sqlupdate.java

一个关于Spring框架的示例应用程序,简单使用,可以参考.

/*
 * Copyright 2002-2004 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.jdbc.object;

import javax.sql.DataSource;

import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.JdbcUpdateAffectedIncorrectNumberOfRowsException;
import org.springframework.jdbc.support.KeyHolder;

/**
 * RdbmsOperation subclass representing a SQL update.
 * Like a query, an update object is reusable. Like all RdbmsOperation
 * objects, an update can have parameters and is defined in SQL.
 *
 * <p>This class provides a number of update() methods analogous to the
 * execute() methods of query objects.
 *
 * <p>This class is concrete. Although it can be subclassed (for example
 * to add a custom update method) it can easily be parameterized by setting
 * SQL and declaring parameters.
 *
 * @author Rod Johnson
 * @author Isabelle Muszynski
 * @author Thomas Risberg
 */
public class SqlUpdate extends SqlOperation {

	/**
	 * Maximum number of rows the update may affect. If more are
	 * affected, an exception will be thrown. Ignored if 0.
	 */
	private int maxRowsAffected = 0;

	/**
	 * An exact number of rows that must be affected.
	 * Ignored if 0.
	 */
	private int requiredRowsAffected = 0;


	/**
	 * Constructor to allow use as a JavaBean. DataSource and SQL
	 * must be supplied before compilation and use.
	 * @see #setDataSource
	 * @see #setSql
	 */
	public SqlUpdate() {
	}

	/**
	 * Constructs an update object with a given DataSource and SQL.
	 * @param ds DataSource to use to obtain connections
	 * @param sql SQL statement to execute
	 */
	public SqlUpdate(DataSource ds, String sql) {
		setDataSource(ds);
		setSql(sql);
	}

	/**
	 * Construct an update object with a given DataSource, SQL
	 * and anonymous parameters.
	 * @param ds DataSource to use to obtain connections
	 * @param sql SQL statement to execute
	 * @param types anonymous parameter declarations
	 */
	public SqlUpdate(DataSource ds, String sql, int[] types) {
		setDataSource(ds);
		setSql(sql);
		setTypes(types);
	}

	/**
	 * Construct an update object with a given DataSource, SQL,
	 * anonymous parameters and specifying the maximum number of rows
	 * that may be affected.
	 * @param ds DataSource to use to obtain connections
	 * @param sql SQL statement to execute
	 * @param types anonymous parameter declarations.
	 * @param maxRowsAffected the maximum number of rows that may
	 * be affected by the update
	 */
	public SqlUpdate(DataSource ds, String sql, int[] types, int maxRowsAffected) {
		setDataSource(ds);
		setSql(sql);
		setTypes(types);
		this.maxRowsAffected = maxRowsAffected;
	}


	/**
	 * Set the maximum number of rows that may be affected by this update.
	 * The default value is 0, which does not limit the number of rows affected.
	 * @param maxRowsAffected the maximum number of rows that can be affected by
	 * this update without this class's update method considering it an error
	 */
	public void setMaxRowsAffected(int maxRowsAffected) {
		this.maxRowsAffected = maxRowsAffected;
	}

	/**
	 * Set the <i>exact</i> number of rows that must be affected by this update.
	 * The default value is 0, which allows any number of rows to be affected.
	 * <p>This is an alternative to setting the <i>maximum</i> number of rows
	 * that may be affected.
	 * @param requiredRowsAffected the exact number of rows that must be affected
	 * by this update without this class's update method considering it an error
	 */
	public void setRequiredRowsAffected(int requiredRowsAffected) {
		this.requiredRowsAffected = requiredRowsAffected;
	}

	/**
	 * Check the given number of affected rows against the
	 * specified maximum number or required number.
	 * @param rowsAffected the number of affected rows
	 * @throws JdbcUpdateAffectedIncorrectNumberOfRowsException
	 * if the actually affected rows are out of bounds
	 * @see #setMaxRowsAffected
	 * @see #setRequiredRowsAffected
	 */
	protected void checkRowsAffected(int rowsAffected) throws JdbcUpdateAffectedIncorrectNumberOfRowsException {
		if (this.maxRowsAffected > 0 && rowsAffected > this.maxRowsAffected) {
			throw new JdbcUpdateAffectedIncorrectNumberOfRowsException(getSql(), this.maxRowsAffected, rowsAffected);
		}
		if (this.requiredRowsAffected > 0 && rowsAffected != this.requiredRowsAffected) {
			throw new JdbcUpdateAffectedIncorrectNumberOfRowsException(getSql(), this.requiredRowsAffected, rowsAffected);
		}
	}

	/**
	 * Generic method to execute the update given arguments.
	 * All other update methods invoke this method.
	 * @param args array of object arguments
	 * @return the number of rows affected by the update
	 */
	public int update(Object[] args) throws DataAccessException {
		validateParameters(args);
		int rowsAffected = getJdbcTemplate().update(newPreparedStatementCreator(args));
		checkRowsAffected(rowsAffected);
		return rowsAffected;
	}

	/**
	 * Method to execute the update given arguments and 
	 * retrieve the generated keys using a KeyHolder.
	 * @param args array of object arguments
	 * @param generatedKeyHolder KeyHolder that will hold the generated keys
	 * @return the number of rows affected by the update
	 */
	public int update(Object[] args, KeyHolder generatedKeyHolder) throws DataAccessException {
		validateParameters(args);
		int rowsAffected = getJdbcTemplate().update(newPreparedStatementCreator(args), generatedKeyHolder);
		checkRowsAffected(rowsAffected);
		return rowsAffected;
	}

	/**
	 * Convenience method to execute an update with no parameters.
	 */
	public int update() throws DataAccessException {
		return update((Object[]) null);
	}

	/**
	 * Convenient method to execute an update given one int arg.
	 */
	public int update(int p1) throws DataAccessException {
		return update(new Object[] {new Integer(p1)});
	}

	/**
	 * Convenient method to execute an update given two int args.
	 */
	public int update(int p1, int p2) throws DataAccessException {
		return update(new Object[] {new Integer(p1), new Integer(p2)});
	}

	/**
	 * Convenient method to execute an update given one long arg.
	 */
	public int update(long p1) throws DataAccessException {
		return update(new Object[] {new Long(p1)});
	}

	/**
	 * Convenient method to execute an update given two long args.
	 */
	public int update(long p1, long p2) throws DataAccessException {
		return update(new Object[] {new Long(p1), new Long(p2)});
	}

	/**
	 * Convenient method to execute an update given one String arg.
	 */
	public int update(String p) throws DataAccessException {
		return update(new Object[] {p});
	}

	/**
	 * Convenient method to execute an update given two String args.
	 */
	public int update(String p1, String p2) throws DataAccessException {
		return update(new Object[] {p1, p2});
	}

}