DBUtils学习一 增删该查
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1 package com.mozq.jdbc.test; 2 3 import java.sql.SQLException; 4 import java.util.List; 5 import java.util.Map; 6 import java.util.Map.Entry; 7 8 import org.apache.commons.dbutils.QueryRunner; 9 import org.apache.commons.dbutils.handlers.BeanHandler; 10 import org.apache.commons.dbutils.handlers.BeanListHandler; 11 import org.apache.commons.dbutils.handlers.BeanMapHandler; 12 import org.apache.commons.dbutils.handlers.ColumnListHandler; 13 import org.apache.commons.dbutils.handlers.MapHandler; 14 import org.apache.commons.dbutils.handlers.MapListHandler; 15 import org.apache.commons.dbutils.handlers.ScalarHandler; 16 import org.junit.Test; 17 18 import com.mozq.domain.User; 19 import com.mozq.jdbc.C3P0Utils; 20 21 public class DBUtilsTest_R { 22 /** 23 * 测试查询用户数量,ScalarHandler处理器，new ScalarHandler<Long>(),注意类型参数只能写Long，不能写Integer 24 */ 25 @Test 26 public void findAll_ScalarHandler() { 27 try { 28 //1.创建核心执行对象 29 QueryRunner queryRunner = new QueryRunner(C3P0Utils.getDataSource()); 30 //2.写sql 31 String sql = "select count(*) from t_user"; 32 //3.准备参数 33 //4.执行sql，进行结果处理 34 Long row = queryRunner.query(sql, new ScalarHandler<Long>()); 35 System.out.println("操作行数：" + row); 36 } catch (SQLException e) { 37 e.printStackTrace(); 38 } 39 } 40 /** 41 * 测试根查询所有用户,MapListHandler处理器，new MapListHandler() 42 */ 43 @Test 44 public void findAll_MapListHandler() { 45 try { 46 //1.创建核心执行对象 47 QueryRunner queryRunner = new QueryRunner(C3P0Utils.getDataSource()); 48 //2.写sql 49 String sql = "select * from t_user"; 50 //3.准备参数 51 //4.执行sql，进行结果处理 52 List<Map<String, Object>> users = queryRunner.query(sql, new MapListHandler()); 53 for(Map<String, Object> user : users) { 54 for(Entry<String, Object> entry : user.entrySet()) { 55 System.out.print(entry.getKey()+":"+entry.getValue()+";"); 56 } 57 System.out.println(); 58 } 59 } catch (SQLException e) { 60 e.printStackTrace(); 61 } 62 } 63 /** 64 * 测试根据id查询单个用户,MapHander处理器，new MapHandler() 65 */ 66 @Test 67 public void findById_MapHandler() { 68 try { 69 //1.创建核心执行对象 70 QueryRunner queryRunner = new QueryRunner(C3P0Utils.getDataSource()); 71 //2.写sql 72 String sql = "select * from t_user where id=?"; 73 //3.准备参数 74 Object[] params = {9}; 75 //4.执行sql，进行结果处理 76 Map<String, Object> user = queryRunner.query(sql, new MapHandler(), params); 77 for (Entry<String, Object> entry : user.entrySet()) { 78 System.out.println(entry.getKey()+ ":" + entry.getValue()); 79 } 80 /* 81 id:9 82 name:刘备 83 password:liu456 84 */ 85 } catch (SQLException e) { 86 e.printStackTrace(); 87 } 88 } 89 /** 90 * 测试查询全部用户名,ColumnList处理器，按列索引处理(需要在查询语句中明确列顺序)和按列名处理 91 */ 92 @Test 93 public void findAllName_ColumnListHandler() { 94 try { 95 //1.创建核心执行对象 96 QueryRunner queryRunner = new QueryRunner(C3P0Utils.getDataSource()); 97 //2.写sql 98 String sql = "select password, name, id from t_user"; 99 //3.准备参数 100 //4.执行sql，进行结果处理 101 List<String> userNames = queryRunner.query(sql, new ColumnListHandler<String>()); 102 for (String userName : userNames) { 103 System.out.println(userName); 104 } 105 List<String> userNames2 = queryRunner.query(sql, new ColumnListHandler<String>("name")); 106 for (String userName : userNames2) { 107 System.out.println(userName); 108 } 109 110 } catch (SQLException e) { 111 e.printStackTrace(); 112 } 113 } 114 /** 115 * 测试查询全部,BeanMap处理器，new BeanMapHandler<Integer, User>(User.class, "id") 116 */ 117 @Test 118 public void findAll_BeanMapHandler() { 119 try { 120 //1.创建核心执行对象 121 QueryRunner queryRunner = new QueryRunner(C3P0Utils.getDataSource()); 122 //2.写sql 123 String sql = "select id, name, password from t_user"; 124 //3.准备参数 125 //4.