显示所有索引的名称。如果指定了 TABLE 表,则只显示匹配 LIKE 模式的 TABLE 表的索引。
.load FILE ?ENTRY?
加载一个扩展库。
.log FILE/off
开启或关闭日志。FILE 文件可以是 stderr(标准错误)/stdout(标准输出)。
.mode MODE
设置输出模式,MODE 可以是下列之一:1. csv 逗号分隔的值 2. column 左对齐的列3. html HTML 的
代码4. insert TABLE 表的 SQL 插入(insert)语句5. line 每行一个值6. list 由 .separator 字符串分隔的值7. tabs 由 Tab 分隔的值8. tcl TCL 列表元素
.nullvalue
STRING 在 NULL 值的地方输出 STRING 字符串。
.output FILENAME
发送输出到 FILENAME 文件。
.output stdout
发送输出到屏幕。
.print STRING...
逐字地输出 STRING 字符串。
.prompt MAIN CONTINUE
替换标准提示符。
.quit
退出 SQLite 提示符。
.read FILENAME
执行 FILENAME 文件中的 SQL。
.schema ?TABLE?
显示 CREATE 语句。如果指定了 TABLE 表,则只显示匹配 LIKE 模式的 TABLE 表。
.separator STRING
改变输出模式和 .import 所使用的分隔符。
.show
显示各种设置的当前值。
.stats ON/OFF
开启或关闭统计。
.tables ?PATTERN?
列出匹配 LIKE 模式的表的名称。
.timeout MS
尝试打开锁定的表 MS 毫秒。
.width NUM NUM
为 "column" 模式设置列宽度。
.timer ON/OFF
开启或关闭 CPU 定时器。
退出sqlite提示符:
sqllite>.quit 或是 sqlite>.exit
查看 SQLite 命令提示符的默认设置。
sqlite>.show
echo: off
explain: off
headers: off
mode: column
nullvalue: ""
output: stdout
separator: "|"
width:
sqlite>
格式化输出
sqlite>.header on
sqlite>.mode column
sqlite>.timer on
sqlite>
上面设置将产生如下格式的输出:
ID NAME AGE ADDRESS SALARY
---------- ---------- ---------- ---------- ----------
1 Paul 32 California 20000.0
2 Allen 25 Texas 15000.0
3 Teddy 23 Norway 20000.0
4 Mark 25 Rich-Mond 65000.0
5 David 27 Texas 85000.0
6 Kim 22 South-Hall 45000.0
7 James 24 Houston 10000.0
CPU Time: user 0.000000 sys 0.000000
//导入需要的包
import java.sql.*;
public class SQLiteJDBC
{
public static void main( String args[] )
{
Connection c = null;
try {
//加载JDBC驱动程序(Driver)至DriverManager
Class.forName("org.sqlite.JDBC");
//从DriverManager中,通过JDBC URL,用户名,密码来获取相应的数据库连接(Connection)
c = DriverManager.getConnection("jdbc:sqlite:test.db");
} catch ( Exception e ) {
System.err.println( e.getClass().getName() + ": " + e.getMessage() );
System.exit(0);
}
System.out.println("Opened database successfully");
}
}
这在当前目录中创建数据库 test.db
8.2 创建表
下面的 Java 程序将用于在先前创建的数据库中创建一个表:
import java.sql.*;
public class SQLiteJDBC
{
public static void main( String args[] )
{
Connection c = null;
Statement stmt = null;
try {
Class.forName("org.sqlite.JDBC");
c = DriverManager.getConnection("jdbc:sqlite:test.db");
System.out.println("Opened database successfully");
stmt = c.createStatement();
String sql = "CREATE TABLE COMPANY " +
"(ID INT PRIMARY KEY NOT NULL," +
" NAME TEXT NOT NULL, " +
" AGE INT NOT NULL, " +
" ADDRESS CHAR(50), " +
" SALARY REAL)";
stmt.executeUpdate(sql);
stmt.close();
c.close();
} catch ( Exception e ) {
System.err.println( e.getClass().getName() + ": " + e.getMessage() );
System.exit(0);
}
System.out.println("Table created successfully");
}
}
上述程序编译和执行时,它会在 test.db 中创建 COMPANY 表。
8.3 INSERT 操作
下面的 Java 代码显示了如何在上面创建的 COMPANY 表中创建记录:
import java.sql.*;
public class SQLiteJDBC
{
public static void main( String args[] )
{
Connection c = null;
Statement stmt = null;
try {
Class.forName("org.sqlite.JDBC");
c = DriverManager.getConnection("jdbc:sqlite:test.db");
c.setAutoCommit(false);
System.out.println("Opened database successfully");
