Spring in Action 笔记(II) part I
Spring in Action 笔记 (II)
今天来看看使用JDBC来操作数据： 使用的是Derby（JavaDB）数据库，关于JavaDB的介绍请点击这里： http://blog.matrix.org.cn/page/icess?catname=%2FJavaDB 。 下面建立一个DatabaseUtils.java的工具类，来操作数据库 。该类在上面的连接的文章中有讲述。
package test.jdbc;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
import java.util.logging.Logger;
public class DatabaseUtils {
private static final String DB_PROPERTIES_FILE = "jdbc.properties" ;
private static final String DB_OPPOSITE_LOCATION = "/.test" ;
static Logger logger = Logger.getLogger(DatabaseUtils. class .getName());
private Connection dbConnection;
private Properties dbProperties;
private boolean isConnected;
// database name
private String dbName;
private static final String strCreateTestClobTeble = "CREATE TABLE APP.test (id INT, name VARCHAR(30),text CLOB(64 K))" ;
private static final String strInsertIntoTestTeble = "INSERT INTO APP.test (id, name) VALUES (?, ?)" ;
public static final String strGetTest = "SELECT * FROM APP.test WHERE ID = ?" ;
private static final String strCreateCourseTable = "create table APP.Course ("
+ " ID INTEGER NOT NULL PRIMARY KEY GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1),"
+ " name VARCHAR(30), "
+ " description VARCHAR(30), "
+ " startDate DATE, " + " endDate DATE " + ")" ;
private static final String strCreateStudentTable = "create table APP.ADDRESS ("
+ " ID INTEGER NOT NULL PRIMARY KEY GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1),"
+ " LASTNAME VARCHAR(30), "
+ " FIRSTNAME VARCHAR(30), "
+ " MIDDLENAME VARCHAR(30), "
+ " PHONE VARCHAR(20), "
+ " EMAIL VARCHAR(30), "
+ " ADDRESS1 VARCHAR(30), "
+ " ADDRESS2 VARCHAR(30), "
+ " CITY VARCHAR(30), "
+ " STATE VARCHAR(30), " + ")" ;
public DatabaseUtils() {
this ( "test" );
}
public DatabaseUtils(String dbName) {
this .dbName = dbName;
setDBSystemDir();
dbProperties = loadDBProperties();
String driverName = dbProperties.getProperty( "db.driver" );
loadDatabaseDriver(driverName);
if (!dbExists()) {
createDatabase();
}
}
private Properties loadDBProperties() {
InputStream dbPropInputStream = null ;
dbPropInputStream = DatabaseUtils. class
.getResourceAsStream(DB_PROPERTIES_FILE);
dbProperties = new Properties();
try {
dbProperties.load(dbPropInputStream);
} catch (IOException e) {
e.printStackTrace();
}
return dbProperties;
}
private void setDBSystemDir() {
String userDir = System.getProperty( "user.dir" , "." );
String systemDir = userDir + DB_OPPOSITE_LOCATION;
System.setProperty( "derby.system.home" , systemDir);
// create the db System dir
File fileSystemDir = new File(systemDir);
fileSystemDir.mkdir();
}
private void loadDatabaseDriver(String driverName) {
try {
Class.forName(driverName);
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
private boolean dbExists() {
boolean bExists = false ;
String dbLocation = getDatabaseLocation();
File dbFileDir = new File(dbLocation);
if (dbFileDir.exists()) {
bExists = true ;
}
return bExists;
}
private boolean createDatabase() {
boolean bCreated = false ;
Connection dbConnection = null ;
String dbUrl = getDatabaseUrl();
dbProperties.put( "create" , "true" );
try {
dbConnection = DriverManager.getConnection(dbUrl, dbProperties);
bCreated = createTables(dbConnection, strCreateTestClobTeble);
} catch (SQLException e) {
e.printStackTrace();
}
dbProperties.remove( "create" );
return bCreated;
}
private boolean createTables(Connection dbConnection, String creatTableSql) {
boolean bCreatedTables = false ;
Statement statement = null ;
try {
statement = dbConnection.createStatement();
statement.execute(creatTableSql);
bCreatedTables = true ;
} catch (SQLException e) {
e.printStackTrace();
}
return bCreatedTables;
}
public String getDatabaseUrl() {
return dbProperties.getProperty( "db.url" ) + dbName;
}
public String getDatabaseLocation() {
String dbLocation = System.getProperty( "derby.system.home" ) + "/"
+ dbName;
return dbLocation;
}
public boolean connect() {
String dbUrl = getDatabaseUrl();
try {
logger.info( "DBUrl: " + dbUrl);