执行sql，进行结果处理 126 /*用主键列来当键，完全没有问题*/ 127 System.out.println("new BeanMapHandler<Integer, User>(User.class, "id")"); 128 Map<Integer, User> users = queryRunner.query(sql, new BeanMapHandler<Integer, User>(User.class, "id")); 129 for (Entry<Integer, User> it : users.entrySet()) { 130 System.out.println(it.getValue()); 131 } 132 133 /*用可重复的列来当键，会发生记录覆盖*/ 134 System.out.println("new BeanMapHandler<String, User>(User.class, "name")----------"); 135 Map<String, User> users2 = queryRunner.query(sql, new BeanMapHandler<String, User>(User.class, "name")); 136 for (Entry<String, User> it : users2.entrySet()) { 137 System.out.println(it.getValue()); 138 } 139 140 } catch (SQLException e) { 141 e.printStackTrace(); 142 //java.sql.SQLException: Cannot determine value type from string ‘liu123‘ Query: select * from t_user Parameters: [] 143 } 144 } 145 /** 146 * 测试查询全部,BeanList处理器，new BeanListHandler<User>(User.class) 147 */ 148 @Test 149 public void findAll_BeanListHandler() { 150 try { 151 //1.创建核心执行对象 152 QueryRunner queryRunner = new QueryRunner(C3P0Utils.getDataSource()); 153 //2.写sql 154 String sql = "select * from t_user"; 155 //3.准备参数 156 //4.执行sql，进行结果处理 157 List<User> users = queryRunner.query(sql, new BeanListHandler<User>(User.class)); 158 for (User user : users) { 159 System.out.println(user); 160 } 161 } catch (SQLException e) { 162 e.printStackTrace(); 163 } 164 } 165 /** 166 * 测试根据id查询单个,Bean处理器，new BeanHandler<User>(User.class) 167 */ 168 @Test 169 public void findById_BeanHandler() { 170 try { 171 //1.创建核心执行对象 172 QueryRunner queryRunner = new QueryRunner(C3P0Utils.getDataSource()); 173 //2.写sql 174 String sql = "select * from t_user where id=?"; 175 //3.准备参数 176 Object[] params = {9}; 177 //4.执行sql，进行结果处理 178 User user = queryRunner.query(sql, new BeanHandler<User>(User.class), params); 179 System.out.println(user);//User [id=9, name=刘备, password=liu123] 180 } catch (SQLException e) { 181 e.printStackTrace(); 182 } 183 } 184 }
1 package com.mozq.jdbc.test; 2 3 import java.sql.SQLException; 4 5 import org.apache.commons.dbutils.QueryRunner; 6 import org.apache.commons.dbutils.handlers.BeanHandler; 7 import org.junit.Test; 8 9 import com.mozq.domain.User; 10 import com.mozq.jdbc.C3P0Utils; 11 12 /** 13 * 测试DBUtils工具类的增删改操作 14 * @author jie 15 * 16 */ 17 public class DBUtilsTest_CUD { 18 /** 19 * 根据id删除用户 20 */ 21 @Test 22 public void DeleteUserById() { 23 try { 24 // 1.创建核心类 25 QueryRunner queryRunner = new QueryRunner(C3P0Utils.getDataSource()); 26 // 2.写sql 27 String sql = "delete from t_user where id=?"; 28 // 3.准备参数 29 Object[] params = { 8 }; 30 // 4.执行sql，进行结果处理 31 int row = queryRunner.update(sql, params); 32 if (row > 0) { 33 System.out.println("删除成功"); 34 } else { 35 System.out.println("删除失败"); 36 } 37 } catch (SQLException e) { 38 e.printStackTrace(); 39 } 40 } 41 42 /** 43 * 根据id修改用户 44 */ 45 @Test 46 public void UpdateUserById() { 47 try { 48 // 1.创建核心类 49 QueryRunner queryRunner = new QueryRunner(C3P0Utils.getDataSource()); 50 // 2.写sql 51 String sql = "update t_user set password=? where id=?"; 52 // 3.准备参数 53 Object[] params = { "jingdong", 8 }; 54 int row = queryRunner.update(sql, params); 55 if (row > 0) { 56 System.out.println("修改成功"); 57 } else { 58 System.out.println("修改失败"); 59 } 60 } catch (SQLException e) { 61 e.printStackTrace(); 62 } 63 } 64 65 /** 66 * 插入用户方法 67 */ 68 @Test 69 public void addUser() { 70 try { 71 // 1.创建核心类 72 QueryRunner queryRunner = new QueryRunner(C3P0Utils.getDataSource()); 73 // 2.写sql 74 String sql = "insert into t_user(name, password) values(?,?)"; 75 // 3.准备参数 76 Object[] params = { "京东0", "刘强东0" }; 77 int row = queryRunner.update(sql, params); 78 if (row > 0) { 79 System.out.println("插入成功"); 80 } else { 81 System.out.println("插入失败"); 82 } 83 } catch (SQLException e) { 84 e.printStackTrace(); 85 } 86 } 87 88 /** 89 * 测试insert方法，查看返回对象 90 */ 91 @Test 92 public void insert2() { 93 try { 94 QueryRunner queryRunner = new QueryRunner(C3P0Utils.getDataSource()); 95 String sql = "insert into t_user(id, name, password) values(?, ?, ?)"; 96 User userObj = queryRunner.insert(sql, new BeanHandler<User>(User.class), 31, "京东5", "刘强东"); 97 System.out.println(userObj); 98 } catch (SQLException e) { 99 e.printStackTrace(); 100 } 101 } 102 }
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