使用 JDBC 核心类控制基本的 JDBC 处理和错误处理

// some JDBC-backed DAO class...
private NamedParameterJdbcTemplate namedParameterJdbcTemplate;

public void setDataSource(DataSource dataSource) {
	this.namedParameterJdbcTemplate = new NamedParameterJdbcTemplate(dataSource);
}

public int countOfActorsByFirstName(String firstName) {
	String sql = "select count(*) from t_actor where first_name = :first_name";
	SqlParameterSource namedParameters = new MapSqlParameterSource("first_name", firstName);
	return this.namedParameterJdbcTemplate.queryForObject(sql, namedParameters, Integer.class);
}

// some JDBC-backed DAO class...
private NamedParameterJdbcTemplate namedParameterJdbcTemplate;

public void setDataSource(DataSource dataSource) {
	this.namedParameterJdbcTemplate = new NamedParameterJdbcTemplate(dataSource);
}

public int countOfActorsByFirstName(String firstName) {
	String sql = "select count(*) from t_actor where first_name = :first_name";
	Map<String, String> namedParameters = Collections.singletonMap("first_name", firstName);
	return this.namedParameterJdbcTemplate.queryForObject(sql, namedParameters, Integer.class);
}

public class Actor {

	private Long id;
	private String firstName;
	private String lastName;

	public String getFirstName() {
		return this.firstName;
	}

	public String getLastName() {
		return this.lastName;
	}

	public Long getId() {
		return this.id;
	}

	// setters omitted...
}

// some JDBC-backed DAO class...
private NamedParameterJdbcTemplate namedParameterJdbcTemplate;

public void setDataSource(DataSource dataSource) {
	this.namedParameterJdbcTemplate = new NamedParameterJdbcTemplate(dataSource);
}

public int countOfActors(Actor exampleActor) {
	// notice how the named parameters match the properties of the above 'Actor' class
	String sql = "select count(*) from t_actor where first_name = :firstName and last_name = :lastName";
	SqlParameterSource namedParameters = new BeanPropertySqlParameterSource(exampleActor);
	return this.namedParameterJdbcTemplate.queryForObject(sql, namedParameters, Integer.class);
}

public class CustomSQLErrorCodesTranslator extends SQLErrorCodeSQLExceptionTranslator {

	protected DataAccessException customTranslate(String task, String sql, SQLException sqlEx) {
		if (sqlEx.getErrorCode() == -12345) {
			return new DeadlockLoserDataAccessException(task, sqlEx);
		}
		return null;
	}
}

private JdbcTemplate jdbcTemplate;

public void setDataSource(DataSource dataSource) {
	// create a JdbcTemplate and set data source
	this.jdbcTemplate = new JdbcTemplate();
	this.jdbcTemplate.setDataSource(dataSource);

	// create a custom translator and set the DataSource for the default translation lookup
	CustomSQLErrorCodesTranslator tr = new CustomSQLErrorCodesTranslator();
	tr.setDataSource(dataSource);
	this.jdbcTemplate.setExceptionTranslator(tr);
}

public void updateShippingCharge(long orderId, long pct) {
	// use the prepared JdbcTemplate for this update
	this.jdbcTemplate.update("update orders" +
		" set shipping_charge = shipping_charge * ? / 100" +
		" where id = ?", pct, orderId);
}

import javax.sql.DataSource;
import org.springframework.jdbc.core.JdbcTemplate;

public class ExecuteAStatement {

	private JdbcTemplate jdbcTemplate;

	public void setDataSource(DataSource dataSource) {
		this.jdbcTemplate = new JdbcTemplate(dataSource);
	}

	public void doExecute() {
		this.jdbcTemplate.execute("create table mytable (id integer, name varchar(100))");
	}
}

import javax.sql.DataSource;
import org.springframework.jdbc.core.JdbcTemplate;

public class RunAQuery {

	private JdbcTemplate jdbcTemplate;

	public void setDataSource(DataSource dataSource) {
		this.jdbcTemplate = new JdbcTemplate(dataSource);
	}

	public int getCount() {
		return this.jdbcTemplate.queryForObject("select count(*) from mytable", Integer.class);
	}

	public String getName() {
		return this.jdbcTemplate.queryForObject("select name from mytable", String.class);
	}
}

private JdbcTemplate jdbcTemplate;

public void setDataSource(DataSource dataSource) {
	this.jdbcTemplate = new JdbcTemplate(dataSource);
}

public List<Map<String, Object>> getList() {
	return this.jdbcTemplate.queryForList("select * from mytable");
}

import javax.sql.DataSource;
import org.springframework.jdbc.core.JdbcTemplate;

public class ExecuteAnUpdate {

	private JdbcTemplate jdbcTemplate;

	public void setDataSource(DataSource dataSource) {
		this.jdbcTemplate = new JdbcTemplate(dataSource);
	}

	public void setName(int id, String name) {
		this.jdbcTemplate.update("update mytable set name = ? where id = ?", name, id);
	}
}

final String INSERT_SQL = "insert into my_test (name) values(?)";
final String name = "Rob";

KeyHolder keyHolder = new GeneratedKeyHolder();
jdbcTemplate.update(connection -> {
	PreparedStatement ps = connection.prepareStatement(INSERT_SQL, new String[] { "id" });
	ps.setString(1, name);
	return ps;
}, keyHolder);

// keyHolder.getKey() now contains the generated key