后端Spring Boot+前端Android交互+MySQL增删查改
文章目录
- 2020.06.23 更新
- 1 概述
- 2 开发环境
- 3 后端
- 3.1 新建一个Spring Boot项目
- 3.2 实体类
- 3.3 持久层
- 3.4 业务层
- 3.5 控制层
- 4 Android端
- 4.1 增
- 4.2 删
- 4.3 查
- 4.4 改
- 4.5 UI
- 4.6 依赖与其他
- 4.7 网络权限
- 5 测试
- 6 源码
2020.06.23 更新
1 概述
使用spring boot作为后端框架与Android端配合mysql进行基本的交互,包含了最基本的增删查改功能.
2 开发环境
- Win
- IDEA 2019.2
- Tomcat 9.0.27
- MySQL 8.0.17
- Spring Boot 2.2.1
- JDK 8
3 后端
3.1 新建一个Spring Boot项目
参考这里.
3.2 实体类
新建User类作为实体类:
@Entity
public class User {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Integer id;
private String name;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
用的其实是3.1链接中的代码,里面有详细的解释.
3.3 持久层
新建UserRepository实现增删查改:
@Repository
public interface UserRepository extends CrudRepository<User,Integer>
{
@Query(value = "select * from user where name = ?1",nativeQuery = true)
public List<User> findByName(String name);
@Modifying
@Query(value = "delete from user where name = ?1",nativeQuery = true)
public int deleteByName(String name);
}
由于CrudRepository中已经包含了"增"与"改",所以按需要实现自己的"查"与"删"即可.
CrudRepository的api很简单,官方文档在这里.
- "增"使用
save即可,参数为实体类 - "删"使用
deleteById,通过主键删除,若不想通过主键删除可以自己编写sql,像上面一样 - "查"使用
findAll或findById,自定义查找的话需要自己编写SQL - "改"也可使用
save,注意需要设置主键
@Query用于设置SQL语句,nativeQuery表示使用原生SQL.
3.4 业务层
新建一个MainService.java:
@Transactional
@Service
public class MainService {
@Autowired
private UserRepository userRepository;
public Iterable<User> getAllUsers()
{
return userRepository.findAll();
}
public List<User> findByName(String name)
{
return userRepository.findByName(name);
}
public boolean add(String name)
{
User user = new User();
user.setName(name);
userRepository.save(user);
return true;
}
public boolean modify(Integer id,String name)
{
User user = new User();
user.setName(name);
user.setId(id);
userRepository.save(user);
return true;
}
public boolean deleteByName(String name)
{
return userRepository.deleteByName(name) != 0;
}
}
getAllUsers():返回所有行,Iterable类型findByName():根据name返回所有name相同的行add直接使用了save,由于save返回的是实体类,原本的代码是这样写的:
return userRepository.save(user) != null;
但是文档说了不会为null,所以只能强制返回true了.
modify使用了id与name作为参数,新建一个user,将其作为setter的参数,然后交给savedeleteByName使用了自定义的删除函数,返回的是int,在UserRepository中这个int代表SQL影响的行数,删除成功则行数不为0,删除失败,或者没有这行数据则行数为0.因此将返回值与0进行比较
3.5 控制层
@Controller
@RequestMapping(path = "/demo")
public class MainController {
@Autowired
private MainService mainService;
@GetMapping(path = "/getAll")
public @ResponseBody Iterable<User> getAllUsers()
{
return mainService.getAllUsers();
}
@PostMapping(path = "/get")
public @ResponseBody List<User> findByName(String name)
{
return mainService.findByName(name);
}
@PostMapping(path = "/add")
public @ResponseBody boolean add(@RequestParam String name)
{
return mainService.add(name);
}
@PostMapping(path = "/modify")
public @ResponseBody boolean modify(@RequestParam Integer id,@RequestParam String name)
{
return mainService.modify(id,name);
}
@PostMapping(path = "/delete")
public @ResponseBody boolean deleteByName(@RequestParam String name)
{
return mainService.deleteByName(name);
}
}
Controller主要就是几个注解,除了getAllUsers使用Get外,其他的都是用Post.另外就是路径设置,直接在path中设置即可.
