Spring中JdbcTemplate小结

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))");

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() + "')");

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});

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()});

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");

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);

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");

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");
}

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);
}
});

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





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

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

Java代码





class UserRowMapper implements RowMapper {
public Object mapRow(ResultSet rs, int index) throws SQLException {
User user = new User();

user.setId(rs.getString("user_id"));
user.setName(rs.getString("name"));
user.setSex(rs.getString("sex").charAt(0));
user.setAge(rs.getInt("age"));

return user;
}
}

public List findAllByRowMapperResultReader() {
String sql = "SELECT * FROM USER";
return jdbcTemplate.query(sql, new RowMapperResultReader(new UserRowMapper()));
}

class UserRowMapper implements RowMapper {     public Object mapRow(ResultSet rs, int index) throws SQLException {         User user = new User();          user.setId(rs.getString("user_id"));         user.setName(rs.getString("name"));         user.setSex(rs.getString("sex").charAt(0));         user.setAge(rs.getInt("age"));          return user;     } }  public List findAllByRowMapperResultReader() {     String sql = "SELECT * FROM USER";     return jdbcTemplate.query(sql, new RowMapperResultReader(new UserRowMapper())); }

在getUser(id)里面使用UserRowMapper
Java代码





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

return (User) list.get(0);
}

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

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);
}

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[]);

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

public void setValues(PreparedStatement ps) throws SQLException {
ps.setInt(index++,3);
});

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    public void setValues(PreparedStatement ps) throws SQLException {    ps.setInt(index++,3);  });

org.springframework.jdbc.core.PreparedStatementSetter 接口 处理预编译SQL
Java代码





public void setValues(PreparedStatement ps) throws SQLException {
ps.setInt(index++,3);
}

public void setValues(PreparedStatement ps) throws SQLException {   ps.setInt(index++,3);  }

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





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

public Object mapRow(ResultSet rs, int arg1) throws SQLException {   int表当前行数    person.setId(rs.getInt("id"));  }  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





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