(  
Hqz?E@bc@  
O)R(==P26P  
public String getSFilePath() rC[6lIP  
{ 8iC:xcN3  
return sFilePath; w(nHD*nm  
} N"[B=fU}  
 ,%
#  
EA<}[4#jS  
public void setSFilePath(String value) |rRG=tG_'  
{ ]7AX%EG3  
sFilePath = value; ^4v*W;Q  
} T_<BVM  
c:M$m3Cs?  
02JL*  
public String getSFileName() vOI[Z0Lq9h  
{ N?4q  
return sFileName; RAs0]K  
} io4A>>W==/  
tZWrz e^  
Fs/?  
public void setSFileName(String value) Ix
DWJ#k  
{ zGcqzYbuA  
sFileName = value; (3,.3)%`  
} &B{8uge1
 
|-2}j2'  
IF k  
public int getNSplitter() &217l2X /  
{ `BZ&~vJ_  
return nSplitter; |I[7,`C~  
} '3l$al:H^  
$<?X7n^  
@=]8^?$t 0  
public void setNSplitter(int nCount) KT*:F(4`  
{ X}4}&  
nSplitter = nCount; -[#n+`M  
} ~bA,GfSn0  
} _.18z+  
SjcL#S($&Y  
BZ+-p5]-  
/* r;cV&T/?  
**Utility.java R -e
lIp  
*/ :_dICxaLZT  
package NetFox; K3$` Kv>I  
_EYB 8e  
#'o7x'n^  
public class Utility { *8g<R  
]Nk!4"  
{gy+3  
public Utility() q{4|Kpx@  
{ fJ80tt?r  
%EbiMo ]3B  
:9d\Uj,  
} ZKbDp~  
V/#v\*JHFc  
//线程睡眠 CSn<]%GL  
public static void sleep(int nSecond) .5tg4%l  
{ X1J;1hRUP  
try{ Bmr<O!  
Thread.sleep(nSecond); *crw^e  
} ')PVGV(D+  
catch(Exception e) !r&Bn6*  
{ \%_ZV9cKF  
e.printStackTrace (); r)l`  
} nTnRGf\T  
} )BV=|,j  
wgd<3 X  
//日志 B1T5f1;uY  
public static void log(String sMsg) =d20Xa  
{ pz}mF D&[  
System.err.println(sMsg); #+sF`qR,  
} 0-e  
M23&<}Q8  
nX x=1*X  
public static void log(int sMsg) iK}v`xq  
{ H*U`  
System.err.println(sMsg); z&'f/w8  
} f~gS
J<t4  
} Z$2L~j"=!  
w6,*9(;$Pk  
6&!l'[hU  
/* (.^8^uc7X  
**TestMethod.java [ #]jC[  
*/ z%2w(&1  
package NetFox; wL eHQ]  
!]DuZ=  
)bW<8f2  
public class TestMethod { X=_Z(;<&  
(wL3 +  
X5E '*W  
public TestMethod() i-13~Dk  
{ ///xx/weblogic60b2_win.exe !UNNjBBP7  
try{ ^87
42.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); <?|6*2_=  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); i:Mc(mW  
SiteFileFetch fileFetch = new SiteFileFetch(bean); lBiovT  
fileFetch.start(); ep?:;98|t  
} $N\+,?  
catch(Exception e){e.printStackTrace ();}
M/w{&&  
gX/NtO%  
EzP#Mnz^  
} bXl8v  
lP0k:  
iSd?N}2,I  
public static void main(String[] args) m`9^.>]P  
{ kMS5h~D[  
new TestMethod(); 0eA5zFU7  
} b>=7B6 Aw  
} m3?e]nL4W  
点击下载更多相关资料