后端的话到这里就基本完成了,剩下的打包部署操作就不说了,需要的可以参考这里.
4 Android端
什么新建工程之类的就不说了.
贴上部分MainActivity,完整代码见文末:
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
register.setOnClickListener(v ->{new Thread(()-> {
OkHttpClient okHttpClient = new OkHttpClient();
String name = ((EditText) findViewById(R.id.name)).getText().toString();
FormBody formBody = new FormBody.Builder().add("name", name).build();
Request request = new Request.Builder()
.url(Constant.ADD)
.post(formBody)
.build();
try (Response response = okHttpClient.newCall(request).execute()) {
Looper.prepare();
if (Boolean.parseBoolean(response.body().string()))
{
Toast.makeText(this, "注册成功", Toast.LENGTH_SHORT).show();
}
else
{
Toast.makeText(this, "注册失败", Toast.LENGTH_SHORT).show();
}
Looper.loop();
}
//...
}).start();});
login.setOnClickListener(v ->{new Thread(()-> {
OkHttpClient okHttpClient = new OkHttpClient();
String name = ((EditText) findViewById(R.id.name)).getText().toString();
FormBody formBody = new FormBody.Builder().add("name", name).build();
Request request = new Request.Builder()
.url(Constant.GET)
.post(formBody)
.build();
try (Response response = okHttpClient.newCall(request).execute()) {
List<User> users = JSONArray.parseArray(response.body().string(),User.class);
Looper.prepare();
if(users.size() == 0)
{
Toast.makeText(this,"登录失败",Toast.LENGTH_SHORT).show();
}
else
{
Toast.makeText(this,"登录成功",Toast.LENGTH_SHORT).show();
}
Looper.loop();
}
//...
}).start();});
delete.setOnClickListener(v ->{new Thread(()-> {
OkHttpClient okHttpClient = new OkHttpClient();
String name = ((EditText) findViewById(R.id.name)).getText().toString();
FormBody formBody = new FormBody.Builder().add("name", name).build();
Request request = new Request.Builder()
.url(Constant.DELETE)
.post(formBody)
.build();
try (Response response = okHttpClient.newCall(request).execute()) {
Looper.prepare();
if (Boolean.parseBoolean(response.body().string()))
{
Toast.makeText(this, "删除成功", Toast.LENGTH_SHORT).show();
}
else
{
Toast.makeText(this, "删除失败", Toast.LENGTH_SHORT).show();
}
Looper.loop();
}
//...
}).start();});
modify.setOnClickListener(v ->{new Thread(()-> {
OkHttpClient okHttpClient = new OkHttpClient();
String name = ((EditText) findViewById(R.id.name)).getText().toString();
String id = ((EditText)findViewById(R.id.id)).getText().toString();
FormBody formBody = new FormBody.Builder()
.add("name", name)
.add("id",id)
.build();
Request request = new Request.Builder()
.url(Constant.MODIFY)
.post(formBody)
.build();
try (Response response = okHttpClient.newCall(request).execute()) {
Looper.prepare();
if (Boolean.parseBoolean(response.body().string()))
{
Toast.makeText(this, "修改成功", Toast.LENGTH_SHORT).show();
}
else
{
Toast.makeText(this, "修改失败", Toast.LENGTH_SHORT).show();
}
Looper.loop();
}
//...
}).start();});
}
}
下面分别进行CRUD操作.
4.1 增
OkHttpClient okHttpClient = new OkHttpClient();
String name = ((EditText) findViewById(R.id.name)).getText().toString();
FormBody formBody = new FormBody.Builder().add("name", name).build();
Request request = new Request.Builder()
.url(Constant.ADD)
.post(formBody)
.build();
try (Response response = okHttpClient.newCall(request).execute()) {
Looper.prepare();
if (Boolean.parseBoolean(response.body().string()))
{
Toast.makeText(this, "注册成功", Toast.LENGTH_SHORT).show();
}
else
{
Toast.makeText(this, "注册失败", Toast.LENGTH_SHORT).show();
}
Looper.loop();
} catch (IOException e) {
e.printStackTrace();
}
使用OkHttp,通过FormBody设置参数,然后创建Request通过OkHttpClient发送.