stmt = c.createStatement();
String sql = "INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) " +
"VALUES (1, 'Paul', 32, 'California', 20000.00 );";
stmt.executeUpdate(sql);
sql = "INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) " +
"VALUES (2, 'Allen', 25, 'Texas', 15000.00 );";
stmt.executeUpdate(sql);
sql = "INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) " +
"VALUES (3, 'Teddy', 23, 'Norway', 20000.00 );";
stmt.executeUpdate(sql);
sql = "INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) " +
"VALUES (4, 'Mark', 25, 'Rich-Mond ', 65000.00 );";
stmt.executeUpdate(sql);
stmt.close();
c.commit();
c.close();
} catch ( Exception e ) {
System.err.println( e.getClass().getName() + ": " + e.getMessage() );
System.exit(0);
}
System.out.println("Records created successfully");
}
上述程序编译和执行时,它会在 COMPANY 表中创建给定记录,并会显示以下两行:
Opened database successfully
Records created successfully
8.4 SELECT 操作
下面的 Java 程序显示了如何从前面创建的 COMPANY 表中获取并显示记录:
import java.sql.*;
public class SQLiteJDBC
{
public static void main( String args[] )
{
Connection c = null;
Statement stmt = null;
try {
Class.forName("org.sqlite.JDBC");
c = DriverManager.getConnection("jdbc:sqlite:test.db");
c.setAutoCommit(false);
System.out.println("Opened database successfully");
stmt = c.createStatement();
ResultSet rs = stmt.executeQuery( "SELECT * FROM COMPANY;" );
while ( rs.next() ) {
int id = rs.getInt("id");
String name = rs.getString("name");
int age = rs.getInt("age");
String address = rs.getString("address");
float salary = rs.getFloat("salary");
System.out.println( "ID = " + id );
System.out.println( "NAME = " + name );
System.out.println( "AGE = " + age );
System.out.println( "ADDRESS = " + address );
System.out.println( "SALARY = " + salary );
System.out.println();
}
rs.close();
stmt.close();
c.close();
} catch ( Exception e ) {
System.err.println( e.getClass().getName() + ": " + e.getMessage() );
System.exit(0);
}
System.out.println("Operation done successfully");
}
}
上述程序编译和执行时,它会产生以下结果:
Opened database successfully
ID = 1
NAME = Paul
AGE = 32
ADDRESS = California
SALARY = 20000.0
ID = 2
NAME = Allen
AGE = 25
ADDRESS = Texas
SALARY = 15000.0
ID = 3
NAME = Teddy
AGE = 23
ADDRESS = Norway
SALARY = 20000.0
ID = 4
NAME = Mark
AGE = 25
ADDRESS = Rich-Mond
SALARY = 65000.0
Operation done successfully
8.5 UPDATE 操作
下面的 Java 代码显示了如何使用 UPDATE 语句来更新任何记录,然后从 COMPANY 表中获取并显示更新的记录:
import java.sql.*;
public class SQLiteJDBC
{
public static void main( String args[] )
{
Connection c = null;
Statement stmt = null;
try {
Class.forName("org.sqlite.JDBC");
c = DriverManager.getConnection("jdbc:sqlite:test.db");
c.setAutoCommit(false);
System.out.println("Opened database successfully");
stmt = c.createStatement();
String sql = "UPDATE COMPANY set SALARY = 25000.00 where ID=1;";
stmt.executeUpdate(sql);
c.commit();
ResultSet rs = stmt.executeQuery( "SELECT * FROM COMPANY;" );
while ( rs.next() ) {
int id = rs.getInt("id");
String name = rs.getString("name");
int age = rs.getInt("age");
