spring JdbcTemplate 的若干问题
来源:互联网 发布:爱青岛网络公开课 编辑:程序博客网 时间:2024/04/30 03:23
spring的javadoc上讲getObject(String, Object[], Class) will return NULL if the result of the query is NUL
这里有0行和nullresult的区别
0行: select salary from user where 1 = 2
null result: select max(salary) from user where 1 = 2 返回就是null
0行一定抛出IncorrectResultSizeDataAccessException异常
原因如下
ResultSetMetaData rsmd = rs.getMetaData();
int nrOfColumns = rsmd.getColumnCount();这里返回ResultSet的列数
if (nrOfColumns != 1) {
throw new IncorrectResultSizeDataAccessException(
"Expected single column but found " + nrOfColumns, 1, nrOfColumns);
}
0行,多于1行,就抛异常了
最好还是用QueryForList,返回的list的size为0,就是0行
还有oracle 10g的问题,jdbc驱动版本10.1.0.20
getObject返回一个日期类型为java.util.Date
但是这个日期只有年-月-日,没有时-分-秒,因为10g对于DATE类型的列,
getObject().getClass().getName()得到 java.sql.Date
System.out.println(rs.getObject("date_created") + " " + rs.getObject("date_created").getClass());
得到 2005-10-06 class java.sql.Date
要得到全部日期,必须使用oracle.sql.TIMESTAMP
但是使用queryForObject("sql", Timestamp.class)
得到org.springframework.dao.TypeMismatchDataAccessException异常
java.sql.Timestamp] and could not be converted to required type [java.sql.Timestamp] 很是莫名其妙
只好使用java -Doracle.jdbc.V8Compatibility="true" MyApp解决
以下是对JdbcTemplate 常规用法总结:
- jdbcTemplate.execute("CREATE TABLE USER (user_id integer, name varchar(100))");
- 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。
- 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() + "')");
jdbcTemplate.update("INSERT INTO USER VALUES('" + user.getId() + "', '" + user.getName() + "', '" + user.getSex() + "', '" + user.getAge() + "')");
3、带参数的更新
- 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});
jdbcTemplate.update("UPDATE USER SET name = ? WHERE user_id = ?", new Object[] {name, id});
- 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()});
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
- int count = jdbcTemplate.queryForInt("SELECT COUNT(*) FROM USER");
- int count = jdbcTemplate.queryForInt("SELECT COUNT(*) FROM USER");
int count = jdbcTemplate.queryForInt("SELECT COUNT(*) FROM USER");
- 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);
String name = (String) jdbcTemplate.queryForObject("SELECT name FROM USER WHERE user_id = ?", new Object[] {id}, java.lang.String.class);
- List rows = jdbcTemplate.queryForList("SELECT * FROM USER");
- List rows = jdbcTemplate.queryForList("SELECT * FROM USER");
List rows = jdbcTemplate.queryForList("SELECT * FROM USER");
- 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");
- }
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
- 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);
- }
- });
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 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"));
- }
- });
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")); } });
- 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()));
- }
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
- 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);
- }
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
- public PreparedStatement createPreparedStatement(Connection con) throws SQLException {
- return con.prepareStatement(sql);
- }
- 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)
- template.update("insert into web_person values(?,?,?)",Object[]);
- template.update("insert into web_person values(?,?,?)",Object[]);
template.update("insert into web_person values(?,?,?)",Object[]);
或
- 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);
- });
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
- public void setValues(PreparedStatement ps) throws SQLException {
- ps.setInt(index++,3);
- }
- 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
- 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);
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
- template.query("select * from web_person where id=?",Object[],new RowCallbackHandler(){
- public void processRow(ResultSet rs) throws SQLException {
- person.setId(rs.getInt("id"));
- });
- template.query("select * from web_person where id=?",Object[],new RowCallbackHandler(){
- public void processRow(ResultSet rs) throws SQLException {
- person.setId(rs.getInt("id"));
- });
- spring JdbcTemplate 的若干问题
- spring JdbcTemplate 的若干问题
- Spring的JDBCTemplate
- Spring的jdbcTemplate使用
- spring jdbcTemplate的使用说明
- Spring的JDBCTemplate
- spring jdbcTemplate的问题
- spring 的JDBCtemplate试用
- Spring的JDBCTemplate详解
- Spring的JDBCTemplate
- Spring的JDBCTemplate
- Spring的JDBCTemplate
- Spring的JDBCTemplate
- Spring的JDBCTemplate
- Spring的jdbcTemplate使用
- Spring的JDBCTemplate
- Spring的JDBCTemplate
- Spring的JDBCTemplate
- c++单例模式
- 如何得到包含隐藏API的Android类库
- Ubuntu 12.10安装与配置
- Jetty源码笔记
- 图的十字链表
- spring JdbcTemplate 的若干问题
- js对时间操作
- sscanf使用经验分享
- JAVASE基础部分之二---------常量与变量、运算符、程序流程控制
- Android APK反编译详解(附图)
- JAVA读取Oracle中的blob图片字段并显示
- spring ioc原理
- Leetcode 108 Convert Sorted Array to Binary Search Tree
- Java 加密解密之对称加密算法PBE