由于后端"增"的方法返回的是一个true,因此这里将response.body().string()转换成boolean判断是否操作成功.
稍微提一下,
Looper.prepare();
Looper.loop();
这两行可以在非UI线程中使用Toast.
4.2 删
OkHttpClient okHttpClient = new OkHttpClient();
String name = ((EditText) findViewById(R.id.name)).getText().toString();
FormBody formBody = new FormBody.Builder().add("name", name).build();
Request request = new Request.Builder()
.url(Constant.DELETE)
.post(formBody)
.build();
try (Response response = okHttpClient.newCall(request).execute()) {
Looper.prepare();
if (Boolean.parseBoolean(response.body().string()))
{
Toast.makeText(this, "删除成功", Toast.LENGTH_SHORT).show();
}
else
{
Toast.makeText(this, "删除失败", Toast.LENGTH_SHORT).show();
}
Looper.loop();
} catch (IOException e) {
e.printStackTrace();
}
删这部分也是差不多的,就是改一下url,然后…然后没有了…好像很简单的样子?2333333
4.3 查
OkHttpClient okHttpClient = new OkHttpClient();
String name = ((EditText) findViewById(R.id.name)).getText().toString();
FormBody formBody = new FormBody.Builder().add("name", name).build();
Request request = new Request.Builder()
.url(Constant.GET)
.post(formBody)
.build();
try (Response response = okHttpClient.newCall(request).execute()) {
List<User> users = JSONArray.parseArray(response.body().string(),User.class);
Looper.prepare();
if(users.size() == 0)
{
Toast.makeText(this,"登录失败",Toast.LENGTH_SHORT).show();
}
else
{
Toast.makeText(this,"登录成功",Toast.LENGTH_SHORT).show();
}
Looper.loop();
} catch (IOException e) {
e.printStackTrace();
}
查这里注意一下后端返回的是List,这里借助阿里的fastjson转换成List.
List<User> users = JSONArray.parseArray(response.body().string(),User.class);
然后判断有没有的话就判断长度是否为0即可.
4.4 改
OkHttpClient okHttpClient = new OkHttpClient();
String name = ((EditText) findViewById(R.id.name)).getText().toString();
String id = ((EditText)findViewById(R.id.id)).getText().toString();
FormBody formBody = new FormBody.Builder()
.add("name", name)
.add("id",id)
.build();
Request request = new Request.Builder()
.url(Constant.MODIFY)
.post(formBody)
.build();
try (Response response = okHttpClient.newCall(request).execute()) {
Looper.prepare();
if (Boolean.parseBoolean(response.body().string()))
{
Toast.makeText(this, "修改成功", Toast.LENGTH_SHORT).show();
}
else
{
Toast.makeText(this, "修改失败", Toast.LENGTH_SHORT).show();
}
Looper.loop();
} catch (IOException e) {
e.printStackTrace();
}
改的话只需一个额外的ID参数,在FormBody中add一个即可,不难.
4.5 UI
UI不详细说了,就几个简单的Button,具体可以看代码中的xml文件.
4.6 依赖与其他
注意一下依赖,还有设置java8.
compileOptions{
sourceCompatibility=1.8
targetCompatibility=1.8
}
dependencies{
implementation 'com.squareup.okhttp3:okhttp:x.x.x'
implementation 'com.alibaba:fastjson:x.x.x'
}
- OkHttp最新版本戳这里查看
- fastjson最新版本戳这里查看
4.7 网络权限
这个笔者之前的文章有说,主要就是AndroidManifest.xml中的权限设置,请看这里.
5 测试
原始数据库:
注册一个:
看看数据库:
测试登录:
试试登录一个不存在的:
修改:
最后是删除:
删除一个不存在的会删除失败.
6 源码
- Github
- 码云
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