JdbcTemplate学习笔记

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JdbcTemplate学习笔记

1、使用JdbcTemplate的execute()方法执行SQL语句

Java 代码

jdbcTemplate.execute("CREATE TABLE USER (user_id integer, name varchar(100))");

2、如果是UPDATE或INSERT,可以用update()方法。

Java 代码

jdbcTemplate.update("INSERT INTO USER VALUES('"
+ user.getId() + "', '"
+ user.getName() + "', '"
+ user.getSex() + "', '"
+ user.getAge() + "')");

3、带参数的更新

Java代码

jdbcTemplate.update("UPDATE USER SET name = ? WHERE user_id = ?",new Object[] {name, id});

Java代码

jdbcTemplate.update("INSERT INTO USER VALUES(?, ?, ?, ?)",new Object[] {user.getId(), user.getName(), user.getSex(), user.getAge()});

4、使用JdbcTemplate进行查询时，使用queryForXXX()等方法

Java代码

int count = jdbcTemplate.queryForInt("SELECT COUNT(*) FROM USER");

Java代码

String name = (String) jdbcTemplate.queryForObject("SELECT name FROM USER WHERE user_id = ?",new Object[] {id}, java.lang.String.class);

Java代码

List rows = jdbcTemplate.queryForList("SELECT * FROM USER");

Java代码

List rows = jdbcTemplate.queryForList("SELECT * FROM USER");
Iterator it = rows.iterator();
while(it.hasNext()) {
Map userMap = (Map) it.next();
System.out.print(userMap.get("user_id") +"\t");
System.out.print(userMap.get("name") +"\t");
System.out.print(userMap.get("sex") +"\t");
System.out.println(userMap.get("age") +"\t");
}

JdbcTemplate将我们使用的JDBC的流程封装起来，包括了异常的捕捉、SQL的执行、查询结果的转换等等。spring大量使用Template Method模式来封装固定流程的动作，XXXTemplate等类别都是基于这种方式的实现。

除了大量使用Template Method来封装一些底层的操作细节，spring也大量使用callback方式类回调相关类别的方法以提供JDBC相关类别的功能，使传统的JDBC的使用者也能清楚了解spring所提供的相关封装类别方法的使用。

JDBC的PreparedStatement

Java代码

 final String id = user.getId();    final String name = user.getName();    final String sex = user.getSex() + "";    final int age = user.getAge(); jdbcTemplate.update("INSERT INTO USER VALUES(?, ?, ?, ?)",  new PreparedStatementSetter() {    public void setValues(PreparedStatement ps) throws SQLException {    ps.setString(1, id);  ps.setString(2, name);  ps.setString(3, sex);  ps.setInt(4, age);      } });

Java代码

    1.final User user = new User();          2.jdbcTemplate.query("SELECT * FROM USER WHERE user_id = ?",        3.new Object[] {id},        4.new RowCallbackHandler() {        5.public void processRow(ResultSet rs) throws SQLException {        6.user.setId(rs.getString("user_id"));      7.user.setName(rs.getString("name"));      8.user.setSex(rs.getString("sex").charAt(0));        9.user.setAge(rs.getInt("age"));        10.}      11.});

Java代码

    1.class UserRowMapper implements RowMapper {      2.      3.public Object mapRow(ResultSet rs, int index) throws SQLException {      4.      5.User user = new User();      6.user.setId(rs.getString("user_id"));          7.user.setName(rs.getString("name"));        8.user.setSex(rs.getString("sex").charAt(0));          9.user.setAge(rs.getInt("age"));          10.return user;             11.}             12.}      13.        14.public List findAllByRowMapperResultReader() {           15.      16.String sql = "SELECT * FROM USER";      17.      18.return jdbcTemplate.query(sql, new RowMapperResultReader(new UserRowMapper()));      19.      20.}

在getUser(id)里面使用UserRowMapper

Java代码

    1.public User getUser(final String id) throws DataAccessException {        2.String sql = "SELECT * FROM USER WHERE user_id=?";        3.final Object[] params = new Object[] { id };        4.List list = jdbcTemplate.query(sql, params, new RowMapperResultReader(new UserRowMapper()));          5.return (User) list.get(0);        6.}

网上收集

org.springframework.jdbc.core.PreparedStatementCreator 返回预编译SQL 不能于Object[]一起用

Java代码

public PreparedStatement createPreparedStatement(Connection con)throws SQLException {
return con.prepareStatement(sql);
}

1.增删改

org.springframework.jdbc.core.JdbcTemplate 类(必须指定数据源dataSource)

Java代码

template.update("insert into web_person values(?,?,?)",Object[]);

或

Java代码

template.update("insert into web_person values(?,?,?)",new PreparedStatementSetter(){ //匿名内部类 只能访问外部最终局部变量        2.public void setValues(PreparedStatement ps) throws SQLException {        3.ps.setInt(index++,3);        4.});      5.    6.    1.org.springframework.jdbc.core.PreparedStatementSetter //接口 处理预编译SQL            2.public void setValues(PreparedStatement ps) throws SQLException {        3.ps.setInt(index++,3);        4.}      5.      6.public void setValues(PreparedStatement ps) throws SQLException {        7.ps.setInt(index++,3);        8.}

2.查询JdbcTemplate.query(String,[Object[]/PreparedStatementSetter],RowMapper/RowCallbackHandler)

org.springframework.jdbc.core.RowMapper 记录映射接口处理结果集

Java代码

    1.public Object mapRow(ResultSet rs, int arg1) throws SQLException { //int表当前行数        2.person.setId(rs.getInt("id"));        3.}        4.List template.query("select * from web_person where id=?",Object[],RowMapper);

org.springframework.jdbc.core.RowCallbackHandler 记录回调管理器接口处理结果集

Java代码

    1.template.query("select * from web_person where id=?",Object[],new RowCallbackHandler(){        2.public void processRow(ResultSet rs) throws SQLException {        3.person.setId(rs.getInt("id"));        4.});

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