String address = rs.getString("address");
float salary = rs.getFloat("salary");
System.out.println( "ID = " + id );
System.out.println( "NAME = " + name );
System.out.println( "AGE = " + age );
System.out.println( "ADDRESS = " + address );
System.out.println( "SALARY = " + salary );
System.out.println();
}
rs.close();
stmt.close();
c.close();
} catch ( Exception e ) {
System.err.println( e.getClass().getName() + ": " + e.getMessage() );
System.exit(0);
}
System.out.println("Operation done successfully");
}
}
上述程序编译和执行时,它会产生以下结果:
Opened database successfully
ID = 1
NAME = Paul
AGE = 32
ADDRESS = California
SALARY = 25000.0
ID = 2
NAME = Allen
AGE = 25
ADDRESS = Texas
SALARY = 15000.0
ID = 3
NAME = Teddy
AGE = 23
ADDRESS = Norway
SALARY = 20000.0
ID = 4
NAME = Mark
AGE = 25
ADDRESS = Rich-Mond
SALARY = 65000.0
Operation done successfully
8.6 DELETE 操作
下面的 Java 代码显示了如何使用 DELETE 语句删除任何记录,然后从 COMPANY 表中获取并显示剩余的记录:
import java.sql.*;
public class SQLiteJDBC
{
public static void main( String args[] )
{
Connection c = null;
Statement stmt = null;
try {
Class.forName("org.sqlite.JDBC");
c = DriverManager.getConnection("jdbc:sqlite:test.db");
c.setAutoCommit(false);
System.out.println("Opened database successfully");
stmt = c.createStatement();
String sql = "DELETE from COMPANY where ID=2;";
stmt.executeUpdate(sql);
c.commit();
ResultSet rs = stmt.executeQuery( "SELECT * FROM COMPANY;" );
while ( rs.next() ) {
int id = rs.getInt("id");
String name = rs.getString("name");
int age = rs.getInt("age");
String address = rs.getString("address");
float salary = rs.getFloat("salary");
System.out.println( "ID = " + id );
System.out.println( "NAME = " + name );
System.out.println( "AGE = " + age );
System.out.println( "ADDRESS = " + address );
System.out.println( "SALARY = " + salary );
System.out.println();
}
rs.close();
stmt.close();
c.close();
} catch ( Exception e ) {
System.err.println( e.getClass().getName() + ": " + e.getMessage() );
System.exit(0);
}
System.out.println("Operation done successfully");
}
}
上述程序编译和执行时,它会产生以下结果:
Opened database successfully
ID = 1
NAME = Paul
AGE = 32
ADDRESS = California
SALARY = 25000.0
ID = 3
NAME = Teddy
AGE = 23
ADDRESS = Norway
SALARY = 20000.0
ID = 4
NAME = Mark
AGE = 25
ADDRESS = Rich-Mond
SALARY = 65000.0
Operation done successfully
Open Source Obfuscators
ProGuard
http://java-source.net/open-source/obfuscators/proguardProGuard is a free Java class file shrinker and obfuscator. It can detect and remove unused classes, fields, m
Maven简介
是什么?
Is a software project management and comprehension tool.项目管理工具
是基于POM概念(工程对象模型)
[设计重复、编码重复、文档重复、构建重复,maven最大化消除了构建的重复]
[与XP:简单、交流与反馈;测试驱动开发、十分钟构建、持续集成、富有信息的工作区]
功能:
wget http://download.redis.io/redis-stable.tar.gz
tar xvzf redis-stable.tar.gz
cd redis-stable
make
前面3步应该没有问题,主要的问题是执行make的时候,出现了异常。
异常一:
make[2]: cc: Command not found
异常原因:没有安装g
nimbus结点配置(storm.yaml)信息:
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements. See the NOTICE file
# distributed with this work for additional inf