1. 我們先看一種最普通的情況 model和Controller都是單例

@Component
public class Order {
    private String orderNum = "12";

    public String getOrderNum() {
        return orderNum;
    }

    public void setOrderNum(String orderNum) {
        this.orderNum = orderNum;
    }

    @Override
    public String toString() {
        return "Order{" +
                "orderNum='" + orderNum + '\'' +
                '}';
    }
}

@Controller
@RequestMapping(value = "/api")
public class MainController {
    @Autowired
    private Order order;
    private String name;

    @RequestMapping(value = "/users/{username}",method = RequestMethod.GET)
    @ResponseBody
    public String userProfile(@PathVariable("username") String username) {
        name = username;
        order.setOrderNum( name);

        try {
            for(int i = 0; i < 100; i++) {
                System.out.println(Thread.currentThread().getId() + "name:" + name + "--order:" + order.getOrderNum());
                Thread.sleep(2000);
            }
        } catch (Exception e) {
        }
        return order.toString();
    }
}

我們分別發(fā)送兩個(gè)請(qǐng)求

http://localhost:8080/api/users/aaa
http://localhost:8080/api/users/bbb

29name:aaa--order:aaa
29name:aaa--order:aaa
29name:aaa--order:aaa
31name:bbb--order:bbb
29name:bbb--order:bbb
31name:bbb--order:bbb

可以看到當(dāng)?shù)诙€(gè)請(qǐng)求發(fā)送后，29線程里的name和order都發(fā)生了改變，因?yàn)楫?dāng)前的Order和Controller都是單例

2. 情況二 model是單例 Controller不是單例

@Component
public class Order {
    private String orderNum = "12";

    public String getOrderNum() {
        return orderNum;
    }

    public void setOrderNum(String orderNum) {
        this.orderNum = orderNum;
    }

    @Override
    public String toString() {
        return "Order{" +
                "orderNum='" + orderNum + '\'' +
                '}';
    }
}

@Controller
@RequestMapping(value = "/api")
@Scope("prototype")
public class MainController {
    @Autowired
    private Order order;
    private String name;

    @RequestMapping(value = "/users/{username}",method = RequestMethod.GET)
    @ResponseBody
    public String userProfile(@PathVariable("username") String username) {
        name = username;
        order.setOrderNum( name);

        try {
            for(int i = 0; i < 100; i++) {
                System.out.println(Thread.currentThread().getId() + "name:" + name + "--order:" + order.getOrderNum());
                Thread.sleep(2000);
            }
        } catch (Exception e) {
        }
        return order.toString();
    }
}

28name:aaa--order:aaa
28name:aaa--order:aaa
29name:bbb--order:bbb
28name:aaa--order:bbb
29name:bbb--order:bbb
28name:aaa--order:bbb

可以看到第二個(gè)請(qǐng)求發(fā)送后，28線程中的name還是aaa沒(méi)有發(fā)生變化，而order受到了影響，發(fā)生了變化，因?yàn)镃ontroller是一個(gè)新的，所以name也是一個(gè)新的變量，但是order是單例的

3.情況三 model不是單例 Controller是單例

@Component
@Scope("prototype")
public class Order {
    private String orderNum = "12";

    public String getOrderNum() {
        return orderNum;
    }

    public void setOrderNum(String orderNum) {
        this.orderNum = orderNum;
    }

    @Override
    public String toString() {
        return "Order{" +
                "orderNum='" + orderNum + '\'' +
                '}';
    }
}

@Controller
@RequestMapping(value = "/api")
public class MainController {
    @Autowired
    private Order order;
    private String name;

    @RequestMapping(value = "/users/{username}",method = RequestMethod.GET)
    @ResponseBody
    public String userProfile(@PathVariable("username") String username) {
        name = username;
        order.setOrderNum( name);

        try {
            for(int i = 0; i < 100; i++) {
                System.out.println(Thread.currentThread().getId() + "name:" + name + "--order:" + order.getOrderNum());
                Thread.sleep(2000);
            }
        } catch (Exception e) {
        }
        return order.toString();
    }
}

29name:aaa--order:aaa
29name:aaa--order:aaa
30name:bbb--order:bbb
29name:bbb--order:bbb
30name:bbb--order:bbb

可以看到name和order都變了，可見(jiàn)只設(shè)置Model是沒(méi)有用的

4.情況四 Controller和Model都設(shè)置不是單例

@Component
@Scope("prototype")
public class Order {
    private String orderNum = "12";

    public String getOrderNum() {
        return orderNum;
    }

    public void setOrderNum(String orderNum) {
        this.orderNum = orderNum;
    }

    @Override
    public String toString() {
        return "Order{" +
                "orderNum='" + orderNum + '\'' +
                '}';
    }
}

@Controller
@RequestMapping(value = "/api")
@Scope("prototype")
public class MainController {
    @Autowired
    private Order order;
    private String name;

    @RequestMapping(value = "/users/{username}",method = RequestMethod.GET)
    @ResponseBody
    public String userProfile(@PathVariable("username") String username) {
        name = username;
        order.setOrderNum( name);

        try {
            for(int i = 0; i < 100; i++) {
                System.out.println(Thread.currentThread().getId() + "name:" + name + "--order:" + order.getOrderNum());
                Thread.sleep(2000);
            }
        } catch (Exception e) {
        }
        return order.toString();
    }
}

28name:aaa--order:aaa
28name:aaa--order:aaa
29name:bbb--order:bbb
28name:aaa--order:aaa
29name:bbb--order:bbb
28name:aaa--order:aaa

這樣29請(qǐng)求的和28請(qǐng)求的就完全分開(kāi)了