dbConnection = DriverManager.getConnection(dbUrl, dbProperties);
isConnected = dbConnection != null ;
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
isConnected = false ;
logger.info( "create connection if failed!" );
}
return isConnected;
}
public Connection getConnection() {
return dbConnection;
}
public void disconnect() {
if (isConnected) {
String dbUrl = getDatabaseUrl();
dbProperties.put( "shutdown" , "true" );
try {
System.out.println( "断开数据库连接????????????????" );
DriverManager.getConnection(dbUrl, dbProperties);
System.out.println( "????????????????" );
} catch (SQLException e) {
// e.printStackTrace();
logger.info( "disconnect the connection Successful!" );
}
isConnected = false ;
}
}
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
DatabaseUtils testdb = new DatabaseUtils();
logger.info(testdb.getDatabaseLocation());
logger.info(testdb.getDatabaseUrl());
testdb.connect();
Connection c = testdb.getConnection();
PreparedStatement ps = null ;
try {
ps = c.prepareStatement(DatabaseUtils.strInsertIntoTestTeble, Statement.RETURN_GENERATED_KEYS);
ps.setInt( 1 , 1 );
ps.setString( 2 , "test Icerain" );
int i =ps.executeUpdate();
System.out.println(i);
ps.close();
ps = c.prepareStatement(DatabaseUtils.strGetTest);
ps.setInt( 1 , 1 );
ResultSet rs = ps.executeQuery();
if (rs.next()) {
String name = rs.getString( 2 );
System.out.println(name);
}
ps.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
testdb.disconnect();
}
}
下面是一个插入数据的类 InsertData.java
package test.jdbc;
import java.sql.Types;
import javax.sql.DataSource;
import org.springframework.jdbc.core.SqlParameter;
import org.springframework.jdbc.object.SqlUpdate;
public class InsertData extends SqlUpdate {
// 需要注入一个DataSource...
public InsertData(DataSource ds) {
setDataSource(ds); // TODO 注意 设置数据源
setSql( "INSERT INTO APP.test (id, name) VALUES (?, ?)" );
declareParameter( new SqlParameter(Types.INTEGER));
declareParameter( new SqlParameter(Types.VARCHAR));
compile(); // TODO 注意 , 要编译以后才可以使用
}
// 覆盖insert方法
public int insert(TestData data) {
Object[] params = new Object[] {data.id,data.name};
return update(params); // 执行插入操作....
}
}
很简单, 并带有详细注释.
下面是一个查询的类 QueryDataById.java
package test.jdbc;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;
import javax.sql.DataSource;
import org.springframework.jdbc.core.SqlParameter;
import org.springframework.jdbc.object.MappingSqlQuery;
public class QueryDataById extends MappingSqlQuery{
private static final String sql = "SELECT * FROM APP.test WHERE ID = ?" ;
public QueryDataById(DataSource ds) {
super (ds,sql);
declareParameter( new SqlParameter( "id" ,Types.INTEGER));
compile();
}
// 覆盖mapRow方法
@Override
protected Object mapRow(ResultSet rs, int index) throws SQLException {
// TODO Auto-generated method stub
TestData tdata = new TestData();
tdata.id = rs.getInt( 1 );
tdata.name = rs.getString( 2 );
return tdata;
}
}
也很简单.
注意:
以上两个类都实现了Spring简化Jdbc操作的一些接口, 关于接口的信息请查考文档, 这里不在详细讲述.
下面是一个很简单的测试(数据)实体类.TestData.java
package test.jdbc;
public class TestData {
public int id;
public String name;
public TestData( int id, String name) {
this .id = id;
this .name = name;
}
public TestData() {}
}
下面是一个测试数据源是否注入正确的类:TestDataSource.java
package test.jdbc;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import javax.sql.DataSource;
public class TestDataSource {
private DataSource dataSource;
// 注入数据源
public void setDataSource(DataSource dataSource) {
this .dataSource = dataSource;
}
//测试数据源
public void testDataSource() {
try {
System.out.println( "Test DataSource!!!" );
Connection connection = dataSource.getConnection();
if (connection != null )
System.out.println( "test ok!" );
PreparedStatement ps = null ;
ps = connection.prepareStatement(DatabaseUtils.strGetTest);
ps.setInt( 1 , 1 );
ResultSet rs = ps.executeQuery();
if (rs.next()) {
String name = rs.getString( 2 );
System.out.println( "测试数据源配置:" + name);
}
ps.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
下面是测试Spring提高的Jdbc功能的主要测试类, 测试了一些使用JDBC操作数据的常用功能, 其他没有测试的请查看其Doc,TestJdbcTemplate.java